bluuebunny/crossref_metadata_2025 huggingface dataset:
The Walloon settlers in Spiš in the Middle Ages
Authors: Marek Miloš
Published: January 2023

In the kingdom of Hungary we assume the presence of a Romance-speakingpopulation as early as in the 11th century. Other groups of Latins, mainlyWalloons, immigrated during the 12th century to Transylvania, along with theFlemish people, and to other important cities of the kingdom (Esztergom,Székesfehérvár, Oradea Mare, Pécs, Zagreb). But also into Spiš county. Themost important Wallonian locality in the upper part of the country (Slovakia)was established in Spišské Vlachy located in the vicinity of the importantGerman locality of Spišské Podhradie, where Saxon “guests” were the firstto be documented in Spiš. The presence of Walloons in Spiš is generally associatedwith the construction of the nearby Spiš castle although there mayhave been other reasons for their arrival. The local settlement is first recordedin sources in 1243, when King Bela IV. granted the settlers from Spišské Vlachya special privilege. But Latin hospites in Spiš county lived not only in SpišskéVlachy and its immediate surroundings. The presence of individuals fromthe Romance language area is testified in other localities of Spiš as well,mostly in villages of the Hornád river valley (Aranyás, Mečedelovce, Odorín,Žehra and so on). The Wallonian community in Spiš wasn´t very numerousin comparison with local Slavs or German (Saxon) settlers and very soonwas gradually assimilated in the domestic Slovak or German environment.
Analysis of Effectiveness Use of Scientific Potential: Personnel Renewal
Authors:   Baranavichy State University, Klimuk Vladimir , Astratova Galina ,   Ural Federal University named after the First President of Russia B.N. Yeltsin
Published: January 2023

The purpose of the research was to study the process of reproduction of scientific personnel in connection with the need to activate the processes of developing high-tech products in the context of ensuring economic growth of Belarus and Russia in modern conditions. The authors analyzed the following main issues: 1) reproduction of scientific personnel in the system of higher education; 2) analysis of the market of scientific personnel; 3) effectiveness of the functioning of the R&D sector of the Union State of Russia and Belarus. The main research methods were: factor analysis method, comparative analysis, indexing method, matrix method, correlation analysis. Statistical data processing was carried out using the Microsoft Excel program, SPSS Statistics. To analyze the development of the R&D sector in the Union State, the authors suggested a system of six economic indicators to assess the effectiveness: share of expenditures on R&D in the total volume of budget expenditures, in the country’s GDP, share of domestic expenditures on R&D in the country’s GDP, labor productivity in the R&D sector, volume of expenditures for R&D per an employee, coefficient of return of internal costs for R&D. The data obtained as a result of the study allowed us to draw a number of conclusions, including: 1) the state of both Belarus and Russia pays attention to the development of the R&D sector, which is characterized by an increase in funding for science; 2) in both countries, a number of problems were identified that require coordination of efforts and immediate solutions. A number of similar problems were identified for Belarus and Russia in the implementation of the strategy for the development of the R&D sector, which justifies the need to develop a joint strategy for the development of research and innovation activities of the Union State of Belarus and Russia. The results of the study can be useful both to employees of the R&D sector and university teachers, as well as to heads of regional and municipal levels of various sectors of the economy.
Mechanisms of Economy Adaptation of the South of Russia to Geopolitical Risks
Authors:   Perm Institute (Branch) of Plekhanov Russian University of Economics, Oborin Matvey
Published: January 2023

Currently, the regional issue is becoming increasingly important, modern world trends led to the appearance of regions as full-fledged subjects of interregional and international relations. In order to preserve their stability, it is necessary to manage effectively the development of regions, what is associated with an increased risk of negative consequences taken under the influence of global changes. Thus, the study of regional processes, the identification of factors that have a destructive impact on the situation in the regions, on the effectiveness of regional development management becomes particularly relevant. The article examines the current geopolitical situation of the Russian regions, examines the current risks and directions of fighting and preventing risks and threats. The purpose of the study is to analyze the current threats in the South of Russia and the directions of their limitation, as well as to search for mechanisms to prevent and reflect negative factors. Different interrelations with the political science research are explored, showing the complexity and multidimensional nature of many problems and risk factors, as well as their significance for the current economic and political situation in the country. The methodological basis of the study was a systematic approach, which made it possible to present the object of research in its unity and integrity as an integral part of the world political system. A systematic approach aimed at the holistic perception of integrated objects contributed to the determination of causeand-effect relationships in the analysis of the direction and content of geopolitical processes developing in the southern regions of Russia. A number of preventive measures were suggested to fight and prevent risks and threats in the field of countering terrorism and armed formations on the territory of Southern Russia. A systematic situational analysis of social, political and ethnopolitical changes based on predictive methods is demanded both in scientific-theoretical and practicalapplied aspects for forecasting and threats prevention of undermining and improvement of the effectiveness of political and managerial practices, taking into account regional specifics.
Large Cities as Epicenters of Social and Economic Dynamics of Southern Macroregion: The First Quarter of the 21st Century
Authors:   National Research University Higher School of Economics, Suschaya Ekaterina
Published: January 2023

The article analyzes demographic, migration, social and economic dynamics of large cities in the South of Russia at the beginning of the 21st century. It is concluded that this period was characterized by the process of metropolization of the urban network, associated with the rapid development of administrative centers, which concentrated a significant share of financial resources, investments, trade, services, and the real estate market in their regions. The share of the regional capitals in these segments of social and economic activity significantly exceeded their share in the population. Other large cities took an intermediate position between the administrative centers and the rest of the territory of their regions, although in many respects they were noticeably closer to the latter. The exception was the large resort centers of the Black Sea region, whose rapid growth was determined their general recreational potential. The largest social and economic centers of the South of Russia are currently Rostov-on-Don and Krasnodar, which together account for about 25–35% of fixed assets, investments, retail trade turnover, and commissioned housing in the macroregion. Volgograd remains the leading industrial center of the South of Russia. However Volgograd has not fully realized its significant social and demographic potential in modern economic clusters. Among the other large cities of the macroregion, two subgroups can be distinguished. They unite centers comparable in their complex social and economic potential. The first group includes Astrakhan, Sochi, and Sevastopol. The second one consists of Novorossiysk, Simferopol, Volzhsky, and Taganrog. The spatial asymmetry of the group of large cities in the southern macro-region continued to increase in the post-Soviet period: 2/3 of them are currently located at a distance of up to 100 km from the coast of the Black or Azov Seas, forming a zone of advanced development of the South of Russia. In the next 10–15 years, only the Black Sea centers of the Kuban and Crimea, Krasnodar and Rostov-on-Don with the satellite city of Bataysk, can show demographic growth.
Northern and Southern Transport Corridors: New Realities and Development Prospects
Authors:   Institute for Regional Economic Studies of the Russian Academy of Sciences, Roslyakova Natalia , Dorofeeva Lyudmila ,   Institute for Regional Economic Studies of the Russian Academy of Sciences
Published: January 2023

Due to the changing geopolitical situation, the development of transport corridors in Eurasia is of critical importance. In recent years, the reliability of the traditional route through the Suez Canal has been repeatedly questioned. There were accidents, arrest of ships, inability to enter ports, piracy and other challenges. Changing geopolitics also imposes its limitations (refusal of insurance because of sanctions, trade embargoes of a number of countries, etc.). Accordingly, countries subject to sanctions’ pressure from the United States and the EU are forced to look for safer, more reliable and faster ways to organize goods and cargo turnover. This actualizes the issue of the development of the two most promising transit corridors – the northern and southern ones. The Northern Sea Route (NSR) and the North–South Corridor (Trans-Caspian Corridor) were initially considered as options for transit transportation of goods from China to Europe. However, due to the growing social and economic crisis in Europe, the vector of routes is changing, reorienting itself to the Middle East, Africa and Asia. Moreover, the rapid social and economic development of countries and changing geopolitical conditions are activating the processes of searching not only for trade, but also for industrial cooperation. At the same time, restrictions on the development of these routes, both technical and institutional, are still in effect today. The article discusses the key prospects for the development of these transport corridors, provides estimates of possible positive effects for the regions of Russia, and also discusses the problems hindering the use of the Northern Sea Route and the North-South corridor.
AVALIAÇÃO DE UMA HISTÓRIA EM QUADRINHOS AUTORAL PARA O ENSINO DE QUÍMICA ORGÂNICA
Authors: Tavares Emilay , Kened Janes
Published: January 2023

Este artigo tem como objetivo realizar uma avaliação de uma história em quadrinhos autorais que faz uso da contextualização do zumbi temático para abordar conceitos de Química Orgânica no Ensino Médio. O estudo contorno com uma pesquisa qualitativa atenta à análise do conteúdo de Bardin (1977). Os dados foram obtidos através da aplicação de interação com professores de Química abrangendo três eixos de análise inspirados em categorias de Leite (2017). A partir dos resultados, observou-se que a H-Quí além de trabalhar satisfatoriamente conceitos da Química Orgânica, apresenta potencial para abordar conceitos de Física e Biologia, possuindo um caráter dinâmico e interdisciplinar, o que lhe potencializa aos olhos da Base Nacional Comum Curricular (BNCC). Outro fator de destaque,a H-Quí apresenta-se como um recurso didático capaz de promover um ensino que contribui com a quebra de paradigmas limitadores como o “não-lugar” da mulher na ciência e da soberania da presença da raça branca na história da ciência e livros didáticos , ao ter como protagonista uma mulher cientista e negra. Por fim, os resultados também evidenciaram que a H-Quí é visualizado como um material de apoio, isto é, como um material capaz de auxiliar o professor durante a administração dos conceitos que estão sendo ensinados em sala de aula. A partir desta pesquisa, foi possível refletir sobre o som da produção e avaliação de produtos didáticos lúdicos e contextualizados como as HQs para o aprimoramento das técnicas educativas e suas inferências no âmbito das ciências naturais.
Probabilistic Resource Assessment of The Ulumbu Geothermal Field, East Nusa Tenggara, Indonesia
Authors: Pratama Heru Berian , Kurniawan Iqbal , Sutopo Sutopo
Published: January 2023

DOI:10.17014/ijog.9.2.183-193A resource assessment of the Ulumbu Geothermal Field, East Nusa Tenggara, Indonesia, is proposed here. The fundamental issue of reserve estimation is determining the optimum capacity to be installed (field size) that affects the decision-making in geothermal projects. The reservoir numerical model and heat stored method are the most appropriate tools for geothermal resource assessment. Therefore, the hybrid numerical simulation and heat stored methods, coupled with the probabilistic approach, are applied to Ulumbu. Based on the calibrated numerical model, the estimation of the reservoir is divided into the steam zone and liquid reservoir. The energy reserve of the Ulumbu is estimated by Monte Carlo simulation with the results P10-P50-P90 are 71 MWe, 95 MWe, and 127 MWe, respectively
Effect of annealing temperature and time on martensitic transformation temperatures and mechanical properties of the Ti–50.7at.%Ni shape memory alloy
Authors: Polyakova K. A. , Komarov V. S.
Published: January 2023

The study covers the effect of recrystallization annealing temperature and time on the characteristic temperatures of martensitic transformations and mechanical properties of the Ti–50.7at.%Ni shape memory alloy in the form of wire after cold drawing at room temperature. Six modes of post-deformation annealing with different temperatures and holding times were studied for the alloy to obtain structures with different sizes of recrystallized grains. The recrystallized grain size was determined by electron backscatter diffraction (EBSD). It was shown that the size of recrystallized grains increases from 2.5 to 9 μm, with both an increase in the annealing temperature (600– 700 °С) and an increase in the holding time (0.5–5.0 h). The characteristic temperatures of direct and reverse martensitic transformations were determined using differential scanning calorimetry. It was shown that the threefold growth of the recrystallized grain size reduces the starting temperature of the direct martensitic transformation, and extends the temperature range of the reverse martensitic transformation. The results of mechanical tests (stretching tests) at room temperature showed that an increase in the grain size leads to a decrease in the dislocation yield strength and an increase in the phase yield strength. It was established that the dislocation yield strength obeys the Hall–Petch law, and the phase yield strength is determined by the test temperature position relative to the starting (or peak) temperature of the direct martensitic transformation. Heat treatment modes for specific products should be recommended taking into account these two competing factors, as well as reverse martensitic transformation temperatures determining the alloy strain recovery temperatures.
Experimental study of single tracks obtained from a mixture of Ti and Al powders with varying selective laser melting parameters
Authors: Dolbachev A. P. , Belov N. A. , Akopyan T. K.
Published: January 2023

The paper studies the effect of the laser scanning speed (vs) on the morphology of single tracks obtained from a mixture of Ti and Al powders in a stoichiometric ratio of 1 : 1 in longitudinal and cross sections. Droplets of splashed liquid were found on the outer surface of the track obtained at vs = 300 mm/s. Their appearance is resulted most likely from the release of gas bubbles formed due to the evaporation of aluminum having a lower melting point. A distortion of a single track along its length was observed with an increase in vs values up to 600 mm/s. It was found that tracks loose stability as the laser beam speed increases with «balls» formed on the track surface due to the significant Marangoni convection and the capillary liquid instability in the molten bath. An increase in the laser speed led to the appearance of pores mainly concentrated in the formed balls, and also influenced the track morphology in the cross section, namely, the width and height of the track, as well as the depth of substrate fusion. An increase in the scanning speed from 300 to 900 mm/s led virtually no substrate fusion, and the track width decreased from 194 to 136 μm, while its height increased almost 4 times – from 21 to 88 μm. X-ray microanalysis was conducted and element distribution maps were obtained to assess the structure of the tracks under study. It was found that the degree of liquid mixing in the molten bath is insufficient at scanning speeds of 300 and 600 mm/s, which leads to the segregation of elements over the track cross section. The central zone turns out to be enriched in aluminum, while titanium predominates at the base and is practically absent in the extreme zone (4.57 at.% Ti). X-ray microanalysis revealed the presence of unmelted titanium powder particles at vs = 900 mm/s. Presumably, it may be caused by insufficient laser power at such a high scanning speed.
Effect of strain rate on the microstructure and mechanical properties of aluminum alloy AA2B06-O of the Al–Cu–Mg system
Authors: Khina B. B. , Pokrovsky A. I. , Shi-Hong Zhang , Yong Xu , Da-Yong Chen , Marysheva А. А.
Published: January 2023

The study covers the tensile properties and microstructure of AA2B06-O aerospace aluminum alloy (Al–Cu–Mg system) at low (0.001–1.0 s–1) and high (1293–5045 s–1) strain rates. The stain rate at relatively slow (quasistatic) tension has a small effect on mechanical properties. Rasing strain rate at fast (dynamic) loading results in a substantial (nearly twofold) simultaneous increase in the ultimate tensile strength and plasticity (elongation to failure) of the alloy with the yield stress virtually unchanged. Transmission electron microscopy revealed a homogeneous nature of plastic deformation on the microlevel at slow loading and inhomogeneous one at fast loading. The latter is observed as localized deformation in the form of adiabatic microshear bands where complex dislocation structures are formed such as dislocation tangles, dipole and multipole configurations. The first stage of dynamic recrystallization is observed in certain domains of microshear bands due to the heat released at localized plastic deformation. It was shown that the changeover of deformation mechanisms when passing from the quasistatic to dynamic tension causes a significant change in mechanical behavior of the material. Thus, a simultaneous increase in both strength and plasticity can take place not only in nanostructured materials obtained by severe plastic deformation techniques (e.g. equal channel angular pressing), but also at the high strain rate deformation of an aluminum alloy having an «ordinary» microstructure after rolling and low-temperature annealing. The experimental results open up new prospects for practical application of high strain rate pulse deformation methods, such as impact hydroforming, for producing complex-shape articles from sheet blanks in one operation due to substantially improved technological plasticity of the material.
Anode paste consumption for aluminum production
Authors: Drizhenko A. A. , Datsyura S. V. , Yasinskiy A. S.
Published: January 2023

In Russia, most aluminum smelters are equipped with cells with self-baking anodes featuring an urgent problem of lowering the anode paste consumption, since the share of anode materials in the cost of aluminum varies from 8 to 20 %. To solve this problem, it is necessary to determine the anode paste demand. The method for calculating the specific anode paste consumption used at aluminum smelters has a poor accuracy. The paper discusses the main errors of this method, shows the stages of anode paste consumption calculation, assesses the adequacy of calculations and gives recommendations for method improvement. It is shown that in general the considered method adequately reflects carbon consumption processes, but the final result of calculations may differ significantly from the actual one. The values taken constant to simplify the calculation, in fact, may vary during the electrolysis, which leads to a significant change in the final result of calculations. For example, an increase in the CO2 fraction from 0.45 to 0.5 leads to a decrease in the anode paste consumption by 15.3 kg/tonAl. At the same time, it is known that the composition of anode gases changes sharply as the anode effect occurs: the CO2 fraction decreases, and the CO fraction increases. In summer, at high ambient temperatures, the proportion of both vaporized pitch and anodes with an increased surface temperature rise. As the latter changes to 0.25, the consumption increases by 6.6 kg/tonAl. The same applies to air oxidation. The number of depressurized cells may increase with the subsequent increase in the carbon consumption. It is necessary to pay attention to factors affecting the anode quality. Incorrectly selected particle size distribution or worn equipment may significantly degrade the anode quality and lead to an increase in carbon consumption. It is necessary to make adjustments to the calculation in order to consider the peculiarities of carbon monoxide formation properly.
Development and experimental testing of the technology for producing deformed bars of D16(T) alloy from continuously cast billets of small diameter with low elongation ratios
Authors: Galkin S. P. , Aleshchenko A. S. , Gamin Yu. V.
Published: January 2023

The article describes the development and pilot-scale testing of the technology for producing bars of the D16(T) aluminum alloy by radial-shear rolling from continuously cast billets with a diameter of 72 mm in several passes. The actual dimensions of rolled bars were within the ±0.16 mm tolerance for all bar diameters, which significantly surpasses the GOST 21488-97 requirements. According to the results of tensile tests, the values of ultimate strength, conventional yield strength, relative elongation and relative reduction were determined. Ultimate strength and relative elongation requirements specified by regulatory documents for the D16(T) alloy were met with a total elongation ratio of more than 4.2. In terms of plastic properties, the obtained bars surpass the GOST requirements by 2.1–2.5 times in the entire range of elongation ratios investigated starting from 2.07. At the same time, there is an increase in the relative elongation by 5.7–6.8 times in comparison with the initial cast state. The microstructure and morphology analysis conducted for secondary phases showed that with a decrease in the bar diameter (with an increase in the total elongation ratio), the average particle size of the α(AlFeMnSi) phase insoluble in the aluminum matrix decreases, which is a consequence of deformation processes developed during rolling. Additional grinding of inclusions during deformation processing can significantly reduce the possible negative effect of the insoluble phase on the mechanical properties of resulting bars, in particular on the plasticity properties. The microstructure analysis showed that bars after rolling and heat treatment are free from cracks, looseness, delamination, and other defects and meet the requirements of GOST 21488-97.
Stanislav Stepanovich Naboichenko is 80 years old
Authors: Editorial Artiсle
Published: January 2023

.
In memory of Stanislav Stepanovich Naboichenko
Authors: Editorial Article
Published: January 2023

.
Extraction of zirconium from its oxide during the electrolysis of KF–AlF3 –Al2O3 –ZrO2 melts
Authors: Filatov A. A. , Nikolaev A. Yu. , Suzdaltsev A. V. , Zaikov Yu. P.
Published: January 2023

Zirconium is one of the most commonly used materials, while the existing methods of its production are multi-stage and energy-intensive. The paper proposes a method for extracting zirconium from its oxide by KF–AlF3 –Al2O3 –ZrO2 low-temperature oxide-flu-oride melt electrolysis with a temperature of 750 °C. For this purpose, voltammetric methods were used to determine potentials of the electrochemical reduction of zirconium and aluminum ions on a glassy carbon electrode. It was shown that the electrochemical reduction of aluminum ions in the KF–AlF3 –Al2O3 melt occurs at a more negative potential than –0.05 V relative to the aluminum electrode with the cathode peak formation in the potential range from –0.18 to –0.2 V. With the addition of 1 wt.% of ZrO2 , cathode current growth on the voltammogram begins at a more negative potential than 0 V, and the cathode peak is formed at a potential of about –0.1 V. Similar results were observed in the study of the cathode process in the KF–AlF3 –Al2O3 melt with and without ZrO2 added by means of square wave voltammetry. It was suggested that zirconium-containing electroactive ions are discharged at a potential that is 0.05–0.08 V more positive than the discharge potential of aluminum-containing ions due to the lower bond energy. At a graphite cathode potential of –0.1 and –0.3 V relative to the aluminum electrode, the KF–AlF3 –Al2O3 –ZrO2  melt electrolysis was carried out, and the elemental and phase composition of deposits obtained was determined by X-ray phase analysis, scanning electron microscopy and energy dispersive microanalysis. It was shown that the 98.5 –99.5 wt. % zirconium deposit was obtained at a potential of –0.1 V. This indicates a reliable possibility of selective zirconium extraction using the proposed method.
Efim Pavlovich Slavsky. Vladikavkaz stage of the biography
Authors: Chedzhemov S. R.
Published: January 2023

.
Deforming devices with a power drive made of a shape memory material Design solutions, calculation and design procedure
Authors: Alekhina V. K. , Glushchenkov V. A. , Grechnikov F. V.
Published: January 2023

The article presents engineering solutions developed to create deforming devices with a power drive made of a shape memory material. As an example, the paper considers designs of a press, a stamp press made using new designs of multi-link power drives. A method is proposed for engineering a universal multi-link power drive with power elements made of a thermally thin shape memory material. The paper provides the analysis of thermal processes in power elements of various shapes, geometric dimensions and using different methods of their heating (current transmission heating, convective and radiant heat exchange) to determine the efficiency of the engineered devices. Processing and operational properties of thermally thin power elements of a multi-link power drive are investigated. To determine their qualitative and quantitative indicators, a measuring bench was created with such functions as recording the amperage, temperature change, displacement, and developed forces on a single time scale. A relationship between the heating rate, rate of operating force development and return deformation force was found. A line of universal power drives with a developed deformation force of 500–10000 N and a displacement of 1.0–8.0 mm was created based on the calculations performed with the results of their testing and use in existing models of deforming devices presented.
Structure and phase composition formation of cast aluminum matrix composites during multiple remelting
Authors: Prusov E. S. , Deev V. B. , Aborkin A. V. , Panfilov A. A. , Kireev A. V.
Published: January 2023

The lack of understanding as to the nature of interfacial interaction between reinforcing particles and the matrix alloy during repeated remelting of cast composite materials is one of the problems hindering the expansion of their industrial application. This research is aimed at establishing the effect of repeated remelting of AK12 + 10 vol.% SiC aluminum matrix composites on the retention and chemical stability of silicon carbide reinforcing particles. It is shown that an increase in the number of remelting iterations is not accompanied by any new phases appearing at the interfaces between particles and the matrix, which indicates the stability of the SiC reinforcing phase in aluminumsilicon melts under the considered temperature-time and concentration conditions. Repeated remelting of aluminum matrix composites with silicon carbide shifts the particle distribution uniformity towards a more uniform distribution degree (on average 0.81046 at the first remelting iteration, 0.6901 at the second one and 0.5609 at the third one) and slightly reduces their average sizes (from 70.74 μm at the first iteration to 65.76 μm at the second one and 61.21 μm at the third one), apparently due to particle fragmentation that leads to an increase in the quantity of finer particles. At the same time, the share of the area occupied by particles in the section regions under consideration remains practically unchanged (10.9293, 10.9607 and 11.6483 % at the first, second and third remelting iterations, respectively). In the course of repeated remelting of Al–SiC aluminum matrix composites, processes of reinforcing particle redistribution occur that lead to the destruction of agglomerates even without intensive mixing with an impeller. Due to this, the uniformity of particle distribution in the structure of secondary aluminum matrix composite ingots can be significantly improved.
Study of the limiting parameters of deep drawing of sheet blanks made of heat-resistant copper alloys
Authors: Demyanenko E. G. , Popov I. P. , Nikonov D. A.
Published: January 2023

This article studies the mechanism of thin-walled workpiece deep drawing in the mould with a conical die and determines the forming limit state that occurs at the time of the bottom detachment in the radius part of the punch when stresses in the meridional direction reach their maximum value. This condition is determined by a decrease in the workpiece edge size at the stage of slow material hardening and a decrease in the workpiece flange area that are main factors hindering the process. This condition makes it possible to establish a criterion used to determine the limiting drawing ratio (ratio of the diameter of the workpiece to the diameter of the part), namely: equality of meridional stresses in the punch radius rounding area and the material tensile strength. The paper establishes the effect of the workpiece material strength properties, friction and die taper on the limiting drawing ratio. A change in the plastic and strength properties of the BrKh08 heat-resistant copper alloy (tensile strength, yield strength) does not affect the material hardening constant values and practically does not affect the limiting drawing ratio. The paper uses a comprehensive research method including theoretical analysis and modeling in the ANSYS/LS-DYNA software with input data for the 1.35 mm thick workpiece 100 mm in diameter made of BrKh08. The article presents computer simulation stages indicating main process parameters such as the workpiece material model, mechanical properties, type of elements, kinematic loads, conditions of contact interaction between elements, etc. Process simulation results confirmed theoretical conclusions necessary for the process implementation without part defects.
Obtaining Ti–Cu–C system composite materials by SHS process
Authors: Tsikarev V. G. , Filippenkov A. A. , Filippov M. A. , Alabushev A. V. , Sharapova V. A.
Published: January 2023

The aim of the research is to obtain wear-resistant products from composite materials of a new type using the SHS technology. The Ti–Cu–C system was selected taking into account the data available in the scientific and technical literature. Various SHS charge compositions consisting of titanium powder, copper powder, and carbon black were experimentally burned to determine compositions that can burn during the SHS process and provide a melt containing titanium carbide and titanium cuprides as a binder featuring higher mechanical properties and lower melting points than pure copper. Model samples of products in the form of bushings with an outer diameter of 70 and 110 mm were produced by burning the SHS charge with selected compositions in a reactor followed by the compaction of the resulting melt with a force of 50–60 t. After the rough workpiece electrical discharge machining, samples were cut out for phase analysis, X-ray spectral analysis, and wear tests. With an optimal ratio of SHS charge components, titanium carbide and a binder in the form of titanium cuprides of different compositions were revealed in the model sample material. Using the method of testing for wear when sliding on a fixed abrasive under a specific pressure of 1 MPa, it was determined that the relative abrasive resistance of the new material at a hardness of 50–52 HRC is 1.8–2.0 units in comparison with the hardened tool and die steel Kh12MFL. In order to implement the technology in practice, an algorithm was developed for calculating the compositions of the newly formulated SHS charge, while its principle is such a ratio of components where the introduced carbon forms titanium carbide with titanium, and the added excess titanium forms titanium cuprides with copper. The developed material can be considered as promising for use as elements of equipment operating under abrasive wear conditions. This development is patented, Patent No. 2691656 (Russian Federation).
Exothermic synthesis of binary solid solutions based on hafnium and zirconium carbides
Authors: Shcherbakov V. A. , Gryadunov A. N. , Alymov M. I.
Published: January 2023

The paper presents the results of an experimental study into the possibility of producing ultra-high temperature ceramics  constituting solid solutions of HfC and ZrC carbides by the single-stage electro-thermal explosion (ETE) method under pressure.  Adiabatic flame temperature and phase composition of the equilibrium final product were calculated based on thermodynamic  data. It was shown that when the ZrC content in the final product is less than 20 wt.%, adiabatic flame temperature reaches 3800– 3900 K, and the combustion product contains hafnium and zirconium carbides. The effect of mechanical activation modes in an  AGO-2 planetary centrifugal mill used for a reaction mixture containing Hf, Zr and C powders on its properties, phase composition  formation and the microstructure of carbide solid solutions was studied. It was shown that high-energy mixing in hexane leads to  the destruction of the crystal structure of Hf and Zr particles and the formation of amorphous composite particles. The synthesized  samples of ultra-high temperature ceramics were studied by X-ray phase and microstructure analyzes. It was shown that exothermic  synthesis leads to the formation of single-phase solid solutions of HfC and ZrC carbides with the average particle size of 0.2–1.5 μm.  The residual porosity of the binary carbides obtained is 10–12 %. It was found that, despite the high temperature of sample heating  during ETE under pressure, the particle size of the resulting solid solutions is significantly (by an order of magnitude) smaller than  the particle size of similar complex carbides (20–50 μm) obtained by other methods (SPS and hot pressing). This is associated with  the rapidity of the exothermic interaction of the reagents (10–50 ms) during ETE.
Mechanical properties and wear resistance of Fe–Ni–Cu-based metal matrix composites reinforced with hollow corundum microspheres
Authors: Bychkova M. Ya. , Manakova O. S. , Akhmetov A. S. , Kaysinov A. , Avdeenko E. N. , Loginov P. A. , Vorotilo S.
Published: January 2023

This paper focuses on the development of composite materials based on the Fe–Ni–Cu alloy with hollow corundum microspheres (HCM). The composites were produced by means of powder metallurgy: by mixing initial metallic powders in various types of mixers followed by hot pressing. Compact samples of Fe–Ni–Cu + HCM composites featured high relative density and microstructure homogeneity. The introduction of HCM leads to a decrease in strength to 30 % (from 1125 MPa to 800 MPa at a HCM concentration of 15 vol.%). However, resulting composite materials retained high plasticity. It was established by the micromechanical modeling method that such composites have stress concentration regions not at the interface between HCM and the matrix, but on the inner surface of microspheres. On the contrary, the adjacent matrix volume around HCM features stress relaxation and «unloaded» regions formed. HCM introduction into the matrix based on the Fe–Ni–Cu alloy increases wear resulting from friction on M300 concrete by 50–170 % with a grain size of 70–100 μm and by 160–325 % with a grain size of 100–140 μm. During friction, HCMs act as a reservoir for debris (concrete particles), so the matrix surface remains free of wear products and directly contacts the material processed. The heavy wear of composites with HCM makes them promising for use as a binder in diamond tools designed for the dry cutting of concrete and reinforced concrete.
Valery Ivanovich Kostikov celebrates his 85th anniversary
Authors: Editorial Article
Published: January 2023

.
Structure and properties of titanium hydride powder obtained from titanium sponge by SHS hydrogenation
Authors: Cherezov N. P. , Alymov M. I.
Published: January 2023

The results of the study of the structure and properties of titanium hydride powders obtained from titanium sponge by SHS hydrogenation and mechanical grinding are presented. Hydrogenation was carried out in a reactor at a constant hydrogen pressure of 3 MPa. After passing the combustion wave, the hot titanium sponge was cooled to room temperature in a hydrogenatmosphere. As a result, titanium hydride spongy granules with a hydrogen content of 4.2 wt.% were obtained. Titanium hydride was ground in a ball mill and divided into 4 fractions corresponding to the fractional composition of titanium powder PTK, PTS, PTM and PTOM. Particle size analysis showed that the samples of the PTK and PTOM powders have a narrower particle distribution in comparison with the PTS and PTM ones. Further, obtained powders chemical composition and surface morphology studies were carried out and bulk density, compaction, pycnometric density and specific surface area were determined. According to the chemical analysis results the content of carbon and oxygen impurities decreases during SHS-hydrogenation and the iron content slightly increases during mechanical grinding depending on the grinding time. The study of morphology showed that the hydride titanium particles have an irregular fragmentary shape, such morphology is characteristic of powders obtained by this technology. The surface structure has partially preserved structure of the initial titanium sponge and consists of elongated oriented grains. It is established that with a decrease in the particle size, the bulk density decreases, and the compaction increases. Pycnometric density and specific surface area values are approximately equal for all powder samples.
Option pricing in emerging markets using pure jump processes: explicit calibration of IST30 European option
Authors: Yilmaz Bilgi , Hekimoglu Alper
Published: January 2023

Purpose- This study aims to illustrate the efficiency of pure jump processes, more specifically Variance Gamma (VG) and Normal Inverse Gaussian models (NIG), in option pricing by comparing with the Black Scholes (BS) option pricing model for emerging markets.
Methodology- This study presents an alternative derivation of option pricing formulas for VG and NIG models. Then, it investigates the VG and NIG models' option pricing performance with the help of new derivation by comparing them with the BS option pricing model for emerging markets for an emerging country, Turkey. The data consists of the BIST30 index daily price and European options written on this index extend from 05 May 2018 to 05 May 2020 for given exercise prices with a maturity of 90 days. In this period, the European call options' strike prices range from 1200 to 1650, and the European put options' strike prices range from 1000 to 1400. To compare the models' efficiency, first, we calibrate the models by minimizing the sum of squared deviations between the observed and theoretical option prices. Second, we compute the option prices and compare the results with the observed option prices.
Findings- The significant contribution to the literature is the calibration of the pure jump processes (VG and NIG processes) using the characteristic functions, the continuous BS prices for an emerging market, and the computation of European options prices in BIST. We find that while the NIG process performs better than VG and BS models, the BS model is the worst in option pricing.
Conclusion- The pure jump processes (VG and NIG processes) can be calibrated using the characteristic functions, and option price estimations with them are better than the continuous BS prices for an emerging market. Thus, the pure jump processes are more efficient in market modeling than the BS model.
Total quality management practices in health services
Authors: Erkan Itir , Unal Mehmet
Published: January 2023

Purpose- The goal of this study is to emphasize the importance of total quality management practices in health services in order to ensure patient satisfaction and to create customer loyalty.
Methodology- The methodology of this study is a thorough literature review of Total Quality Management in health services.
Findings- Health services are a vital service area that does not accept mistakes and is directly related to human life. Due to the fact that its area of interest is human health and human life, quality in health services appears as a necessity rather than a choice. It is possible for societies to live in health and well-being if the individuals that make up that society are healthy. Protection of individual health and investments and sanctions aimed at protecting this are the most fundamental steps in the health of the society. The implementation of patient rights within the health system has brought the concept of "Quality Health Care" to our agenda. Quality in health care; it includes the diagnosis and treatment services to be in accordance with modern medical science, scientific standards and norms, and the services provided to meet patient expectations.
Conclusion- The fact that health services are directly related to human life, the fact that mistakes to be made will cost expensive, the obligation to provide services with zero margin of error have made it obligatory to provide quality health services in health services and therefore in health institutions.
Customs brokerage company selection problem with hybrid method
Authors: Kara Karahan , Yalcin Galip Cihan
Published: January 2023

Purpose- Customs are the main transit points in cross-border trade activities. Customs logistics activities are carried out by authorized customs brokerage companies (CBC). Export/import companies that execute customs clearance with the right CBC partners gain competitive advantage. Therefore, selecting the right CBC is an important decision-making problem. In this research, CBC selection problem is handled with fuzzy-based multi criteria decision-making (MCDM) methods.
Methodology- The research application covers the CBC selection process of an export firm. The criteria for the problem are obtained as a result of the literature review. The opinions of the decision makers are also taken. Seven criteria have been identified. These criteria are cost/price, service quality, information system and technology, flexibility, relationship, professionalism, reputation. Fuzzy-based stepwise weight assessment ratio analysis (F-SWARA) method is used for criterion weighting. In order of alternatives, ranking of alternatives through functional mapping of criterion sub-intervals into single interval (F-RAFSI) method is applied. Four decision makers are used to compare the criteria.
Findings- Four CBC alternative rankings based on criteria are made. According to the research findings, the highest criterion weight is determined as service quality. The first alternative is chosen as the best alternative.
Conclusion- CBC alternative sequencing has been made for the export company by applying fuzzy-based MCDM methods. Thus, the applicability of MCDM methods is supported in CBC company selection. In addition, the CBC selection criteria are determined, and the CBC selection problem are shed light on. Suggestions are also made to export companies and researchers based on the results of the research.
The effect of healthcare professionals perceptions of emotional commitmemt and organizational trust on the level of task performance
Authors: Erdal Nurgul , Filiz Mustafa , Budak Olkan
Published: January 2023

Purpose- This study aims to investigate the effect of healthcare workers' emotional commitment on performance through organizational trust.
Methodology- To examine the relationship between dependent and independent variables, data were collected through questionnaires with 420 health workers working in various hospitals. The collected data were analyzed with statistical methods used in social sciences.
Findings- As a result of data analysis, it has been proven that continuance commitment and normative commitment have a positive effect on organizational trust. While continuance commitment had a positive effect on performance, normative commitment did not have a positive effect on performance. It has been observed that organizational trust has a positive effect on performance. While the partial mediating effect of continuance commitment on performance through an organizational trust has been proven,
No positive effect of normative commitment on performance through the organizational trust was observed.
Conclusion- This study shows that the emotional commitment of health workers, which is extremely important for health businesses, can increase their performance through organizational trust. This model can be a role model for other healthcare organizations and fills a research gap by providing an experimental study of repeated hospital management.
The Use of Virtual Worlds in the Field of Education: A Bibliometric Study
Authors: BATTAL Ali , TAŞDELEN Abdulkadir
Published: January 2023

The purpose of this study is to examine the publications conducted in education related to virtual worlds with the bibliometric analysis method. This study employed the appropriate keywords determined via digging the Web of Science database. A total of 2,978 publications meeting the criteria of the current study were examined. VOSviewer software was used for the analysis. We utilized co-authorship analysis to see the descriptive characteristics of the examined publications. The most conducted type was proceedings and the number of publications fluctuated over time with a peak in 2012. England, USA, and Spain had the most publications among the countries, and Open University, Coventry University, and the Polytechnic University of Bucharest had the most publications among the organizations. The majority of the studies were published in the journal of Computers & Education, British Journal of Educational Technology, and Interactive Learning Environments. For revealing the most common keywords, we used the co-occurrence analysis. “e-learning”, “second life” and “higher education” were the most occurred keywords in the publications. The citations analysis was used to see which authors and publications were mostly cited in the examined papers. The most cited authors were Dede, C., Lan, Y. and Ketelhut, D. J. According to the analysis of the cited references, Dalgarno and Lee, (2010), Merchant, Goetz, Cifuentes, Keeney-Kennicutt, and Davis, (2014) and Dunleavy et al. (2008) were the most cited studies. Technological developments have affected the interest in the use of VWs in education. As a new type or extension of virtual worlds, metaverse promises new opportunities in education. The findings of this study would present a road map for those future research to see the general picture of the relevant area.
La antropología y los cronistas
Authors: Arcila Vélez Graciliano
Published: January 2023

-