Engines equipped with camless valve trains will have greater space for performance optimization. In this paper, based on the electromagnetic actuated valve train system, one-dimensional and three-dimensional simulation models on engine thermodynamic cycle and in-cylinder charge motion are established, respectively. With the application of early-intake-valve closing (EIVC) strategy，unthrottled l...

A 1arge-scale tumble rather than swirl would exist in cylinders in the case of two valves’ opening in a fourvalve engine. A strong swirl is generated when one valve is closed, yet the flow capacity is less than that of two valves being opened. In order to change it, different lifts of valves (DLV) present are achieved. In the case of using different lifts of two intake valves, both tumble and s...

Premature opening of the aortic valve in late diastole has been demonstrated by echocardiography in a patient with severe aortic regurgitation. Valve opening coincided with the end of the diastolic murmur and equalization of aortic and left ventricular diastolic pressures. Echocardiography of the aortic valve in severe aortic reflux may, therefore, provide valuable information about the underly...

To increase the efficiency of hydraulic systems by eliminating valve throttling losses, a direct displacement open circuit is proposed to control a single rod hydraulic actuator. The circuit provides three control inputs, including the displacement of a variable displacement pump, the opening area of a proportional valve, and the position of a directional valve. Pump control has a low bandwidth...

Early stages of aortic valve disease involve a subtle increase in leaflet stiffness which affects valve performance seen particularly in the opening and closing of the valve. In this study, a pulse duplicator which recreates physiologic flow waveforms was used to evaluate how changes in experimental conditions such as downstream resistance and flow rate affect the opening and closing patterns o...

In this paper, the effect of the Intake Valve Deactivation (IVDA) on engine performance is investigated in detail. Based on an optimization platform with Genetic Algorithm (GA) and engine thermodynamic model, the characteristics of the engine volumetric efficiency and pumping loss were studied under the cam-drive, Single Intake Valve (SIV) and Dual Intake Valves (DIV) operating modes, and the e...

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 ...

Introduction: Methane is one of the most widely used gases in industries with a high flammability potential. This study aimed to evaluate the efficiency of ventilation systems installed on methane valve pits based on hazardous areas classification. Material and Methods: This study was implemented in a steel industry in Qom Province in 2019. The tools used in this study were a DELTA OHM pitot t...

SUMMARY Clinically suspected coronary artery disease was assessed in 52 patients by 16-mm biplane left ven-triculography. Outward movement of the left ventricular wall was observed prior to mitral valve opening in normal patients and those with coronary artery disease. In the normal ventriculogram, outward movement was usually visible in the anterior wall and the apex. In the asynergic ventricl...