Pressure sensors, medical applications

There are several applications of ZnO that are due to its excellent piezoelectric properties [28,164]. Examples are surface-acoustic wave (SAW) devices and piezoelectric sensors [28,165-167]. Typically, SAW devices are used as band pass filters in the tele-communications industry, primarily in mobile phones and base stations. Emerging field for SAW devices are sensors in automotive applications (torque and pressure sensors), medical applications (chemical sensors), and other industrial applications (vapor, humidity, temperature, and mass sensors). Advantages of acoustic wave sensors are low costs, ruggedness, and a high sensitivity. Some sensors can even be interrogated wirelessly, i.e., such sensors do not require a power source. 

Fig. 6.20 (a) Piezoceramic parts for a range of applications including accelerometers, underwater acoustics, pressure and liquid level sensors, medical diagnostics and therapeutics and NDT the ultrasound focusing bowls are for medical imaging and for producing high-intensity focused ultrasound. 

Figure 2.8 Typical semiconductor strain gage units (a) unbonded, uniformly doped (b) diffused p-type gage (c) integrated pressure sensor (d) integrated cantilever beam force sensor. (From R S C Cobbold Transducers for Medical Measurements Application and Design, copyright 1974, John Wiley and Sons, Inc.)...

Figure 2.22 An extravascular pressure sensor system. A catheter couples heparinized saline through a three-way stopcock to the extravascular sensor element. The three-way stopcock is used to flush the catheter and to take blood samples. (From Peura R A and Webster J G Basic sensors and principles in Medical Instrumentation Application and Design, 2nd edition, edited by J G Webster, copyright ( ) 1992 Houghton Mifflin Co., Boston.)... 

Sensobi Sensoren GmbH has several new products available, each of which can be customized, if necessary. There are systems for continuous breath analysis (8-16 sensors), detection of volatile components in air (1-16 sensors), detection of organic traces in liquids (16 sensors), and for pressure measurements within narrow cavities for medical applications having <4 sensors [22]. 

Pinet, E. Pham, A. and Rioux, S. Miniature Fiber Optic Pressure Sensor for Medical Applications an Opportunity for Intra-Aortic Balloon Pumping (lABP) therapy. 17th Int. Conf. on Optical Fibre Sensors (OFS-17), Bruges, Belgium, SPIE-Vol. 5855 (2005), pp. 234-237... 

Commercial sensors are used to measure pressure, strain, acceleration, and sound propagation. These sensors are usually mounted on walls of granular experiments, for example, on hoppers [142] and shear cells [183]. However, there are sensors developed in the late 1950s, which can be placed into a granular material and report measurements wirelessly. The "rf-pill" was developed for medical applications [353-357] to measure the pressure in the digestive tract. The rf-pill is a small transmitter and sensor, which has been used to measure stress in vertical tube flow [158] and pressure in hopper discharge [128,133]. 

Once the functional relation between the electric quantity and the concentration of a gas constituent is well known for a solid/gas system, numerous development steps remain until a sensor can be put to practical use. The determining factor is the goal of application, for example the gas analysis in the laboratory, industrial gas analysis, its use in medical devices or in motor vehicles. In any case, long-term stable physico-chemical systems have to be established which have to fulfill certain conditions. These concern for example the sample extraction and treatment, the temperature, the stability of total pressure and of material qualities, and the construction in a miniature or mechanically and thermally robust form. With solid electrolytes of the same kind one has come across to completely different sensor designs, depending on the application (Figure 25-1). 

Test and measurement sensors, pressure transducers, torque sensors, instrumentation, accelerometers, and displacement sensors An extensive array of instruments and systems for applications ranging from automotive R D, process and environmental monitoring, in vitro medical diagnostics Surface plasmon resonance biosensors for the determination of the affinity and kinetics of biomolecular interactions... 

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