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, M.Sc. Thesis Sharif University of Technology ; Bastani, Daruoosh (Supervisor)
Abstract
In liquid-liquid extraction, as in gas absorption, two phases must be brought into good contact to permit transfer of material. The presence of nanoparticles in liquid phase can enhanced the rate of gas-liquid mass transfer. The benefits of nanofluids can be used to enhance the heat and mass transfer of liquid-liquid extraction. Standard test system with low interfacial tension that recommended by EFCE: n-butanol/water/succinic acid, was used in this project. The CNTs/n-butanol that was saturated of water used as dispersed phase. Water and succinic acid used as continuous phase and solute. Since there is no chemical reaction to take place between CNTs and n-butanol, In order to obtain well...
Semi-Active Intelligent Control for an Offshore Steel Jacket Platform with Magnetorheological Damper Wave-Induced Forces
, M.Sc. Thesis Sharif University of Technology ; Khayyat, Amir Ali Akbar (Supervisor)
Abstract
Due to the inherent non-linear nature of the MR damper, an intelligent non-linear neuro-fuzzy control strategy is designed for control of wave-induced vibration of an offshore steel jacket platform equipped with MR dampers. In the proposed control system, a dynamic-feedback neural network is employed to model non-linear dynamic system and the fuzzy logic controller is used to determine the control forces of MR dampers. Required voltages and actual forces of MR dampers are obtained by use of two feedforward neural networks, in which the first neural network and second one act as the inverse and forward dynamics model of the MR dampers, respectively. The most important characteristic of the...
Performance of an offshore platform with MR dampers subjected to wave
, Article 2011 IEEE International Conference on Mechatronics, ICM 2011 - Proceedings, 13 April 2011 through 15 April 2011 ; April , 2011 , Pages 242-247 ; 9781612849836 (ISBN) ; Hamid Zareh, S ; Khayyat, A. A ; Zabihollah, A ; Sharif University of Technology
2011
Abstract
The vibration suppression of semi-actively controlled jacket-type offshore platforms using Magnetorheological (MR) dampers is studied. The main goal of using MR damper system is to reduce vibration caused by wave hydrodynamic forces. A fixed jacket-type offshore platform affected by wave-induced hydrodynamic forces and controlled by MR dampers is modelled as a semi-active controlled system with 30 DOFs. In comparison with earlier studies, an improvement in problem modelling is made. Based on the wave theory and Morison equation, an exosystem is designed to simulate regular wave forces. The necessary input voltage to MR dampers to generate desired damping force is derived by clipped optimal...
Intelligent vibration control of micro-cantilever beam in MEMS
, Article 2011 IEEE International Conference on Mechatronics, ICM 2011 - Proceedings, 13 April 2011 through 15 April 2011, Istanbul ; April , 2011 , Pages 336-341 ; 9781612849836 (ISBN) ; Zareh, S. H ; Zabihollah, A ; Khayyat, A. A ; Sharif University of Technology
2011
Abstract
Considerable attention has been devoted recently to vibration control using intelligent materials as sensor/actuator. An intelligent control technique using a neural network is proposed for vibration control of micro-cantilever beam with bonded piezoelectric sensor and actuator. Structure modal characteristic analysis is done to determine the optimal configuration of piezoelectric sensor and actuator. With the piezoelectric elements are surface-bonded near the same position to the fixed end of micro-cantilever beam, an optimal controller, linear quadratic Gaussian (LQG), and an intelligent strategy based on neural network are investigated. Finally, the simulation results are given to...
Neuro-fuzzy control strategy for an offshore steel jacket platform subjected to wave-induced forces using magnetorheological dampers
, Article Journal of Mechanical Science and Technology ; Volume 26, Issue 4 , 2012 , Pages 1179-1196 ; 1738494X (ISSN) ; Zareh, S. H ; Khayyat, A. A. A ; Zabihollah, A ; Sharif University of Technology
2012
Abstract
Magnetorheological (MR) damper is a prominent semi-active control device to vibrate mitigation of structures. Due to the inherent non-linear nature of MR damper, an intelligent non-linear neuro-fuzzy control strategy is designed to control wave-induced vibration of an offshore steel jacket platform equipped with MR dampers. In the proposed control system, a dynamic-feedback neural network is adapted to model non-linear dynamic system, and the fuzzy logic controller is used to determine the control forces of MR dampers. By use of two feedforward neural networks required voltages and actual MR damper forces are obtained, in which the first neural network and the second one acts as the inverse...