Taguchi gas sensors

Tag open-cup test Taguchi designs Taguchi gas sensors Taiguie acid Tailings... 

The length of time over which a chemical sensor can be expected to function reliably can be remarkably great (in the range of years), as in the case of glass-membrane or solid-state membrane electrodes, the lambda probe (Section 28.2.2.3), and the Taguchi gas sensor (see Section 28.2.2.2). On the other hand, a biosensor that depends upon a cascade of enzymes to... 

Figure 63. QMB-based gas sensing with polyepichlorohydrin (PECH) as polymer. The upper original recorder traces show 13 complete calibration cycles and demonstrates the very high reproducibility of this gas sensor in this low concentnuion range. The lower part shows the details of one cycle between 2,5 and 20 ppm tetrachloroethene. With a sensitivity of S 10 Hz/ppm tetrachloroethene and an LOD of about 100 ppb this device is more sensitive than any Taguchi gas sensor or the FID considering its low noise, in the range of only about 0.5 Hz Compared with a 25 MHz QMW the sensitivity could be increased by one order of magnitude (257)...

The high T ceramic superconductors have been tested in Taguchi-type sensois. The Taguchi gas sensor is based on a semiconducting metal oxide, which exhibits a resistance change when gas molecules adsorb at the surface and influence the charge carrier concentration in the metal oxide. SnOj, lUjOj, and solid solutions based on these oxides have frequently been studied as active material of the Taguchi sensor. 

The history of electrochemical sensors began in the thirties of the twentieth century, when the pH-sensitive glass electrode was deployed, but no noteworthy development was carried out till the middle of that century. In 1956, Clark invented his oxygen-sensor based on a Ft electrode in 1959, the first piezoelectric mass-deposition sensor (a quartz crystal microbal-ance) was produced. In the sixties, the first biosensors (Clark and Lyons, 1962) and the first metal oxide semiconductor-based gas sensors (Taguchi, 1962) started to appear. 

The seminal research by Taguchi and Seiyama et al. led to the successful commercialization of tin oxide based gas sensors. The tin oxide can be sintered, forming a disk, on which electrical conductivity metal contacts can be formed. The MOS can also be formed by other techniques, such as sputtering or sol-gel techniques. 

Metal oxide semiconductor gas sensor (Taguchi sensor)... 

In some ways, this is the same requirement faced when developing electronic nose technology. Sensor-based electronic noses are based upon an array of non-specific gas sensors coupled with a pattern recognition technique (Gardner and Bartlett, 1999 Pearce et al, 2003). Electronic noses tend to be large, expensive instruments. For example, the Fox 4000 electronic nose (Alpha MOS, France) comprises 18 power-hungry Taguchi-like metal oxide resistive gas sensors (see Fig. 15.11). 

Ihokura K, Watson J (1994) The stannic oxide gas sensor—principles and applications. CRC Press, Boca Raton, FL Itoh T, Matsubara I, Shin W, Izu N, Nishibori M (2008) Analytical study of resistance drift phenomena on (PANHxMoO hybrid thin films as gas sensors. Bull Chem Soc Jpn 81(10) 1331-1335 Jamnik J, Kamp B, Merkle R, Maier J (2002) Space charge influenced oxygen incorporation in oxides in how far does it contribute to the drift of Taguchi sensors Solid State Ion 150 157-166... 

Table 1 demonstrates that this is the general behavior of semiconductor gas sensors. The slope of the calibration curve can vary by up to a factor of 5. In this table, three different Taguchi sensors (TGS 800. TGS 813, and TGS 822) were carefully compared [257] with respect to their humidity interference using ethanol as the analyte. 

Figure 31. The change in the ionic surface conductivity upon a variation in the partial pressure of the acidbase active gas (bottom) is analogous to the Taguchi sensor which works for redox-active gases.20...

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