Limiting number of cycles

Thus in this system, in addition to the usual requirements, the separator has the task of delaying penetration for as long as possible. A membrane would be regarded as perfect which lets hydroxyl ions pass, but not the larger zincate ions. This requirements is best met by regenerated cellulose ( cellophane ) [10,11], which in swollen condition shows such ion-selective properties but at the same time is also chemically very sensitive and allows only a limited number of cycles the protective effects of additional fleeces of polyamide or polypropylene have already been taken into account. 

A detailed fatigue analysis is required if any of these conditions is likely to occur to any significant extent. Fatigue failure will occur during the service life of the vessel if the endurance limit (number of cycles for failure) at the particular value of the cyclic stress is exceeded. The codes and standards should be consulted to determine when a detailed fatigue analysis must be undertaken. 

Although all reactions showing a closed sequence could be considered to be catalytic, there is a difference between those in which the entity of the active site is preserved by a catalyst and those in which it survives for only a limited number of cycles. In the first category are the truly catalytic reactions, whereas the second comprises the chain reactions. Both types can be considered by means of the steady-state approximation, as in Christiansen s treatment. This important development dates to 1919 (reaction between hydrogen and bromine reported earlier by Bodenstein and Lind. 

Another problem is that switching of the SHG signal is possible only for a limited number of cycles the higher SHG value reached after UV irradiation decreases with the performed number of cycles. This decrease is interpreted as an effect of disorientation. Indeed, in the absence of a poling field, the chromophores have no reason to recover exactly the same orientation after one isomerization cycle. In the worst cases, the poled order is completely lost after one switching attempt. Usually, this type of disorientation occurs faster in side-chain polymers than in doped ones. ... 

While all reactions showing a closed sequence may be said to be catedytic, there is a distinct difference between those where the active centers are provided by a separate entity called the catalyst which in principle has a very long lifetime and those where the active centers are generated within the system itself and may survive only during a limited number of cycles around the... 

Because of isotropic expansion of the particles/grains, amorphous thin-hlm silicon anodes typically perform better than crystalline thin hlms. Maranchi et al. [12, 72] demonstrated that 250-nm-thick amorphous silicon thin hlms deposited by radio-frequency magnetron sputtering on copper substrates achieved near theoretical capacity for a limited number of cycles. The authors stated that growth of... 

Face-centred cubic metals and hardened steels do not have a true fatigue limit S-N curve of type II, figure 10.19(b)). At a number of cycles beyond 10, the slope of the S-N curve is rather small and a limiting number of cycles of A b = 10 to 10 can be used to design safely against fatigue [130]. 

Recently, it has been found even in body-centred cubic metals that a specimen can fail in fatigue even beyond the limiting number of cycles (10 ). At a very large number of cycles (more than 10 °), the S-N curve may drop again [93,135]. This is called ultra-high-cycle fatigue (uhcf)... 

A result of the first item is that in general zinc electrodes can stand only a very limited number of cycles. One possibility to overcome this problem is to replace the used zinc electrodes after each discharge by new ones ( mechanical recharge ). The zinc oxide of the removed negative electrodes is regenerated in a central electrolysis unit that operates for a whole fleet of cars, equipped with such zinc/air batteries (81). 

Figure 5 A typical example of transmission efficiency versus resolution for an instrument with a well-defined source emittance. There are three regions of transmittance as resolution is increased. (I) Sensitivity is source limited, (II) sensitivity is filter acceptance limited, (III) resolution is length limited (number of cycles in the field) and (IV) resolution is limited by field imperfection.

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