• Energy Research
• 7. Clean energy close
• 8. Economic growth close
• RU close

Torrefaction is considered as a method for producing biofuels with improved characteristics compared to those of the “raw” biomass (higher calorific value, moisture resistance, better grindability). The torrefaction process is an endothermic process that is usually carried out in a gaseous atmosphere in the absence of oxygen. To reduce the required heat input, it is proposed to employ the oxidative torrefaction and conduct the process in a fluidized bed agitated with flue gases containing less than 6% oxygen. Preliminary studies of the oxidative torrefaction of sunflower husks, including thermogravimetric analysis of the treated material, have shown that the heat treatment time for the biomass should be at least 5 min. A fluidized bed is a reactor with ideal mixing of the treated material where uniform treatment of raw material particles cannot generally be attained. To overcome this disadvantage of the fluidization technique and achieve the required residence time for biomass in a fluidized bed during a continuous torrefaction process, it was proposed to equip a torrefaction reactor with a series of vertical baffles spaced at 50 mm. These baffles induce a loop-like flow of the processed biomass from the inlet to the outlet of the reactor. To investigate the residence time for husk particles in the reactor, a tracer, which was colored to husk particles' color with a water-soluble dye which did not change the weight and size of the particles, was injected into the bed of uncolored particles. Tracer samples were taken every 30 s at the outlet of the reactor and were analyzed using a special procedure to determine the fraction of colored particles in each sample. This enabled us to gauge the time during which the colored particles injected into the fluidized bed reached the point of their discharge from the bed. Studies performed in a “cold” model of the reactor showed that a series of vertical baffles in the bed can provide the required residence time for biomass in a reactor including commercial reactors. Plates can provide the necessary biomass residence time in the reactor.

Abstract An ideal tracker which follows the sun both north-south and east-west is designed and constructed. It is suitable for mounting a linear concentrator, focusing parabolic concentrator or photovoltaic array of aperture area 2 m2. The apparatus is built with two axes equational mount and controlled by a microprocessor system. The tracking is carried out by utilizing the astronomical coordinates of the sun. As such the present system gives improved tracking capability over the conventional sensor controlled tracker systems. The performance of the tracking system was studied with photovoltaic array mounted on it and tracking error of less than one degree was achieved. This tracking error can be reduced further by proper software.

The formation and decay of excited states of light‐harvesting bacteriochlorophyll (BChl) molecules and primary charge separation in reaction centres (RCs) of pigment‐protein complex B890 of the purple bacterium Chromatium minutissimum were studied as a function of excitation wavelength by means of picosecond absorbance difference spectroscopy. Selective excitation in the RC absorption band (at 800 nm) induced rapid bleaching of the absorption band of the RC BChl dimer (τ ∼ 1 ps) without absorption changes due to excited light‐harvesting BChl. It is concluded that excitation energy transfer from the BChl dimer of the RC to light‐harvesting BChl molecules is considerably slower than RC charge separation. Therefore, energy transfer from the light‐harvesting antenna to the RC in bacterial photosynthesis may be described as a ‘migration‐limited model’.

We investigate the effect of slowly-varying parameter on the energy transfer in a system of weakly coupled nonlinear oscillators, with special attention to a mathematical analogy between the classical energy transfer and quantum transitions. For definiteness, we consider a system of two weakly coupled oscillators with cubic nonlinearity, in which the oscillator with constant parameters is excited by an initial impulse, while a coupled oscillator with slowly-varying parameters is initially at rest. It is proved that the equations of the slow passage through resonance in this system are identical to equations of the nonlinear Landau-Zener (LZ) tunneling. Three types of dynamical behavior are distinguished, namely, quasi-linear, moderately nonlinear and strongly nonlinear. The quasi-linear systems exhibit a gradual energy transfer from the excited to the attached oscillator, while the moderately nonlinear systems are characterized by an abrupt transition from the energy localization on the excited oscillator to the localization on the attached oscillator. In the strongly nonlinear systems, the transition from the energy localization to strong energy exchange between the oscillators is revealed. A special case of the rapid irreversible energy transfer in the strongly nonlinear system with slowly-varying parameters is also investigated. The conditions providing different types of the dynamical behavior are derived. Explicit approximate solutions describing the transient processes in moderately and strongly nonlinear systems are suggested. Correctness of the constructed approximations is confirmed by numerical results.

The Internet of Things (IoT) provides opportunities to control interconnected smart devices via pre-designed scenarios with littleor no human involvement. Due to the need for systematic improvement of industrial energy efficiency, the relevance of IoT-based energy management systems (EMS) is constantly increasing. Industrial IoT (IIoT)-enhanced EMS are created to support the digital transformation of enterprises. They increase the transparency of energy consumption statistics, enhance the personnel awareness of energy losses, provide predictive analytics tools for forecasting potential industrial accidents and future energy demand. This paper hence provides a system architecture of the energy management assistant that can be used at enterprises to archive the aforementioned aims. Authors identify the relevance of EMS, list the conditions at modern enterprises that define the requirements for the energy management assistant, demonstrate the identified requirements in the UML diagrams. Specification of energy planning and energy monitoring stages demonstrate the possibilities of the designed system architecture. For demonstration purposes, authors present examples of linear and nonlinear regression models implemented to specify energy consumption target functions based on real data. Finally, future research directions and open energy management problems are presented. The analysis has been carried out within the priority area of scientific development established in the National Research University Higher School of Economics - "Research on control methods in Cyber-Physical Systems".

This paper provides the rationale for applying an exergetic method when evaluating the thermodynamics of column-rectification apparatuses, while reviewing the operating profiles of typical purifying columns and purifying columns with stripping modules operating under atmospheric pressure, vacuum, and with mechanical vapour recompression. Graphical representations of the purifying column's exergy balance are provided as Grassmann-Szargut diagrams. The exergy balance data showed that the total value of exergy loss is comparable between conventional purifying columns and those equipped with a stripping module (30.94% and 30.78% efficiency, respectively); moreover, exergy loss is lower in systems where the components operate under a vacuum (31.33% efficiency). For purifying columns that operate using mechanical vapour recompression, their exergetic efficiency is highest (32.6%), which indicates that the thermodynamic precision of system being studied increases when a heat pump is used as the primary source of high-grade energy supply in the column apparatus.

Aviation is one of the most significant growth drivers not only for the transportation infrastructure, but also for country’s economy as it contributes to both industrial and social progress of society. The paper focuses on Sheremetyevo International Airport, one of the largest Russian airports and analyzes it in terms of short-term and long-term perspectives. Using real statistical data, the article presents the models for forecasting essential performance indicators of airports, namely, passenger traffic and revenue. By comparing quality characteristics, most suitable models were selected and checked for adequacy. Forecasts of the probable changes in the values of the performance indicators were made under the assumption of maintaining the previously formed development trend.

Achieving economic development is one of the most important economic goals of every country. Identifying the determinants of economic growth, is a useful tool for adopting appropriate economic policies. This study, therefore, empirically examines the impact of trade openness, foreign direct investment, and financial development on economic growth, across 62 countries over the period 1995–2016. These countries are divided into two groups: low-income and high-income countries. We employ the pooled mean group (PMG), mean group (MG), and dynamic fixed effect (DFE) estimation techniques on the cross-country panel data. The findings show a positive long run association between trade openness, foreign direct investment (FDI), financial development, labor, government expenditure, and economic growth in low-income countries, with a positive and negative short run effect from capital and government expenditures, respectively. For high-income countries, a positive long run association between trade openness, FDI, capital, and economic growth exist. The short run estimates indicate a positive effect on trade openness and capital as well as a negative effect on government expenditure. Our study shows that the adoption of policies that improves access to skilled labor and international trade, affect the attainment of a sustainable economic development.