OBJECTIVES Proper valve selection is critical to ensure appropriate valve replacement for patients, because implantation of a small valve might place the patient at risk for persistent gradients. Labeled valve size is not the same as millimeter measure of prosthetic valve diameters or the annulus into which it will fit. Studies that use the labeled valve size in lieu of actual measured diameter...

The main challenge facing the oil industry is to reduce development costs while accelerating recovery with maximizing reserves. One of the key enabling technologies in this area is intelligent well completions. Intelligent well technology (IWT) is a relatively new technology that has been adopted by many operators in recent years to improve oil and gas recovery. Intelligent well completions emp...

PURPOSE Only mechanical and biological heart valve prostheses are currently commercially available. The former show longer durability but require anticoagulant therapy; the latter display better fluid dynamic behavior but do not have adequate durability. New Polymeric Heart Valves (PHVs) could potentially combine the hemodynamic properties of biological valves with the durability of mechanical ...

OBJECTIVE Balloon-expandable stent valves require flow reduction during implantation (rapid pacing). The present study was designed to compare a self-expanding stent valve with annular fixation versus a balloon-expandable stent valve. METHODS Implantation of a new self-expanding stent valve with annular fixation (Symetis, Lausanne, Switzerland) was assessed versus balloon-expandable stent val...

BACKGROUND Functional tricuspid regurgitation (TR) is increasingly recognized as a source of morbidity. Current repair strategies focus on annular remodeling because annular dilatation is common in patients with TR. Although papillary muscle (PM) displacement is recognized in functional mitral regurgitation, its role in TR is less well characterized. The objective of this in vitro study was to ...

Conventional electro-hydraulic precision motion control systems are controlled by either servo valves or proportional directional control valves. Neither of the valves are able to control the pressures at the two cylinder chambers independently or to use the regeneration flow. The result is that while precision motion control is possible, significant energy saving is not. In order to save energ...

In this paper, the hydraulic servo position control system with generalization pulse code modulation (GPCM) control is studied. The flow rate of the GPCM control system is controlled by a series of N solenoid on-off valves which are calibrated having different flow, and are activated by N bits binary pulse codes. In traditional PCM control, the flow rates of valves are arranged increasing accor...

In this paper, numerical investigation of upward two phase flow of air-water has been studied. Different conditions of flow regimes including annular, wispy annular, slug, churn and bubbly are simulated based on Hewitt and Roberts map, and a good agreement between the experimental data of the map and the numerical simulation has been observed. Accordingly, a proper CFD model in CFD software of ...

Cavitation has been investigated in directional control valves in order to identify damage mechanisms characteristic of components o f aircraft hydraulic systems. Tests have been conducted in a representative metal spool valve and in a model three times larger. Data taken under noncavitating conditions with both valves showed that the position of the high-velocity annular jet shifts orientation...