The influence of modification by superdispersed powders on the lead-tin-base bronze structure

The paper presents data on the influence of additives of the pre-treated aluminium oxide powder on the structure of cast lead-tin-based bronzes. Different quantities of the modifier, based on the superdispersed aluminum oxide powder, were added to the bronze melt. The studies have shown that addition of a small amount of aluminum oxide powder (0.07... 0.25 %) allows modifying the micro structure of the obtained castings. This modification includes grain refinement, reduction of the matrix dendrites size of tin solid solution in copper, as well as formation of spherical inclusions of the low-melting phase - lead. In this case, the addition of such modifier influences weakly the morphology and the quantity of solid eutectoid inclusions based on electron compound Cu[31] Sn[8]

Formation of high-carbon abrasion-resistant surface layers when high-energy heating by high-frequency currents

The paper shows the possibility of carburization of low-carbon steel surface layers using high-frequency currents. The mathematical modeling of carburization using high-energy heating by high-frequency currents (HEH HFC) has been carried out, the temperature fields formed during the given processing have been calculated, as well as the structural changes in the surface layers have been simulated. The features of the structure formation in the surface layers of low-carbon steel after carburizing via HEH HFC have been determined by optical and scanning microscopy, which is confirmed by the computational models. The rational mode of fusion via HEH HFC has also been determined (power density of the source q[s]=(1.5...4.0)•10{8} W m{-2}, (the relative travel speed of parts V[p]=5 ... 100 mm /sec), with forming the compressive retained stresses in the surface layer ([sigma][RS]=-300...-400 MPa)

Temperature evaluation of a hyper-rapid plasma jet by the method of high-speed video recording

In this paper the procedure of comparative evaluation of plasma temperature using high-speed video filming of fast processes is presented. It has been established that the maximum plasma temperature reaches the value exceeding 30 000 K for the hypervelocity electric-discharge plasma, generated by a coaxial magnetoplasma accelerator with the use of the 'Image J' software

Investigation of the structure and microhardness of Mo-Fe-C coatings obtained by the electron beam injected in the atmosphere

In this work 'Mo-Fe-C' coatings fabricated on medium carbon steel by non-vacuum electron beam cladding were investigated. The structure of coatings and transition zones were studied by scanning electron microscopy (SEM). It was shown that an increase of Fe percentage in the cladding mixture led to a decrease of the eutectic volume fraction in the coating and was accompanied by the formation of the gradient structure between the coating and a substrate material. Measurements of microhardness in the cross section of samples revealed that the cladding of a 'Mo-C powder mixture contributed to a 4.5-fold increase of microhardness

Fabrication of the Ni[3]Al-based alloy formed by spark plasma sintering of VKNA powders

The material based on Ni[3]Al intermetallic has been obtained from the industrial powder of a VKNA type by the method of spark plasma sintering. Materials sintering was conducted at the temperature of 1100 °С, compacting pressure of 20 MPa, and during soaking time equal to 5 minutes. The heating rate of samples amounted to 50 and 200 °С/min. It has been established that the material obtained by sintering at the rate of 50 °С/min possesses a maximum value of density (5.93 g/cm{3}) and a maximum level of bending strength (~ 400 MPa)

Investigation of the structure and microhardness of Mo-Fe-C coatings obtained by the electron beam injected in the atmosphere

In this work 'Mo-Fe-C' coatings fabricated on medium carbon steel by non-vacuum electron beam cladding were investigated. The structure of coatings and transition zones were studied by scanning electron microscopy (SEM). It was shown that an increase of Fe percentage in the cladding mixture led to a decrease of the eutectic volume fraction in the coating and was accompanied by the formation of the gradient structure between the coating and a substrate material. Measurements of microhardness in the cross section of samples revealed that the cladding of a 'Mo-C powder mixture contributed to a 4.5-fold increase of microhardness

Reproduction of reservoir pressure by machine learning methods and study of its influence on the cracks formation process in hydraulic fracturing

Hydraulic fracturing is an effective way to stimulate oil production, which is currently widely used in various conditions, including complex carbonate reservoirs. In the conditions of the considered field, hydraulic fracturing leads to a significant differentiation of technological efficiency indicators, which makes it expedient to study in detail the crack formation patterns. For all affected wells, the assessment of the resulting fractures spatial orientation was performed using the developed indirect technique, the reliability of which was confirmed by geophysical methods. In the course of the analysis, it was found that in all cases the fracture is oriented in the direction of the development system element area, which is characterized by the maximum reservoir pressure. At the same time, reservoir pressure values for all wells were determined at one point in time (at the beginning of hydraulic fracturing) using machine learning methods. The reliability of the used machine learning methods is confirmed by high convergence with the actual (historical) reservoir pressures obtained during hydrodynamic studies of wells. The obtained conclusion about the influence of the formation pressure on the patterns of fracturing should be taken into account when planning hydraulic fracturing in the considered conditions

Environmental Behavior of Youth and Sustainable Development

The relationship between people and nature is one of the most important current issues of human survival. This circumstance makes it necessary to educate young people who are receptive to global challenges and ready to solve the urgent problems of our time. The purpose of the article is to analyze the experience of the environmental behavior of young people in the metropolis. The authors studied articles and monographs that contain Russian and international experience in the environmental behavior of citizens. The following factors determine people’s behavior: the cognitive capabilities of people who determine the understanding and perception of nature and the value-affective component that determines the attitude towards nature. The next task of the study is surveying young people through an online survey and its analysis. The research was realized in Ekaterinburg, the administrative center of the Sverdlovsk region (Russia). The study of the current ecological situation in Ekaterinburg made it possible to conclude that the environmental problem arises not only and not simply as a problem of environmental pollution and other negative influences of human economic activity. This problem grows into transforming the spontaneous impact of society on nature into a consciously, purposefully, systematically developing harmonious interaction with it. The study results showed that, from the point of view of the youth of Ekaterinburg, the city’s ecological situation is one of the most pressing problems. Despite minor improvements over the past 3–5 years, this problem has not lost relevance, and regional authorities and city residents should be responsible for its solution. Young people know environmental practices, but they often do not apply them systematically. Ecological behavior is encouraged and discussed among friends/acquaintances. The key factors influencing the formation of environmental behavior practices are the mass media and social networks. The most popular social network for obtaining information on ecological practices among young people is Instagram, and the key persons are bloggers. This study did not reveal the influence of the socio-demographic characteristics of young people on the application of eco-behavior practices, which may indicate the need for a survey of a larger sample. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Acknowledgments: This research was supported by TPU development program

Formation of high-carbon abrasion-resistant surface layers when high-energy heating by high-frequency currents

The paper shows the possibility of carburization of low-carbon steel surface layers using high-frequency currents. The mathematical modeling of carburization using high-energy heating by high-frequency currents (HEH HFC) has been carried out, the temperature fields formed during the given processing have been calculated, as well as the structural changes in the surface layers have been simulated. The features of the structure formation in the surface layers of low-carbon steel after carburizing via HEH HFC have been determined by optical and scanning microscopy, which is confirmed by the computational models. The rational mode of fusion via HEH HFC has also been determined (power density of the source q[s]=(1.5...4.0)•10{8} W m{-2}, (the relative travel speed of parts V[p]=5 ... 100 mm /sec), with forming the compressive retained stresses in the surface layer ([sigma][RS]=-300...-400 MPa)

Predictive use of the Maximum Entropy Production principle for Past and Present Climates

In this paper, we show how the MEP hypothesis may be used to build simple climate models without representing explicitly the energy transport by the atmosphere. The purpose is twofold. First, we assess the performance of the MEP hypothesis by comparing a simple model with minimal input data to a complex, state-of-the-art General Circulation Model. Next, we show how to improve the realism of MEP climate models by including climate feedbacks, focusing on the case of the water-vapour feedback. We also discuss the dependence of the entropy production rate and predicted surface temperature on the resolution of the model