Self-sensing effect

The following sections focus on the self-sensing effect in piezoelectric and magnetostrictive actuators. Therefore, the most important and basic principles of this group of solid-state actuators will be given below from the standpoint of system theory. 

As just shown, the use of the self-sensing effect requires an inversion of the y-F mapping according to (6.58) in the case of the state quantity-related approach and an inversion of the 7e-F mapping according to (6.64) in the case of the parameter-related approach. Therefore, above all, the precondition for a successful inversion and thus a successful reconstruction of the mechanical load has to be specified. This object should now be discussed representatively by means of the y-F mapping. 

Thereby, F represents by itself a free energy of random walks independent on the conformational state of a chain F(x) brings a positive contribution into F and the sense of this consists in a fact that the terms F(x) and S(x) represent the limitations imposed on the trajectories of random walk by request of the self-avoiding absence. These limitations form the self-organization effect of the polymeric chain the conformation of polymeric chain is the statistical form of its self-organization. 

Fig. 2 Representative data to illustrate self-healing effects in an RTD. The true value of the RTD resistance at this temperature is 54.194 fl. Test currents of around 1 mA cause small self-heating errors of less than 0.1 K. Larger test currents of around 5 mA cause significant selfheating errors of 1.5 K or more. The slope of the curve is related to the thermal coupling G between the sensing element and the fluid or solid being measured...

The installation of an additional position sensor is not always possible. Reasons may be costs and/or unavailable space. In this case, the internal sensoric effect displayed by some NiTiCu-alloys may be employed for indirect position sensing [84]. This leads to the use of a self-sensing actuator (cf. Sect. 6.9). In Fig. 6.58 the actuator length Ld of a NiTiCu shape memory wire is plotted against its electrical resistance Rd. The relation is free of hysteresis and is only slightly shifted by the actuators load. 

As self-sensing actuators, the internal sensoric effect can be used for position sensing (see Sects. 6.1.4 and 6.9). Again, this property is useful in small-sized applications where additional sensors cannot be accoimno-dated for space and weight reasons. 

Fig. 6.135. Self-sensing solid-state actuator with state quantity-related use of the inherent sensor effect...

Caffeine has non-specific stimulant effects on attention and alertness, in the sense that it affects multiple capacities. Furthermore, imlike many illegal drugs it has a self-limiting effect in the sense that users do not desire to increase the amount they drink the more they drink. In fact, at low doses increases in caffeine improve performance but at high doses caffeine actually impairs performance. At high doses users tend to feel anxiety and tension which cause them to abstain from further use (Bonnefond et al., 2004 Smith, 2002). This self-limiting nature also means that caffeine has a very low addictive potential (Lorist and Tops, 2003). 

MDA had unique psychoactive properties that were different from hallucinogens such as LSD or mescaline. While MDA in high doses appears to be hallucinogenic or psychotomimetic, it seems not to have been used for this effect, but rather for its effects on mood production of a sense of decreased anxiety and enhanced self-awareness. Even early reports described the desire of MDA users to be with and talk to other people (Jackson and Reed 1970). MDA is also the only substituted amphetamine that received serious clinical study as an adjunct to psychotherapy (Yensen et al. 1976). 

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