Alternate selection strategies

We will not describe the iterative design process in any more detail than this. There are many fine books on the subject, and the interested reader is referred to the list at the end of the chapter for further information. After a brief diversion into alternative design strategies in the next section, we will return to the iterative design process to see how the concepts of materials selection fit into mechanical design. 

Subsequent cleavage of the resin-bound Diels-Alder adducts employing lithium aluminium hydride (LiAlH4) via a traceless linker strategy afforded the cyclic phenylethy-lamines. Alternatively, selective reduction of the nitro group using tin(II) chloride... 

Two alternative operating strategies are shown on Figure 4.48a that both achieve the specified 75% conversion and 76% selectivity. With an initial feed flowrate of 2.0 L/min and zero slope, the productivity is 6.52 mol C/min with a batch time of 287 min. With an initial feed flowrate of 2.48 L/min and a slope of 3 x 10 6 L/min2, the productivity is 6.82 mol C/min with a batch time of 275 min. 

Laboratory experiments, transport modeling, field data, and engineering cost analysis provide complementary information to be used in an assessment of the viability of an MNA approach for a site. Information from kinetic sorption/ desorption experiments, selective extraction experiments, reactive transport modeling, and historical case analyses of plumes at several UMTRA sites can be used to establish a framework for evaluation of MNA for uranium contamination (Brady et al, 1998, 2002 Bryan and Siegel, 1998 Jove-Colon et al, 2001). The results of a recent project conducted at the Hanford 100-N site provided information for evaluation of MNA for a °Sr plume that has reached the Columbia River (Kelley et al, 2002). The study included strontium sorption-desorption studies, strontium transport and hydrologic modeling of the near-river system, and evaluation of the comparative costs and predicted effectiveness of alternative remediation strategies. 

In searching for new separation processes, the chromato-grapher develops new types of stationary phase materials in order to gain improvements in selectivity. The development of zirconia-silica composites is an example which—although, at present, applications on these surfaces are limited to their development—typifies the ongoing search. Whether the separations achieved on the zirconia-silica composites are better or worse than those achieved on either zirconia or silica is immaterial to the fundamental process of discovery. The important factor is that the separation is different and, therefore, an alternative separation strategy may be employed. In addition to the differences in selectivity that may be found when new surfaces are developed, beneficial surface properties may also be realized. These may be related to aspects such as the pore stmcture, the acidic or basic properties, or the solubility of the support. 

As an alternative, the strategy outlined in Scheme 5 could also be used. Reaction of the activated linker unit 7 with the amine yielded an amine-linker conjugate 8, which, after selective hydrolysis of the ester function, was attached to the sohd support via an ester or an amide bond to yield polymer-bound amine 9 [20]. 

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