The acousto-optic effect, in which an acoustic wave causes variations in the optical index of refraction, imposes a fundamental limitation on the determination of the normal velocity, or normal displacement, distribution on the surface of an acoustic transducer or optically reflecting pellicle by a scanning heterodyne, or homodyne, laser interferometer. A general method of compensation is devel...

Introduction: Glycyrrhiza glabra (Licorice) has been traditionally used as a medicinal plant in Iran for treatment of diseases such as gastric ulcer and arthrosclerosis. In this study, in order to determine some of its mechanisms, effects of hydroalcoholic extract of Glycyrrhiza glabra was examined on the blood pressure in rats. Methods: Adult male rats were anesthetized via injection of pen...

With some design care, a mass flow sensor, pressure transducer and a temperature sensor can provide a fast and accurate method of measuring many difficult volumes.

The article deals with pneumatic and hot wire anemometry measurement on subsonic axi-symmetric air ejector. Performances of the ejector with and without pulsations of primary flow are compared, measuring of characteristic pressures and mass flow rates are performed and ejector efficiency is evaluated. The pulsations of primary flow are produced by a synthetic jet generator, which is placed in t...

A finite-element model is presented for numerical simulation in three dimensions of acoustophoresis suspended microparticles a microchannel embedded polymer chip and driven by an attached piezoelectric transducer at MHz frequencies. In accordance with the recently introduced principle whole-system ultrasound resonances, optimal resonance mode identified that related to acoustic combined transdu...

The Spiegelberg brain pressure catheter is a low cost implantable intracranial pressure measuring system which has the unique ability to perform regular automatic zeroing. A new version of the catheter has become available with a subdural bolt fixation to allow insertion of the device into the brain parenchyma. The accuracy of this system has been evaluated in comparison with a ventricular flui...

sensors are the closest available systems to this ideal. For the more commonly used manometric systems, the total measuring chain, consisting of catheter or cannula, tubing, stopcocks and transducer, has a much lower resonant frequency, and damping is therefore vital for increasing accuracy. Optimally damped systems can accurately reproduce frequencies up to 67% of the resonant frequency. An op...

the security and stability of dams for flood passing through the spillway should be provided. so, kinetic energy of flow over large spillway must be dissipated. one of the energy dissipation structures at downstream dams, are plunging pools. the aim of this paper is to investigate dynamic pressure that is created by the impact of a series of rounded non-submerged jets on a flat plate with the r...

hemodynamic monitoring is needed in up to 58% of patients presented to the emergency department. central venous pressure (cvp) monitoring is generally useful to assess general volume status. there are several methods of cvp measurement, which can be categorized as invasive and non-invasive. cvp manometer and electronic transducer are among the invasive methods and direct observation, ultrasonog...