Zone Flaws

Somewhat irregular zone fronts occur always, since slight inhomogeneity of the support, non-uniform moisture content and electrolyte concentration and temperature differences in the electric field can never be avoided completely. This zone imperfection is of subsidiary importance in qualitative detection of individual fractions but interferes in a quantitative evaluation. 

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Insurance in pressure boundary integrity of NPP unit is strongly influenced by technical capabilities and efficiency of metal examination system. Ordinary ultrasonic examination tools and procedures have limitations in flaw sizing and positioning. The problems arise for welds and repair zones of welds made by filler materials of austenitic type. 

The main purpose of AUGUR4.2 expert ISI is the application to zones where some flaws (indications) had been revealed by scheduled manual ultrasonic inspections. Information provided by AUGUR 4.2 is used for decision-making further surveillance of these zones or corrective measures. The procedure of AUGUR 4.2 examination is included into the approved general scheme of ISI [1]... 

AUQUR 4.2 revealed a number of small-size defects with the height of about 2 mm did not detected by manual inspection. These flaws were located near the boundaries of cut-off zone of repaired welds and likely had originated after near-boundary passes of repair welding [3]. 

The easy and convenient postprocessing of test findings enables an exact survey of flaws, enlargement of any zones requested, and shifting of the recording threshold within the recorded dynamic range of 24 dB. 

In this paper, the following aspects have been studied (A) Flaw detection can be made directly on the surface of the pipes, (B) The defects within the range of wall thickness can be tested out, that is to say, the ultrasonic testing without dead zone for the pipe wall can be realized and (C) Testing the defects of FBH as our testing. Objects, we may make the testing... 

The variability in fracture stress when small artificial flaws were controlling strength was particularly pronounced for H-451 graphite, as can be seen in Fig. 12. Here the crack dimensions and crack trip process zone dimensions are comparable to the microstructural dimensions. Consequently, local variations in microstmeture... 

In the case of crystalline polymers it may be that solvents can cause cracking by activity in the amorphous zone. Examples of this are benzene and toluene with polyethylene. In polyethylene, however, the greater problem is that known as environmental stress cracking , which occurs with materials such as soap, alcohols, surfactants and silicone oils. Many of these are highly polar materials which cause no swelling but are simply absorbed either into or on to the polymer. This appears to weaken the surface and allows cracks to propagate from minute flaws. 

Detonation Waves, Spherically Symmetric Flaw in the Steady Zone of. See under Detonation Waves Steady-State, Three-Dimensional, Axially Symmetric... 

This method is the simplest of all the methods and is capable of detecting surface flaws such as corrosion, contamination, surface finish and surface discontinuities on joints.47 The discontinuities on joints such as welds, seals, solder connections and adhesive bonds can be detected. General corrosion, qualitative pitting corrosion, stress-corrosion cracking, weld-heat-affected zone attack, erosion corrosion and other type of degradation can be observed by visual examination aided by microscopes with sufficient magnification. Degradation of plastics can also be detected by visual examination. Visual examination is also used in conjunction with other techniques, such as powerful microscopes. 

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