The zero modes of the Dirac operator in the background of center vortex gauge field configurations in R 2 and R 4 are examined. If the net flux in D = 2 is larger than 1 we obtain normalizable zero modes which are mainly localized at the vortices. In D = 4 quasi-normalizable zero modes exist for intersecting flat vortex sheets with the Pontryagin index equal to 2. These zero modes are mainly lo...

This paper presents a new numerical method for the compressible Navier-Stokes equations governing the flow of an ideal isentropic gas. To approximate the continuity equation, the method utilizes a discontinuous Galerkin discretization on piecewise constants and a basic upwind flux. For the momentum equation, the method is a new combined discontinuous Galerkin and finite element method approxima...

We consider the full time-harmonic Maxwell equations in the presence of a thin, high-contrast dielectric object. As an extension of previous work by two of the authors, we continue to study limits of the electric field as the thickness of the scatterer goes to zero simultaneously as the contrast goes to infinity. We present both analytical and computational results, including simulations which ...

Recently Thienel [Ann. Phys. (N.Y.) 280 (2000), 140] investigated the Pauli equation for an electron moving in a plane under the influence of a perpendicular magnetic field which is the sum of a uniform field and a singular flux tube. Here we criticise his claim that one cannot properly solve this equation by treating the singular flux tube as the limiting case of a flux tube of finite size. Ty...

This paper presents a novel method of Hybrid pulse width modulation (HPWM) algorithm for control of induction motor drive based on model referencing adaptive system (MRAS). In the conventionally used space vector pulse width modulation (CSVPWM) scheme the duration of zero voltage application is equally distributed in each and every sampling period. In this is paper a HPWM is presented for senso...

In this paper we present several nonlinear control designs for a single one-degree-of-freedom (1-DOF) Active Magnetic Bearing (AMB). The primary control objective is to globally asymptotically stabilize the mechanical states of an AMB while reducing the AMB power losses. This suggests operation with zero or low bias flux. We derive a flux-based model for an AMB using a generalized complementary...

We present a method for obtaining atmospheric temperature, pressure, and number density profiles for small bodies through inversion of light curves recorded during stellar occultations. This method avoids the assumption that the atmospheric scale height is small compared with the radius of the body, and it includes the variation of gravitational acceleration with radius. First we derive the int...