BACKGROUND The surgical approach to aortic root aneurysm and/or dissection remains controversial. The use of valve-sparing operations, which are thought to have many advantages, is increasing. We hypothesized that the particular technique and type of surgery could influence valve motion characteristics and function. Therefore, we studied the instantaneous opening and closing characteristics of ...

Valvetrain flexibility enables the optimization of the engine’s ability to breathe across the operating range, resulting in more efficient operation. The authors have shown the merit of improving volumetric efficiency via valvetrain flexibility to improve fuel efficiency at elevated engine speeds in the previous work. This study focuses on production viable solutions targeting similar volumetri...

Pulmonary autograft valve replacement has been simulated by implanting the pulmonary valve into the aortic position of the same cadaver heart from both human and porcine sources. The forces acting on the pulmonary valve leaflets have been calculated on the basis of a triaxial ellipsoid mathematical model. These forces on the pulmonary autograft valve were shown to be essentially similar to thos...

Methodology combines holographic flow cytometry and AI to identify circulating tumor cells with high-throughput

This paper presents an analysis of six sets engine valves, each set consisting one exhaust valve and intake valve. Each pair valves was used in with different displacement mileage. The were subjected to microscopic analysis, hardness measurement chemical composition using a glow discharge spectrometer energy dispersive spectroscopy (EDS). design materials the showed that both their present form...

This paper developed a 3D physical model of the hydraulic end high-pressure liquid hydrogen reciprocating pump to research dynamic characteristics valve system. Based on mesh technology, we analyzed coupling and plunger motion spool force considering leakage model, closure gap, compressibility hydrogen. Further, effect spring stiffness preload laws valve. Finally, pressurization test was conduc...

The movements of two ultrasound echo signals, believed to arise from the anterior mitral leaflet and from the mitral ring, were studied in 30 normal subjects and in 100 heart-catheterization patients. Fifty patients had proven mitral stenosis. The echo from the anterior mitral leaflet is shown to have a complex pattern of movement. This pattern is analyzed into the opening and closing movements...

Tracheoesophageal speakers can achieve speech without digital occlusion by using a tracheostoma valve. Laryngectomized patients who are successful with this device can regain considerable freedom. However, little is known about which valve suits the patient best. Valve aerodynamics may give a guideline for its use. Three major tracheostoma valves, each divided into four subtypes, were repeatedl...