Echographic aortic valve closure was compared to the dicrotic notch of the aortic pressure and intracardiac A2 to define the exact temporal relationship of the echographic, pressure, and sound parameters of aortic valve closure. Sixteen children, ages 3--20 years, were evaluated by simultaneous aortic valve echograms, micromanometric aortic root pressure tracings, and intracardiac phonocardiogr...

The aortic valve, located between the left ventricle and the aorta, allows for unidirectional blood flow, preventing backflow into the ventricle. Aortic valve leaflets are composed of interstitial cells suspended within an extracellular matrix (ECM) and are lined with an endothelial cell monolayer. The valve withstands a harsh, dynamic environment and is constantly exposed to shear, flexion, te...

Relief valves are widely used in industrial machinery. Due to the outlet of the relief valve being connected to the tank, the pressure drop of the relief valve is frequently equal to the inlet pressure. Accordingly, the energy loss of the relief valve is very high in some cases and this will worsen with an increase in the rated pressure of the hydraulic system. In order to overcome the disadvan...

The experimental study was conducted to investigate the effects of different opening ranges of waste gate of a turbocharged medium displacement spark ignition engine on improving work parameters such as exhaust emission, torque characteristics and fuel consumption. The object of the experimental tests was an engine with modified intake and exhaust manifolds. The intake and exhaust manifold modi...

The paper describes tests carried out on disc valves in which the valve seat was withdrawn from the valve wh).le a pressure difference existed across the valve. Simultaneous measurements were made of the force on the valve, the pressure in the plenum chamber and the displacement of the seat from the valve. Force measurements are compared with values of force measured during continuous flow cond...

The effects of greenhouse gases (GHG) on the growth of global warming, and increase of GHG and air pollutant emissions for energy production have forced the need of energy recovery which is normally wasted in industrial plant. The present research work focused on the GHG and air pollutant emissions reduction employing pressure waste energy recovery. Pressure break-down via Joule-Thomson valve i...

The valve testing unit is a high pressure test equipment to test the valve manufactured in industries. Valves are tested to ensure that they sustain high pressure in the range of 10000 to 15000 PSI for the required amount of time without any leakage. It has few drawbacks such as inefficient usage of power, fatal accidents due to the proximity of the users with the testing unit to note the valve...

OBJECTIVES To investigate the effects of transvalvar flow rate on aortic valve resistance and valve area after percutaneous transvenous balloon dilatation of the mitral valve in a homogeneous group of patients with rheumatic heart disease. DESIGN Retrospective analysis of 12 patients with combined aortic and mitral stenosis who had undergone balloon dilatation of the mitral valve over a perio...

Joule-Thomson cooling systems are used in refrigeration processes such as cryogenic gas liquefaction. Although extensive studies have been carried out by researchers, most of them include cryogenic heat exchangers and their associated fields. In the current study, an attempt was made to indicate the effect of using inappropriate operational conditions in a cryogenic Joule-Thomson cooling system...

Programmable valve shunts allows selection of opening pressure of shunt valve. In the presented article, a unique complication pertaining to programmable shunts has been discussed. A 5-year-old boy who had tectal plate low grade glioma with obstructive hydrocephalus was managed with Codman programmable ventriculoperitoneal shunt. There was a spontaneous change in the opening ...