Fractography of Fatigue Fracture Surface in Silumin Subjected to Electron-Beam Processing

The surface modification of the eutectic silumin with high-intensity pulsed electron beam has been carried out. Multi-cycle fatigue tests were performed and irradiation mode made possible the increase in the silumin fatigue life more than 3.5 times was determined. Studies of the structure of the surface irradiation and surface fatigue fracture of silumin in the initial (unirradiated) state and after modification with intense pulsed electron beam were carried out by methods of scanning electron microscopy. It has been shown, that in mode of partial melting of the irradiation surface the modification process of silicon plates is accompanied by the formation of numerous large micropores along the boundary plate/matrix and microcracks located in the silicon plates. A multi-modal structure (grain size within 30-50 μm with silicon particles up to 10 [mu]m located on the boundaries) is formed in stable melting mode, as well as subgrain structure in the form of crystallization cells from 100 to 250 [mu]m in size). Formation of a multi-modal, multi-phase, submicro- and nanosize structure assisting to a significant increase in the critical length of the crack, the safety coefficient and decrease in step of cracks for loading cycle was the main cause for the increase in silumin fatigue life

Fatigue variation of surface properties of silumin subjected to electron-beam treatment

The analysis of structure-phase states modification of silumin subjected to electron beam treatment with the following fatigue loading up to the failure is carried out by methods of transmission electron diffraction microscopy. The tribology and strength properties of silumin surface after electron beam treatment and fatigue tests are studied and hardness decrease, wear coefficient and friction coefficient increase with the growth of cycles number are revealed. The possible reasons of the tribology and strength properties of silumin surface layers decrease are discussed

Fractography of Fatigue Fracture Surface in Silumin Subjected to Electron-Beam Processing

The surface modification of the eutectic silumin with high-intensity pulsed electron beam has been carried out. Multi-cycle fatigue tests were performed and irradiation mode made possible the increase in the silumin fatigue life more than 3.5 times was determined. Studies of the structure of the surface irradiation and surface fatigue fracture of silumin in the initial (unirradiated) state and after modification with intense pulsed electron beam were carried out by methods of scanning electron microscopy. It has been shown, that in mode of partial melting of the irradiation surface the modification process of silicon plates is accompanied by the formation of numerous large micropores along the boundary plate/matrix and microcracks located in the silicon plates. A multi-modal structure (grain size within 30-50 μm with silicon particles up to 10 [mu]m located on the boundaries) is formed in stable melting mode, as well as subgrain structure in the form of crystallization cells from 100 to 250 [mu]m in size). Formation of a multi-modal, multi-phase, submicro- and nanosize structure assisting to a significant increase in the critical length of the crack, the safety coefficient and decrease in step of cracks for loading cycle was the main cause for the increase in silumin fatigue life

Degradation of structure and properties of rail surface layer at long-term operation

The microstructure evolution and properties variation of the surface layer of rail steel after passed 500 and 1000 million tons of gross weight (MTGW) have been investigated. The wear rate increases to 3 and 3.4 times after passed 500 and 1000 MTGW, respectively. The corresponding friction coefficient decreases by 1.4 and 1.1 times. The cementite plates were destroyed and formed the cementite particles of around 10-50 nm in size after passed 500 MTGW. The early stage dynamical recrystallization was observed after passed 1000 MTGW. The mechanisms for these have been suggested. The large number of bend extinction contours is revealed in the surface layer. The internal stress field is evaluated

Le pluralisme politique à l’épreuve de la vie privée : entre normes et pratiques

L’espace des relations interpersonnelles et privées, en tant qu’espace de politisation et d’expression des choix politiques, est peu connu. C’est à une meilleure connaissance du « citoyen privé » et de la « politisation intime » que cet article veut contribuer, en étudiant les ressemblances et les divergences idéologiques au sein du cercle des proches. Présentant les résultats d’une enquête quantitative et représentative de la population française inédite, « Famille, amour et politique », réalisée par le CEVIPOF, il examine la filiation, la conjugalité, et l’amitié et montre les interactions et les transactions qui opèrent entre le système des normes et le système des affects des individus. La famille apparaît plus hétérogame politiquement tandis que le couple et le cercle des amis sont plus homogames. Toutefois, c’est le niveau de politisation des individus qui est en dernière instance le plus déterminant. Une affiliation politique affirmée, et tout particulièrement à gauche, ainsi qu’un intérêt marqué pour la politique, renforcent toujours l’homogamie politique au sein du cercle des proches, dans les principes comme dans les faits. Plus largement, l’article ouvre une réflexion sur l’espace de la vie privée en tant que terrain d’expérience des conditions de la pluralité démocratique.Little is known of the role played by private interpersonal relationships in politicization and the expression of political choices. This article aims to improve our understanding of “private citizens” and “personal politicization” through a study of ideological similarities and divergences within family and friendship circles. The analysis, based on findings from an unprecedented quantitative representative French population survey by the CEVIPOF (Center for the study of French political life) entitled “Famille, amour et politique” [Family, love and politics], examines filiation, conjugality and friendship, showing the interactions and transactions that take place between the system of norms and the system of individual feelings. Families appear more heterogamous politically, while couples and friendship circles are more homogamous. However, individuals’ level of politicization is ultimately the most determinant factor. Having a strong political affiliation, particularly on the left of the political spectrum, and a strong interest in politics always strengthens intra-circle political homogamy in terms of both principles and actions. At a more general level, the article reflects on the sphere of private life as a field for the development of conditions of democratic pluralism

Deformation behavior of Technical Pure Titanium in a Constant Magnetic Field of 0.3 T

В результате испытаний образцов титана ВТ1–0 на многоцикловую усталость установлено, что наблюдается увеличение усталостной долговечности на 64 % в постоянном магнитном поле 0,3 Тл. Экспериментальные результаты по исследованию процесса ползучести показали, что в постоянном магнитном поле скорость ползучести увеличивается на 30,71 %.As a result of tests of VT1–0 titanium specimens for high-cycle fatigue, it was found that there is an increase in fatigue life by 64 % in a constant magnetic field of 0,3 T. Experimental results on the study of the creep process showed that in a constant magnetic field, the creep rate increases by 30,71 %.Исследование выполнено за счет гранта Российского научного фонда (проект № 21-79-00118).The research was carried out at the expense of a grant from the Russian Science Foundation (project No. 21-79-00118)

Deformation Hardening of Steels of Different Structural Classes

Получены кривые деформационного упрочнения сталей различных структурных классов, подвергнутых пластической деформации одноосным сжатием. Установлено, что деформационное упрочнение исследуемых сталей носит многофакторный характер.The curves of strain hardening of steels of various structural classes subjected to plastic deformation by uniaxial compression are obtained. It was found that the strain hardening of the investigated steels is multifactorial

Application of Geoinformation Technologies for Assessment of the Epizootiological and Epidemiological Situation on Anthrax in the Volgograd Region

Objective of the study was to assess the epizootiological and epidemiological situation on anthrax in the Volgograd Region in the period of 1920–2019, to zone the territory according to the degree of disadvantage as regards anthrax using geographic information technologies. Materials and methods. The reporting data of the Rospotrebnadzor Administration, Veterinary Committee in the Volgograd Region, and literature sources were studied. ESRI-ArcGIS 10 software was used as a GIS-platform. Epizootic index was applied in the zoning according to the degree of disadvantage regarding anthrax in the territories of the region. Results and discussion. Currently, 529 stationary potentially hazardous as regards anthrax areas have been registered in 33 districts of the Volgograd Region, 53 anthrax burial sites are accounted for in 20 districts. During the period of 1970–2019, 226 cases of infection of farm animals and 37 cases of anthrax among humans were detected. Most of the stationary potentially hazardous as regards anthrax areas (347 sites, 66 %) were formed in 1930–1949. Maximum activity was observed in 1930–1959. The zoning of the territory of the Volgograd Region was carried out using ESRI-ArcGIS 10 software, as a result of which the municipal districts were divided into four groups according to the degree of disadvantage regarding anthrax. The potential of different soil and landscape zones in the persistence of the anthrax microbe was studied. It has been found that chernozem, chestnut, dark-chestnut soil types, which occupying more than 50 % of the total region area and predominate in the zones of moderately arid and dry steppes, alongside alluvial meadow soils of river valleys, floodplains of rivers are very favorable for the persistence of the anthrax pathogen. The territory of the Volgograd Region is endemic for this infection and epizootiological and epidemiological well-being in the region largely depends on the completeness and timelines of preventive measures. The use of geographic information technologies provides a comprehensive analysis of the infection activity manifestations with reliable improvement of the anti-anthrax surveillance system and control in making differentiated managerial decisions

Синдром обструктивного апноэ сна и нарушения ритма сердца: современное состояние проблемы

The factors contributing to the development of cardiac arrhythmias in obstructive sleep apnea syndrome and the main methods of treating this syndrome have been analyzed and summarized.The review discusses the relationships of obstructive sleep apnea syndrome (OSAS) with various types of heart rhythm disorders. Pathogenetic factors of obstructive sleep apnea syndrome leading to the development of cardiac arrhythmias, current treatment strategies and their impact on heart rhythm disorders are summarized.Проанализированы и обобщены данные о факторах, способствующих развитию нарушений ритма сердца при синдроме обструктивного апноэ сна, и основных методах лечения синдрома.В обзоре представлен анализ современных данных о связи синдрома обструктивного апноэ сна с различными видами нарушений ритма сердца; патогенетических факторах синдрома, приводящих к развитию нарушений ритма сердца; существующих методах лечения обструктивного апноэ сна и их влиянии на нарушения ритма сердца