Dumb instrument

The cost of an intelligent instrument can be twice that of the equivalent device without the smart facility (the latter is termed a dumb instrument)(99). However, the use of a smart transmitter does generally improve the inherent accuracy of the sensor itself. 

Mechanical properties of polymer blends during elongation were determined with a Zwick 1435 instrument, according to ISO 37. Dumb-bell specimen geometry n°2 was applied. 

For brittle thermosets, parallel-sided dumb-bell or waisted dumb-bell specimens are preferred simple parallel-sided specimens often fail in the jaws of the testing instrument. Moreover, in our experience, sample preparation is absolutely critical. Even minor imperfections and scratches on the surface of the specimen can lead to failure occurring in times several orders of magnitude earlier than expected. 

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