A systematic overview of various electric-field induced pattern forming instabilities in nematic liquid crystals is given. Particular emphasis is laid on the characterization of the threshold voltage and the critical wavenumber of the resulting patterns. The standard hydrodynamic description of nematics predicts the occurrence of striped patterns (rolls) in five different wavenumber ranges, whi...

Source locations and depths to magnetic contacts were estimated from the total intensity magnetic field of an area of 3,025.25 square kilometres on geographical latitude N o ' 00 7 to N o ' 30 7 and longitude E o ' 00 3 to E o ' 30 3 within Abeokuta area, using local wavenumber method. This study was carried out using digitised airborne magnetic data of basement complex formation. Structural in...

Spaceborne scatterometers are the only proven method for global all-weather measurement of vector winds at the ocean’s surface. Such measurements are critical inputs in studies of oceanic circulation and air/seainteraction where the time variability of the surface wind field and the wind stress curl drive the ocean; hence, our interest in the spectrum of the surface wind field. In this paper we...

Abstract. This paper studies the regularity problem for the 3D incompressible resistive viscous Hall-magneto-hydrodynamic (Hall-MHD) system. The Kolmogorov 41 phenomenological theory of turbulence [16] predicts that there exists a critical wavenumber above which the high frequency part is dominated by the dissipation term in the fluid equation. Inspired by this idea, we apply an approach of spl...

For every two-dimensional system with helical boundary conditions, there is an isomorphic one-dimensional system. Therefore, the one-dimensional FFT of a 2-D function wrapped on a helix is equivalent to a 2-D FFT. We show that the Fourier dual of helical boundary conditions is helical boundary conditions but with axes transposed, and we explicitly link the wavenumber vector, k, in a multi-dimen...

A novel method to stabilize a channeled spectropolarimeter is described. The fluctuating retardations of the high-order retarders used in the spectropolarimeter are calibrated in parallel to the measurement of the wavenumber-dependent state of polarization (SOP) of light. Both the calibration of the retarders and the measurement of the SOP can be made simultaneously using a single light to be m...

This paper proposes a spectral-domain approach to the electromagnetic scattering problem of lamellar grating with defects. The fields in imperfectly periodic structures have continuous spectra in the wavenumber space, and the main problem of the spectral-domain approach is connected to the discretization scheme on the wavenumber. The present approach introduces the pseudo-periodic Fourier trans...

The current work focuses on applying an artificial viscosity approach to the Spectral Difference (SD) method to enable high-order computation of compressible fluid flows with discontinuities. The study uses an artificial viscosity approach similar to the high-wavenumber biased artificial viscosity approach introduced by Cook and Cabot, and modified by Kawai and Lele. The model employs a bulk vi...