Characterizing nonlinear characteristics of asymmetric tristable energy harvesters

2022 ◽  
Vol 168 ◽  
pp. 108612
Author(s):  
Xiaoqing Ma ◽  
Haitao Li ◽  
Shengxi Zhou ◽  
Zhichun Yang ◽  
Grzegorz Litak
Author(s):  
Junyi Cao ◽  
Shengxi Zhou ◽  
Daniel J. Inman

This paper investigates the nonlinear dynamic characteristics of a magnetically coupled piezoelectric energy harvesters under low frequency excitation, where the angle of external magnetic field is adjustable. The nonlinear dynamic equation with the identified nonlinear magnetic force is derived to describe the electromechanical interaction of variable inclination angle harvesters. The effect of excitation amplitude and frequency on dynamic behavior is proposed by using the phase trajectory and bifurcation diagram. The numerical analysis shows that a rotatable magnetically coupling energy harvesting system exhibits rich nonlinear characteristics with the change of external magnet inclination angle. The nonlinear route to and from large amplitude high energy motion can be clearly observed. It is demonstrated numerically and experimentally that lumped parameters equations with an identified polynomials for magnetic force could adequately describe the characteristics of nonlinear energy harvester. The rotating magnetically coupled energy harvester possesses the usable frequency bandwidth over a wide range of low frequency excitation by adjusting the angular orientation.


2002 ◽  
Vol 728 ◽  
Author(s):  
Munir H. Nayfeh

AbstractWe dispersed electrochemically etched Si into ultrabright ultrasmall nanoparticles, with brightness higher than fluorescein or rhodamine. The emission from single particles is readily detectable. Aggregates or films of the particles exhibit emission with highly nonlinear characteristics. We observe directed blue beams at ∼ 410 nm between faces of aggregates excited by femtosecond radiation at 780 nm; and at ∼ 610 nm from aggregates of red luminescent Si nanoparticles excited by radiation at 550-570 nm from a mercury lamp. Intense directed Gaussian beams, a pumping threshold, spectral line narrowing, and speckle patterns manifest the emission. The results are analyzed in terms of population inversion and stimulated emission in quantum confinement-induced Si-Si dimer phase, found only on ultrasmall Si nanoparticles. This microlasing constitutes an important step towards the realization of a laser on a chip.


Author(s):  
V. A. Shishkin ◽  
E. P. Rybalkin ◽  
E. B. Balykina

Simulation modeling of phytophagans’ influence on the yield of seed fruit crops, in particular apple trees, was carried out. By means of simulation models the importance of phytophagans’ influence at different stages of the vegetation period and the period of fruit ripening was revealed. The software package Matlab was used to build simulation models. As a result, simulation models with nonlinear characteristics were obtained, which maximally reflected the studied processes. The developed models imitate the process of phytophagans’ development. Generation change of pests and all stages of their development are simulated. Their respective numbers are recorded at each stage for all generations. The development process at each stage is modeled by separate subsystems of the simulation model. To simulate the development of one generation of pests, these subsystems are connected by external links. In addition, part of the relationships provides a simulation of generational change. There are a number of input parameters that allow to configure the simulation of the process of changing generations, taking into account the peculiarities of the development of various phytophagans.


IEEE Access ◽  
2021 ◽  
pp. 1-1
Author(s):  
Eustaquio Martinez-Cisneros ◽  
Luis A. Velosa-Moncada ◽  
Ernesto A. Elvira-Hernandez ◽  
Omar I. Nava-Galindo ◽  
Luz Antonio Aguilera-Cortes ◽  
...  

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