This study proposes a method for determination of material characteristics by inverse analysis of free bulging tests results. The blow-forming tests were carried out at the temperature of 415 °C using aluminum alloy (AMg-6) sheets of a 0.92 mm thickness. Each test was performed at constant pressure. For each fixed value of pressure, a series of experiments was carried out with different forming times to obtain evolutions of dome height H and thickness s. Two different constitutive equations were used to describe the dependence of flow stress on the effective strain rate: the Backofen power equation and the Smirnov one taking into account an s-shape of stress-strain rate curve in the logarithmic scale. The constants of these equations were obtained by least squares minimization of deviations between the experimental variations of H and s and ones predicted by a simplified engineering model formulated for this purpose. Using the Smirnov constitutive model to describe the dependence of flow stress on strain rate, unlike the classical power law, makes it possible to analyze the variation of strain rate sensitivity index m with strain rate. On the basis of the obtained data, the optimum strain rate for AMg-6 processing was estimated as one corresponding to the maximum of strain rate sensitivity index. The validity of the proposed method was examined by finite element simulation of free bulging process.
We studied the information basis for the assessment of wind power potential on the territory of Russia. We described the methodology to determine the parameters of the Weibull function, which reflects the density of distribution of probabilities of wind flow speeds at a defined basic height above the surface of the earth using the available data on the average speed at this height and its repetition by gradations. The application of the least square method for determining these parameters, unlike the use of graphical methods, allows performing a statistical assessment of the results of approximation of empirical histograms by the Weibull formula. On the basis of the computer-aided analysis of the statistical data, it was shown that, at a fixed point where the wind speed changes at different heights, the range of parameter variation of the Weibull distribution curve is relatively small, the sensitivity of the function to parameter changes is quite low, and the influence of changes on the shape of speed distribution curves is negligible. Taking this into consideration, we proposed and mathematically verified the methodology of determining the speed parameters of the Weibull function at other heights using the parameter computations for this function at a basic height, which is known or defined by the average speed of wind flow, or the roughness coefficient of the geological substrate. We gave examples of practical application of the suggested methodology in the development of the Atlas of Renewable Energy Resources in Russia in conditions of deficiency of source meteorological data. The proposed methodology, to some extent, may solve the problem related to the lack of information on the vertical profile of repeatability of the wind flow speeds in the presence of a wide assortment of wind-driven power plants with different ranges of wind-wheel axis heights and various performance characteristics in the global market; as a result, this methodology can become a powerful tool for effective selection of equipment in the process of designing a power supply system in a certain location.
Superplasticity characteristics of two!component and multicomponent brasses in the temperature range 525–600°C have been investigated at tension tests under the conditions of stepwise enhancement in the strain rate and when maintaining a constant strain rate of 1 × 10–3 s–1. The effective energy for activating superplastic deformation has been determined. It has been shown that brass alloyed with aluminum, tin, and iron exhibits large elongations and less porosity due to superplastic deformation. Changes in the granular structure and sample surfaces have been analyzed after deformation, and signs of grain!boundary sliding and intragrain deformation have been revealed in the alloys studied.
Results of technical and economical comparison of competing schemes of heat supply to lowsto
ried housing areas for different regions of Russia are presented. Limitations on using heat pumps for these
purposes are analyzed.
The energy sector of Russia is one of the most potent in the world - it is the second in extraction of oil and gas, the third for total output of fuel and energy resources. While exporting nearly 45% of its total production of energy resources, Russia produces more energy per capita than most other countries - 5 times higher the global average and 3 times higher than the average level for OECD countries. The energy sector of Siberia represents the crucial part of the country's energy sector. Over decades, the energy resources of the region massively contributed to the Russian federal budget and brought in a major part of hard currency from export trade. In the current conditions of existing geopolitical challenges and expected global demand for energy resources, it is much more of a priority for Russia not to raise the output of fuel and energy resources but to improve the overall quality and reliability of the whole energy supply system, increase the depth of mineral fuel, including solid fuel and waste recycling.
Russia is one of the key players at the world's energy markets. The country's plans to further research and innovation in the sector impact the world energy outlook. The paper examines the energy block of the Russian S&T Foresight 2030, developed by experts in 2011-2013 and approved by the Prime minister in January 2014. The official document, which covers six areas, including 'Energy efficiency and energy saving', defines the key science and technology (S&T) areas Russia has to embark upon in order to boost its competitiveness. The energy part of the study covers global challenges, threats, and opportunities for Russia, prospective innovative markets for its products and services. Moreover, Russia's innovative technologies and products are assessed, including the potential demand and competition aspects and benchmarking against global leaders. The paper features major outcomes of the energy block and puts the exercise in a comparative perspective with similar international studies of Kazakhstan, Germany, Canada, the UK, USA and international organizations. The author concludes that in Russia energy efficiency and energy saving priorities dominate the policy agenda, with relatively little attention to advancing renewable energy technologies. The Foresight horizon is also markedly shorter than that of similar studies in the OECD countries. Following international practice, in 2015 Russia plans to perform a new government-led S&T Foresight for the energy sector alone.
Protection of the environment can be achieved by creating conditions that ensure the complete absence, or at least minimal content, of hazardous substances in industrial waste. Therefore, in production processes where the main and/or additive product is material with mercury content, the prevention of mercury vapor emissions into the atmosphere is an essential prerequisite for safety and environmental protection. However, achieving these indispensable safety conditions requires significant energy input. Detailed analysis of existing techniques and equipment for mercury extraction from mercury-containing and mercury-contaminated materials as well as plastics containing waste showed that all of the proposed methods are energy-intensive and cannot entirely remove mercury vapor from the emissions. A new technique of the thermal demercurization of mercury-containing materials has been offered. The original feature of the proposed technique is the distillation and condensation of mercury vapor within an inert gas flow circulating in the closed loop system. The offered technique ensures a substantial reduction in energy consumption while cooling the mercury vapor for its condensation and almost entirely eliminates mercury emissions into the atmosphere. Keywords: recycling of mercury-containing materials, environmental protection, energy consumption, thermal demercurization, inert gas flow, closed gas loop system, closed liquid loop system.
The elastic moduli of a composite material made of high-temperature modified phenolic resins with short carbon fibers are studied. Several analytical formulas used to determine the effective moduli of such composites are compared and experimentally verified.
A transformer type superconducting fault current limiter (FCL) for electric power grids was developed utilizing a nonlinear resistor made of the second generation HTS wire. Using of the second generation HTS wire instead of the first one was found to reduce by an order the required amount of superconducting materials. Fault current limiting action and transients in an electric circuit with the prototype FCL have been studied. The effective limitation of peak and steady state fault current was demonstrated using the FCL. The physical basis of the FCL operation was investigated by studying a superconducting-to-normal transition in the second generation HTS wires.
After analyzing the characteristics and pricing models on the Russian wholesale electricity market, some important features for econometric modeling are introduced. This paper suggests econometric forecasting models developed to predict daily and hourly electricity prices on the day-ahead market for two price zones in Russia: European and Siberian ones. A set of 24 models, which are similar in nature but different in included regressors, are introduced. On the basis of the actual database for 2014, different modifications of price formation are offered and analyzed with the help of the Eviews econometric package. Dynamic forecasts on various distances (day, week, and month) are conducted and the most suitable models from the point of minimizing the norms of the vectors residuals are chosen. Constructed ARMA models have high predictive power and are able to reflect the price trend on the base of exogenous factors and the previous price values.
The article presents the results of predictive studies of the development of new energy sources using the example of wind energy technologies in the countries of the North Sea Basin. Predictive estimates (based on the mathematical technique of learning curves), the dynamics of installed power and the generation of electric power by floating wind power stations, as well as the processes of replacing traditional energy with developing energy technologies in various countries, including Russia, are considered. The economic characteristics of energy technologies at an early stage of development are given.
A proсеss for fabriсating 5.mm-thiсk shеets from alloy l565сh with rеcrystallized grains lеss than l0 µm in sizе is dеvеlopеd, whiсh involvеs supеrplastiс forming and providеs еlеvatеd mесhaniсal propеrtiеs at room tеmpеratuге.Тhе paramеtеrs of supеrplastiсitу and thе mесhaniсal propеrtiеs of alloy l565сh arе dеtегminеd. Tеst forming оf a domе-shapе modеl part is pеrformеd.
The newsbreak for writing this article was a kind of jubilee: 25 years ago, in 1992, a conference in Rio de Janeiro adopted the United Nations Framework Convention on Climate Change. This event became the first in a series of follow-up conferences and documents aimed primarily at limiting carbon dioxide emissions into the atmosphere to counter global warming. The author is an active advocate of the concept of the anthropogenic impact on climate as a leading factor in climate change. He stresses the positive potential of international agreements in this field and a new energy-environmental paradigm, which implies the development of low-carbon industry and transition to renewable energy sources and the “green” economy.
The article covers geographical and technological factors which determine the location and development of Russia’s timber industry in the market environment. Trends in the spatial pattern of Russian timber and pulp-and-paper exports in 2000–2010 are analyzed. The production pattern of timber and pulp-and-paper products is analyzed for Russia’s largest interregional timber industry manufacturers. The post-Soviet shifts in the geographies of timber resources and the relevant demand are evaluated. Synthesis of three sets of factors helps formulate a long-term forecast of the future spatial shifts in the location of the timber industry’s production facilities. Development centers are expected in regions adjacent to Irkutsk oblast that have a common border with China—the largest importer of Russian timber and pulp-and-paper products-and combine significant timber resources with a relatively dense population and infrastructure.
Transforming the housing stock to a low energy performance is a key priority in the context of sustainable development and a post-carbon transition. However, in terms of its practical implementation it, firstly, faces a number of complex institutional barriers, while, secondly, involves a risk of being dominated by a narrow technocratic agenda for energy/carbon reduction that may overtake the socially progressive pursuits of housing policy. Energy efficiency strategies for the residential sector must, therefore, be multidimensional, fully synergised with housing policy, and incorporating the principles of equity, access and a balanced geographical development. This paper discusses a strategic policy framework, which was designed by the United Nations Economic Commission for Europe (UNECE) to address those important needs in international policy. The document – Action Plan for Energy-efficient Housing in the UNECE Region – outlines a number of goals, targets and actions structured at three dimensions: (i) governance and finance, (ii) technological advancement, and (iii) access and affordability. The Action Plan provides a comprehensive and integrated framework, based on which governments can shape their own pathways towards a sustainable low-energy residential sector.
We have performed a comparative analysis of the bio-oil produced by thermal liquefaction of microalgae in different solvents using high-resolution Orbitrap mass spectrometry and GC-MS approach. Water, methanol, ethanol, butanol, isopropanol, acetonitrile, toluene, and hexane were used as solvents in which the liquefaction was performed. It was observed that all resulting oils demonstrate a considerable degree of similarity. For all samples, compounds containing 1 and 2 nitrogen atoms dominated in the positive ESI spectra, while a relative contribution of other compounds was small. In negative ESI mode, compounds having 2 to 7 oxygens were observed. Statistical analysis revealed that products can be combined in two groups depending on the solvent used for the liquefaction. To the first group, we can attribute the products obtained by using protic (alcohols) and to the second by using aprotic (acetonitrile, toluene) solvents. Nevertheless, based on our results, we concluded that solvent possesses a minor impact on molecular composition of bio-oil. We suggested that the driving force of the liquefaction reaction is the thermal dehydration of the carbohydrate in algae, resulting in water formation, which could be the trigger of the producing of bio-oil. To prove this hypothesis, we performed the reaction with the dry algae in the absence of the solvent and observed the formation of bio-oil.
Syntheses are reported for catalysts derived from platinum and palladium nanoparticles supported on a mesoporous phenol formaldehyde polymer modified by an ionic liquid. These catalysts are used for the hydrogenation of unsaturated compounds, specifically, acyclic and cyclic isoprenoids: isoprene, 2,5 – dimethyl–2,4–hexadiene, limonene, α –terpinene, γ –terpinene, as well as phenylacetylene, transstilbene, and 1,4–diphenyl–1,3–butadiene. High activity was found for these catalysts in hydrogenation reactions. The palladium catalysts were more active than their platinum analogs. The products of complete hydrogenation predominate in the hydrogenation of isoprenoids on the palladium catalysts, while monoene products predominate in the reactions on platinum catalysts.
This article presents results of an integrated analysis of technological capabilities and economic results of implementation of active policy on the restriction of greenhouse gas emission in the electric power industry of Russia, which is the biggest CO2 emitter in the fuel and energy complex. To accomplish this, introducing a payment for CO2 emission is considered as the main economic mechanism of a new ecological policy. The investigation incorporates a whole range of tasks on screening analysis of low- and non-carbon technologies on a carbon-avoided cost basis, system optimization of their development scales and identification of generating capacity mix improvements until 2030 with a sequential estimation of an additional investment and price load on the economy in the implementation of the ecology-emphasized development strategy of the Russian electric energy.
The Circumpolar North has been changing rapidly within the last decades, and the socioeconomic systems of the Eurasian Arctic and Siberia in particular have displayed the most dramatic changes. Here, anthropogenic drivers of environmental change such as migration and industrialization are added to climate-induced changes in the natural environment such as permafrost thawing and increased frequency of extreme events. Understanding and adapting to both types of changes are important to local and indigenous peoples in the Arctic and for the wider global community due to transboundary connectivity. As local and indigenous peoples, decision-makers and scientists perceive changes and impacts differently and often fail to communicate efficiently to respond to changes adequately, we convened a meeting of the three groups in Salekhard in 2017. The outcomes of the meeting include perceptions of how the three groups each perceive the main issues affecting health and well-being and recommendations for working together better.
Binary Al–Ni, Al–Mg and ternary Al–Mg–Ni alloys containing various dispersions and volume fraction of second-phase particles of crystallisation origin were compressed in a temperature range of 200–500 °C and at strain rates of 0.1, 1, 10, 30 s−1 using the Gleeble 3800 thermomechanical simulator. Verification of axisymmetric compression tests was made by finite-element modelling. Constitutive models of hot deformation were constructed and effective activation energy of hot deformation was determined. It was found that the flow stress is lowered by decreasing the Al3Ni particle size in case of a low 0.03 volume fraction of particles in binary Al–Ni alloys. Intensive softening at large strains was achieved in the alloy with a 0.1 volume fraction of fine Al3Ni particles. Microstructure investigations confirmed that softening is a result of the dynamic restoration processes which were accelerated by fine particles. In contrast, the size of the particles had no influence on the flow stress of ternary Al–Mg–Ni alloy due to significant work hardening of the aluminium solid solution. Atoms of Mg in the aluminium solid solution significantly affect the deformation process and lead to the growth of the effective activation energy from 130–150 kJ/mol in the binary Al–Ni alloys to 170–190 kJ/mol in the ternary Al–Mg–Ni alloy.
Free bulging process is an experimental technique which can be used to characterize a sheet material in conditions of biaxial tension during hot forming. Analytical and semi-analytical models of this process are usually based on the hypothesis offering certain relations between the geometrical characteristics of a bulge during forming. The paper presents an original relation between a specimen thickness at the dome pole and the dome height which is used at the semi-analytical method for simulation of free bulging process. In order to obtain this relation, the finite-element computer simulation results were generalized. The influence of the material constants on the geometrical parameters of the bulge was studied. It was shown that the sheet thickness corresponding to a specific dome height is dictated by the strain rate sensitivity index of the material. The equation describing the influence of the strain rate sensitivity index on the dome apex thickness is presented.