نتایج جستجو برای: wave velocity
تعداد نتایج: 341742 فیلتر نتایج به سال:
Limited and partly controversial data are available regarding the relationship of arterial pulse wave velocity and childhood cardiovascular risk factors. We studied how risk factors identified in childhood and adulthood predict pulse wave velocity assessed in adulthood. The study cohort consisted of 1691 white adults aged 30 to 45 years who had risk factor data available since childhood. Pulse ...
In this study, the effect of small-scale of both nanostructure and nano-fluid flowing through it on the natural frequency and longitudinal wave propagation are investigated. Here, the stationary and axially moving single-walled carbon nanotube conveying fluid are studied. The boundary conditions for the stationary nanotube is considering clamped-clamped and pined-pined and for the axially movin...
In an absorbing medium, where the vector W5]v/]k usually is complex for real values of the wave vector k, the group velocity W may become real for some complex values of k. The role of real group velocity in the propagation of one-dimensional wave packets in homogeneous absorbing media is examined. Applying the saddle point method to an analysis of the asymptotic behavior of the Gaussian wave p...
Two optical techniques are experimentally investigated to measure the shock wave velocity and particle velocity in metals subjected to hyper velocity impacts. Fabry-Perot interferometer based optical system has been developed and used to measure the interface velocity profile of impacted Tantalum-Glass and Aluminum-Glass targets. Optical fibers coupled to fast photodiodes are implemented to mea...
Several studies showed a positive association between heart rate and pulse wave velocity, a sensitive marker of arterial stiffness. However, no study involving a large population has specifically addressed the dependence of pulse wave velocity on different components of the cardiac cycle. The aim of this study was to explore in subjects of different age the link between pulse wave velocity with...
Caspian Sea is one of the most low-lying areas of the region which is located between latitudes 36.34 and 47.13 degrees north. Its considerable vast area and depth have provided an opportunity to gain renewable energy by different methods. This paper analyzes the performance and mechanism of a floating wave energy converter known as WaveStar, in the above-mentioned sea. Different parts of mecha...
Problems of measuring pulse wave velocity and its utilization in diagnostics have been examined for many years. Pulse wave velocity is a quantity that can be measured non-invasively, and it may bring much information about the state of circulatory system. The R-wave of electrocardiogram (ECG) is most frequently used as the reference point for measuring the pulse wave velocity but it can also be...
In order to study the impact of microfractures on the elastic wave velocity, multi-azimuth elastic wave velocity experiments were performed with coal rock samples under a confining pressure similar to the one in the buried coal strata of the Qinshui basin. The results indicate that (1) the microfractures in coal rock reduce the elastic wave velocity. In the experiments, the velocity was increas...
BACKGROUND The problems of patients with erectile dysfunction have been recognized, leading to the emergence of sildenafil, which has led to successful treatment in many cases. The purpose of this study is to examine the effect of sildenafil on the pulse wave velocity of patients with erectile dysfunction. METHODS Fifteen patients with erectile dysfunction were enrolled for this study. The br...
laboratory data, which relate the liquefaction resistance of firoozkooh sand and non-plastic silt mixtures to shear wave velocity are presented and compared to liquefaction criteria derived from seismic field measurements by andrus and stokoe [1]. in the work described herein, cyclic triaxial and resonant column tests were conducted on specimens of clean sand and sand-silt mixtures with silt co...
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