At very low Reynolds number, the regime in which fluid dynamics is governed by Stokes equations, a helix that translates along its axis under an external force but without an external torque will necessarily rotate. By the linearity of the Stokes equations, the same helix that is caused to rotate due to an external torque will necessarily translate. This is the physics that underlies the mechan...

Introduction: Ghost magnetic resonance angiography (MRA) is a new method for angiography that suppresses background tissue without subtraction. The method is predicated on the creation of arterial ghost artifacts within a region containing no MR signal (e.g. air), and can be used for both unenhanced and contrast-enhanced MRA. When used for unenhanced MRA, cardiac gating is not required. This ca...

In this article we discuss the application of a Lagrange multiplier based ®ctitious domain method to the numerical simulation of incompressible viscous ̄ow modeled by the Navier±Stokes equations around moving rigid bodies; the rigid body motion is due to hydrodynamical forces and gravity. The solution method combines ®nite element approximations, time discretization by operators splitting and c...

We describe a method for 3D reconstruction of plant seed surfaces, focusing on small seeds with diameters as small as 200μm. The method considers robotized systems allowing single seed handling in order to rotate a single seed in front of a camera. Even though such systems feature high position repeatability, at sub-millimeter object scales, camera pose variations have to be compensated. We do ...

This paper presents an alternative approach for the control of an antagonistic muscle actuated manipulator. The proposed method uses a neuronal network called NeuraBase to learn the sensor events obtained via a rotary encoder and to control the motor events of two DC motors, to rotate the manipulator. A neuron layer called the controller network links the sensor neuron events to the motor neuro...

A Microelectromechanical System-based (MEMS) PICOSAT Inspector (MEPSI) picosatellite on STS-116, in December 2006, used a five thruster cold gas propulsion system to translate and rotate. The inspector picosatellite measured 4 x 4 x 5 inches in dimension and weighted 1.4 kg. Our propulsion system was produced by a unique (to spacecraft) method of manufacturing that is low cost, tightly integrat...

The structure of boron nitride nanotubes is investigated using a generalized tight-binding molecular dynamics method. It is shown that dynamic relaxation results in a wave-like or ‘rippled’ surface in which the B atoms rotate inward and the N atoms move outward, reminiscent of the surface relaxation of the III–V semiconductors. More importantly, the three different morphologies of the tube clos...