f all valve lesions, mitral stenosis has the most options for ntervention and in many ways is the valve lesion where it is asiest to make a decision that intervention is necessary. his was the first acquired valve lesion where patient ymptoms and ultimate prognosis could be improved surgially even before cardiopulmonary bypass was available. The ndications for the timing of valve repair or repl...

In this paper, we propose a control scheme for the position of Variable Cam Timing (VCT) actuators. We take into account the observation by (Genç et al., 2001) that these actuators feature a significant nonlinearity, but we use a different approach. We perform a model reduction of mechanics, pressure, flows and balance equations. It serves to design an observer used in a motion planning strateg...

The timing of surgery has been a major problem in the management of chronic severe mitral regurgitation (MR). In adults, because of poor prognosis of postoperative left ventricular (LV) dysfunction, sequential echocardiographic assessment of LV function for optimal operation time is recommended. 2 However, in children, therapeutic guidelines of chronic MR are less well defined and severe sympto...

We address the control of the airpath of a turbocharged S.I. engine equipped with Variable Valve Timing actuators (VVT). Compared to standard configurations, the engine does not possess any external EGR (Exhaust Gas Recirculation) loop. Rather, VVT are used to produce internal EGR, providing similar beneficial effects in terms of emissions reduction. The airpath dynamics takes the form of a sin...

This paper summarizes the results of design of new mechanical variable valve actuation (hereafter VVA) systems, developed for high performance motorcycle engines, at University of Napoli Federico II, Department of Industrial Engineering–Section Mechanics and Energy (hereafter DiME). In addition to a first simple (and limited) system used just as a model for the previous analysis, the work has e...

Many problems and complications associated with heart valves are related to the dynamic behavior of the valve and the resultant unsteady flow patterns. An accurate depiction of the spatial and temporal velocity and rms distributions imparts better understanding of flow related valve complications, and may be used as a guideline in valve design. While the generalized correlation between increase...

Variable intensity and timing of valvular sounds were noted in two patients with permanent pacemakers and prosthetic valves. In the first patient, who had a mitral and a tricuspid prosthesis, valvular opening sounds became widely separated with a change from nodal to ventricular paced rhythm. In a second patient, who had a mitral prosthesis in sinus rhythm with first-degree atrioventricular blo...

Echocardiographic assessment prior to valve surgery is crucial for clinical decision making, timing of surgery, planning the adequate surgical therapy and predicting the patient's outcome. Description of transvalvular velocities is not enough for sending a patient to the operating room. There are specific functional and morphological characteristics of each valve dysfunction that have to be add...

We propose a new simulation algorithm for combinational circuits which accurately models delay variations in the gates. The algorithm can also be used for the timing veriication of asynchronous circuits, eg hazard detection, race/oscillation of sequential circuits, etc. The basic idea is to assign a time variable to each signal transition (edge). The gate delays translate to algebraic relations...

We present a low power, on demand Parylene MEMS electrothermal valve. A novel Omega-shaped thermal resistive element requires low power (approximately mW) and enables rapid valve opening (approximately ms). Using both finite element analysis and valve opening experiments, a robust resistive element design for improved valve opening performance in water was obtained. In addition, a thermistor, a...