Back-Exchange Consideration

10 and 30% [14, 29, 30, 34, 35], The number of deuterons exchanged in each peptide can be adjusted for back-exchange using Equation 2.2 [27]  

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Another important concern is related to the chemical stability in solution of the analyte or SIS itself. Special consideration should also be given to the dangers inherent in use of protic solvents (water, alcohols etc.), e.g., hydrolysis or transesterification of ester analytes, D/H back exchange of a D-labeled SIS. 

Considerable engineering judgment and effort are needed to ensure that the heat recovery is efficient, yet has low pressure drop. Since a large portion of the heat contained in the reactor effluent has to be transferred back to the cold recycle gas, this exchanger arrangement received our special attention. 

The calculation of the radiation heat transfer between black surfaces is relatively easy because all the radiant energy which strikes a surface is absorbed. The main problem is one of determining the geometric shape factor, but once this is accomplished, the calculation of the heat exchange is very simple. When nonblackbodies are involved, the situation is much more complex, for all the energy striking a surface will not be absorbed part will be reflected back to another heat-transfer surface, and part may be reflected out of the system entirely. The problem can become complicated because the radiant energy can be reflected back and forth between the heat-transfer surfaces several times. The analysis of the problem must take into consideration these multiple reflections if correct conclusions are to be drawn. 

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