نتایج جستجو برای: velocity ratio

تعداد نتایج: 630497  

Journal: :the journal of tehran university heart center 0
maryam esmaeilzadeh echocardiography research center of shaheed rajaei cardiovascular medical and research center, tehra ahmad mirdamadi echocardiography research center of shaheed rajaei cardiovascular medical and research center, tehra mozhgan parsaee echocardiography research center of shaheed rajaei cardiovascular medical and research center, tehra anita sadeghpour echocardiography research center of shaheed rajaei cardiovascular medical and research center, tehra majid maleki echocardiography research center of shaheed rajaei cardiovascular medical and research center, tehra hooman bakhshandeh abkenar echocardiography research center of shaheed rajaei cardiovascular medical and research center, tehra

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 ...

Journal: :international journal of environmental research 0
t.h. choo department of civil engineering, pusan national university, jangjeon-dong, geumjeong-gu, busan, 609-735, south korea s.j. maeng chungbuk national university, jangjeon-dong, geumjeong-gu, south korea h.c. yoon department of civil engineering, pusan national university, jangjeon-dong, geumjeong-gu, busan, 609-735, south korea d.m. kim department of civil engineering, pusan national university, jangjeon-dong, geumjeong-gu, busan, 609-735, south korea s.c. kim department of civil engineering, pusan national university, jangjeon-dong, geumjeong-gu, busan, 609-735, south korea

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...

Journal: :the journal of tehran university heart center 0
shokoufeh hajsadeghi rasoul-e-akram hospital, tehran university of medical sciences,tehran, iran. seyed-mohammad fereshtehnejad firoozgar clinical research development center, tehran university of medical sciences, tehran, iran. saeid gholami student scientific research committee, tehran university of medical sciences,tehran, iran. mitra chitsazan student scientific research committee, tehran university of medical sciences,tehran, iran. mohammad reza keramati firoozgar clinical research development center, tehran university of medical sciences, tehran, iran.

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...

2001
Taehong Cho Bruce Hayes Jody Kreiman Peter Ladefoged

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...

2011
Rashid Ali Nafis Ahmad

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...

Journal: :Entropy 2015
Kai Yan Zhi Ning Ming Lü Chunhua Sun

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...

ژورنال: مهندسی دریا 2010
Abedi, Karim, Mostafa Gharabaghi, Ahmad Reza, Omrani, Zahra,

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...

ژورنال: مهندسی دریا 2016
احمدی اصل, حمید, راد, منوچهر, کمالی منفرد, رضا,

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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