592 research outputs found
Piezoaeroelastic energy harvesting based on an airfoil with double plunge degrees of freedom: modeling and numerical analysis
No full textIn this paper, a piezoaeroelastic energy harvester based on an airfoil with double plunge degrees of freedom is proposed to additionally take advantage of the vibrational energy of the airfoil pitch motion. The analytical model of the proposed harvester is built, and an equivalent model using the well-explored pitch–plunge configuration is presented. The nonlinear aerodynamics is calculated based on the dynamic stall model. The dynamic response, average power output, energy harvesting efficiency, and cut-in speed (flutter speed) of the proposed harvester are numerically studied. It is demonstrated that the harvester with double-plunge configuration outperforms its equivalent pitch–plunge counterpart in terms of both the power output and energy harvesting efficiency beyond the flutter boundary. In addition, case studies are performed to reduce the cut-in speed and to enhance the energy harvesting efficiency of the proposed harvester, including the airfoil mass characteristics, the configuration, mass, damping, and stiffness characteristics of the two plunge supporting devices, and the load resistances in the external circuits. It is shown that the cut-in speed is greatly reduced by increasing the airfoil mass while tuning the mass eccentricity. The mass of the first (windward) supporting device should be a bit smaller than that of the second one for an applicable cut-in speed and a high-energy harvesting efficiency. Besides, the decrease of airfoil mass moment of inertia or the damping of the supporting devices is shown to be beneficial for the energy harvesting performance. In addition, the optimal location of the first supporting device is found to be at the airfoil leading edge. Decreasing the distance between the two supporting devices reduces the cut-in speed. The load resistances affect the cut-in speed slightly, and optimal values are found to maximize the energy harvesting efficiency
A modified airfoil-based piezoaeroelastic energy harvester with double plunge degrees of freedom
No full textIn this letter, a piezoaeroelastic energy harvester based on an airfoil with double plunge degrees of freedom is proposed to additionally take advantage of the vibrational energy of the airfoil pitch motion. An analytical model of the proposed energy harvesting system is built and compared with an equivalent model using the well-explored pitch-plunge configuration. The dynamic response and average power output of the harvester are numerically studied as the flow velocity exceeds the cut-in speed (flutter speed). It is found that the harvester with double-plunge configuration generates 4%–10% more power with varying flow velocities while reducing 6% of the cut-in speed than its counterpart
Energy harvesting by means of flow-induced vibrations on aerospace vehicles
No full textThis paper reviews the design, implementation, and demonstration of energy harvesting devices that exploit flow-induced vibrations as the main source of energy. Starting with a presentation of various concepts of energy harvesters that are designed to benefit from a general class of flow-induced vibrations, specific attention is then given at those technologies that may offer, today or in the near future, a potential benefit to extend the operational capabilities and to monitor critical parameters of unmanned aerial vehicles. Various phenomena characterized by flow-induced vibrations are discussed, including limit cycle oscillations of plates and wing sections, vortex-induced and galloping oscillations of bluff bodies, vortex-induced vibrations of downstream structures, and atmospheric turbulence and gusts. It was found that linear or linearized modeling approaches are commonly employed to support the design phase of energy harvesters. As a result, highly nonlinear and coupled phenomena that characterize flow-induced vibrations are neglected in the design process. The Authors encourage a shift in the current design paradigm: considering coupled nonlinear phenomena, and adequate modeling tools to support their analysis, from a design limitation to a design opportunity. Special emphasis is placed on identifying designs and implementations applicable to aircraft configurations. Application fields of flow-induced vibrations-based energy harvesters are discussed including power supply for wireless sensor networks and simultaneous energy harvest and control. A large body of work on energy harvesters is included in this review journal. Whereas most of the references claim direct applications to unmanned aerial vehicles, it is apparent that, in most of the cases presented, the working principles and characteristics of the energy harvesters are incompatible with any aerospace applications. Finally, the challenges that hold back the integration of energy harvesting technologies in the aerospace field are discussed
Anaceratagallia venosa
No full textAnaceratagallia venosa (de Fourcroy) Figs 1 B, F, J; 7 A–I. Cicada venosa de Fourcroy, 1785: 188. Agallia aspera Ribaut, 1935: 36 Anaceratagallia venosa (Fourcroy): Zachvatkin, 1946: 159. Material examined. CHINA: 13, Xinjiang, Qinghe, Qinghe Forestry Farm, 5. viii. 2006, 1800m, Dai Wu and Kang Juxia; 1 Ƥ, Xinjiang, Shihezi, 1. vii. 1980, Liu Jie, grass; 1 Ƥ, Xinjiang, Yining, Yili river, 28. vii. 2006, Dai Wu; 13, Xingjiang, Wushi, Banong, 8. ix. 1986, Zhang Yalin; 1 Ƥ, Xinjiang, Yili, 19–20. viii. 1979, Chen Tong; 1 Ƥ, Xinjiang, Malasi, viii. 1982, Yang Haifeng, clover; 1 Ƥ, Xinjiang, Bukang, 11. ix. 1986, Zhang Yalin; 13, Xinjiang, Changji, 12. xi. 1986, Zhang Yalin; 1 Ƥ, Ningxia, Helanshan, vi. 1989. Distribution. China (Gansu, Inner Mongolia, Xinjiang), Widespread in Europe, United Kingdom, Scandinavia, Western Mediterranean, Baltic region, Northern Africa, Canary Islands. Remarks. Zhang et al. (2010) recorded this European species for the first time from China. The anal collar appendage is variable within populations from China. In two males, the anal collar appendage bears a dorsal tooth projection (Fig. 7 C) whereas on a third male the projection was not seen (Fig. 7 D). This species closely resembles A. ribauti but differs in several characters (see remarks of Anaceratagallia ribauti).Published as part of Dai, Wu & Zhang, Yalin, 2012, Taxonomic revision of the leafhopper tribe Agalliini (Hemiptera: Cicadellidae: Megophthalminae) from China, with description of new taxa, pp. 1-49 in Zootaxa 3430 on page 6, DOI: 10.5281/zenodo.21515
China’s urban environmental governance: An introduction
No full textThis introductory chapter explains China’s recent turn to strengthened environmentalism and discusses the features of environmental governance. The chapter introduces the framework of this handbook, stressing the need to interrogate environmental governance at the urban level. Beyond environmental policies, the handbook examines environmental practices from the perspective of the interactions between the state, market and society across multiple scales. The core concern of this handbook is how to characterise China’s environmental governance: whether the governance aims to promote economic growth through environmental regulation or is invoked to implement ‘ecological civilisation’. We reveal the purposeful ecologic fix under ‘state entrepreneurialism’, in which the state vision of ‘ecological civilisation’ occupies the centrality. At the same time, market instruments are mobilised, and the society actors are primarily reactive in environmental contestation or campaigns. Examining state-centred governmentality across a series of environmental practices such as eco-city planning, waste management and low-carbon energy transition, we highlight the need for collaborative environmental governance and greater attention to social justice
CSCI01 CLIMAT reports - China ; available from BABJ(PEKING (BEIJING)) at MONTHLY .
No full textCSCI01 - CLIMAT reports - China. GTS Priority level: 4. Included stations: (53772, Taiyuan); (52533, Jiuquan); (50527, Hailar); (51076, Altay); (51463, Wu lu mu qi); (57083, Zhengzhou); (57131, Jinghe); (51709, Kashi); (54342, Shenyang); (53068, Erenhot); (51431, Yining); (51777, Ruoqiang); (52836, Doulan); (53614, Yinchuan); (54511, Beijing); (54857, Qingdao); (51828, Hotan); (52203, Hami); (50745, Qiqihar); (52983, Yu zhong); (54292, Yanji). Format: FM 71-XI(Refer to WMO No.306 - Manual on Codes). The CSCI01 Data Designator decodes as follow: T1(C):Climatic data;T1T2(CS):Monthly means (surface);A1A2(CI):China.(Refer to WMO No.386 - Manual on the GTS). Related words: meteorology;meteorological
Statistical analysis plan for the second INTEnsive blood pressure Reduction in Acute Cerebral hemorrhage Trial (INTERACT2): a large-scale investigation to solve longstanding controversy over the most appropriate management of elevated blood pressure in the hyperacute phase of intracerebral hemorrhage
No full textCraig Anderson, Emma Heeley, Stephane Heritier, Hisatomi Arima, Mark Woodward, Richard Lindley, Bruce Neal, Yining Huang, Ji-Guang Wang, Mark Parsons, Christian Stapf, Tom Robinson, Pablo Lavados, Candice Delcourt, Stephen Davis, and John Chalmers for the INTERACT2 Investigator
Soil phosphorus accumulation changes with decreasing temperature along a 2300 m altitude gradient
No full textISCN01 CLIMAT ; available from BABJ(PEKING (BEIJING)) at XXX .
No full textISCN01 - CLIMAT. GTS Priority level: 2. Included stations: (53772, Taiyuan); (52533, Jiuquan); (50527, Hailar); (51076, Altay); (51463, Wu lu mu qi); (57083, Zhengzhou); (57131, Jinghe); (51709, Kashi); (54342, Shenyang); (53068, Erenhot); (51431, Yining); (51777, Ruoqiang); (52836, Doulan); (53614, Yinchuan); (54511, Beijing); (54857, Qingdao); (51828, Hotan); (52203, Hami); (50745, Qiqihar); (52983, Yu zhong); (54292, Yanji). Format: FM 94-XIII(Refer to WMO No.306 - Manual on Codes). The ISCN01 Data Designator decodes as follow: T1(I):Observational data (Binary coded) - BUFR;T1T2(IS):Surface/sea level;T1A2(IN):Northern hemisphere.(Refer to WMO No.386 - Manual on the GTS). Related words: meteorology;meteorological
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