Transducer design

Fig 1. (a) Phase (b) group velocity dispersion curves for aluminium. Circles show minimum dispersion points. Diamonds show excitation positions for transducer designed for X/d = 2.4 where d is the plate thickness. 

Since 1945 an increasing understanding of the phenomenon of cavitation has developed coupled with significant developments in electronic circuitry and transducer design (i. e. devices which convert electrical to mechanical signals and vice versa). As a result of this there has been a rapid expansion in the application of power ultrasound to chemical processes, a subject which has become known as Sonochemistry . 

Smith, N., et al. 2003. Ultrasound-mediated transdermal transport of insulin in vitro through human skin using novel transducer designs. Ultrasound Med Biol 29 311. 

Yeh, C., Altaf, S. A., and Hoag, S. W. (1997), Theory of force transducer design optimization for die wall stress measurement during tablet compaction Optimization and validation of split-web die using finite element analysis, Pharm. Res., 14, 1161— 1170. 

Hoag, S. W., Nair, R., and Muller, F. X. (2000), Force-transducer-design optimization for the measurement of die-wall stress in a compaction simulator, Pharm. Pharmacol. Commun., 6(7), 293-298. 

On a typical R D grade compression transducer, a compression roll pin is machined with incisions made for placing strain gages (Fig. 4). The actual form of these cavities constitutes the very art of the transducer design that is usually proprietary and is based on the know-how of instrumentation vendor. 

Yang, Q.L, Atanasov, P., and Wilkins, E. (1997) A novel amperometric transducer design for needle-type implantable biosensor applications. Electroanalysis, 9 (15), 1252-1255. 

Certain relations between intensive and extensive signals are of fundamental significance for system (or transducer) design. According to [3], these relations can be summarized as follows ... 

Several variations of these are possible, particularly for large-scale operation. Figure 22.1 shows schematic sketches of different types of devices used to generate ultrasound (Berlan and Mason, 1992). By using any of these transducer designs, it is possible to introduce power ultrasound (as it is normally called) into the reacting system. A reaction conducted under the influence of ultrasound is usually represented as... 

This latter requirement is becoming more and more important as VIP technology moves closer to the market. Recent improvements have been based on the use of a novel dual heat flow transducer design and a tight control of plate temperatures [48]. 

The accelerometer is a transducer designed to measure vertical acceleration and used to establish the inertial reference and effectively the response of the vehicle to the road surface (instant height of accelerometer in the host vehicle). The vertical distance between the accelerometer and the travelled surface is measured by displacement transducers or sensors (laser, acoustic or infrared sensors) and the distance travelled by distance transducers. Eigure 16.29 shows an accelerometer and a single sensor mid-mount on a vehicle. 

Figure 1 Transducer designs (see text for details). S, source D, detector F, optical fiber R, reagent phase M, membrane.

The images shown in Figure 6 were obtained by surface wave (Rayleigh wave) inspection of 4 silicon nitride modulus of rupture test bars with laser-machined simulated voids. The technique utilized a focused 50 MHz transducer designed to produce a radial surface wave. Centrally positioned surface voids of 100,50, and 20 micrometers were readily detected. One bar (shown on bottom) had a 10 micrometer surface void, indicated by a marker pen, which would probably not have been detected. Longitudinal grinding marks were also apparent. 

By decreasing the interactive length (acoustic aperture) L of a modulator, a larger bandwidth can be achieved. However, this would be at the expense of the diffraction efficiency as can be seen in Eq. (3.19). To satisfy both conflicting conditions more elaborate transducer designs have been employed. Wide band-widths have been accomplished by such schemes as the following... 

Although gross displacement transducers are designed specifically for either rectilinear or rotary motion, a rack and pinion, or a similar motion converter, is often used to adapt transducers designed for rectilinear motion to the measurement of rotary motion, and vice versa. 

In brief, a biosensor is an instrument or device containing a sensing element of biological origin, which is either integrated within or is in intimate contact with a physicochemical transducer designed for quantitative or semiquantitative analysis of analyte (Thakur and Karanth 2003) as shown in Figure 27.1. 

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