To determine the source of errors in the Gorlin formula for estimating stenotic valvular orifice area, we used a pulsatile flow model that emulated left ventricular and aortic pressures and flow and allowed control of ventricular outflow orifice area. After comparing orifice areas calculated by the Gorlin formula with actual orifice areas, the Gorlin formula constant (k) was found to be highly ...

To determine the source of errors in the Gorlin formula for estimating stenotic valvular orifice area, we used a pulsatile flow model that emulated left ventricular and aortic pressures and flow and allowed control of ventricular outflow orifice area. After comparing orifice areas calculated by the Gorlin formula with actual orifice areas, the Gorlin formula constant (k) was found to be highly ...

Eight patients with mixed mitral stenosis and regurgitation underwent hemodynamic and angiographic study prior to mitral valve replacement. The stenotic orifice of the mitral valve was calculated employing the total left ventricular stroke volume by cineangiography as the numerator of the Gorlin Formula. Excellent agreement with the measured orifice of the mitral valve was obtained using a valu...

Strong velocity scale effect on cavitation for orifice tunnels was revealed through comparing the results of model tests in vacuum tanks and that of prototype measurements at construction site. A new formula predicting incipient cavitation number of orifice rings is presented in this paper. The predicted data for the prototype scale are coincident well with the prototype measured one.

Numerical investigation of gravity flow of granular solids in a hopper through orifices of different shapes has been conducted using the discrete element method. The simulations are validated by comparing with the experimental results for rapeseed cases. It is observed that with orifices of the same area the flow rate decreases in the order of circle, square, rectangle and triangle, which is si...

Because aortic stenosis results in the loss of left ventricular stroke work (due to resistance to flow through the valve and turbulence in the aorta), the percentage of stroke work that is lost may reflect the severity of stenosis. This index can be calculated from pressure data alone. The relation between percent stroke work loss and anatomic aortic valve orifice area (measured by planimetry f...

To overcome the space limit of orifice-type and capillary restrictors in hybrid bearings, a kind of atypical long orifice-type restrictor is proposed and its experimental model is established. Through the analysis of the structure and flow rate of orifice-type restrictor and capillary restrictor, a long orifice-type restrictor and a feasible experimental modeling method are presented by use of ...

As a successive alkalinity-producing system pond for purifying mine drainage is operated, sediment accumulates in the limestone layer of pond, and as amount accumulated increases, water permeability treatment efficiency decrease. Hence, flushing required, comprising network perforated pipes installed layers, to periodically discharge outside. The performance depends on four distinct characteris...