Two schemes for processing signals obtained from the Doppler global velocimeter are described. The analog approach is a simple, real time method for obtaining an RS -170 video signal containing the normalized intensity image. Pseudo colors are added using a monochromatic frame grabber producing a standard NTSC video signal that can be monitored and/or recorded. The digita l approach is more com...

In the framework of the Gas-Power Conversion System for the Advanced Sodium Technological Reactor for Industrial Demonstration (ASTRID) project design, works done at CEA are focused on the design of the sodium-gas heat exchanger. Compact plate heat exchangers are indicated as the most suitable technology for such applications. An innovative compact heat exchanger geometry is proposed in this pa...

The flow of a polystyrene Boger fluid through axisymmetric contraction–expansions having various contraction ratios (2 ≤ β ≤ 8) and varying degrees of re-entrant corner curvatures are studied experimentally over a large range of Deborah numbers. The ideal elastic fluid is dilute, monodisperse and well characterized in both shear and transient uniaxial extension. A large enhanced pressure drop a...

UNLABELLED Doppler ultrasound is a non-invasive method for evaluating vascularization and is widely used in clinical practice. Gestational trophoblastic neoplasia includes a group of highly vascularized malignancies derived from placental cells. This review summarizes data found in the literature regarding the applications of Doppler ultrasound in managing patients with gestational trophoblasti...

Abstract Background: Epidemiologic studies have shown the relationship of maternal hemoglobin level and abnormal findings in uterine Doppler sonography with pregnancy- related complications. In this study, we evaluated the relationship of uterine artery Doppler velocimetry findings and hemoglobin level with the outcomes of pregnancy in women with preeclampsi...

We report on experiments on the effects of air bubbles on ultrasound velocity measurements in fluids. We used an acoustic Doppler velocimeter system for measuring the three velocity components in a single point and an acoustic Doppler velocimetry profiler system for measuring axial velocity in several points along the beam. The results suggest that both systems essentially measure the velocity ...

Photon Doppler velocimetry (PDV) has made the transition among many experimental groups from being a new diagnostic to being routinely fielded as a means of obtaining velocity data in high-speed test applications. Indeed, research groups both within and outside of the shock physics community have taken note of PDV’s robust, high-performance measurement capabilities. As PDV serves as the primary...

The development of data processing techniques and algorithms for Doppler Global Velocimetry is presented. The discussion begins with the fundamental calculation of the velocity dependent transfer function of Iodine vapor, and proceeds through laboratory and wind tunnel investigations to develop insight into the physics of the technique. The knowledge gained through this process provided the bas...