Integrated Energy System is beneficial for promoting the distributed renewable energy (DRE) consumption, thereby alleviating environmental pollution and energy shortage. In this paper, we propose a virtual power plant...
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The unavoidable wind power forecast error results in the pervasive uncertainty in power system economic *** order to solve optimization problem such as economic dispatch with random variables,the commonest and simples...
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The unavoidable wind power forecast error results in the pervasive uncertainty in power system economic *** order to solve optimization problem such as economic dispatch with random variables,the commonest and simplest method is using a deterministic value to replace this random *** kinds of predictions are used such as maximumlikelihood approximation,expectation and *** study analyses the effect of these prediction choices on uncertainty of power system via comparing their statistical *** is shown that when the wind power output is very volatile,the quality of these prediction choices is not ***,a simplified three-unit thermal system and a tenunit system are studied for illustrating the consequence of statistical inconsistency.
Insufficient power capacity for peak load regulation has caused loss of wind power accommodation in China.A regulation capacity market is under consideration to encourage more peak regulation service,thus how much the...
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Insufficient power capacity for peak load regulation has caused loss of wind power accommodation in China.A regulation capacity market is under consideration to encourage more peak regulation service,thus how much the market would be is important for each participant.A new peak-load regulation capacity planning method is proposed for long-term market based on the wind power curtailment evaluation model using probabilistic production *** method is suitable for the situation in the planning stage without the knowledge of detailed sequences of load and renewable power,and includes modeling of two peak load regulation measures,increasing the adjustable capacity and to shift some long-lasting units to on/off cycling units.A typical area in China is studied in the paper to evaluate the actual effects of different measures.
The male bovines generally have huge hones. Hones are their weapons to compete for territory, hunt for food and get the opportunity to mate with the females. As a means of defense and attack, the sheep horns can withs...
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The male bovines generally have huge hones. Hones are their weapons to compete for territory, hunt for food and get the opportunity to mate with the females. As a means of defense and attack, the sheep horns can withstand the maximum impact force of approximately 3400 N during their head-on collision. During bovines' life, the horn will not be sloughed off, so the horn needs to have sufficient strength and toughness when the bovines fight. In the long-term evolution process, the bovine's horn has evolved into a kind of natural composite material which has excellent structure and mechanical property. The microstructure and mechanical properties of sheep horn living in northeast China are investigated in the paper. We make the specimens from the base, center and tip of the horn sheath to do the quasi static tensile tests and compression tests. In the tensile tests, the mechanical properties of the horn sheath can be divide into four stages: liner elasticity, plateau, strengthen and local deformation, the longitudinal elastic modulus of the three parts are 1.68± 0.09 GPa, 2.23±0.12 GPa and 1.85±0.17 GPa, respectively. Besides, the transverse and longitudinal contrast samples are derived from the base. The maximum tensile strength of the transverse specimens are only half of the longitudinal tensile strength and the ductility is far less than that of the longitudinal samples. In the compression tests, the compression modulus and the yield strength of the longitudinal samples in center part are 2.14±0.19 GPa and 68.52 ±3.58 MPa, respectively. The results show the similar trend with the longitudinal samples of center part in tensile test. The mechanical properties of the horn is closely related to the macro and micro structure, The sheep horn is composed of the inner and outer layers in macrostructure, outer layer is mainly made up of keratinized protein which possesses excellent load bearing capacity and impact strength, the inner layer is loose and porous which has the
In order to explore the method for reducing aerodynamic noise caused by the cavity structure, the typical cavity model M219 scale model was chosen as the basic model. The maximum noise of the basic model and the flow ...
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In order to explore the method for reducing aerodynamic noise caused by the cavity structure, the typical cavity model M219 scale model was chosen as the basic model. The maximum noise of the basic model and the flow inside the cavity can be obtained through the numerical simulation. Inspired by the bionic design, selecting the bionic non-smooth structure by the following two ways: one is selecting the known bionic non-smooth structure from the reference literature which has the good effect on the aerodynamic flow field of the bionic non-smooth structure, such as the bionic v-shaped non-smooth structure and the bionics hemispherical structure;The second is using the method of engineeringbionics to select the structure that can realize the improvement of the cavity flow field, which is according to the analysis for the cavity inside flow and cavity aerodynamic noise principle, such as triangle structure and arc structure. In order to get the optimized plan for the cavity aerodynamic noise reduction, for the same bionic non-smooth structure, it mainly considers the position of the structure, especially on the front of the cavity and the bottom of the cavity and the after of the cavity. In the study on the location of the process, this paper considered the different between the single factor and multiple factors on aerodynamic noise reduction effect. In addition, I put the bionic non-smooth structure size for the cavity aerodynamic noise reduction effect into account. Furthermore, for different bionic non-smooth structure, this paper also considers the impact on aerodynamic noise reduction effect between each other. The research mainly using a hybrid LES-Fw-H and SST-Fw-H method to obtain the sound pressure level curve of the optimization structures, and then pick out the structure which has the best effect. So, we not only won the location and size of the bionic non-smooth structure on the influence of the noise reduction effect, but also through the establishment of
Promising applications of metal-organic frameworks (MOFs) in various fields have raised concern over their environmental fate and safety upon inevitable discharge into aqueous environments. Currently, no information r...
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Wind-photovoltaic-energy storage (ES) hybrid generating system has numerous reactive power sources. It is crucially important for coordinated control of these reactive power sources. According to the test results, the...
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Wind-photovoltaic-energy storage (ES) hybrid generating system has numerous reactive power sources. It is crucially important for coordinated control of these reactive power sources. According to the test results, there are unbalanced control problem in subsystem voltage of the hybrid generating system. The problem caused reactive power circulation and loop current. A subsystem voltage balance optimisation strategy is proposed to solve the problem. The case study shows the efficiency of the proposed strategies.
Practical application of superhydrophobic surfaces is limited by the fragility of nanoscale asperities. Combining chemical etching and anodization, microscale pits and nanoscale pores, instead of the micro and nano pr...
Practical application of superhydrophobic surfaces is limited by the fragility of nanoscale asperities. Combining chemical etching and anodization, microscale pits and nanoscale pores, instead of the micro and nano protrusions on traditional superhydrophobic surfaces mimicking Lutos leaves, were fabricated on commercially pure aluminum surfaces. After modified by FDTS, the surfaces were superhydrophobic and self-cleaning. The ultrahigh hardness and electrochemical stability of Al2O3 coating endowed the surface excellent mechanical durability and good corrosion resistance. Because the method is scalable, it may find practical application on body panels of automobiles and aircrafts and so on.
The research shows that earthworm's non-smooth surface makes its son body freeing to through in the crusty earth and itself being intact. In this article, LX-2V automobile engine was taken as the experimental subj...
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The research shows that earthworm's non-smooth surface makes its son body freeing to through in the crusty earth and itself being intact. In this article, LX-2V automobile engine was taken as the experimental subject. Drag reduction and wear-resisting structure of earthworm surface were used to piston skirt, which was major friction pair of engine. Firstly, arrangement, line distance, diameter range of bionic holes was made by dorsal pore arrangement and detail size of earthworm and boundary dimension of piston. bionic holes diameters were confirmed by relative speed drag reduction rate. Secondly, based on results of finite element analysis of standard piston, max stress was on the top, max deformation was at the bottom. bionic holes diameters were designed by different sizes, the nearer piston top was, the bigger diameter size could be. bionic holes had variable line-spacing, the nearer piston top was, the longer line-spacing would be. So that piston could drag reduction and wear-resisting, and it was less fatigue failure at work. This paper made L9 (33) with the orthogonal experiment method. Used three hole distributions, they were homogeneous form, interlaced form, gradual increase by line;three form bionic holes, they were pit, through-bore, pit & through-bore alternating;three type hole sizes, they were "I II III". Standard piston and nine bionic pistons made thermal-mechanical coupling FEM on the most adverse working condition. Selected three test indexes, which are done by range analysis, then reached primary-secondary factors and optimal combination. Thirdly, cold test-bed of automobile engine was installed. The standard piston, the best comprehensive property piston of finite element analysis and optimal combination piston were trial on this test-bed. Finally, the following conclusions were gained: (1) Design of variable diameter and variable line spacing was more advantageous than uniform distribution. (2) Best hole diameter was from 1 to 3.5 mm. (3) Abras
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