Cleaning steps, repetition

Table 2.9 Repetition of Cleaning Steps to Achieve a High Level of Soil Removal ...

Repetition of the same cleaning steps until a desired cleanliness result has been achieved can be completed in all cleaning equipment described in this chapter. 

We prepared a combinatorial library that satisfied the following criteria (1) the chemistry was general and applicable to a wide range of substrates (2) the yields of all the transformations were high or the reactions were amenable to repetitive cycling under the reaction conditions to drive reactions to completion (3) the reaction profiles were clean, minimizing the production of resin-bound impurities and (4) the synthetic sequence minimized the number of chemical steps on solid... 

In order to achieve clean catalytic surfaces before reactant adsorption and reproducible results, it is necessary to establish a repetitive pretreatment schedule of cathodic and anodic pulses of fixed duration for removal of impurities and of oxides. Figure 14 gives such a pretreatment procedure followed by a constant potential equilibration step. It is also important to establish the effect of sweep rates on the i-t curves. At slow sweep rates readsorption of the desorbed species is possible at fast sweeps oxidative removal of the adsorbate may be incomplete or the capacitance current may not be separable from the reaction current. 

A cleaning process is a sequence of steps. Although cleaning processes may be lengthy of time or require repetitive steps under different operating conditions, a cleaning process is usually composed of only three different steps. Each of these steps is described and illustrated in detail. 

The notion of error reduction in the execution of an operation by a way of repetition of the same step is adopted also in the phases of pre-cleaning of the parts to be passed onto electronic selection. 

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