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Kien L.C.,Ho Chi Minh City University of Technology and Education
Journal of Electrical Engineering and Technology | Year: 2013

This paper examines the effects of magnetic induction attenuation on current distribution in the exit regions of the Faraday-type, non-equilibrium plasma Magnetohydrodynamic (MHD) generator by numerical calculation using cesium-seeded helium. Calculations show that reasonable magnetic induction attenuation creates a very uniform current distribution near the exit region of generator channel. Furthermore, it was determined that the current distribution in the middle part of generator is negligible, and the output electrodes can be used without large ballast resistors. In addition, the inside resistance of the exit region and the current concentration at the exit electrode edges, both decrease with the attenuation of magnetic flux density. The author illustrates that the exit electrodes of the diagonal Faraday-type, non-equilibrium plasma MHD generator should be arranged in the attenuation region of the magnetic induction, in order to improve the electrical parameters of the generator.

Thai H.-T.,University of New South Wales | Nguyen T.-K.,Ho Chi Minh City University of Technology and Education | Vo T.P.,Northumbria University | Lee J.,Sejong University
European Journal of Mechanics, A/Solids | Year: 2014

In this paper, a new first-order shear deformation theory is presented for functionally graded sandwich plates composed of functionally graded face sheets and an isotropic homogeneous core. By making a further assumption to the existing first-order shear deformation theory, the number of unknowns and governing equations of the present theory is reduced, thereby making it simple to use. In addition, the use of shear correction factor is no longer necessary in the present theory since the transverse shear stresses are directly computed from the transverse shear forces by using equilibrium equations. Equations of motion are derived from Hamilton's principle. Analytical solutions for bending, buckling and free vibration analysis of rectangular plates under various boundary conditions are presented. Verification studies show that the present first-order shear deformation theory is not only more accurate than the conventional one, but also comparable with higher-order shear deformation theories which have a greater number of unknowns. © 2013 Elsevier Masson SAS. All rights reserved.

Nguyen T.-K.,Ho Chi Minh City University of Technology and Education
International Journal of Mechanics and Materials in Design | Year: 2015

This paper presents a new higher-order hyperbolic shear deformation theory for analysis of functionally graded plates. In this theory, the transverse shear stresses account for a hyperbolic distribution and satisfy the free-traction boundary conditions on the top and bottom surfaces of the plate. By making a further assumption, the present theory contains only four unknowns and its governing equations is therefore reduced. Equations of motion are derived from Hamilton’s principle and Navier-type analytical solutions for simply-supported plates are compared with the existing solutions to verify the validity of the developed theory. The material properties are continuously varied through the plate thickness by the power-law and exponential form. Numerical results are obtained to investigate the effects of the power-law index and side-to-thickness ratio on the deflections, stresses, critical buckling load and natural frequencies. © 2014, Springer Science+Business Media Dordrecht.

Van Phan C.,Ho Chi Minh City University of Technology and Education
2014 IEEE 5th International Conference on Communications and Electronics, IEEE ICCE 2014 | Year: 2014

We propose a game-theoretic framework for opportunistic transmission strategy for wireless networks that operate in a strict energy-constrained environment. To reduce unsuccessful transmissions due to channel error and packet collision causing a waste of energy, the opportunistic transmission strategy attempts to transmit at good channel conditions while meeting the delay constraint under time-varying wireless channel. We formulate Constrained cost-coupled stochastic game to obtain the optimum threshold for successful transmission in the opportunistic transmission manner. © 2014 IEEE.

Vu T.N.L.,Ho Chi Minh City University of Technology and Education | Lee M.,Yeungnam University
ISA Transactions | Year: 2013

A new design method of fractional-order proportional-integral controllers is proposed based on fractional calculus and Bode's ideal transfer function for a first-order-plus-dead-time process model. It can be extended to be applied to various dynamic models. Tuning rules were analytically derived to cope with both set-point tracking and disturbance rejection problems. Simulations of a broad range of processes are reported, with each simulated controller being tuned to have a similar degree of robustness in terms of resonant peak to other reported controllers. The proposed controller consistently showed improved performance over other similar controllers and established integer PI controllers. © 2013 ISA.

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