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response-stability
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Stability analysis of a new class of MEMS gyroscopes with parametric resonance
, Article Acta Mechanica ; Vol. 223, Issue 6 , 2012 , pp. 1169-1185 ; ISSN: 00015970 ; Salarieh, H ; Alasty, A ; Sharif University of Technology
Abstract
In this paper, a parametrically resonated MEMS gyroscope is considered, and the effect of its parameters on the system stability is studied. Unlike the general case of MEMS gyroscopes with harmonic excitation, in this new class of gyroscopes with parametric excitation, the origin is one stationary point of the system. The study starts with the stability analysis of the origin, and then it goes on to analyze the effect of each parameter on the stability of periodic orbits. Stabilities are studied by means of Floquet theory. As the results indicate, presence of a non-trivial response for the system is closely interconnected to the stabilities (and instabilities) of the system. It is...
Stability analysis of a new class of MEMS gyroscopes with parametric resonance
, Article Acta Mechanica ; Volume 223, Issue 6 , 2012 , Pages 1169-1185 ; 00015970 (ISSN) ; Salarieh, H ; Alasty, A ; Sharif University of Technology
2012
Abstract
In this paper, a parametrically resonated MEMS gyroscope is considered, and the effect of its parameters on the system stability is studied. Unlike the general case of MEMS gyroscopes with harmonic excitation, in this new class of gyroscopes with parametric excitation, the origin is one stationary point of the system. The study starts with the stability analysis of the origin, and then it goes on to analyze the effect of each parameter on the stability of periodic orbits. Stabilities are studied by means of Floquet theory. As the results indicate, presence of a non-trivial response for the system is closely interconnected to the stabilities (and instabilities) of the system. It is...
An input-to-state stability approach to inertial frequency response analysis of doubly-fed induction generator-based wind turbines
, Article IEEE Transactions on Energy Conversion ; Volume 32, Issue 4 , 2017 , Pages 1418-1431 ; 08858969 (ISSN) ; Bahrami, S ; Ranjbar, A. M ; Sharif University of Technology
Abstract
Due to the proliferation of wind turbines in power networks, participation of doubly-fed induction generator (DFIG)-based wind turbines in the frequency regulation task is attracting more attention during recent decades. It is a challenge to design an effective DFIG's auxiliary frequency controller, since back-to-back converters used in DFIG make the possibility of large deviations in current and speed of rotor during frequency support period. Hence, it is necessary to use exact expression of DFIG's output power in the frequency-related studies. This paper addresses this challenge by developing a nonlinear dynamic model for the DFIG's output power integrated into the dynamic model of power...
Effect of shape memory alloy-magnetorheological fluid-based structural control system on the marine structure using nonlinear time-history analysis
, Article Applied Ocean Research ; Volume 91 , 2019 ; 01411187 (ISSN) ; Alam, M. S ; Seethaler, R. J ; Zabihollah, A ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Marine structures, as key elements in the global energy network, constantly are subjected to harsh environmental loading conditions. Therefore, reliable yet efficient structural control mechanisms are required to ensure their safe functionality and structural stability. In the present work, a novel hybrid structural control element for marine structures has been designed in which the superelasticity effect of shape memory alloy (SMA) and damping controllability of magnetorheological fluid (MRF), as smart materials, have been combined. The novel system does not require huge external energy for activation and in addition, the system has the ability to be tuned for variable loading conditions....
Mediator-less highly sensitive voltammetric detection of glutamate using glutamate dehydrogenase/vertically aligned CNTs grown on silicon substrate
, Article Biosensors and Bioelectronics ; Volume 31, Issue 1 , 2012 , Pages 110-115 ; 09565663 (ISSN) ; Shahrokhian, S ; Iraji zad, A ; Mohajerzadeh, S ; Vosoughi, M ; Darbari, S ; Sanaee, Z ; Sharif University of Technology
Abstract
A sensitive glutamate biosensor is prepared based on glutamate dehydrogenase/vertically aligned carbon nanotubes (GLDH, VACNTs). Vertically aligned carbon nanotubes were grown on a silicon substrate by direct current plasma enhanced chemical vapor deposition (DC-PECVD) method. The electrochemical behavior of the synthesized VACNTs was investigated by cyclic voltammetry and electrochemical impedance spectroscopic methods. Glutamate dehydrogenase covalently attached on tip of VACNTs. The electrochemical performance of the electrode for detection of glutamate was investigated by cyclic and differential pulse voltammetry. Differential pulse voltammetric determinations of glutamate are performed...