Jackson

Another design option that can be considered if a column will not fit is use of an intermediate reboiler or condenser. An intermediate condenser is illustrated in Fig. 14.5. The shape of the box is now altered because the intermediate condenser changes the heat flow through the column. The particular design shown in Fig. 14.5 would require that at least part of the heat rejected from the intermediate condenser be passed to the process. An analogous approach can be used to evaluate the possibilities for use of intermediate reboilers. Flower and Jackson," Kayihan, and Dhole and Linnhofl have presented procedures for the location of intermediate reboilers and condensers. 

Shalashilin D V, Jackson B and Persson M 1999 Eley-Rideal and hot atom reactions of H(D) atoms with D(H)-covered Cu(111) surfaces quasiclassical studies J. Chem. Phys. 110 11 038... 

Mastuura S, Blake G A, Wyss R, Pearson J, Kadow C, Jackson A and Gossard A C 1999 A travelling-wave photomixer based on angle-tuned phase matching Appl. Rhys. Lett. 74 2872-4... 

Gil-Villegas A, McGrother S C and Jackson G 1997 Reaction-field and Ewald summation methods in Monte Carlo simulations of dipolar liquid crystals Mol. Phys. 92 723-34... 

Jackson B 1994 Quantum and semiclassical calculations of gas surface energy transfer and sticking Comput. Rhys. Commun. 80 119... 

Jackson B and Metiu H 1985 An examination of the use of wave packets for the calculation of atom diffraction by surfaces J. Chem. Phys. 83 1952... 

Jackson J D 1962 CiassicaiEiectrodynamics (New York Wiley) Born M and Wolf E 1970 Principies of Optics (Oxford Pergamon)... 

Strynadka et al., 1996] Strynadka, N., Eisenstein, M., Katchalski-Katzir, E., Shoichet, B., Kuntz, I., Abagyan, R., Totrov, M., Janin, J., Cherflls, J., Zimmerman, F., Olson, A., Duncan, B., Rao, M., Jackson, R., Sternberg, M., and James, M. Molecular docking programs successfully predict the binding of a /3-lactamase inhibitory protein to TEM-1 /3-lactamase. Nature Struct. Biol. 3 (1996) 233-239... 

P. Jackson, Introduction to Expert Systems, Addison Wesley Longman, Harlow, 1999. 

The approximations of Kehoe and Aria and of Hite and Jackson (denoted "high permeability" in the diagrams) are indistinguishable from the exact results, while the method of Apecetche et al. introduces substantial error. 

At the limit of Knudsen diffusion control it is not reasonable to expect that any of the proposed approximation methods will perform well since, as we know, percentage variations in pressure are quite large. Nevertheless it is interesting to examine their results, which are shown in Figure 11 4 At this limit it is easy to check algebraically that equations (11.54) and (11.55) become the same, while (11.60) differs from the other two. Correspondingly the values of the effectiveness factor calculated using the approximation of Kehoe and Aris coincide with the results of Apecetche et al., and with the exact solution, ile Hite and Jackson s effectiveness factors differ substantially. 

More computational results are provided by Hite [75], including a second order reaction with different stoichiometry, and slab, as well as sphere geometry for the pellet. Overall it can be concluded that the approximate procedure of Hite and Jackson gives results of quite adequate... 

As a particular case of this result, it follows that the stoichiometric relations are always satisfied in a binary mixture at the limit of bulk diffusion control and Infinite permeability (at least to the extent that the dusty gas equations are valid), since then all the binary pair bulk diffusion coefficients are necessarily equal, as there is only one of them. This special case was discussed by Hite and Jackson [77], and the reasoning set out here is a straightforward generalization of their treatment. 

Though the case of constant matrix elements and the example investigated by Hite are the only situations for which Che stoichiometric relations have been fully established in pellets of arbitrary shape, it is worth mentioning situations in which these relations are known not to hold. When the composition and pressure at the surface of the pellet may vary in an arbitrary way from point to point it seems unlikely on intuitive grounds that equations (11.3) will be satisfied, and Hite and Jackson [77] confirmed by direct computation that there are, indeed, simple situations in which they are violated. Less obviously, direct computation [75] has also shown them to be violated even when the pressure and composition of the environment are the same everywhere, in the case where finite resistances to mass transfer exist at the surface of Che pellet. 

Figure 12.2. Real part of the dominant eigenvalue versus Lewis number for steady state E of Figure 12,1, (From Hite and Jackson CSl].)...

More complete results are reported by Hite and Jackson [8l] and by Hite [75]. 

Watson G W, P Tschaufeser, A Wall, R A Jackson and S C Parker 1997. Lattice Energy and Free Energy Minimisation Techniques. Computer Modelling in Inorganic Crystallography. San Diego, Academic Press, pp. 55-81. 

Bell R G, R A Jackson and C R A Catlow 1990. Computer Simulation of the Monoclinic Distortion in Silicalite. Journal of the Chemical Society Chemical Communications 10 782-783. 

Flow chart showing the design of novel orally active HIV-1 protease inhibitor. (Figure adapted from Lam P K ]adhav, C E Eyermann, C N Hodge, Y Ru, L T Bacheler, ] L Meek, M ] Otto, M M Rayner, Y N V /ong, ang, P C Weber, D A Jackson, T R Sharpe and S Erickson-Viitanen 1994. Rational Design of Potent, able. Nonpeptide Cyclic Ureas as HIV Protease Inhibitors. Science 263 380-384.)... 

A mild procedure which does not involve strong adds, has to be used in the synthesis of pure isomers of unsymmetrically substituted porphyrins from dipyrromethanes. The best procedure having been applied, e.g. in unequivocal syntheses of uroporphyrins II, III, and IV (see p. 251f.), is the condensation of 5,5 -diformyldipyrromethanes with 5,5 -unsubstituted dipyrromethanes in a very dilute solution of hydriodic add in acetic acid (A.H. Jackson, 1973). The electron-withdrawing formyl groups disfavor protonation of the pyrrole and therefore isomerization. The porphodimethene that is formed during short reaction times isomerizes only very slowly, since the pyrrole units are part of a dipyrromethene chromophore (see below). Furthermore, it can be oxidized immediately after its synthesis to give stable porphyrins. 

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