Coverage design

Coverage design objective select a subset of molecules that is most representative of the entire library. Heuristically, the distance from the chosen subset to the remaining candidate points should be small. One might imagine a set of umbrellas positioned to cover as many candidate points as possible. 

Figure 5. Coverage design for fictitious example. (Reproduced from Higgs et al., 1997 with permission.)...

This measure is particularly useful in selecting diverse compound sets from a corporate collection, as exemplified by Higgs et al. (68). They also introduce the concept of a coverage design for lead follow-up, in which compounds are selected to be maximally similar to a set of leads. 

Aluminum, the most common material used for contacts, is easy to use, has low resistivity, and reduces surface Si02 to form interfacial metal-oxide bonds that promote adhesion to the substrate. However, as designs reach submicrometer dimensions, aluminum, Al, has been found to be a poor choice for metallization of contacts and via holes. Al has relatively poor step coverage, which is nonuniform layer thickness when deposited over right-angled geometric features. This leads to keyhole void formation when spaces between features are smaller than 0.7 p.m. New collimated sputtering techniques can extend the lower limit of Al use to 0.5-p.m appHcations. 

The subjects covered aim at providing methods to form specihcations and then design a switchgear assembly for all power distribution needs. It also provides coverage of draw-out asseinblies. Establishing the fault level of a system is described including the electrodynamic and electromagnetic forces that arise. 

More specifically, data bases are now available which are designed as aids to plastics material selection. One estimate in 1993 was that there were 300-400 systems in the field.Systems vary as to whether they are limited to the products of a particular company, to a particular area of activity and to the depth of coverage over a broad area. 

The L-foot fm covers the tube more or less completely to protect the base tube against corrosive attack, but still leaves a potential corrosive site at the base of the fin adjacent to the preceding fin. The double L-foot is intended to provide complete coverage of the tube, where corrosion would otherwise be a problem. Where corrosion is troublesome, soldered or galvanized tubes may offer a solution. The dimensions of fmned tubes are results of past experience in the design of air cooled heat exchangers. Tube diameters range from about 1.905 cm (0.75 in.) to 5.08 cm (2.0 in,). 

The Spray tree is used to distribute water over the wet deck in counterflow cooling towers. It can consist of a single header fitted with spray nozzles or, it can utilize spray branches with nozzles for wider coverage. Spray nozzle designers seek minimal pressure requirements and uniform coverage over wide flow ranges. 

A final note is with regard to flat bottom cyclones which have gained acceptance in recent years. The installation of a flat bottom in place of the conical section will coarsen the separation by more than twofold. Additionally, the sharpness of the recovery curve will decrease significantly. As such, flat bottom cyclones should be restricted to those applications in which coarse separations are required. The flat bottom cyclone does produce a very clean underflow but at the expense of a large amount of misplace coarse solids in the overflow. An illustration of a flat bottom cyclone is shown in Figure 58. The reader should refer to the reference section of this chapter for citations that provide more in-depth coverage of this equipment, as well as design case studies and example. 

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