Continuous trapping

On a more positive note, it seems clear that steels can be made more resistant to the effects of hydrogen by incorporating as many strong, finely dispersed traps in the microstructure as is possible, while ensuring that there are no continuous trap sites (such as embrittled grain boundaries). 

The carbon dioxide emission has been quantified using the apparatus shown in Figure 1. Under controlled conditions of temperature and relative humidity the emitted carbon dioxide was continuously trapped in a solution of ethanolamine in dimethylformamide (11) and titrated continuously to a preset potential with tetrabutylammonlum hydroxyde in isopropanol. 

In this work we present results obtained with the YSZ reactor operated in the hatch mode with electrochemical oxygen addition, and with the quartz plug flow reactor operated in the continuous-flow steady-state mode. In the case of continuous flow operation, the molecular sieve trap comprised two packed bed units in parallel in a swing-bed arrangement (Fig. 1), that is, one unit was maintained at low temperature (<70°C) to continuously trap the reactor products while the other was heated for -30 min to 300°C to release the products in a slow stream of He. 

In polar ice sheets air gets continuously trapped, and ice cores obtained by drilling through the ice caps therefore constitute a continuous set of ancient air samples. 39Ar/Ar and 81Kr/Kr measurements on these samples primarily reflect the production rates of these radioisotopes averaged over a few half-lives. 

In studies of low-mobility insulators, two types of continuous trap distributions are commonly used the exponential distribution of traps [364] and the Gaussian distribution of traps [365]. 

Membrane extraction with sorbent interface (MESI) is an interesting example of an extraction device, which is the most useful system for interfacing with GC. In this approach, the donor phase is a gas or a liquid sample, and the acceptor phase is a gas. The volatiles are continuously trapped on sorbent and then desorbed into GC [112]. Another solution is a combination of off-line GC-MESI through a cryogenic trap, which allows preparation of environmental samples in the field and performance of GC analysis after transportation to the laboratory [113,114]. MESI allows the extraction of volatile and relatively nonpolar analytes. 

The purity of the xenon difluoride can be checked by measuring the absorption in the infrared (synthesis 66). Samples prepared as described above, with continuous trapping, contain less than 1 % xenon tetrafluoride, even if the initial fluorine-to-xenon ratio is varied from 0.1 to over 6. 

Since aldehydes are, in general, more electroactive than the corresponding acids or esters, alcohols can be obtained according to a sole four-electron step. If, on the contrary, the hemiacetal transient is fairly stable, the aldehyde may be isolated from the solution or be continuously trapped as soon as it is formed in the catholyte. 

One method involves passive on board continuous trap regeneration using NO/O and NO ... 

This method is very reliable but suffers from the drawback that the lithium aluminum hydride contains carrier carbon that reduces the specific radioactivity. A solid phase technique has also been reported for the synthesis of [ C]methyl iodide (Sarkadi et al. 1997,1998). In an alternative method, that gives higher specific radioactivity, [ C] methane undergoes a free radical iodination in a circulating gas phase while the [ C] methyl iodide formed is continuously trapped on a solid phase to prevent further iodination (Larsen et al. 1997). 

Figure 10 Internal trapping assays can be used to prove that transport really occurs across the membrane of intact vesicles. Transporters are added in small portions well below EC50 to labeled vesicles (a) with or (b) without internal inactivators. Without inactivators, activity will gradually increase and reach the value obtained when all transporters are added at once (b vs c). With inactivators, transporters are continuously trapped intravesicularly, and no activity is observed even at high total concentrations (a vs c).

Hindered amine antioxidants, as shown below, undergo the same two basic reactions as their fellow radical trapping phenolic counterparts. In addition, the amines can enter into a cyclic process to continuously trap radicals without being consumed. This can yield a longer lifetime at elevated temperature. 

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