This study investigates the unsteady dynamics and inherent instabilities of a cavitating propeller operating in a water tunnel. First, the steady characteristics of the cavitating propeller such as the thrust coefficient are obtained by applying continuity and momentum equations to a simple one-dimensional flow tube model. The effects of the tunnel walls as well as those of the propeller operat...

BACKGROUND AND PURPOSE Fluid-attenuated inversion recovery hyperintense vessels in stroke represent leptomeningeal collateral flow. We presumed that FLAIR hyperintense vessels would be more closely associated with arterial stenosis and perfusion abnormality in ischemic stroke on T2-PROPELLER-FLAIR than on T2-FLAIR. MATERIALS AND METHODS We retrospectively reviewed 35 patients with middle cere...

Introduction: Fast-spin echo (FSE) imaging is one of the most frequently used pulse sequences for brain imaging due to its scan time efficiency, good tissue contrast, and high effective resolution. Practical problems that occur are mostly due to patient motion, which leads to blurring and imaging ghosting (Fig. 1b). To make the acquisition robust to motion, the T2-w PROPELLER pulse sequence can...

The PROPELLER sequence is clinically used for T2 and DW imaging and can be motion corrected. Parallel imaging techniques have been used in axial PROPELLER imaging to effectively widen the blade, thus reducing motion artifacts and improving general image quality. However, parallel imaging is not suitable for all image orientations with all available coils (e.g. PROPELLER spine imaging). We propo...

We compared two methods of 3D digital subtraction angiography (DSA)--propeller and standard rotation--for the assessment of aneurysmal morphology and its relation to neighboring vessels. Aneurysms were correctly visualized and localized with both techniques. 3D DSA with propeller rotation technique seems to be effective and allows us to reduce the amount of contrast material related to a shorte...

The coframe (teleparallel) description of gravity is known as a viable alternative to GR. One of advantages of this model is the existence of a conserved energy-momentum current witch is covariant under all symmetries of the threeparameter Lagrangian. In this paper we study the relation between the covector valued current and the energy-momentum tensor. Algebraic properties of the conserved cur...

A new method for computing all elements of the lattice quark propagator is proposed. The method combines the spectral decomposition of the propagator, computing the lowest eigenmodes exactly, with noisy estimators which are ‘diluted’, i.e. taken to have support only on a subset of time, space, spin or colour. We find that the errors are dramatically reduced compared to traditional noisy estimat...

The efficient representation and manipulation of time information is key to any successful implementation of a verification tool. We extend the syntax and semantics of the higher level specification language Promela to include constructs and statements based on the model of timed Bfichi automata [2]. We implement these extensions on top of the verification tool Spin.