Medical research

Engineers harness muscle power for healing

Bioengineers have developed biocompatible generators that create electrical pulses when compressed by body motions. The generators are made up of self-assembling "piezoelectric wafers" which can be made rapidly and inexpensively ...

Health

Study shows vibrating insoles could reduce falls among seniors

Findings published in the Archives of Physical Medicine and Rehabilitation show that imperceptible vibratory stimulation applied to the soles of the feet improved balance by reducing postural sway and gait variability in ...

Cardiology

First demonstration of a self-powered cardiac pacemaker

As the number of pacemakers implanted each year reaches into the millions worldwide, improving the lifespan of pacemaker batteries has been of great concern for developers and manufacturers. Currently, pacemaker batteries ...

Cardiology

New device could allow your heartbeat to power pacemaker

An experimental device converted energy from a beating heart to provide enough electricity to power a pacemaker, in a study presented at the American Heart Association's Scientific Sessions 2012.

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Piezoelectricity

Piezoelectricity ( /piˌeɪzoʊˌilɛkˈtrɪsɪti/) is the charge which accumulates in certain solid materials (notably crystals, certain ceramics, and biological matter such as bone, DNA and various proteins) in response to applied mechanical stress. The word piezoelectricity means electricity resulting from pressure. It is derived from the Greek piezo or piezein (πιέζειν), which means to squeeze or press, and electric or electron (ήλεκτρον), which stands for amber, an ancient source of electric charge. Piezoelectricity is the direct result of the piezoelectric effect.

The piezoelectric effect is understood as the linear electromechanical interaction between the mechanical and the electrical state in crystalline materials with no inversion symmetry. The piezoelectric effect is a reversible process in that materials exhibiting the direct piezoelectric effect (the internal generation of electrical charge resulting from an applied mechanical force) also exhibit the reverse piezoelectric effect (the internal generation of a mechanical strain resulting from an applied electrical field). For example, lead zirconate titanate crystals will generate measurable piezoelectricity when their static structure is deformed by about 0.1% of the original dimension. Conversely, those same crystals will change about 0.1% of their static dimension when an external electric field is applied to the material.

Piezoelectricity is found in useful applications such as the production and detection of sound, generation of high voltages, electronic frequency generation, microbalances, and ultrafine focusing of optical assemblies. It is also the basis of a number of scientific instrumental techniques with atomic resolution, the scanning probe microscopies such as STM, AFM, MTA, SNOM, etc., and everyday uses such as acting as the ignition source for cigarette lighters and push-start propane barbecues.

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