This paper presents a method for three-dimensional (3D) segmentation of blood vessels, i.e. determining the surface of the vessel wall, using a combination of velocity data and magnitude images obtained using phase contrast MRI. In addition to standard MRI images, phase contrast MRI gives velocity information for blood and tissue in the human body. The proposed method uses a variational formula...

We study the finite element approximation of the stationary Stokes equations in the velocitypressure formulation using continuous piecewise quadratic functions for velocity and discontinuous piecewise linear functions for pressure. For some meshes this method is unstable, even after spurious pressure modes are removed. For other meshes there are spurious local pressure modes, but once they are ...

An ion projectile stopping at a velocity smaller than the target electron thermal velocity in a strong magnetic field is investigated within a different diffusion formulation, based on Green-Kubo integrands evaluated in magnetized one component plasma models, respectively framed on target ions and electrons. Analytic expressions are reported for slowing down orthogonal and parallel to an arbitr...

We develop a vorticity-based approach for modeling quasi-steady, supercritical gravity currents propagating into a finite-height channel with arbitrary density and velocity stratification. The model enforces the conservation of mass, horizontal and vertical momentum. In contrast to previous approaches it does not rely on empirical, energy-based closure assumptions. Instead, the effective energy...

This paper presents the analysis of vibration control of a laminated composite beam that including magnetostrictive layers. The formulation of problem is presented based on the shear deformation beam theory. For vibration suppression, the velocity feedback control with constant gain distributed is considered. Navier's method is applied to analyze the solution of vibration suppression of laminat...

Abstract. In this paper, we present a stabilized mixed formulation for unsteady Brinkman equation. The formulation is systematically derived based on the variational multiscale formalism and the method of horizontal lines. The derivation does not need the assumption that the fine-scale variables do not depend on the time, which is the case with the conventional derivation of multiscale stabiliz...

Electrons and photons, when interacting via a nanostructure, produce a new way of imaging in space and time, termed photon-induced near field electron microscopy or PINEM [Barwick et al. Nature 2009, 462, 902]. The phenomenon was described by considering the evanescent field produced by the nanostructure, but quantification of the experimental results was achieved by solving the Schrödinger equ...

We consider the Stokes problem in a square or a cube provided with non standard boundary conditions which involve the normal component of the velocity and the tangential components of the vorticity. We write a variational formulation of this problem with three independent unknowns: the vorticity, the velocity and the pressure. Next we propose a discretization by spectral methods which relies on...

Abstract. A numerical algorithm for the solution of the velocity-vorticity formulation of Navier-Stokes equations is presented. This formulation results in splitting of fluid flow into its kinematic and kinetic aspect. The Boundary Element Method (BEM) used for the solution of flow kinematics results in an implicit calculation of vorticity values at the boundary, whereas all transport equations...

We analyse acoustic streaming flows using an arbitrary Lagrangian Eulerian (ALE) perspective. The formulation stems from an explicit separation of time scales resulting in two subproblems: a first-order problem, formulated in terms of the fluid displacement at the fast scale, and a second-order problem, formulated in terms of the Lagrangian flow velocity at the slow time scale. Following a rigo...