Characterizing Damage Condition

In order to generate practical service life predictions - taking the mentioned limitations into consideration - two requirements have to be fulfilled the conditions occurring in load tests and in service must be determined as exactly as possible in addition, the criteria used for characterizing damage conditions have to be practical and meaningful, see Chapter 2. 

In order to predict service life, it is important to recognize and evaluate any induced material damage. A large number of analytical methods are available for this characterization, see Chapter 2. 

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Isolation and characterization of variants deficient in known enzyme activities play an important part in elucidation of the role of those enzymes in cellular processes. We took advantage of the involvement of poly(ADP-ribose) polymerase in the suicide response to develop a selection procedure for cells deficient in this enzyme activity. We have shown that a 10-20 fold decrease in poly(ADP-ribose) syntiiesis in the variants under maximum DNA damaging conditions was not due to an increase in either poly(ADP-ribose) glycohydrolase or NAD glycohydrolase activities. We have also shown that induction of high levels of DNA damage by MNNG in intact cells did not result in drastic depletion of NAD in the variants as it did in the parental cell line. Moreover, the variants showed qualitative as well as quantitative differences in the auto ADP-ribosylation pattern of the enzyme. All these observations point to the fact that the variants are tmly defective in poly(ADP-ribose) polymerase activity. 

Cathodic protection of water power turbines is characterized by wide variations in protection current requirements. This is due to the operating conditions (flow velocity, water level) and in the case of the Werra River, the salt content. For this reason potential-controlled rectifiers must be used. This is also necessary to avoid overprotection and thereby damage to the coating (see Sections 5.2.1.4 and 5.2.1.5 as well as Refs. 4 and 5). Safety measures must be addressed for the reasons stated in Section 20.1.5. Notices were fixed to the turbine and the external access to the box headers which warned of the danger of explosion from hydrogen and included the regulations for the avoidance of accidents (see Ref. 4). 

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