Charging sequence

Additionally, consequences of possible process maloperations, such as incorrect charging sequence, contamination of reactants, agitation failure and poor temperature control, adding reactants too quickly. 

As mentioned in Section IX, the sequence of additions may be determined by safety considerations and the reactivity of components—or simply by the convenience of adding a liquid or a solution. The starting material may be added last in order to control a reaction exotherm. If a key reagent is particularly toxic and special care is needed for its transfer, such a reagent may be added early in the charging sequence. 

PRESS START button to start charging sequence... 

NOTIFY Operator A that charging sequence has started. 

Posttranscriptional processing of tRNA requires several distinct steps, as summarized in Figure 25.8. First, the 50 and 30 ends must be cleaved to release the tRNA sequence from the larger precursor transcript and introns must be removed if they are present. Second, the required CCA charging sequence at the 30 end of tRNA must sometimes be added by a nucleotidyl transferase. Third, all tRNAs contain a large number of modified bases which result from reductions, methylations, and deaminations. These modifications can affect codon recognition by the tRNAs during protein synthesis (Chapter 26). 

The failure of a material to return to its nonconductive state prior to the sueeeeding charging sequence will result in a decrease in the maximum charge acceptance of the photoconductor. This phenomenon is addressed as fatigue. It can he avoided by the selection of photoconductive materials having a rapid switching capacity. 

Effect of different charging sequence on explosion properties... 

Alternatively, toluene can be first charged into a reaction flask, and then nitric acid is added portion-wise with stirring and cooling. Initially, the reaction rate is slow, and it dramatically increases when the temperature of reaction solution reaches certain values like 30-40 °C, which in turn would increase the reaction temperature enormously. However, if too much nitric acid is added at the beginning, it will be extremely diflicult to control the reaction rate and temperature. The explosion properties of explosives prepared through different charging sequences appear to be quite similar, as illustrated in Table 7.32. 

Nitric acid concentration (%) Amount of nitric acid (%) Amount of toluene (%) Charging sequence Brisance (mm) Explosion crater volume (L)... 

In order to check this supposition, Teunissen, Rosenthal and Zaayer compared the reversal of charge concentrations of oleate, trioxystearate, hexaoxystearate and arabinate for the alkali and alkaline earth cations. In this investigation also another factor — the influence of pH — showed it self very markedly. In the following survey the reversal of charge sequences at different pH values follow one another in such a way, that the inverse sequence for oleate (at pH 10 but also at pH 7) and arabinate (at pH 10 but also at pH 6) are interlinked as successively as possible. The intermediate sequences have in part the character of transition series ( 2g) ... 

It is of course erroneous to speak of the behaviour of the carboxyl group of proteins, the reversal of charge sequences in reality informing us about the mean polarisabilities of the different categories of carboxyl groups present. 

Earlier investigations have shown, that the ammonium ion in general resembles the K ion or stands between Na and K as regards its place in reversal of charge sequences (see p. 289, Fig. 17). Now we can derive organic cations in two ways from the ammonium cation ... 

With three positively charged proteins, the reversal of charge sequence was investigated for three sodium alkyl-ester-sulphates. The results (see Fig. 30) showed the same sequence for all three proteins ... 

A propos of this these reversal of charge sequences have been determined more extensively with all kinds of colloids and the reversal of charge spectra so obtained can serve as the basis for the interpretation of all kinds of phenomena which depend on interrelations between colloids and ions. 

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