In this study, nonlocal nonlinear instability and the vibration of a double carbon nanotube (CNT) system have been investigated. The Visco-Pasternak model is used to simulate the elastic medium between nanotubes, on which the effect of the spring, shear and damping of the elastic medium is considered. Both of the CNTs convey a viscose fluid and a uniform longitudinal magnetic field is applied t...

Railway structures are one of the most important structures in transportation. So the lack of precise study of their dynamic behavior leads to irreparable damages. The significant factors contributing to the accurate analysis of the dynamic behavior of railways are the type of load and foundation used in it. In this study, an Euler-Bernoulli beam subjected to a moving load on a finite depth fou...

Orthogonal polarization spectroscopy (OPS) is a technique for taking images to finally characterise microcirculation. Current image analysis algorithms have limitations when applied to image sequences obtained from the liver. We developed an automatic analysis tool which enables detection of liver vessels, measurement of vessel diameters, and determination of blood flow velocities with sparse u...

BACKGROUND: CBFV (cerebral blood flow velocity) is lower in the morning than in the afternoon and evening. Two hypotheses have been proposed to explain the time of day changes in CBFV: 1) CBFV changes are due to sleep-associated processes or 2) time of day changes in CBFV are due to an endogenous circadian rhythm independent of sleep. The aim of this study was to examine CBFV over 30 hours of s...

Diameter, blood flow velocity and volumic flow of the brachial artery were measured in 36 patients with sustained essential hypertension and compared with 25 normal subjects. Both hypertensives and control subjects were classified according to age into those younger than and those older than 40 years. For the determinations, a pulsed Doppler velocimeter with an adjustable range-gated time syste...

Marinho DA, Amorim RA, Costa AM, Marques MC, Pérez-Turpin JA, Neiva HP. “Anaerobic” critical velocity and swimming performance in young swimmers. J. Hum. Sport Exerc. Vol. 6, No. 1, pp. 80-86, 2011. Recent studies explored a new trend of critical velocity as a parameter to evaluate and monitor anaerobic training. The aim of this study was to analyse the relationship between anaerobic critical v...

Because little is known about spontaneous changes in cerebral blood flow in neonates, a newly developed online Doppler technique was used to insonate continuously the middle cerebral arteries of a group of sick (n = 20) and full term healthy (n = 16) newborn infants for a period of one minute. A total of 290 recordings of epochs each lasting one minute were analysed, and pronounced regular, cyc...

Two methods for making vector velocity estimation in medical ultrasound are presented. All of the techniques can find both the axial and transverse velocity in the image and can be used for displaying both the correct velocity magnitude and direction. The first method uses a transverse oscillation in the ultrasound field to find the transverse velocity. In-vivo examples from the carotid artery ...