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The following topics are dealt with: thermal power; wind power; geothermal energy; tidal wave energy; bio-energy technologies; smart grid; power system management; power transmission; power system monitoring; power system control; power system planning; power system operation; power system optimization; hydropower energy; solar power energy; nuclear energy; energy efficiency; environmental-friendly...
Power is the rate at which energy is being used to do work. A negative sign of power indicates that it is an energy source. With this notion it is easy to explain photoelectric effect and nuclear reactions. Also, recent research indicates that speed of light is not a constant. In fact, the speed of light has been decreasing very very slowly over time. As a consequence of this fact, there is a potential...
This article on the basis of studying optical fiber sensor puts forward and realize a kind of optical fiber liquid-level transducer based on optical amplifier which has advantages such as high accuracy, high reliability, free of electromagnetic interference and so on. The detection device which used in the flammable an de explosive field.
Adaptive reclose can remarkably enhance power system reliability. Rapid and accurate calculation of reclosing time proves to be difficult. This paper presents a stochastic calculus approach to this problem, deduces formulae to calculate reclosing time.
Grouting to reinforce the surrounding rock is new technology in coal mine supporting. The hole sealing material is a key to grouting. In this paper, properties such as setting time, swelling rate and strength of a new hole sealing material which was fabricated using high alumina cement, lime,gypsum and additives were studied. The swelling mechanism of this material was probed experimentally. The results...
At the stage of oilfield with high water-cut, the yield declines year by year. In order to slow down its declining rate, the annual water injection ought to be increased year after year for the water flooding oilfield. Then it is important to determine the reasonable water injection so as to control the rising rate of water-cut and to extend the lifespan of the oilfield. In this paper, the yield declining...
Before a synchronous generator puts into operation, it may be suddenly connected to the grid by accident and led to be an asynchronous operation under high-slip condition, that can cause serious damage to the rotor. This paper analyzes the rotor wedge temperature under above condition, calculation results show that the temperature will increase rapidly, and then the mechanical strength of the rotor...
A experimental table of new solar-assisted air source heat pump (SA-ASHP) which used the non-homostasis two heat source complex heat exchanger as the core component has been constructed. Based on the national standards, three experimental conditions have been chosen, which the ambient temperature are respectively 7??C, 2??C, -7??C. The experimental results show that the heating performance of the...
Based on sufficient study on the output characteristics of the solar cell, in this paper, a kind of simulator simulating the output of the solar cell, using the single-chip computer (SCM) and DC/DC inverter is designed. This simulator can simulate the output of the solar cell, completely according to the working characteristic curve given by the solar cell. Thereby it can eliminate the outside influence...
In recent decades, with the unlimited use of fossil fuels, energy crisis has come. This is especially true for developing countries because of the increasing population and pollution. In this condition, new energy sources are becoming essential, which may be needed to alleviate energy sources pressure and promote economic development in the developing world. This paper focuses on the potential for...
A new partial discharge (PD) number estimation method in oil is presented based on ultrasonic array sensors and modified CCT in this paper. Firstly, ultrasonic array sensors are developed which can receive and format the wideband array ultrasonic signal of PD. Secondly, sub-band averaging and CCT are applied to realize PD number estimation in Oil. Lastly, the results of experimental research indicate...
Si-doped AlSb polycrystalline films were grown on silex by magnetron co-sputtering. The conducting type, Hall mobility and carrier concentration of the films were determined. The films appear to be p-type indicating Si is shown to be predominantly an acceptor in AlSb, and holes as dominant charge carriers. Scanning electronic microscope (SEM) shows that prepared film is uniform and compact. The conductivity...
In order to achieve the maximal diathermanous efficiency, this paper introduces two calculation methods about the most economical diathermanous area of the Shell and tube heat exchanger which works in two different conditions, and establishes the corresponding mathematical models.
This paper is concerned with a new numerical method of two-dimensional flow. The governing system of differential equations is transformed into an equivalent system applied over a square-grid network in order to overcome the difficulties and inaccuracies associated with the determination of characteristics near the flow boundaries. The MacCormack two-step explicit scheme with second-order accuracy...
The inertia, damp and friction force of machine are not conducive to the capacity of return-to-center in electric power steering system. In this paper the fuzzy logic control scheme based on angle absolute position for steer wheel return-to-center is proposed to improve the return ability of electric power steering system. The different resistive force is imposed on the steer column through the reducer...
The paper conducted the research on surface heat transfer coefficient of external cross-flow over tube bundles, proposed two different measures on calculating surface heat transfer coefficient of the tube bank according to law of conservation of energy, gained two groups of results through calculation examples, and analyzed discipline of the change of convection bank surface heat transfer coefficient.
Stability against up-sliding along contact plane between arch dam and its foundation had attracted much attention in hydro-engineering world. In this paper, combining the engineering example of Ko??lnbrein arch dam which was 200 m high in Austria, we analyzed the shearing stress in contact plane between dam body and its foundation using 3-D finite element method. The conclusion was that up-sliding...
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