Activity on projects of ITER and DEMO reactors has shown that solution of problems of divertor target plates and other plasma facing elements (PFEs) based on the solid plasma facing materials cause serious difficulties. Problems of PFE degradation, tritium accumulation and plasma pollution can be overcome by the use of liquid lithium–metal with low Z. Application of lithium will allow to create a self-renewal and MHD stable liquid metal surface of the in-vessel devices possessing practically unlimited service life; to reduce power flux due to intensive re-irradiation on lithium atoms in plasma periphery that will essentially facilitate a problem of heat removal from PFE; to reduce Zeff of plasma to minimally possible level close to 1; to exclude tritium accumulation, that is provided with absence of dust products and an opportunity of the active control of the tritium contents in liquid lithium. Realization of these advantages is based on use of so-called lithium capillary-porous system (CPS) – new material in which liquid lithium fill a solid matrix from porous material. The progress in development of lithium technology and also activity in lithium experiments in the tokamaks TFTR, T-11M, T-10, FTU, NSTX, HT-7 and stellarator TJ II permits of solving the problems in development of steady-state operating lithium divertor module project for Kazakhstan tokamak KTM. At present the lithium divertor module for KTM tokamak is under development in the framework of ISTC project # K-1561. Initial heating up to 200 °C and lithium surface temperature stabilization during plasma interaction in the range of 350–550 °C will be provided by external system for thermal stabilization due to circulation of the Na–K heat transfer media. Lithium filled tungsten felt is offered as the base plasma facing material of divertor. Development, creation and experimental research of lithium divertor model for KTM will allow to solve existing problems and to fulfill the basic approaches to designing of lithium divertor and in-vessel elements of new fusion reactor generation, to investigate plasma physics aspects of lithium influence, to develop technology of work with lithium in tokamak conditions. Results of this project addresses to the progress in the field of fusion neutrons source and fusion energy source creation.
Grand Canonical Molecular Dynamics (GCMD) simulations were performed to investigate the intercalation of CO2 and H2O molecules in the interlayers of the smectite clay, Na-hectorite, at temperatures and pressures relevant to petroleum reservoir and geological carbon sequestration conditions and in equilibrium with H2O-saturated CO2. The computed adsorption isotherms indicate that CO2 molecules enter the interlayer space of Na-hectorite only when it is hydrated with approximately three H2O molecules per unit cell. The computed immersion energies show that the bilayer hydrate structure (2WL) contains less CO2 than the monolayer structure (1WL) but that the 2WL hydrate is the most thermodynamically stable state, consistent with experimental results for a similar Na-montmorillonite smectite. Under all T and P conditions examined (323–368 K and 90–150 bar), the CO2 molecules are adsorbed at the midplane of clay interlayers for the 1WL structure and closer to one of the basal surfaces for the 2WL structure. Interlayer CO2 molecules are dynamically less restricted in the 2WL structures. The CO2 molecules are preferentially located near basal surface oxygen atoms and H2O molecules rather than in coordination with Na+ ions. Accounting for the orientation and flexibility of the structural −OH groups of the clay layer has a significant effect on the details of the computed structure and dynamics of H2O and CO2 molecules but does not affect the overall trends with changing basal spacing or the principal structural and dynamical conclusions. Temperature and pressure in the ranges examined have little effect on the principal structural and energetic conclusions, but the rates of dynamical processes increase with increasing temperature, as expected.
The application of finite element simulation to the problem of roll pass design for round bar rolling is considered. Two roll pass sequences were developed by analytical methods and then optimized using 2.5D Finite Element Method (FEM). The first one is a classical oval-round roll pass design. The second one is a combination of flat rolls and round roll passes. Relying on the simulation data obtained by FEM, the roll gaps were adjusted to achieve the required bar shape and the uniform distribution of rolling force between the passes. Advantages and disadvantages of each roll pass design were considered.
The problem of planar oscillations of a pendulum with variable length suspended on the Moon’s surface is considered. It is assumed that the Earth and Moon (or, in the general case, a planet and its satellite, or an asteroid and a spacecraft) revolve around the common center of mass in unperturbed elliptical Keplerian orbits. We discuss how the change in length of a pendulum can be used to compensate its oscillations. We wrote equations of motion, indicated a rule for the change in length of a pendulum, at which it has equilibrium positions relative to the coordinate system rotating together with the Moon and Earth. We study the necessary conditions for the stability of these motions. Chaotic dynamics of the pendulum is studied numerically and analytically.
The problem of motion of a heavy particle on a sphere uniformly rotating about a fixed axis is considered in the case of dry friction. It is assumed that the angle of inclination of the rotation axis is constant. The existence of equilibria in an absolute coordinate system and their linear stability are discussed. The equilibria in a relative coordinate system rotating with the sphere are also studied. These equilibria are generally nonisolated. The dependence of the equilibrium sets of this kind on the system parameters is also considered. © 2015, Pleiades Publishing, Ltd.
This article discusses research done on modeling, analyzing, and optimizing the technology used to forge the titanium sections of pressure vessels. The finite-element method was used for computer modeling of the deformation of the material during the forging operation. The study examined the forging force, the uniformity of deformation of the vessel’s walls, the filling of the dies, and the probability of crimping. Consideration was given to the possibility of using the phenomenon of superplasticity to forge the given product. The superplastic flow regime is maintained only during the final stage of the forging operation (the last 20% of the stroke of the die) in order to shorten operation as a whole. This is done by setting the die speed at a value which ensures that the material is deformed within a prescribed rate range and that the limits specified for the maximum forces are observed. Several alternatives were examined for making the vessel, these variants differing in the form of the semifinished product and the configuration of the dies. With constraints on the maximum loads and forging time, the technology that was chosen makes it possible to significantly increase the coefficient that characterizes the utilization of titanium in the production process.
In the usual everyday life, it is well known that the inverted pendulum is unstable and is ready to fall to “all four sides,” to the left and to the right, forward and backward. The theoretical studies and the lunar experience of moon robots and astronauts also confirms this property. The question arises: Is this property preserved if the pendulum is “very, very long”? It turns out that the answer is negative; namely, if the pendulum length significantly exceeds the Moon radius, then the radial equilibria at which the pendulum is located along the straight line connecting the Earth and Moon centers are Lyapunov stable and the pendulum does not fall in any direction at all. Moreover, if the pendulum goes beyond the collinear libration points, then it can be extended and manufactured from cables. This property was noted by F. A. Tsander and underlies the so-called lunar space elevator (e.g., see ). In the plane of the Earth and Moon orbits, there are some other equilibria which turn out to be unstable. The question is, Are there equilibria at which the pendulum is located outside the orbital plane? In this paper, we show that the answer is positive, but such equilibria are unstable in the secular sense. We also study necessary conditions for the stability of lunar pendulum oscillations in the plane of the lunar orbit. It was numerically discovered that stable and unstable equilibria alternate depending on the oscillation amplitude and the angular velocity of rotation.
Представлен сценарный прогноз эволюции в период до 2040 г. мировых энергетических рынков, разработанный на модельно-информационном комплексе SCANER. Рассмотрены перспективы развития важных для электроэнергетики топливных рынков с прогнозами спроса, производства и цен нефти, газа, угля и неуглеродных ресурсов по регионам мира. Прогнозируемое замедление роста мирового спроса на ископаемые топлива и достаточность их ресурсов с относительно низкими затратами на добычу удержат цены топлива (здесь и далее по тексту данные приводятся в ценах 2014 г.) ниже пика их значений в 2012 г. Показан опережающий рост спроса на электроэнергию по сравнению с другими энергоресурсами по регионам и крупным странам мира. Исследованы условия межтопливной конкуренции в электроэнергетике с учетом изменения прогнозных цен топлива и стоимостных показателей разных технологий электрогенерации. Для этого оценены соотношения дисконтированных затрат на производство электроэнергии новыми газовыми и угольными ТЭС, ветровыми и солнечными электростанциями. Показано, что учет системных эффектов [режимов работы, необходимого дублирования и резервирования мощности электростанций на основе возобновляемых источников энергии (ВИЭ)] заметно ухудшает конкурентоспособность возобновляемой энергетики и далеко не всегда компенсируется ожидаемым снижением ее капиталоемкости и ростом цен топлива для ТЭС. Но даже при сдержанном (относительно других прогнозов) росте роли электростанций на ВИЭ выработка электроэнергии на них в мире утроится. При этом тепловые электростанции сохранят свою ведущую роль, обеспечивая до 60% мирового производства электроэнергии, в том числе около половины – за счет использования газа.
Изучено влияние методов мягкого пиролиза (гидротермальной карбонизации и торрефакции) на физико-химические свойства биоугля. Установлено, что биоуголь, полученный гидротермальной карбонизацией, отличается большой удельной поверхностью и экзотермическим эффектом при разложении, имеет более дисперсную структуру и меньшую зольность по сравнению с образцами, полученными торрефакцией.
The urbanisation process growing rapidly during the latest several dozens of years leads to proliferation of infrastructurally complex territories. At the same time, growing interaction of critical infrastructures in combination with the increased frequency and scales of anomalous natural processes result in the growth of the intersystem failures. The intersystem failures can be characterised by cascading processes and disastrous consequences. Such failures are characterised by a high level of social and economic impact affecting various critical infrastructures (energy supply, transport, water supply, telecommunications, finance, etc.), which requires development of the methods and models for assessment of their occurrence and progress. The given paper is devoted to the problems of classification and quantitative assessment of intersystem accident consequences including cascade failure process. Classification of intersystem accident is proposed based on topology of cascade process. Moreover, topology-based and flow-based approaches are used for modelling of intersystem accidents in power and gas supply systems.
The paper is oriented toward the determination of constitutive equation constants by the inverse analysis of plane strain compression test results. The interpretation of such results is complicated by the inhomogeneity of strain rate distribution in the specimen caused by rigid ends, the lateral spreading of a specimen friction and the variation of temperature during the test. The results of plane strain compression tests of AISI-304 stainless steel are presented and significant deviations of temperature are observed at higher strain rates. Finite element simulation was performed to estimate the inhomogeneity of strain rate within the specimen and evaluate the effect of friction on the test results. Constitutive equations of the material were obtained by inverse analysis minimizing the deviations between the measured load values and the ones predicted by numerical simulation.
This article presents a detailed analysis of the economic efficiency of peat utilization for generating electricity and heat in Russian rural areas and decentralized power consumption areas on the basis of the comparison of power tariffs (prices) and full costs of peat-based electricity and heat production. The research was performed using the model-information complex detailed with respect to municipal areas and major peat deposits that was developed at the Energy Institute, National Research University Higher School of Economics. It is shown that the firing of lignin helium fuel (LHF) granules that are made from peat extracted by the excavating method according to the new, patented technology is considered most efficient. In nongasified areas, the total cost of heat power that is generated in new boiler houses on the basis of LHF granules is often lower than the total heat cost for the gasification of the area and construction of gas boiler houses. In some cases, the heat cost in gasified areas is lower when using a boiler house based on LHF granules than that provided by the conversion of a boiler house to gas fuel. It is also shown that the construction of peat-based heat sources with the overall power of up to 27600 GJ/h that generate a heat power of up to 167.5 million GJ/year will be economically efficient in the coming years, provided that the tariffs for energy sources remain the same. Taking into account the supportive measures that were accepted on a legislative basis in July 2016, sources with the total power of up to 70 GW may be effective for peat-based plants with combined heat-andpower generation. To stimulate the utilization of peat in decentralized power consumption areas and rural areas located in the vicinity of deposits of this fuel type, it is also suggested to make amendments in the normative legal base.
В знак признания важности энергетики для устойчивого развития Генеральная Ассамблея ОрганизацииОбъединенных Наций постановила провозгласить 2012 год Международным годом устойчивой энергетики. Формирование концепции устойчивого развития. Живя на земле, человек должен осознавать, что природа является его средой обитания и единственным источником существования. Отношение к экономике и природе - проблема нравственная, затрагивающая судьбу не только нынешних, но и всех последующих поколений, требующая духовного совершенствования человека - природопользователя, выбирающего путь, реализующего стратегию и участвующего в процессах экономического развития и бытия. В истории экономического развития можно выделить четыре основных периода, отличающихся отношением человека к природопользованию.