نتایج جستجو برای: fluid induced vibration

تعداد نتایج: 1225740  

Journal: :Industrial health 2012
Kristine Krajnak Danny A Riley John Wu Thomas McDowell Daniel E Welcome Xueyan S Xu Ren G Dong

Occupational exposure to vibration through the use of power- and pneumatic hand-tools results in cold-induced vasospasms, finger blanching, and alterations in sensorineural function. Collectively, these symptoms are referred to as hand-arm vibration syndrome (HAVS). Currently the International Standards Organization (ISO) standard ISO 5349-1 contains a frequency-weighting curve to help workers ...

Journal: :Acta physiologica Scandinavica 1993
K Uvnäs-Moberg G Bruzelius P Alster T Lundeberg

The objective of the present study was to investigate whether oxytocinergic mechanisms may contribute to the antinociceptive effect of non-noxious, sensory stimulation. To test this hypothesis, oxytocin levels in plasma and cerebrospinal fluid (CSF) were measured in control rats as well as in rats exposed for 30 min to electro-acupuncture (2 Hz), thermal stimulation (40 degrees C) or vibration ...

Journal: :Industrial health 2001
Y Takahashi Y Yonekawa K Kanada

To assess high-level low frequency noise in the working environment, adverse extra-aural effects caused by the noise should be taken into account. The human body vibration induced by low frequency noise, 'noise-induced vibration', was measured on the body surface and the equal-acceleration level contours of the vibration were tentatively estimated. With these contours, we can predict the magnit...

The evaluation and control of the trains induced vibrations needs even more attention in the case of underground tracks which passes near to monuments and historical sites. The rail corrugations which occur due to the wheels’ impulse loads during the operation period of underground railway tracks, usually amplify the ground borne noise and vibration. In the current study, the mentioned phenomen...

2014
Javad Farrokhi Derakhshandeh Maziar Arjomandi Benjamin Cazzolato Bassam Dally

The use of non-turbine systems to generate hydropower energy has drawn the attention of researchers. In the current paper, Wake Induced Vibration (WIV) is experimentally and numerically studied. For this purpose, two circular cylinders were arranged in a tandem in a water channel; the upstream cylinder was fixed and the downstream one was supported by a virtual elastic base. Force and displacem...

2005
Gary Dyson

The vibration of centrifugal pumps, running at both best efficiency point (BEP) and at low flow, is of interest to both pump designers and users. This vibration is responsible for the poor seal and bearing life and reduced mean time between failure (MTBF). The cause of vane pass vibration and multiples of this are explained in this paper. The causes of low flow vibrations are also explored. The...

In this work, nonlocal vibration of double of carbon nanotubes (CNTs) system conveying fluid coupled by visco-Pasternak medium is carried out based on nonlocal elasticity theory where CNTs are placed in uniform temperature change and magnetic field. Considering Euler-Bernoulli beam (EBB) model and Knudsen number, the governing equations of motion are discretized and Ritz method is applied to ob...

Journal: :Physical review. E, Statistical, nonlinear, and soft matter physics 2009
S Shklyaev A A Alabuzhev M Khenner

We consider the dynamics of a thin liquid film in the attractive substrate potential and under the action of a longitudinal or a tilted vibration. Using a multiscale technique we split the film motion into the oscillatory and the averaged parts. The frequency of the vibration is assumed high enough for the inertial effects to become essential for the oscillatory motion. Applying the lubrication...

2016
Isabelle Dufour E. Lemaire B. Caillard C. Lucat Stephen M. Heinrich Fabien Josse I. Dufour H. Debéda S. M. Heinrich F. Josse O. Brand

At the microscale, cantilever vibrations depend not only on the microstructure’s properties and geometry but also on the properties of the surrounding medium. In fact, when a microcantilever vibrates in a fluid, the fluid offers resistance to the motion of the beam. The study of the influence of the hydrodynamic force on the microcantilever’s vibrational spectrum can be used to either (1) optim...

Nowadays, atomic-force microscopy plays a significant role in nanoscience and nanotechnology, and is widely used for direct measurement at atomic scale and scanning the sample surfaces. In tapping mode, the microcantilever of atomic-force microscope is excited at resonance frequency. Therefore, it is important to study its resonance. Moreover, atomic-force microscopes can be operated in fluid e...

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