Geometrical filter

The effect of geometric filtering by the limiting size of optical elements is the vignetting. This means that the power is modulated by the point spread function of the optical elements. In the case of a circular aperture, the modulation function has a sine like profile for squared apertures, the modulation function has a Bessel profile in both x and y directions of the signal. This effect can be simulated and understood, and can be reduced by re-designing the system to accommodate larger optical elements. 

Kuntz et al. 1982, DOCK spheres (site points) geometric filter shape or force field <1 9 ... 

Jiang and Kim 1991 SOFT DOCK surface cubes geometric filter interact NR NR... 

Miller et al. 1994 FLOG site points geometric filter H-bond -(- hydrophobic -(- e" NR ... 

Fischer et al. 1995 surf points and normals geometric filter surface contact <1 X... 

Sobolev et al. 1996 LIGIN atomic surface geometric filter steric -t- interact -I- H-bond <1 20... 

Direct interception refers to a sieve-type mechanism in which contaminants larger than the filter pore size are directly trapped by the filter. This sieve retention mechanism of particle arrest is the mechanism of choice and occurs owing to geometric or spatial restraint. This type of particle arrest is considered to be absolute, that is, it is independent of filtration conditions. 

The precise description of geometrical structures of CNTs has been reported by lijima [1], who was the first discoverer of carbon microtubules. Electron diffraction (ED) results are presented in Chap. 3. In this chapter, the authors will focus on the electronic structures of CNTs from the viewpoint of EELS by using TEM equipped with an energy-filter in the column or under the column. 

An impurity in a water stream at a very small concentration is to be removed in a charcoal trickle bed filter. The filter is in a cylindrical column that is 2 ft in diameter, and the bed is 4 ft deep. The water is kept at a level that is 2 ft above the top of the bed, and it trickles through by gravity flow. If the charcoal particles have a geometric surface area to volume ratio of 48 in.-1 and they... 

Tiller and Huang(13) give further details of the problem of developing a usable design relationship for filter equipment. Studies by Tiller and Shirato 14-1, Tiller and Yeh 15-1 and Rushton and Hameed(16) show the difficulty in presenting practical conditions in a way which can be used analytically. It is very important to note that tests on slurries must be made with equipment that is geometrically similar to that proposed. This means that specific resistance is very difficult to define in practice, since it is determined by the nature of the filtering unit and the way in which the cake is initially formed and then built up. 

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