This paper aims to research the position control of the hydraulic cylinder controlled by the high-speed on-off valve to realize the precise position control. The strategy combining the pulse width modulation with pulse frequency modulation is proposed to compensate the dead and saturated zones of the high-speed on-off valve, which is on the groundwork of the analysis of the flow characteristic ...

Boiler-turbines are one of the most important parts in power generation plants. The safety problem in such systems has always been a special concern. This paper discusses the application of control reconfig uration by fault-hiding approach for a boiler-turbine unit. In Fault-hiding approach, after occurrence of a fault, nominal controller of the system remains unchanged; instead, a reconfigurat...

OBJECTIVE To investigate the presence of myocardial fibrosis determined by fragmented QRS in patients with severe aortic valve stenosis. SUBJECTS AND METHODS Eighty-seven consecutive patients with severe aortic valve stenosis and 83 age- and gender-matched control subjects were enrolled into this study. Severe aortic valve stenosis was defined as an aortic valve area <1 cm(2), a Vmax >4 m/s, ...

Hydraulic applications requiring a variation in the speed or torque of actuators have historically used throttling valve control or a variable displacement pump or motor. An alternative method is switch-mode control that uses a high-speed valve to rapidly switch between efficient on and off states, allowing any hydraulic actuator to have virtually variable displacement. An existing barrier to s...

1. Abstract Recently there is a growing need for micro water cooling systems with the development of small-sized fuel cells for mobile electric devices. In general, a water cooling system requires a valve for controlling flow rate of coolant in order to keep targeted devices at appropriate working temperature. Traditional type of a flow control valve is driven by an external power source and a ...

Introduction: It is well-documented that right-sided heart dysfunction and significant tricuspid valve regurgitation (TVR) have adverse effects on patient outcomes after left-sided heart valve surgery. Therefore, the evaluation of right ventriclular (RV) function and TR severity in patients who had undergone mitral valve replacement (MVR), associated with/without concomitant su...

The prevalence of mitral valve prolapse was investigated in 126 patients with hyperthyroidism due to Graves' disease or toxic nodular goitre and that of hyperthyroidism in 64 patients with mitral valve prolapse. One hundred and eleven asymptomatic healthy subjects comprised a control group. The patients with hyperthyroidism were divided into those with Graves' disease and those with toxic nodul...

This paper proposes a variation on a sliding mode control approach that provides significant energy savings for the control of pneumatic servo systems. The control methodology is formulated by first decoupling the standard four-way spool valve used for pneumatic servo control into two three-way valves, then using the resulting two control degrees of freedom to simultaneously satisfy both the sl...

BACKGROUND We invented novel mitral valve repair technique; rough-zone trimming procedure (RZT) for anterior mitral valve prolapse. Prolapse site was resected in obtuse triangle shape and sutured edges to creates deep coaptation and improves regurgitation. Though it is simple and reproducible technique, functional mitral stenosis is a risk. Valve function and hemodynamics were investigated usin...