Scan coverage

Manual ultrasonic testing offers the advantages of low equipment cost combined with the flexibility of the human operator to provide good access and complex scanning capability. However, a total reliance on the capabilities of the ultrasonic technician to visualise the physical situation leads to a number of drawbacks, including lack of accuracy and consistency of defect size and location measurements, lack of verification that the required scan coverage has been fully achieved, and lack of consistency in flaw classification. A further disadvantage is that the ultrasonic data is not permanently recorded there is therefore no opportunity for the data to be re-examined at a later date if required. 

A device providing both serial and parallel scan coverage of a scene is disclosed in GB-A-2207801. 

Strategies for Reducing Dose Exposition in Cardiac CT 77 Scan Coverage 77 ECG-Controlled Tube Current Modulation 77 Low-Dose Protocol and Adaptation to Patient Morphology 77 Non-Spiral Scanning and Prospective Gating 78 Adaptive Pitch 79... 

The colon is usually examined as part of an upper and lower abdominal examination. Scan coverage should include the region from the diaphragm to the ischial tu-... 

The signal display area contains windows for both the A-scan signal and the Coverage diagram. These windows can be sized by the user, and can be viewed individually or simultaneously. 

The system also consists of a LCD-screen located nere the object to be scanned. This screen is a slave to the one on the acqusition computer and consequently shows the same image. The purpose of this screen is to help the scanner technician to acheive a full coverage of the area to be scanned. 

The screen shows the predefined area to be scanned and filled to ensure maximum coverage The transmitter operates with a frequency of 40 kHz and with a pulse repetition frequency of 200 Hz. This gives the system an accuracy in positioning of better than 1 mm. 

After inspecting a bank of near drum generator tubes using full coverage scans, the following information can be obtained ... 

Wastage does not have to be dramatic to be easily observed on a full coverage scan. Figure 14 and 15 show a tube with 0,2 ram of eccentricity that has been in service for two years and has 0,15 mm of wastage near the drum. New tubes are good indicators to determine wastage rates as the scans are very clean without noise of uneven rough corrosion. 

Figure 9. Cyclic voltammogram of Fe-TsPc adsorbed on Vulcan XC-72 at monolayer coverages. This measurement was obtained with the material In the form of a thin porous coating. Scan rate 50 mV s. Other conditions are the same as those In caption of Fig. 6.

Figure 12.13 Electrochemistry and kinetics of CO resulting from methanol decomposition on polycrystalline Pt with O.IM H2SO4 electrol3de and 0.1 M methanol, (a-d) Current, SFG amphtude, frequency, and width of adsorbed CO, scanning the potential in both directions as indicated with the solid hne and fiUed circles denoting the forward (anodic) scan and the dashed hne and unfilled circles denoting the back (cathodic) scan, (e-g) Starting at 0.6 V, where the adsorbed CO is rapidly electro-oxidized, the potential is suddenly jumped to 0.2 V. The reformation of the CO layer (CO chemisorption) due to methanol decomposition occurs in about 20 s. The adsorbed CO molecules are redshifted, and have a broader spectrum at shorter times, when the adlayer coverage is low.

Figure 12.17 Representation of a scanning tunneling microscope image of Ru spontaneously deposited on aPt(lll) surface [Crown et al., 2002], The Ru coverage was about 0.2 ML. (Ru is in white on the figure and inset.) The inset indicates that monoatomic Ru deposition predominates diatomic deposition is found only with 10% of the Ru deposit.

Figure 12.18 Voltammetric CO stripping from a Pt(l 11)/Ru electrode (Ru coverage approximately 0.2 ML) to aCO-free 0.1 M H2SO4 solution. The baseline voltammogramfromPt(lll)/ Ru after CO stripping is shown. The scan rate was 1 mV/s. CO was adsorbed at 0 V for 5 minutes, and was purged from solution by Ar bubbling for 25 minutes.

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