Numerical And Experimental Study Of Multi-Point Forming Of Thick Double-Curvature Plates From Aluminum Alloy 7075

The paper describes various rod type work tools intended for forming parts and their design peculiarities and technological processes they are used in. We present the device for multi-point forming thick double-curvature plates with the use of reconfigurable core punch and die in large temperature and speed range. The results of finite element modeling of forming and machining process are demonstrated. It is revealed that heating the work piece results in pressing of the rod into the work piece in the areas of maximum pressure. The depth of pressing depends on mechanical behavior of the material at forming temperature and force to forming rods. The paper presents the results of experiments on developing of multi-point forming plates

A process-based model of methane consumption by upland soils

This study combines a literature survey and field observation data in an ad initio attempt to construct a process-based model of methane sink in upland soils including both the biological and physical aspects of the process. Comparison is drawn between the predicted sink rates and chamber measurements in several forest and grassland sites in the southern part of West Siberia. CH4 flux, total respiration, air and soil temperature, soil moisture, pH, organic content, bulk density and solid phase density were measured during a field campaign in summer 2014. Two datasets from literature were also used for model validation. The modeled sink rates were found to be in relatively good correspondence with the values obtained in the field. Introduction of the rhizospheric methanotrophy significantly improves the match between the model and the observations. The Q10 values of methane sink observed in the field were 1.2-1.4, which is in good agreement with the experimental results from the other studies. Based on modeling results, we also conclude that soil oxygen concentration is not a limiting factor for methane sink in upland forest and grassland ecosystems.Peer reviewe

THE CRYSTALLOGRAPHIC TEXTURE SIMULATION OF TMCP

The TMCP crystallographic texture has been simulated. This texture arises as a result of hot austenite rolling and subsequent transformation into conformity with the ORs of Kurdjumov-Sachs. From the possible orientations of ferrite, the orientations arising on the austenite boundaries of CSL Σ3 were.Работа выполнена при финансовой поддержке стипендии Президента Российской Федерации (проект СП-3775.2021.1)

METHANE EMISSIONS FROM THERMOKARST LAKES IN THE SOUTHERN TUNDRA OF WESTERN SIBERIA

Lakes are an important natural source of methane – significant greenhouse gas of the modern atmosphere. Monitoring of methane emission from lakes ofnorthern territoriesis needed to update the available estimates of CH4 emission intensity into the atmosphere and to obtain multi-year series of observations. Field measurements of diffuse methane fluxes were carried out on lakes at different stages of thermokarst process located in Yamalo-Nenets Autonomous District (Western Siberia, Russia) during summer 2016 using static chamber method. Some statistical characteristics of measured fluxes were calculated (medians vary from 0.46 to 0.93 mgC-CH4∙m ∙h ), as well as annual diffuse emissions from studied lakes, which values are determined by the area of the lake’s water surface. Daily dynamics of methane fluxes were defined and approximation of fluxes with simple model was done, major factors are temperatures of lake bottom and of the surface air layer

О параллельной кинематике обтяжного пресса FET в операциях обтяжки при производстве изделий сложной пространственной геометрии

The kinematics of a stretching press mechanism of a parallel structure are investigated. The kinematic dependences aimed at setting the spatial position of the working elements of a cross-stretching press of FET type, which allow positioning its jaws at any time during the technological operations, are obtained. The forward and inverse control kinematics problems of the jaw mechanism stretching press are solvedИсследуется кинематика механизма обтяжного пресса с параллельной структурой. Получены кинематические зависимости, которые направлены на задание пространственного положения рабочих органов пресса поперечной обтяжки типа FET и позволяют позиционировать зажимы в каждый момент времени при выполнении технологических операций. Решаются прямая и обратная задачи кинематикой для управления зажимами обтяжного пресс

Schemes, parameters, work process, characteristics and structure of long-range interception aircraft engines

The article presents an analysis of promising directions of improving the design and layout schemes of power plants of modern long-range interception aircraft, related to the implementation of the capabilities of bypass turbojet engines. Research of power plants of unconventional design-layout schemes opens significant prospects for improving flight performance of the long-range intercept aviation systems. These are primarily engines with variable parameters of the work process due to wider control of the elements in the flow passage. In engines with variable parameters the elements of the flow duct compressor guide vanes, turbine nozzle guide vanes, the exhaust system, the combustion chamber and other elements are controlled. Additional components are used that can be switched off or over during the operation of the power plant (combustion chambers in the bypass duct, bypass valves, turbofan adapters), which ensures the adaptation of the engine operation mode to the flight conditions due to the integrated control system adapted to possible failures and malfunctions. It is expedient to use the range of the interception line in the case of a typical flight profile and providing the specified values of the maximum flight speed and altitude as a criterion of efficiency. It is shown that the computational methods based on mathematical modeling are an effective tool for justifying the decision-making in choosing rational values of the parameters of the work process of aviation gas turbine engines

A process-based model of methane consumption by upland soils

This study combines a literature survey and field observation data in an ad initio attempt to construct a process-based model of methane sink in upland soils including both the biological and physical aspects of the process. Comparison is drawn between the predicted sink rates and chamber measurements in several forest and grassland sites in the southern part of West Siberia. CH4 flux, total respiration, air and soil temperature, soil moisture, pH, organic content, bulk density and solid phase density were measured during a field campaign in summer 2014. Two datasets from literature were also used for model validation. The modeled sink rates were found to be in relatively good correspondence with the values obtained in the field. Introduction of the rhizospheric methanotrophy significantly improves the match between the model and the observations. The Q10 values of methane sink observed in the field were 1.2–1.4, which is in good agreement with the experimental results from the other studies. Based on modeling results, we also conclude that soil oxygen concentration is not a limiting factor for methane sink in upland forest and grassland ecosystems