Permanent-magnetic gears are magneto-mechanical devices that are widely used to replace the ordinary mechanical gears and to transmit torque without any mechanical contact. The transmitted torque is one of the most important properties of magnetic gears. The torque characteristics of radial type permanent magnetic gears are investigated using ANSYS Program. The Maxwell stress tensor technique i...

This paper presents detailed numerical calculations of the dielectrophoretic force in traps designed for single-cell trapping. A trap with eight planar electrodes is studied for spherical and ellipsoidal particles using the boundary element method (BEM). Multipolar approximations of orders one to three are compared with the full Maxwell stress tensor (MST) calculation of the electrical force on...

The use of pulse width modulation (PWM) to drive permanent magnet synchronous motors (PMSM) inevitably creates current harmonics. generated harmonics create harmonic components the electromagnetic force, causing noise and vibration in PMSM affecting applied system. In this paper, effect PMSM’s force on a reciprocating compressor is analyzed. First, two PMSMs with different forces were designed....

The formalism developed by Chandrasekhar for the linear polar perturbations of the Reissner-Nordström solution is generalized to include the case of dipole (l=1) perturbations. Then, the perturbed metric coefficients and components of the Maxwell tensor are computed. PACS numbers: 04.70.Bw 04.25.Nx 04.40.Nr 1

Grinding can introduce surface and subsurface damage into ceramics, which may reduce the load-bearing area, and thus the residual strength of a ground component. In this study, the principle of continuum damage mechanics (CDM) is applied to predicting grinding damage for ceramics. A nonlinear thermodynamic constitutive model is established to describe the response of ceramics to complex grindin...

To my family. iv ACKNOWLEDGEMENTS I wish to express my deepest gratitude to a number of people who have helped or involved in this thesis research. First of all, I would like to thank my advisor Dr. Kok-Meng Lee. His advices were always stimulating and helpful when I was facing difficulties in my research. Furthermore, his enthusiastic and tireless work attitude has taught me what the professio...

We develop the holographic renormalization of AdS2 gravity systematically. We find that a bulk Maxwell term necessitates a boundary mass term for the gauge field and verify that this unusual term is invariant under gauge transformations that preserve the boundary conditions. We determine the energy-momentum tensor and the central charge, recovering recent results by Hartman and Strominger. We s...

We derive a generalization of the prolongation formula for tensorvalued functions, by taking into account the natural action of di eomorphisms on tensor elds. This di ers from the usual procedure, where such elds are viewed as de ning \multi-component scalars;" it replaces the ordinary derivative in the expression of the \characteristic" by a Lie derivative. The resulting version of Noether's t...

The Maxwell equations are formulated in a generally covariant and metric-free way in 1+3 and subsequently in 4 dimensions. For this purpose, we use the excitations D, H and the field strengths E,B. A local and linear constitutive law between excitations and field strengths is assumed, with a constitutive tensor χ = −χjikl = −χijlk of 36 components. The properties of this tensor are discussed. I...

We develop and apply a fully covariant 1 + 3 electromagnetic analogy for gravity. The free gravitational field is covariantly characterized by the Weyl gravito-electric and gravito-magnetic spatial tensor fields, whose dynamical equations are the Bianchi identities. Using a covariant generalization of spatial vector algebra and calculus to spatial tensor fields, we exhibit the covariant analogy...