Calm ratio

In principle, the concrete structures undamaged are statically stable with high redundancy. AE activity is very low in a stable structure, because the Kaiser effect is closely associated with structural stability. Such ratios as the load ratio and the calm ratio are defined to estimate the Kaiser effect. 

The change of AE activities under cyclic loading is studied to qualify the damages. At each loading stage, two of the load ratio and the calm ratio were determined. Results are shown in Fig. 10.11 (Ohtsu, Uchida et al. 2002). Based on the maximum CMOD observed in the beams, classification limits are set as 0.9 for the load ratio and 0.05 for the calm ratio. This is because the serviceability limit of the CMOD is less than 0.1 mm in the standard specification, and the Kaiser effect was not observed in the case of the CMOD over 0.1 - 0.2 mm. 

Into three zones of the minor damage, the intermediate, and the heavy, data plotted are reasonably classified in good agreement with the maximum CMODs. This implies that the damage levels of RC beams can be qualified by the criterion based on the load ratio and the calm ratio, monitoring AE activity under cyclic loading or in the mobile-load test (Colombo, Forde et al. 2005). It is noted that the limits classified for qualification should be determined in advance, based on preliminary tests for practical applications. 

Fig. 13.9. Definitions of load ratio and calm ratio in a cyclic loading.

The load ratio and the calm ratio were estimated in the test of the dismantled girder. Results are shown in Fig. 13.10. It is clearly observed that with the increase in loading cycles, plotted points move from the sound zone to the serious damaged zone. The zones classified are not yet clearly described with threshold values, because these values are to be specified from experiments data of structural members. In the case of the present test, the loading cycle up to 200 kN is to be one threshold value. Thus the applicability of the recommended practice (NDIS 2421) is confirmed. Data... 

Fig. 13.10. Diagram of the load ratio and the calm ratio during the test...

As given in Chapter 4, combination of the calm ratio and the RTRI ratio is known to be effective to estimate the stmctural damage in railway struc-... 

Fig. 14.18. Calm ratio obtained from 1-D and 3-D locations of AE events.

Fig. 14.19. Relations between the calm ratio and RTRl values.

Fig. 14.22. Damage quantification with the calm ratio and the RTRI values. Dotted lines show the criteria for damage qualification. Labels H, 1 and M show heavy damage (H), intermediate damage (1) and minor damage (M), respectively.

Ljgand Ground state e (cm-1) 7 State ratio AH (calM-1) AS (eu)... 

Pracejus also studied the tandem nucleophilic addition/diastereoselective protonation of optically pure (S)-phenylethylamine on phenylmethylketene [11], With the aim of synthesizing amino acids and their derivatives, Calmes and coworkers reinvestigated the reaction of prochiral ketenes (generated in situ from acid chorides in the presence of a tertiary amine) with (R)-pantolactonc, an a-hydroxylactone [12], The authors have shown that the diastereoselectivity is dependent on the base used. Particularly, triethylamine and quinuclidine afforded complementary results and the diasteromeric ratios observed with quinuclidine suggest that the high stereoselections could be observed in nucleophilic additions to prochiral ketenes in the presence of cinchona alkaloids. 

The point of measurement may be at the centerline of the channel and the average velocity found from the ratio of the average to the maximum velocity. (See Chap. 5.) Alternatively, the sensor may be located at the critical point in the channel where the local velocity equals the average velocity. In either case precautions must be taken, usually by providing long calming sections upstream of the meter, to ensure that the velocity profile is fully developed and not distorted. 

Fig. III.1.2 1 Gradient of dimensionless concentration dc at the stationary planar electrode surface in a calm solution, and 2 the dependence of the ratio c/c on the dimensionless distance jc/5,...

Fig. 4.3. Damage quantification with a combination of Calm and Load ratio.

A similar batch ether process was operated on a scale of 1 ton/day by the U.S. Mallinckrodt Works as early as 1942. It was, however, modified in 1946 to a counter-current acid ether process using 40 ft high columns of about four theoretical stages. These columns had centrifugal pumps and jet mixers at 4 ft intervals, and relatively calm zones between. Advantage was taken of the increased uranium distribution coefficient in the presence of excess nitric acid, to reduce the solvent-to-aqueous fiow ratio and achieve a... 

Similar (or similarly labeled) treatments can have widely different B/C ratios. Areawide traffic calming is one such example, and implementation of roads safety audits is another. 

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