bluuebunny/crossref_metadata_2025 huggingface dataset:
Reception of Sophocles’ Antigone in the Baltic States
Authors: Lotman Maria-Kristiina , Bodniece Līva , Dikmonienė Jovita
Published: January 2023

This paper analyzes the translations of Antigone by Sophocles and later authors and the performances based on them in the theaters of Estonia, Latvia and Lithuania. It investigates the necessity to translate the Antigone dramas by Sophocles, Jean Anouilh and Janusz Głowacki into national languages and stage them in theaters. The article analyzes how these works are related to the history of the Baltic countries. This paper is divided into three subparts that match the historical periods from the end of the nineteenth century to the beginning of the twenty-first century. The most important performances of Antigone in the Baltic countries are analyzed, highlighting the individual style of each director and their attention to the form and expression of the performances. The main themes revealed by the artists of the Baltic countries are conscious self-sacrifice for one’s neighbor and individual resistance to conformity and tyranny.
Easy way to produce iron-doped titania nanoparticles via the solid-state method and investigation their photocatalytic activity
Authors: Rosa Domenico , D’Agostino Francesca , Bavasso Irene , Bracciale Maria Paola , Di Palma Luca
Published: January 2023

This study focuses on the synthesis of iron-doped TiO2 nanoparticles “via solid-state” method, as an alternative to the more common doping strategies, with different iron content (0.5, 1.0, 1.5, and 2.0 wt%) using commercial titania Degussa P25 and TiO2 synthesized (sTiO2) via microemulsion method. The samples were characterized by SEM, BET, UV–Vis-DRS, and XRD. The photocatalytic activity was evaluated in terms of methylene blue (MB) degradation in aqueous solution under visible radiation (LED lamp 13 W) and under different conditions (pH, catalyst dosage, pollutant initial concentration, irradiance). The tests showed a big difference between sTiO2 and Degussa 25. The sTiO2 with an iron load of 1.0 wt% (1% Fe–TiO2) has been proven to be the best photocatalyst. This behavior is attributed to the Fe3+ species in sTiO2 crystal lattice whose presence decreases the bandgap.

Graphical abstract
The impact of new European policies on the regulation of Spanish public service media: a decisive influence?
Authors: Llorens Carles , Muñoz-Saldaña Mercedes
Published: January 2023

This study analyses the extent to which European legislation and, in particular, the latest regulatory initiatives for audiovisual media and for digital markets and services affect the regulation of public service media (PSM) in Spain. A three-fold analysis is performed using a document review methodology. Firstly, the influence of European competition policies on the origin, development and adaptation of PSM to the digital market is studied. Secondly, the transposition into Spanish law of the 2018 Audiovisual Media Services Directive (EU, 2018) is evaluated. Third and lastly, the impact of the draft European Acts referring to digital platforms on PSM in Spain and the European Union (European Commission, 2020a; 2020b) is analysed, as is that of the European Media Freedom Act (European Commission, 2022). The concept of Europeanisation (Harcourt, 2002) is taken as the basis for the assessment of such impact. The conclusions show that while the European regulatory umbrella is a necessary and influential framework, it is insufficient when it comes to understanding the regulatory and political development of PSM in Spain. The path dependence and circumstances of each country are crucial to understanding the why and how of specific regulation. There is European convergence on economic and competition policy protection issues, but not on political and cultural issues, such as the definition of PSM governance or structure, where the European Union’s influence is much weaker.
Tools for Accounting Digitalization and Analytical Processes of Regional Companies (Exemplified by Consumer Credit Cooperatives)
Authors:   Volgograd State University, Isaeva Iraida , Anikina Irina ,   Volgograd State University
Published: January 2023

The availability of complete and timely accounting information about the facts of the economic life of companies is a prerequisite for their effective work. The relevance of improvement of accounting and analytical work in credit and consumer cooperatives is due to both changes in the legislation, such as the introduction of a unified chart of accounts and updating of industry accounting standards for non-credit financial organizations, and the need to comply with regulatory requirements and optimize risks. An important tool for the modernization of accounting work is its digitalization. Digitalization of accounting makes it possible to increase the objectivity, rationality and speed of making financial and investment corporate decisions by managers, thereby increasing the competitiveness, sustainability and security of business activities. Digitalization of accounting and analytical processes is of particular importance for regional companies, which, on the one hand, operate in conditions of fierce competition with companies at federal and international levels of administration, and on the other hand, are obliged to comply with the requirements of the regulator for accounting and analytical systems. At the same time, regional companies often have limited budgets for the introduction of digital services, which necessitates the effectiveness of justifying the choice of software for accounting and analytical processes of regional companies based on certain criteria. The purpose of the study was to specify the sources of accounting and analytical information and to develop a methodology for financial standards’ calculation, taking into account the specifics of the activities of credit consumer cooperatives and the requirements of the unified chart of accounts. In the paper, the authors showed the possibilities of software use by credit consumer cooperatives for making managerial decisions and presented accounting information necessary for financial standards calculation. The methodological tools presented in the study can be used by companies to increase the sustainability of their activities and optimize risks.
South of Russia: Social and Economic Line of Macroregion (2000–2020s)
Authors:   Federal Research Centre the Southern Scientific Centre of the Russian Academy of Sciences, Suschiy Sergey
Published: January 2023

The article examines the main directions of social and economic dynamics of the southern macroregion of Russia at the beginning of the 21st century. The development of these territories in the 2000–2010 was determined by a complex correlation of the influence of the federal center, managerial practices of regional authorities, activities of local, Russian and international businesses, demographic and socioeconomic processes of various scales (metropolization, interregional migration, depopulation, the flow of the working population into the service sector). Generally, in the last 20–25 years, the southern Russian regional economies demonstrated the stability of their sectoral structure and several main specializations. This allowed the South of Russia to remain as the leading granary of Russia, the epicenter of its tourist and recreational complex, the most important transport and logistics center in the international trade system. In 2000–2010, the development of the near-Caspian hydrocarbon resources became noticeably more active. The dynamic growth of the economy and social sphere of the South of Russia was largely ensured by the active development of the Azov-Black Sea zone, which concentrated a significant share of the human and economic potential of the macroregion. A new period in the social and economic dynamics of the South of Russia begins in the spring of 2022. The stable positions of the macroregion in the Russian agroindustry, the recreational sector and the system of transport communications give us reasons to believe that these economic niches will remain central ones for the South of Russia for the entire foreseeable future. But the scale of ongoing and upcoming changes makes inevitable a fairly significant correction in the southern Russian economic specializations of the second order, the current composition of which will respond to the international and all-Russian market conditions. It is currently not possible to predict the directions and timing of these shifts, since they will depend on the resulting set of factors of different scales that represent variables.
ARDUINO-BASED MAXIMUM POWER POINT TRACKING CHARGE CONTROLLER USING PERTURB & OBSERVE AND CONSTANT-VOLTAGE ALGORITHMS
Authors: Ilori O. A. , Willoughby A. A. , Dairo Oluropo F. , Osinowo M. O. , Ewetumo T.
Published: January 2023

The output power delivered by a photovoltaic (PV) module to charge a battery is dependent on solar radiation incident upon it and the ambient temperature. To reduce PV energy loss, the PV panel is kept at peak efficiency by operating the PV system at the maximum power point (MPP) to deliver maximum power to the battery under charge. In this work, Perturb & Observe (P&O) algorithm was implemented in conjunction with constant voltage (CV), using the MATLAB/Simulink tool. Results obtained from these simulations show that the tracking efficiency of the P&O algorithm decreases with solar irradiation. However, the relatively good performance of the CV algorithm at low irradiation levels augments the P&O method. Both algorithms were implemented in a maximum power point tracking (MPPT) design using an ATMega328 microcontroller operating on a minimal Arduino-compatible integrated development environment (IDE) prototype circuit.
THE EFFECT OF FIBER ORIENTATION AND MULTIPLE PAPERMAKING ON RECONSTRUCTION AND INTERNAL MASS TRANSPORT OF A CARBON PAPER
Authors: Gao Yanan , Liu Xunliang , Wen Zhi , Dou Ruifeng , Zhou Wenning , Jiang Kai 
Published: January 2023

Carbon paper is often used as the current collector and gas diffusion layer in lithium-air batteries and fuel cells, and its internal morphology greatly influences the diffusion of materials. Relevant literature shows that carbon paper is an anisotropic porous medium, and the distribution of carbon fiberrs has a regular pattern. The difference in fiber distribution angle leads to a difference in internal morphology, which affects the transport properties and anisotropy of carbon paper. In this paper, a numerical method that considers fiber placement angle range for reconstructing carbon paper is proposed, and some geometric models of carbon paper are reconstructed. The pore size distribution and transport properties of geometric model are calculated and studied by improved thirteen direction average method and lattice Boltzmann method. The effects of carbon fiber distribution angle and multiple papermaking on the transport properties and anisotropy coefficient of carbon paper are studied. Results with an increase in dφ include an increase in the average effective diffusion coefficient in through-plane direction and a decrease in the anisotropy coefficient and average effective diffusion coefficient in in-plane direction. Double papermaking can improve the average anisotropy coefficient of carbon paper and the average effective diffusion coefficient in in-plane direction and reduce the average effective diffusion coefficient in through-plane direction. However, the influence of papermaking times (layer number > 1) on transport properties of carbon paper is insignificant.
WHY (AND HOW) DO WOMEN ENGINEERS STAY?: A POSITIVE PSYCHOLOGY APPROACH TO UNDERSTANDING THE CAREER SUSTAINABILITY OF WOMEN IN ENGINEERING
Authors: Smith Christine Rutledge
Published: January 2023

Much of the research on the attrition of women in engineering has identified the existence of gender
bias and the disproportionate challenges women engineers face as the primary reasons women leave the profession. While noteworthy, researchers have not focused their investigations on why (and how) women who stay in the field do so. The present study utilized a positive psychology lens to explore factors that have supported career sustainability for women who have remained in the engineering field.
Phenomenological data analysis was used to examine interviews with 14 women in engineering. A
model of career sustainability was developed, which yielded six internal (psychological) and two external
(environmental) factors. Internal factors included navigating sexism, work attitudes and behavior,
stress management, self-concept, work-life-family balance, and interpersonal strategies. External
factors included social supports and workplace characteristics. This career sustainability model is
likely applicable to aspiring youth, students of engineering, early-career engineers, senior practicing
engineers, managers, and organizational leaders of all genders, as the engineers who participated in
the study provided inspiring, creative strategies and reflections about how they have thrived.
Assessing dynamic compression of AA2024-T351 with split Hopkinson pressure bar simulation
Authors: Gupta Manish Kumar
Published: January 2023

To understand the dynamic compressive behaviour of aluminium alloy AA2024-T351, which is commonly used in maritime and offshore structures, is vital. This is generally achieved using Taylor impact tests, projectile tests and split Hopkinson pressure bars (SHPBs). It can also be obtained in a less expensive way by using a finite-element simulation of an SHPB under different conditions. This paper numerically investigates the effects of striker velocity, striker shape and specimen shape on the dynamic compressive behaviour of AA2024-T351 using a simulated SHPB. The material behaviour was found to be sensitive to strain rates, striker shapes and specimen shapes under various situations.
The Pedogenesis of Inceptisols on Southeast Toposequence of Mount Manglayang in West Java, Indonesia
Authors: Herdiansyah Ganjar , Arifin Mahfud , Suriadikusumah Abraham
Published: January 2023

DOI:10.17014/ijog.9.2.195-208The most potential soil order in Indonesia is dominated by Inceptisols, whereas the topography combined with a climatic factor are the main factors to regulate pedogenetic process. This research was intended to determine the pedogenetic process and soil development on various terrain positions at the southeast toposequence of Mount Manglayang areas that have hilly topography. The researched area was 28.83 ha. Based on those conditions, this research aims to study the pedogenetic process and soil development in the southeast slope toposequence of Mount Manglayang, the relationship between the physical, chemical, and mineralogical soil properties, the soil classification to family level based on soil taxonomy, National Soil Classification, and FAO soil classification systems. This research used survey, descriptive, and comparative methods. The result showed that the pedogenetic processes identified were the formation of B horizon through clay accumulation, soil colour, and soil structure development, and the formation of amorphous kaolinite and halloysite minerals. Based on soil taxonomy, the soil were classified as Fluventic Humudepts, coarse-loamy, kaolinitic, isohyperthermic at the upper slope and Fluventic Dystrudepts, fineloamy, kaolinitic, isohyperthermic at the middle and lower slopes. According to National Soil Classification, the soil is Humic Cambisol at the upper slope, Distric Cambisol at the middle slope, and Cromic Cambisol at the lower slope. FAO classified the soil as Umbric Cambisols at the upper slope and Dystric Cambisols at the middle and lower slopes.
Technology development for obtaining titaniumcontaining bar ligature for aluminum alloy modification
Authors: Kulikov B. P. , Bezrukikh A. I. , Sidelnikov S. B. , Bondarenko D. N. , Baranov V. N. , Lopatina E. S. , Startsev A. A. , Stepanenko N. A. , Nadolko A. S.
Published: January 2023

The paper provides the results of experimental studies on the development of a method for obtaining titanium-containing bar ligature, the study of its structure and modifying ability. The distinctive features of the new technology are the use of titanium sponge and/or titanium shavings as titanium raw materials, the primary alloying of aluminum with titanium, and then boron, titanium introduction in two stages: initially, 2/3 of titanium metal raw materials are dissolved in the aluminum melt, and the remaining amount is introduced after the potassium tetrafluoroborate reduction. Titanium sponge pre-impregnation with halide-containing flux and the use of a briquetted KBF4 + Al-powder mixture are also provided. The experimental technology for Al–Ti–B melt preparation is described, titanium and boron extraction into the ligature is calculated, ligature microstructure is investigated, and chemical and molecular compositions of resulting slags are determined. Deformation processing for bar ligature production was carried out by the method of direct extrolling that smoothed over cast structure defects. It was found that the use of high-speed crystallization-deformation in the combined direct extrolling process makes it possible to obtain alloying bars of a given diameter at minimal energy consumption with the required set of mechanical and operational properties. A quantitative modifying ability assessment of the experimental cast-iron ligature and the deformed cast-iron rod obtained by the direct extrolling method was carried out in comparison with the mass-produced cast-iron ligature produced by KBM Affilips (the Netherlands/Belgium). Based on theoretical and experimental studies, the composition and technology for producing Al–Ti–B modifying ligature using titanium sponge and/or shavings and potassium tetrafluoroborate containing 3.0±0.3 % titanium and 1.0±0.2 % boron as alloying additives have been developed that meet the aluminum ligature composition requirements.
Influence of melt superheating treatment on cast structure of Al–Sn alloys
Authors: Chikova O. A. , Vyukhin V. V. , Tsepelev V. S.
Published: January 2023

The study covers the effect of Melt Superheating Treatment (MST) for Al–Sn alloys. To determine the optimal superheating temperature, the authors measured the temperature dependences of the kinematic viscosity, electrical resistivity, density and surface tension of Al–Sn melts with tin contents of 10, 20, 30, 40, and 50 wt.%. According to the measurement results, the temperature t* was determined for each Al–Sn alloy sample. Heating to this temperature breaks down the micro-inhomogeneous state and leads to the heterogeneous liquid – homogeneous liquid structural transition. Melt superheating (MST) results in a decrease in melt viscosity. It was found that the temperature t* rises with increasing tin concentration in the Al–Sn melt. An increase in the tin content in the Al–Sn melt also leads to a decrease in the absolute values of kinematic viscosity and surface tension, while the electrical resistivity and density increase accordingly. Thus, the Melt Superheating Treatment (MST) mode for Al–Sn alloys was determined. The effect of MST of Al–50wt.%Sn melt on the microstructure and mechanical properties of the ingot was studied in order to determine the structural sensitivity to the degree of melt overheating, and to find a new strategy to improve the shaping ability of the Al–Sn alloy two-phase structure. The results demonstrated that the method of resistivity and viscosity determination are more sensitive and effective for melt superheating temperature (MST mode) evaluation. In addition, the desired modified Al–Sn ingot structure can be formed under normal casting conditions; MST can contribute to the modified ingot structure formation by increasing the solidification time and decreasing the average solidification rate by reducing melt viscosity after superheating.
Structure and mechanical properties of Al–Ca–Mn–Fe– Zr–Sc eutectic aluminum alloy after equal channel angular pressing
Authors: Rogachev S. O. , Naumova E. A. , Karelin R. D. , Andreev V. A. , Perkas M. M. , Yusupov V. S. , Khatkevich V. M.
Published: January 2023

Multicomponent eutectic alloys developed in recent years based on the Al–Ca system have high practical application prospects due to their low density, high corrosion resistance, good processability when casting, and high formability in the as-annealed state. Alloy hardening is achieved by doping with Mn, Fe, Zr, Sc and other elements. Obtaining an ultrafine-grained state in aluminum alloys by the methods of severe plastic deformations, e.g. equal channel angular pressing (ECAP), significantly increases the complex of their mechanical properties. In this regard, the purpose this paper was aimed to study the effect of warm ECAP on the structure, mechanical properties and thermal stability of the eutectic aluminum alloy, wt.%: Al–3.5Ca–0.9Mn–0.5Fe–0.1Zr–0.1Sc. The ECAP process was carried out on as-cast alloy specimens with a diameter of 20 mm (temperature 400 °C, route BC, channel intersection angle 110°, number of passes N = 6). It is shown that as a result of ECAP, a developed substructure with high-density dislocations and released nanosized Al6(Mn, Fe), and Al3Sc particles is formed in the alloy, as well as primary coarse Al6(Mn, Fe) particles and eutectic Al4Ca particles are reduced in size. Such a change in the structure during ECAP leads to the significant hardening of the alloy: its strength properties increased by 1.5–2.0 times, and relative elongation decreased by 1.3 times in the longitudinal section sample and slightly changed in the «transverse» section sample as compared to the initial condition.
Structure and properties of EP741NP heat-resistant nickel alloy produced by selective laser melting
Authors: Baskov F. A. , Sentyurina Zh. A. , Logachev I. A. , Bychkova M. Ya. , Logachеva A. I.
Published: January 2023

EP741NP alloy samples featuring various types of defects with the volume fraction varying from 0.31 to 0.65 % were produced by the method of selective laser melting (SLM) at various process conditions. The structure of SLM samples was investigated using optical and scanning electron microscopy, and mechanical properties were determined by tensile tests. All investigated SLM samples featured by low strength characteristics due to the metastable single-phase structure formation, as well as structural defects in the form of cracks. To improve mechanical properties, various types of post-processing were carried out including hot isostatic pressing (HIP), heat treatment according to the «solution + aging» (HT) type, and comprehensive processing combining HIP and HT. According to the research results, the influence of various post-processing types on the microstructure and properties of SLM samples were determined. It was established that the use of HIP contributes to a decrease in porosity to 0.04 %, structure recrystallization, and the precipitation of a strengthening intermetallic phase based on Ni3Al (γ ′-phase) in the form of large particles of different sizes forming agglomerates. HT leads to the structure recrystallization and precipitation of a finely dispersed γ ′-phase uniformly distributed in the alloy matrix. In this case, strength characteristics of samples after HIP and HT are approximately at the same level (σв ~ 1250÷1290 MPa), however, the ductility of samples after HT is significantly lower. This is associated with the retention of defects in the structure in the form of cracks and large pores. The maximum increase in mechanical characteristics (σ up to 1460 MPa, δ up to 21.3 %) was recorded during comprehensive post-processing (HIP + HT) that ensures defect elimination and optimal alloy structure formation.
Investigation of Pobeda furnace bubbling zone physics using cold modeling method. Message 1. Investigation of fluid and gas dynamics of bubbling using a side-blowing gas-protected lance
Authors: Bulatov K. V. , Zhukov V. P. , Bratygin E. V. , Tomilov N. A. , Menshikov V. A.
Published: January 2023

Pobeda furnace operation was studied in the Archimedes criteria range from 5 to 60 using the cold modeling method to determine fluid and gas dynamics of bubbling using a side-blowing gas-protected lance. A transparent reactor of the laboratory setup was made on a scale of 1 : 10. Cylindrical lance nozzle diameter was 5 mm, annular space was 1 mm and angle to the horizontal in the reactor working position was 12°. It is shown that air interaction with water at its excessive pressure of 105 N/m2 occurs in the form of a pulsating stream in a cyclical pattern with the different maximum torch size amplitude and the time required to achieve it. Dynamic borders of the primary near-nozzle zone were determined depending on the Archimedes criterion value for separate and cooperative gas flow through the lance shell and central channel in the stream straight-line development area (lmin ≤ I ≥ lmax). Dynamic head of torch pulsation at extremum points varies in the range of 6,00 • 10-5÷8,26 • 10-4 Pa. Empirical equations for stream length in straight-line and full stream development areas and liquid release height were obtained depending on the Archimedes criterion value. An intermediate layer of ejected liquid was found between circular and cylindrical submerged streams. Cooperative axial gas flow is maintained at identical Archimedes criteria of air supply to the shell and central channel for the values Arsh = Arc = 25 at a distance of 0.0094—0.0116 m from the nozzle edge. As a result of research conducted it should be assumed that there is no interaction of blast oxygen from the central channel of the double -flow lance with surrounding melt at a distance of 9—11 cm from the Pobeda furnace lining.
Influence of cerium on the phase composition and crystallization behavior of cast aluminum alloys based on the Al—Mg—Si system
Authors: Deev V. B. , Prusov E. S. , Shurkin P. K. , Ri E. H. , Smetanyuk S. V.
Published: January 2023

This study was conducted with calculations made in Thermo-Calc software (TCAl4.0 database) to find out the unexplored data on the phase composition, crystallization behavior of Al—Mg—Si—Ce alloys as regards the compositions of two-phase (Al) + Mg2Si cast aluminum-magnesium alloys. It was shown that (Al), Al4Ce, Mg2Si, Al8Mg5 phases may form during crystallization. At 4% Mg and (Si + Ce) concentrations of 1.5 %, a simultaneous increase in Ce and decrease in Si contents from 0.2 % and 1.3 % points promote consistent reactions L + (Al) + Al4Ce and L + (Al) + Al4Ce + Mg2Si. This suggests that the Al4Ce phase may hinder the growth of Mg2Si phase eutectic inclusions. Moreover, at 20 °C such a change in concentrations promotes a simultaneous decrease in the contents of Al4Ce and Al8Mg5 phases, along with a decrease in the amount of magnesium silicide. While adding Ce in the Al—4%Ce—0.5%Si alloy, the fraction of Mg2Si is approximately constant throughout the entire crystallization range (1.34 %), but each 0.1% Ce increases the Ce-bearing intermetallic fraction by 0.17 %, and at 0.7 % Ce the proportions of two phases are equal. When studying the phase composition at representative annealing temperatures of 400 и 550 °C, it was revealed that the (Al) solid solution becomes supersaturated as a result of Al8Mg5 phase dissolving. Each 0.1% Ce increases the Mg content in the (Al) solid solution by 0.005 % in the first case and by 0.01 % in the second one. This indicates a potentially positive influence of Ce on matrix strengthening. Based on the results, it was concluded that it is advisable to add Ce in an amount of up to 0.7 %, which slightly reduces the liquidus temperature (to ~636+638 °C), but reduces the non-equilibrium solidus temperature by ~30 °C to 421 °C. At the same time, at a constant Mg2Si phase formation temperature (581 °C), the eutectic crystallization range (Al)+Al4Ce expands with Ce addition, which can compensate for the decrease in casting properties. The Al—4%Ce—0.5%Si—0.7% Ce alloy has the following phase composition: Al4Ce 1.19 %, the [Mg2Si/Al4Ce] ratio = 0.89, Al8Mg5 fraction is 7.92 % at 20 °C, Mg concentrations in the (Al) solid solution are 3.22 % and 3.36 % at temperatures of 400 °C and 550 °C, respectively. The presented results serve as the basis for subsequent experiments and justify compositions and temperature conditions for obtaining cast aluminum-magnesium alloys with cerium having a modifying effect on Mg2Si eutectic inclusions.
Ensuring the strength of welded joints in laser welding of EP693 heat-resistant dispersion-hardening nickel alloy
Authors: Baranov D. A. , Zhatkin S. S. , Nikitin V. I. , Deev V. B. , Nikitin K. V. , Barinov A. Yu. , Yudin D. M.
Published: January 2023

The paper considers the process of creating a permanent connection from the EP693 heat-resistant alloy of the Ni-Cr-W-Co-Mo system used in the manufacture of components and parts of gas turbine engines by welding on the TruLaser Cell 7020 CO2 complex with pulse-periodic radiation. EP367 filler wire of the Ni—Mo—Cr—Mn system was used to obtain the weld. The influence of heat treatment on the structure and properties of the heat-affected zone and the weld was studied. Based on the research results, the weld structure and kinks obtained by laser welding was studied, weld physical and mechanical properties were identified, the maximum endurance limit for welded joints was determined at 2•106 cycles. The expediency of laser welding of the heat-resistant dispersion-hardening nickel alloy in the manufacture of shells for the turbine support and stator of gas turbine engines was determined. It was found that combined heat treatment (quenching and aging) provides optimal values of strength limits at room and elevated temperatures, as well as short-term strength of welded joints. Based on the strength calculation of the turbine support and stator of gas turbine engines and the obtained experimental data on the strength of welded joints made using laser welding with pulse-periodic radiation, the safety factor was 1.35 to 3.0. This technology is proposed to be introduced into production in the manufacture of parts and assemblies such as shells for the turbine support and stator of gas turbine engines in order to improve the quality of welds by reducing the time of high-temperature heating due to lower heat input.
Structure and properties of Ta-Zr alloy obtained by high-speed melt quenching from liquid state
Authors: Serov M. M. , Patrushev A. Yu. , Farafonov D. P. , Valeev R. A. , Safaryan A. I.
Published: January 2023

The paper considers the effect of Ta-Zr binary system splat quenching implemented by the method of pendant drop melt extraction. The study was conducted using two mixtures of tantalum and zirconium elementary powders with a content of 60 and 6 % of tantalum respectively. After mixing, the compositions were pressed at 250 MPa in a steel mold on a hydraulic press. Sintering was carried out in a vacuum furnace at 1350 °C and a pressure of 10-3 Pa. Splat quenching was carried out in a vacuum at 2•10-2 Pa using electron-beam heating and a spinning disk absorber. Resulting fiber thickness was 15 to 80 gm. The results of testing splat-quenched Ta—Zr alloy discrete fibers and samples formed as a result of rod stock melting by electron-beam heating (as-cast) were studied and compared. It was found that the structure of splat-quenched fibers of the alloy with a Ta content of 6 wt.% consists of 5—10 gm needle-shaped grains, and the alloy with a Ta content of 60 wt.% has a columnar dendritic structure. A study of tantalum and zirconium distribution across the fiber cross-section showed that cooling rate reduction to less than 105 K/s leads to monotectoid transformation in the alloy with a tantalum content of 60 wt.%. It was found that for an alloy with 6 wt.% Ta the fiber microhardness value is 1.5 times higher in comparison with the same alloy without quenching, and for an alloy with Ta 60 wt.% it is higher by a factor of two.
Purification of alumina-containing sweepings by dry air classification methods
Authors: Burdonov A. E. , Barakhtenko V. V. , Zelinskaya E. V. , Gavrilenko L. V.
Published: January 2023

The article deals with the formation and processing of waste at aluminum production plants. Based on the analysis of literary sources and practical data, the reasons for the formation of metallurgical waste in the territory of the Russian Federation are established. The analysis of research conducted in scientific organizations is presented. It was found that one of the most promising for waste processing is alumina-containing sweepings formed during the production of liquid aluminum in Soderberg cells during various process operations. Alumina-containing sweepings are waste of complex variable composition swept away in electrolysis shops. It was found that alumina-containing sweepings consist of cryolite (Na3AlF6), chiolite (Al3F14Na5), corundum (Al2O3), siderite (FeCo3), pyrite (FeS2), quartz (SiO2), feldspar ((Ca, Na)(Al, Si) AlSi2O8), carbonaceous matter and (NaF)•1,5CaF2•AlF5 technogenic phase. Their processing is of interest due to the fact that they contain a significant amount of valuable components (Na3AlF6, Al2O3, AlF3) that can be extracted and reused in aluminum production to reduce the cost per unit. The problem is that sweepings contain components (SiO2, Fe2O3), which have a negative effect on the electrolysis process when in contact with electrolyte. The data obtained when studying the chemical composition of monofractions made it possible to conclude that the exclusion of the dark (grayish-black mass) with the maximum content of impurities (SiO2, Fe2O3) will substantially solve the stated problem of the study. Based on the hypothesis put forward, the paper presents the results of 0—10 mm and 0—5 mm sweepings air classification in cascade-gravity and centrifugal classifiers. Based on the studies conducted, we recommend using 0—10 mm sweepings air classification in the cascade gravity classifier in the processing flow of alumina-containing sweepings of aluminum production.
Modification of Al–Mg–Si casting aluminum alloys by liquid phase processing with nanosecond electromagnetic pulses
Authors: Deev V. B. , Ri E. Kh. , Prusov E. S. , Ermakov M. A. , Goncharov A. V.
Published: January 2023

The AA 511 alloy of the Al–Mg–Si system was used as an example to demonstrate that aluminum melt irradiation with nanosecond electromagnetic pulses (NEPs) leads to a significant change in the nature of structure formation during crystallization. It was found that an increase in the frequency of melt irradiation with NEPs is accompanied by the refinement of the alloy structural components, while the greatest grain size reduction of the α-solid solution and intergranular inclusions of the eutectic Mg2Si phase is observed at a NEPs frequency f = 1000 Hz. An increase in the NEPs frequency leads to a significant increase in the concentration of magnesium in the α-solid solution and the fragmentation of Mg2Si phase intergranular inclusions, which is released in the form of compact isolated inclusions when the melt is irradiated at a frequency of 1000 Hz. It was shown that melt processing with NEPs leads to an increase in the Brinell hardness of as-cast specimens, as well as to a significant increase in the microhardness of α-solid solution grains (from 38.21 HV in the initial state to 61.85 HV after irradiation with a frequency of 1000 Hz). It was assumed that the effect of a pulsed electromagnetic field leads to a decrease in the critical values of the Gibbs free energy required to initiate nucleation processes, and to a decrease in the surface tension at the «growing crystal – molten metal» interface, which causes a modifying effect on the alloy structure due to a decrease in the critical size of crystal nuclei.
Combined gravitation-flotation technology for technogenic gold placer concentration
Authors: Evdokimov S. I. , Gerasimenko T. E.
Published: January 2023

Gold recovery from placer washing waste was carried out using a flotation method where circulating rough concentrate is used to increase the recovered metal content in the rougher flotation operation. Moreover, flotation is carried out with a mixture of air with hot steam. Pressure in bubbles drops and their sizes decrease as a result of vapor condensation at the first moment of time under conditions of vapor-air flotation. Heat exchange between the phases worsens when the bubble is compressed, and mass transfer stops at the minimum bubble size, while temperature and vapor pressure in the bubble reach their maximum. As the bubble grows in size, superheated steam becomes saturated and pressure in the bubble decreases resulting in resumed condensation. The bubble surface undergoes damped oscillations. When the bubble surface vibrates, the motion of a slowly developing concentration-capillary Marangoni flow to the center of the interphase film cannot compensate for its thinning by the counter thermocapillary flow with a high hydrodynamic stability potential from the film center to its periphery. The vapor-air flotation results obtained can be interpreted in the context of this mechanism of wetting film stability changes during the vapor-liquid phase transition. Pilot tests of gravity and gravity-flotation technologies for gold extraction from a technogenic placer of gold have been carried out. It has been proved that the main effect of using the developed configuration of the scheme and the mode of flotation with a vapor-air mixture is a decrease in the concentrate yield by ~ 25% rel. while maintaining the achieved level of recovery and concentrate quality. When using the combined technology, the added value of marketable products provides an increase in the value of net discounted income and the return on investment index, and a decrease in their payback period.
Physical and chemical regularities of zinc sulfide concentrate pressure leaching in the presence of lignosulfonate
Authors: Kolmachikhina E. B. , Lugovitskaya T. N. , Tret’yak M. A. , Naumov K. D.
Published: January 2023

The study covers physical and chemical regularities of zinc sulfide concentrate oxygen pressure leaching in sulfuric acid. The effect of lignosulfonate concentration (CLSN = 0.2÷0.8 g/dm3), leaching time (τ = 20÷120 min), temperature (T = 393÷423 K), and oxygen partial pressure (РО2= 0.3÷0.7 MPa) on the degree of zinc and iron extraction into the solution and on the cake grain-size distribution was established. It was shown that lignosulfonate additive intensifies zinc and iron extraction into the solution. Maximum extraction of zinc and iron was 89 and 37 %, respectively, for 120 min of leaching at CLSN = 0.6÷0.8 g/dm3. The differential rate law with respect to lignosulfonate was 0.3 for sphalerite, and 0.9 for iron sulfides. A controversial influence of rising temperature on the process under investigation was found. Temperature elevation from 413 to 423 K leads to a decrease in zinc extraction by 3–4 % due to the formation of sulfur-sulfide aggregates over 150 μm in size. The calculated values of apparent activation energy (Еа) of sphalerite and iron sulfide leaching in the presence of lignosulfonate were 30 and 45 kJ/mole, respectively. It was found out that an increase in oxygen partial pressure from 0.3 to 0.5 MPa has a positive influence on leaching and increases extraction of zinc and iron by 22 and 27 %, respectively. However, an increase in oxygen partial pressure up to 0.7 MPa in the presence of lignosulfonate after 40 min of leaching led to a decrease in leaching rate, possibly as a result of lignosulfonate destruction. It was found that differential rate laws with respect to oxygen are 1.2 for sphalerite and 2.5 for iron sulfides.
Sn–Pb alloy processing for commercial tin production
Authors: Korolev A. A. , Timofeev K. L. , Maltsev G. I. , Krayukhin S. A.
Published: January 2023

The aim of the research is to develop an optimal method for Sn–Pb alloy processing to obtain a marketable product – high-grade tin O1–O3 (Sn  98.5 %). Laboratory studies were conducted on the refining of the Sn–Pb alloy with the following composition, wt.%: 53–60 Sn; 18–29 Pb, first by vacuum distillation (t = 1085÷1300 °C, P = 15÷100 Рa; τ = 3÷36 h) for As, Sb and Pb sublimation, then by reagent deposition with elemental sulfur and aluminum as part of the Al–Sn master alloy in the presence of NH4Cl for Cu, Fe and Sb separation. This resulted in obtaining a Sn-containing residue (yield ~60 %) of the following composition, wt.%: 92.39 Sn; 0.46 Pb that was subjected to reagent refining to obtain O3 grade tin (metal yield ~68 %) with the following composition, wt.%: 99.5 Sn; 0.009 Pb. It was found that it is feasible to carry out refining from a preliminarily decopperized Sn–Pb alloy to obtain a finished O1 grade product with a direct extraction of 90 %. A schematic diagram was developed and recommendations were formulated for the process regulations on Sn–Pb alloy processing to obtain commercial tin and recover resulting intermediate products and waste. A furnace with separate production of As, Sb, Pb condensates with the following composition, wt.%: 94.2–98.3 As; 5.1–14.5 Sb; 78.9–86.4 Pb, respectively, was chosen as a vacuum distillation unit. The economic effect of processing ~480 ton/year of Sn–Pb alloy (~50.8 % Sn) with the production of ~235 ton/year of O1–O3 grade tin is ~39 million rubles/year.
Study into the effect of different energy sources on the structure and mechanical properties of EP693 nickel alloy weld joint
Authors: Baranov D. А. , Zhatkin S. S. , Nikitin K. V. , Parkin A. A. , Shchedrin E. Yu. , Deev V. B.
Published: January 2023

The paper provides the results of a study on the influence of welding types (laser, electron beam, and TIG welding) on the properties of a permanent connection made of an EP693 alloy of the Ni–Cr–W–Co–Mo system used in the production of gas turbine engine components and parts. EP367 filler wire of the Ni–Mo–Cr–Mn system was used to obtain a weld during laser and TIG welding. A comparative analysis of heating areas and power densities was performed for the welding types studied. It was established that TIG welding features by greater values of the heating area and power density in comparison with laser and electron beam welding. It was found that the type of welding affects the features of weld formation. For example, a weld is formed with the transition to knife fusion penetration in the weld root for electron beam welding, and in the form of an «hourglass» for laser welding. The analysis of the heat affected zone microstructure showed that the smallest grain size is formed during laser welding. The distribution of elements in the weld joint was analyzed. It was found that when welding with the use of filler wire, the Mo content increases and the W, Co, Al, and Ti content decreases in the weld and heat affected zone relative to the base metal. This determines the peculiarities of failure for samples obtained using the welding types studied. Samples obtained by TIG and laser welding broke along the heat affected zone on the weld reinforcement side. Samples obtained by electron beam welding broke along the weld. Mechanical tests of samples at room and elevated temperatures showed that samples obtained by laser and electron beam welding have the highest tensile strength.
Effect of cooling rate on C92900 bronze microstructure and properties
Authors: Bazhenov V. E. , Titov A. Yu. , Shkalei I. V. , Sannikov A. V. , Nikitina A. A. , Plisetskaya I. V. , Bazlov A. I. , Mezrin A. M. , Koltygin A. V.
Published: January 2023

In the mechanical engineering, antifriction tin bronzes are used for the manufacture of friction parts. For example, the C92900 bronze has found use in aircraft braking system components. One of the ways to improve the properties of leaded tin bronzes is to increase the cooling rate during solidification. This paper studies the effect of the cooling rate and changes in the content of alloying elements within the limits established by the C92900 bronze industry standard OST 1 90054-72. In order to provide different cooling rates, the prepared alloys were casted into molds made of resin-bonded sand, steel and graphite with cooling rates 0.4, 5.0, and 14.6 °C/s, respectively. The influence of the cooling rate and the bronze composition on the freezing range, macrostructure, microstructure, thermal conductivity, mechanical, and tribological properties were investigated. Differential thermal analysis demonstrated that the upper-limit alloying of C92900 bronze leads to a decrease of the solidus temperature by 40 °C, which should be considered during deformation processing and heat treatment. An increase in the cooling rate during C92900 bronze ingot solidification provides a significant grain refinement and changes the amount, size and morphology of phases. For example, in case of metallic and graphite mold casting, the size of lead particles decreases, and its circularity increases. The change in the Sn content within the range established by the industrial standard has a significant effect on the γ-(Cu,Ni)3Sn intermetallic phase fraction. The increase in the cooling rate has no significant effect on the C92900 bronze thermal conductivity but increases hardness by 30 HB as well as cooling rate and yield strength and ultimate tensile strength. Wear tests carried out in accordance with the «shaft – partial insert» scheme in a kerosene medium using a steel counterbody showed that an increase in the cooling rate during solidification leads to an increase in the bronze wear rate from ~0.4·10–8to ~1.2·10–8. The change in the bronze composition within the industrial standard range has practically no effect on the wear rate but leads to a slight increase of the coefficient of friction.
Vladimir Ivanovich Nikitin is 80 years old
Authors: Editorial Article
Published: January 2023

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Effect of direct metal deposition technology on the structure and properties of Ni–Cr–W–Mo heat-resistant nickel alloy
Authors: Khakimov A. M. , Zhatkin S. S. , Nikitin K. V. , Nikitin V. I. , Deev V. B.
Published: January 2023

The study covers the quality of a metal powder composition (MPC) made of a heat-resistant EP648 alloy (Ni–Cr–W–Mo system) used to produce parts by direct metal deposition (DMD). It was established that the MPC meets the TU 136-225-2019 specification in terms of basic requirements (chemical composition and grain size distribution, purity, bulk density, fluidity, moisture content). The effect of direct metal deposition parameters (laser radiation power, surfacing speed) on the structure and microhardness of test samples was studied. The largest number of defects (looseness, pores and lack of fusion) is formed in the sample obtained at a laser radiation power (RP) of 1000 W and a surfacing speed of 40 mm/s. At the same time, the defects have maximum dimensions. The smallest number of such defects is observed in samples obtained at a RP power of 1400 and 1600 W and a surfacing speed of 45 and 38 mm/s. In this case, the most homogeneous structure of laser surfacing zones is formed due to the complete melting of powder particles and the melt spreading. Nevertheless, the sample obtained at a RP of 1600 W and a surfacing speed of 38 mm/s has a structure with cracks located along the faces of subgrains in the center of surfacing tracks. Crack formation is caused by material overheating due to the increased laser radiation power and accumulated high internal stresses from the previous deposited layers. The microhardness of samples obtained at all direct metal deposition modes varies slightly and amounts to 270– 310 HV. According to the research results, it was found that the most optimal structure is formed in the sample obtained at a RP of 1400 W and a surfacing speed of 45 mm/s.