Operant-training techniques

Through this study, we have shown that ultrasonic imagery can be an optimal solution to the different problems in Non Destructive Testing. This method, largely used, would have to be introduced in industry by an investment of the NDT users. This also requires a reorientation and supplementary operators trained in ultrasonic techniques. 

D ye penetration inspection. This is a simple technique, requiring a minimum of operator training. In the hands of a skilled operator, it is capable of detecting fine cracks such as chloride stress corrosion cracks in austenitic stainless steels and fatigue cracks. 

The operator s testing technique should be monitored during every test session by use of negative product controls. The examination of test and control containers during and at the end of the incubation period should be included as part of the operator training. Statistics show that skilled operators working under the prescribed conditions can achieve a level as low as one contamination in 5000 control inoculations (0.02%). Personnel training should be documented and records maintained. 

Operant training of an animal allows a very detailed evaluation of sensory function. Such techniques are time-consuming and sometimes expensive, but they are useful for careful characterization of toxicant effects for which there is good evidence of sensory impairment. The species chosen for testing must have sensory function as similar to humans as possible. For visual system testing, for example, the rodent is usually not an appropriate model because its visual system differs in fundamental ways from that of humans. 

The simple and nondestructive Barcol hardness test has the added advantage that it can be conducted in situ on the factory floor (see Section 6). The other techniques are more costly, require a greater degree of operator training, and are not practical for in situ factory use. However, they are suitable for checking incoming material as preimpregnates or laminates. 

The perceptual training techniques are often developed with simulation and perceptual training techniques and then practiced in varions environments. The final task in training is distraction accommodation with simnlated in-bus activities on off-street practice facilities. Video technology in school bns operation may be used for assessment reviews and further remedial training as reqnired. 

Compiling performance criteria helps make clear the right techniques for the task. The field should now be narrowed down to establish a set of practical criteria, which might eliminate some of the less suitable techniques for a particular application. Some of these criteria will include (but not be limited to) detection limits, precision requirements, quality of data, sample throughput capability, ease of use, instrument reliability, operator training needs, or availability of application material. 

In the near future the technique will be further evaluated using ultrasonic signals from natural defects, e.g., fatigue cracks. The performance measure and the parameter optimization procedure wilt also be refined in order to obtain a computationally efficient implementation, easy to use for a trained operator. 

For several years, the French Atomic Energy Commission (CEA) has developed modelling tools for ultrasonic NDT configurations. Implemented within the CIVA software for multiple technique NDT data acquisition and processing [1,2], these models are not only devoted to laboratory uses but also dedicated to ultrasonic operators without special training in simulation techniques. This approach has led us to develop approximate models carrying out the compromise between as accurate as possible quantitative predictions and simplicity, speed and intensive use in an industrial context. 

Most EDS systems are controlled by minicomputers or microcomputers and are easy to use for the basic operations of spectrum collection and peak identification, even for the computer illiterate. However, the use of advanced analysis techniques, including deconvolution of overlapped peaks, background subtraction, and quantitative analysis will require some extra training, which usually is provided at installation or available at special schools. 

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