Current Issue : January - March Volume : 2019 Issue Number : 1 Articles : 5 Articles
This paper presents an analytical approach for the development of a new wideband\npiezoelectric energy harvesting system. The proposed model is based on Adomian decomposition\nmethod to derive the dynamic response of the general non-uniform smart structures under external\nenvironmental excitations over a wide frequency domain efficiently harvesting the subsequent\nvibrational energy. The steady-state response of a nonlinearly tapered piezoelectric harvester\nsubjected to harmonic base motion is obtained, and the higher potential electromechanical outputs\ncompared with traditional uniform harvester are analytically derived. Afterward, a group of\nnonlinearly tapered cantilevers with the same volume and length but different taper ratios and\nsurface bonded piezoelectric layers are assembled together in order to build a broadband piezoelectric\nenergy harvester. Through numerical studies, it is proven that with the proposed non-uniform\nconfiguration, the new energy harvester design can function effectively and efficiently with high\nvoltage output over a wide frequency range. The designed wideband harvester can automatically\nactivate one of the non-uniform bimorphs to resonate at particular ambient vibration frequencies\nand eventually reach the maximum electromechanical output. Based on the proposed theoretical\nmodel, an optimum structural design for the wideband piezoelectric energy harvester in the required\noperational frequency range can be efficiently achieved...
Gaoshiti-Moxi structure belt of An-Yue Sinian gas reservoir, which was Chinaâ??s\nlargest monomer Marine carbonate gas reservoir up to now, located in\nvying-dragon female temple structure group that belong to the ancient uplift\nslope of the middle of Sichuan. With the exploration and development of\nhigh temperature and high pressure carbonate reservoir, a large number of\nchallenges and problems, such as long isolation section, active oil-gas show,\nlarge temperature difference, prone to super retarding cement slurry and gas\nchanneling at flare position, have been encountered in the cementing of 177.8\nmm hang-liner. In order to solve these problems, numerous measures and\nmethods have been put into use for reducing the safety risk of cementing and\nimproving cementing quality. The large temperature difference channeling\ncement slurry system, effective anti-pollution spacer and high-pressure packer\ntype liner hanger were developed and applied for field tests in the early\nstage of development. In addition, equilibrium pressure cementing technology,\noptimizing of centralizer placement and plasma column structure, improvement\nof pump displacement and hold pressure while waiting on cement\nwere used to ensure nice displacement efficiency and cementing quality. As\nMoxi X well for example, the cementing quality factor of merit was 40.29%\nand the qualification rate was up to 78.87% after adopting the cementing\nmeasures and methods above. The cementing quality was much higher than\nprevious level and provided technical support for Gaoshiti-Moxi area....
For decades, the power system was highly centralized. With the growing integration\nof distributed generations into the system, there is a necessity for\nbi-directional communication methods to monitor and control the remote\nassets. The primary objective of this paper is to develop a communication link\nfor monitoring and controlling a grid-connected inverter in a remote location.\nFurthermore, the paper presents developments that have been incorporated\nto improve the communication link. The literature survey indicates that\nLoRa is superior compared to other technologies, but has some security and\nreliability issues. This paper also presents an encryption algorithm to improve\nthe security of the LoRa link. Local data storage added to the system before\ntransmitting data increases the system reliability. A display at the transmission\nend is added to improve the user-friendliness of the communication\nlink. A Powerline Communication link is parallelly added to the LoRa link to\nimprove the reliability. Finally, tests are conducted with an actual inverter\nand the results are presented. The tests show that the developed communication\nlink has improved security and reliability, while its open nature makes it\nhighly scalable and adaptable for employment in other smart grid applications...
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This paper focuses on vibration suppression and energy harvesting using a non-traditional\nvibration absorber referred to as model B. Unlike the traditional vibration absorber, model B has its\ndamper connected between the absorber mass and ground. The apparatus used in the study consists\nof a cantilever beam attached by a mass at its free end and an electromagnetic energy harvester.\nThe frequency tuning is achieved by varying the beam length while the damping tuning is realized by\nvarying the harvester load resistance. The question addressed is how to achieve the best performance\nunder transient responses. The optimum tuning condition for vibration suppression is based on\nthe Stability Maximization Criterion (SMC). The performance of energy harvesting is measured by\nthe percentage of the harvested energy to the input energy. A computer simulation is conducted.\nThe results validate the optimum parameters derived by the SMC. There is a trade-off between\nvibration suppression and energy harvesting within the realistic ranges of the frequency tuning ratio\nand damping ratio. A multi-objective optimization is conducted. The results provide a guideline for\nobtaining a balanced performance. An experimental study is carried out. The results verify the main\nfindings from the computer simulation. This study shows that the developed apparatus is capable of\nachieving simultaneous vibration suppression and energy harvesting under transient responses....
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