Maximum spread design

Selection of test items so that they are as dissimilar a possible to each other is accomplished by choosing items which are projected far from each other and on the periphery of the plot. Such designs are useful for answering the question of whether or not the properties have an influence. A maximum spread design wa used to determine whether modification of the solvent would increase the endo/exo stereoselectivity in the reduction of an enamine from camphor. The answer was negative [17 a],... 

The reaction showed promising stereoselectivity when it was run without any solvent. As the reaction might involve charged species, it was quite natural to examine whether or not the selectivity could be increased in the presence of a solvent. The solvents used to investigate this were selected according to a "maximum spread" design in their principal properties, see Fig. 16.2. 

Selections which afford a maximum spread also provide a good initial screening design for totally new reactions. Poor candidates can be eliminated early and the study can be continued with more promising candidates, see Sect. 4.6.2. 

The ECAP incorporates an electrostatic lens in the time-of-flight spectrometer in order to improve the mass resolution by compensating for small spreads in the energies of the ions evaporated from the specimen under the pulsed electric field. A lens design by Poschenrieder or a reflectron type of electrostatic lens is used for this purpose, and is standard equipment for metallurgical or materials applications of APFIM. These typically improve the mass resolution at full width half maximum (FWHM) from m/Am 250 to better than 2000. 

For prefilming type of atomizers, minimum droplet sizes are obtained with nozzle designs that spread liquid into thinnest sheet before subjecting its both sides to air-blast action 86] and provide maximum contact between liquid and air. 468 From experimental data obtained over a wide range of process conditions and material properties, it was found 469 that the effect of liquid viscosity on the mean droplet size is independent of that of surface tension and air velocity. Therefore, the mean droplet size can be expressed as a sum of two terms one dominated by surface tension, air velocity and air density, and the other by liquid viscosity, as suggested by Lefebvre 4691... 

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