A flexible birdcage-type resonant RF detector for magnetic resonance imaging is described. The circuit consists of a polygonal ring of magnetically coupled L–C resonators, a periodic structure supporting backward magnetoinductive waves. The elements are mechanically linked to allow relative rotation, and the pivot point is optimised to hold the nearest-neighbour coupling coefficient invariant t...

We follow the unstable manifold of periodic and quasi-periodic solutions for the Poiseuille problem, using two formulations: holding constant flux or mean pressure gradient. By means of a numerical integrator of the Navier-Stokes equations, we let the fluid evolve from a perturbed unstable solution. We detect several connections among different configurations of the flow such as laminar, period...

This paper presents an efficient method of quasi-periodic noise detection and filtering. Taking into account that periodic noise leaves peaks in the amplitude spectrum, the proposed approach focuses on their detection and elimination. The detection is performed semiautomatically using a local median whereupon the localized peaks are eliminated by a modified Gaussian notch filter. The proposed a...