نتایج جستجو برای: velocity ratio
تعداد نتایج: 630497 فیلتر نتایج به سال:
background: the evaluation of prosthetic valves is very difficult with two-dimensional transthoracic echocardiography alone. doppler and color flow imaging as well as transesophageal echocardiography are more reliable to detect prosthetic valve dysfunction. however, doppler study sometimes tends to be misleading due to the load-depending characteristics of peak and mean pressure gradients. the ...
this study proposed a new discharge estimation method using a mean velocity formula derived from chiu’s 2d velocity formula of probabilistic entropy concept and the river bed shear stress of channel. in particular, we could calculate the mean velocity, which is hardly measurable in flooding natural rivers, in consideration of several factors reflecting basic hydraulic characteristics such as ri...
background: the p ulsatility index (pi) shows continuous blood flow to the end organs and is a significant factor believed to decrease in aortic coarctation. correction of this factor is of great importance in the treatment of stenotic lesions of the aorta. however, there are minimal data regarding the trend of changes in the pi after stent implantation. furthermore, the association between the...
Effect of V2 Accent on relationships (a) between duration and displacement/velocity ratio, and (b) between peak velocity and displacement for /i/-to-/a/ tongue lowering gestures in the y dimension.. Figure 6.6. Effect of V2 Accent on relationships (a) between duration and displacement/velocity ratio, and (b) between peak velocity and displacement for /a/-to-/i/ tongue fronting gestures in the x...
A new model for turbulent flame velocity of premixed flame in spark ignition engine for Iso-octane air mixture has been developed and validated for a wide range of engine operating parameters. The model developed is a zero dimensional thermodynamic model. The effects of engine speed (600-1160 rpm), equivalence ratio (0.7-1.1), unburnt mixture temperature (532650 Rankine), compression ratio (5-8...
A predictive model for droplet size and velocity distributions of a pressure swirl atomizer has been proposed based on the maximum entropy formalism (MEF). The constraint conditions of the MEF model include the conservation laws of mass, momentum, and energy. The effects of liquid swirling strength, Weber number, gas-to-liquid axial velocity ratio and gas-to-liquid density ratio on the droplet ...
In this work, we applied Chebychev spectral collocation method to analyze the unsteady two-dimensional flow of nanofluid in a porous channel through expanding or contracting walls with large injection or suction. The solutions are used to study the effects of various parameters on the flow of the nanofluid in the porous channel. From the analysis, It was established that increase in expansion r...
A pipeline is considered as shell structure so its design is based on stability concepts due to the exerted high pressure, local instability is probable to occur and so prevention of its occurrence and propagation are important subjects in its design. In this paper, dynamic buckle propagation has been modeled by 3D finite element method, results are verified with experimental tests and velocity...
Existence of the coasts in the north and south of Iran cause to create potential areas to produce electricity by tidal and wave energies. Therefore, increase of fluid velocity is required to exploit these areas. A new generation of turbines is created by designing and building a shroud to increase fluid velocity which it increases kinetic energy of flow and generates more electricity at coastli...
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