Ultrasonic sensors composition

Xiao F, Zhao FQ, Zeng BZ et al (2009) Nonenzymatic glucose sensor based on ultrasonic-electrodeposition of bimetallic PtM (M=Ru, Pd and Au) nanoparticles on carbon nanotubes-ionic liquid composite film. Biosens Bioelectron 24 3481-3486... 

Designed to sort compacted bottles, the Poly-Sort system employs conveyors for singulation, and two devices for color and chemical composition identification. A vibratory conveyor singulates bottles a read conveyor transports bottles to an ultrasonic sensor that detects their position a near-infrared system detects the resin type a camera detects the color of the container a computer integrates data and makes an identification air jets divert bottles to the appropriate segregation conveyor or hopper. 

Associated with refueling, inspection and maintenance (RIM) operations is the need for sensors. In addition to the traditional sensors used in other high-temperature reactors (thermocouples, ultrasonic sensors, etc ), liquid salts allow the use of optical systems. Salts are transparent between 200 and 2500 mn (50,000 to 4000 wave numbers). This includes the UV, visible, and near-infrared, with some transparency into the infrared from 2500 to 5000 nm (4000 to 2000 wave numbers). In other words, these salts are transparent over a wider range of the spectrum than is water. The liquid salt, depending upon its composition and activation, provides some radiation shielding for the optical systems. The coolant properties create new sensor options. 

PZT appUcations (see e.g. Herbert 1982 Mattiat 1971 Rogacheva 1994 Setter and Colla 1993 Uchino 1997,2000 Waanders 1991) cover mainly the field of ultrasonics (ultrasound transducers, cleaners, fluid atomizers, welding etc ), sensors (e.g. for acceleration), gas ignitors, ceramic filters for TV and delay fines, sound transducers for buzzers and also various actuators (e.g. PZT bimorphs, ink-jet printer heads) etc. Although PZT compositions are known for many years they are still excellent for many applications. New PZT modifications are imder development. 

Shown in Fig. 3.16 is a 1-3 piezoelectric composite with PZT ceramic rods embedded in a polymer resin. This structure is now widely used in medical ultrasonic transducers because the polymer helps reducing the acoustic impedance mismatch between human body and the PZT so that energy transmission becomes more efHcient. The load on the polymer phase can be transferred to the ceramic so that the effective load on the ceramic is enhanced, which produces higher electric signal when it is used as stress sensor. This composite structure also gives a much higher figure of merit for hydrophone applications [18],... 

An immunosensor based on amine-functionalized CNT-SPE was described for detection of the cardiac troponin T, an important marker of acute myocardial infarction. The disposable sensor was fabricated by squeezing an adhesive carbon ink containing carbon nanotubes onto a polyethylene terephthalate substrate forming a thin film. The use of CNTs increased the reproducibility and stability of the sensor, and the amine groups permitted a nonrandom immobilization of antibodies against cardiac troponin T. Another example of the use of carboxylated CNTs is found by the work presented by Rafiee and Fakhari, who prepared a composite based on CNTs and Nafion for the development of a biosensor for the determination of insulin. Carboxylated CNTs plus Nafion were dispersed in water under ultrasonic conditions to get a homogeneous suspension and then a certain volume of that dispersive solution was dropped on the carbonaceous surface of the SPE. 

Zhang et al. [83,84] have shown theoretically that the basic elastic coupling mechanism between the two componeata b the 2>2 piezoelectric composite is similar to that of the 1-3 composite, although the 2-2 structure b not widely us There ate two major areas where 1-3 composites have been widely used underwater hydrophone applications and ultrasonic actuators and sensors for medical dUgnostk devices [15,16,24,8334]. 

Acoustic analysis detects changes in the properties of acoustic waves as they travel at ultrasonic frequencies in piezoelectric materials. The interaction between the waves and the phase-matter composition facilitates chemical selectivity and, thus, the detection of CWA s. These are commonly known as surface acoustic wave (SAW) sensors. Reported studies indicate detection limits as low as 0.01 mg m for organophosphorus analytes within a 2 min analysis [1]. There are several commercially available SAW instruments, which can automatically monitor for trace levels of toxic vapors from G-nerve agents and other CWAs, with a high degree of selectivity. A major advantage of SAW detectors is that they can be made small, portable and provide a real-time analysis of unknown samples. One of the drawbacks of these instruments is that sensitivity and a rapid response time are inversely related. In an ideal instrument, both parameters would be obtained without sacrificing one for the other. 

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