We propose a design for an energy harvester which has the potential to harvest vibrational energy over a broad range of ambient frequencies. The device uses two flexible ceramic piezoelectric elements arranged in a buckled configuration in the absence of vibrations. Experimental data show that this design allows enhanced harvesting of energy relative to a comparable cantilever design, both for ...

The major component of the normal first heart sound is that due to valvular closure. Preceding this there occur low frequency, low amplitude vibrations commonly attributed to auricular systole. It has been shown in this study that such vibrations appear invariably even though the auricles are fibrillating, and in heart block when auricular systole is widely seperated from ventricular systole. I...

Soft tissue exposure to vibrations was shown to increase the muscle activity [1]. External soft tissue vibration damping, using compression apparel, was associated with an increase of the damping coefficient of the soft tissue compartments of the leg and a decrease of the muscle activity during vibrations exposure [2]. It is assumed, but not known, that a decrease in muscle activity induced by ...

Infrared four-wave mixing experiments performed upon deuterated amorphous silicon layers (a-Si:D) reveal profound differences in the dynamics of Si-D stretch vibrations compared to those of analogous Si-H vibrational modes in hydrogenated amorphous silicon (a-Si:H). Remarkably, transient-grating measurements of the population decay rate of the Si-D vibrations show single-exponential decay direc...

Vibration isolators are widely used in high-precision machines to reduce the transmissibility function T , which represents the transfer from base frame vibrations to payload vibrations. Active vibration control (AVC) can be used to further improve T . However, for industrial systems with AVC it is often difficult to show improvement of T via system identification, since it is hard to sufficien...

We consider the effect of random variation in the material parameters in a model for machine tool vibrations, specifically regenerative chatter. We show that fluctuations in these parameters appear as both multiplicative and additive noise in the model. We focus on the effect of additive noise in amplifying small vibrations which appear in subcritical regimes. Coherence resonance is demonstrate...

ABSTRACT. This paper is concerned with the torsional vibrations of a nonhomogeneous magnetostrictive elastic cylinder. The cylinder is subjected to the action of a circumferential magnetic field produced by an axial current of constant density and the deformation of a magnetostrictive cylinder is produced by a constant longitudinal magnetic field. The frequency equation is determined, and the d...

This work describes a set of research studies that were made with the intent of studying vibrations created by the circulation of trains. In the last decades, the development of high-speed trains emphasized the need to closely monitor this phenomenon. The purpose of this study is to provide a state-of-the-art about data acquisition process. It also presents a new experience, including important...