Electronic high-pressure sensors

The rate of sampling with piezoelectric sensors is limited by their physical characteristics and present technology to the millisecond range for applications in the liquid phase. The technique is versatile in that it can be used in a variety of locations. The solid state electronics necessary to operate the piezoelectric sensor are easily miniaturized, and data can be recorded continuously or periodically. A small computer with a reasonable memory could easily record data over long times. There may be some problems in deep-sea locations, simply because of the complications in packaging the sensor for high-pressure environments, although this problem may be surmountable. 

CNTs find applications in the areas such as micro electronics, field emission displays. X-ray sources and gas sensors. Single waUed and multi-waUed CNTs can be grown using high pressure arcs, laser ablation and chemical vapour deposition. 

The brothers Jacques and Pierre Curie are credited with the discovery of piezoelectricity in a number of hemiedric crystals (Curie and Curie, 1880). Today, piezoelectrics are utiUzed in acousto-electronic devices and sensors based on bulk and surface acoustic waves, piezomechanical sensors to monitor pressure, power, and acceleration, as actuators for micropositioning devices, band pass filters with low insertion losses, as electro-optic devices for optical memories, displays for high-definition televisions, and possibly as transparent piezoelectric speaker membranes as well as miniaturized piezoelectric transformers and motors. As the classic piezoelectric material is a-quartz, the basic relationships are detailed below using it as a model structure. Further details on the piezoelectric properties of quartz, and of its history, discovery and utilization, are available elsewhere (Ballato, 2009). 

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