Plant diagnostics

Bruce Hammock developed the section on new immunochemical techniques. These chapters describe investigation of disease resistance in plants neuronal development in insect embryos pesticide residue analysis for plant diagnostics and quarantine and the development of a biosensor for applying monoclonal antibodies and microelectronics for environmental analysis. 

Immunoassays have been used in research in the plant diagnostic field for over 25 years (3). Kits for the detection of a variety of plant diseases now are appearing on the market, but regulatory... 

Provides a tool to help the plant diagnostics and performance identification. 

The programme consists of baseline measurements and in-plant diagnostic testing of valves and actuators. The Forsmark Kraftgrupp AB valve diagnosis concept uses the active power and operating time. 

A more recent approach in plant diagnostic techniques is the study of relationships between seed yield as affected by sulphur supply, and the total sulphur concentration in seed. Although the range of sulphur concentrations found in seeds is often narrower than in leaves, significant correlations were obtained between total sulphur concentrations in seed and yield, and critical values have been derived for upland rice, cowpea, and wheat. Piper-Steenbjerg effects have been noticed in some pot experiments, and it-has been observed that nitrogen deficiency depressed grain sulphur concentrations to values... 

The results of over 1 year of continuous, on-line acoustic emission (AE) structural surveillance of high temperature / high pressure steam headers, gained on 2 M-scale 600MW supercritical multifuel ENEL power units in normal operation, are presented in the paper. The influence of background noise, the correlation between plant operating conditions (steady load, load variations, startup / shutdown transients) and AE activity and the diagnostic evaluation of recorded AE events are also discussed. 

Finally, preliminary diagnostic evaluation criteria, based on preventive identification of critical areas of interest on the monitored item, spatial concentration of localized AE events as compared with average AE event density and evolution of local event concentration vs time and/or plant parameters, have been worked out and submitted to extensive testing under real operation conditions. Work on this very critical issue is still to be consohdated. 

The development of computer capabiUties in hardware and software, related instmmentation and control, and telecommunication technology represent an opportunity for improvement in safety (see COMPUTER TECHNOLOGY). Plant operators can be provided with a variety of user-friendly diagnostic aids to assist in plant operations and incipient failure detection. Communications can be more rapid and dependable. The safety control systems can be made even more rehable and maintenance-free. Moreover, passive safety features to provide emergency cooling for both the reactor system and the containment building are being developed. 

If the nature of the problem is not readily apparent, then it might be necessary to go to the rule-based level. In this case a diagnostic rule will be applied to identify the state of the plant and an action rule used to select an appropriate response. Control will revert to the skill-based level to actually execute the required actions. More abstract functions such as situation evaluation and planning will only be required at the knowledge-based level if the problem cannot not be resolved at the rule-based level. 

For fault-diagnostic tasks, they can help the analyst to identify whether new staff members make effective use of plant information. 

Enhance Plant Operation with Compressor Diagnostic Software, Southwest Research Institute, San Antonio, Texas. 

Much present electronic equipment deals with signals which are not sinusoidal and which may not even be periodic in nature. However, these signals can be divided into a series of components, each of a single specific frequency, and each can then be studied in turn in order to determine its characteristics. Where plant instrumentation is concerned, this technique can be particularly useful for diagnostic purposes. 

The use of vibration analysis is not restricted to predictive maintenance. This technique is useful for diagnostic applications as well. Vibration monitoring and analysis are the primary diagnostic tools for most mechanical systems that are used to manufacture products. When used properly, vibration data provide the means to maintain optimum operating conditions and efficiency of critical plant systems. Vibration analysis can be used to evaluate fluid flow through pipes or vessels, to detect leaks, and to perform a variety of non-destmctive testing functions that improve the reliability and performance of critical plant systems. 

Use of heat emissions of machinery or plant equipment as a monitoring and diagnostic predictive maintenance tool. For example, temperature differences on a coupling indicate misalignment and/or uneven mechanical forces. 

While providing many advantages, simplified data acquisition and analysis also can be a liability. If the database is improperly configured, the automated capabilities of these analyzers will yield faulty diagnostics that can allow catastrophic failure of critical plant machinery. 

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