The aim of the paper is to analyze electro-thermo nonlinear vibration of a double-piezoelectric composite microplate-system (DPCMPS) based on nonlocal piezoelasticity theory. The two microplates are assumed to be connected by an enclosing elastic medium which is simulated by Pasternak foundation. Both of smart composite microplates are made of poly-vinylidene fluoride (PVDF) reinforced by zigza...

A coupled spring-pendulum system in a conservative field was studied where the equation of motion using Lagrangian and Hamiltonian were obtained. The represented by second-order differential from three generalized coordinate used. potential energy equal to zero when is its equilibrium position. that being used angle first pendulum θ_1, second θ_2, increase length spring x. resulting can be dete...

â â  the present study attempts to investigate the urban hierarchy in iran between 1996-2006. the research method is content and statistical analysis. the necessity data were collected by documental method. in addition to the analysis and sorting of the data regarding the situation of iranian cities based on different models such as entropy ,ginny coefficients, urban concentration index, and ra...

The importance of the equipment and secondary systems in seismic design and performance evaluation is well recognized and has been the subject of many studies. In all of these studies, earthquake is considered as a single component, and in most of them the primary system is considered as shear building. Most attention has been concentrated on the response of secondary system and its response sp...

The hybrid AC-DC microgrid (HMG) architecture has the merits of both DC and AC coupled structures. Microgrids are subject to intermittence when the renewable sources are used. In the HMG, since power fluctuations occur on both subgrids due to varying load and unpredictable power generation from renewable sources, proper voltage and frequency regulation is the critical issue. This article propos...