most previous laboratory studies of local scour at bridge abutments were performed in rectangular channels in which the distributions of flow velocity and bed shear stress were considered uniform in the transverse direction. in reality however, bridge abutments are usually located in the floodplain zone of rivers where velocity and shear stress distributions are directly affected by the lat...

AIMS This study was conducted to analyse flow velocity parameters and predictors of a suboptimal coronary flow reserve (<2.5) following balloon angioplasty. METHODS Two hundred and twenty-five patients underwent sequential intracoronary Doppler as part of the DEBATE I study. Of these, 183, with complete angiography and Doppler at the 6-month follow-up, were included. Univariate and multivaria...

We propose a cross-correlation-based method to measure blood-flow velocity by using photoacoustic microscopy. Unlike in previous autocorrelation-based methods, the measured flow velocity here is independent of particle size. Thus an absolute flow velocity can be obtained without calibration. We first measured the flow velocity ex vivo, using defibrinated bovine blood. Then flow velocities in ve...

Tidal energy is the most foreseeable form of renewable energy. Tidal energy can be harnessed by tidal barrage, tidal fence and tidal current technologies. Present efforts are focused on diffuser augmented tidal turbines that exploit the kinetic energy of the tidal currents. The power output by a tidal turbine is directly proportional to the cube of velocity of incoming fluid flow. Thus, even a ...

Applying corona wind as a novel technique can lead to a great level of heat and mass transfer augmentation by using a very small amount of energy. The enhancement of forced flow evaporation rate by applying electric field (corona wind) has been experimentally evaluated in this study. Corona wind produced by a fine wire electrode charged with positive high DC voltage impinges on water surface an...

this paper addresses the combined effects of couple stresses, thermal radiation, viscous dissipation and slip condition on a free convective flow of a couple stress fluid induced by a vertical stretching sheet. the cogley- vincenti-gilles equilibrium model is employed to include the effects of thermal radiation in the study. the governing boundary layer equations are transformed into a system o...

sudden pipe expansions have been known as efficient hydraulic energy dissipaters for a long time. the complex phenomenon of flow separation and velocity discontinuity at the interface of incoming jet and the recirculation flow, results in intensive shear and tensile rupture of the fluid and the associated destructive phenomenon of cavitation. this paper focuses on aeration in sudden pipe expans...

We used contrast echocardiography to estimate changes in flow velocity at the tricuspid and pulmonic valve orifices, as reflected by varying angles of the moving linear contrast echoes. The validity of the method was established by catheterization and echocardiographic studies in 14 patients. Flow velocity at the tricuspid and pulmonic valve orifices was measured by means of an electromagnetic ...

To assess coronary flow characteristics in congenital heart defect with left ventricular (LV) volume overload, we examined 24 children (mean 12.1 +/- 7.1 months) with ventricular septal defect. The pulmonary to systemic flow ratio ranged from 1.1 to 3.0. Control group consisted of 10 age-matched children who had a history of Kawasaki disease with angiographically normal coronary artery in the a...

The relationship between the velocity of the cerebral circulation and the cerebral blood flow was explored at varying levels of PaCO(2), systemic arterial pressure, intracranial pressure, and perfusion pressure, using radioisotope techniques in baboons. Only at low flow rates did velocity increase with flow, and then non-linearly; at high rates velocity increased progressively less. Changes in ...