Computer comparisons

Computational comparison of structures of the benzyl cation (A) and singlet phenylcarbene (B) indicates a much greater double-bond character for the exocyclic... 

M. Benes. On a computational comparison of phase-field and sharp-interface model of microstructure growth in solidification. Acta Technica CSAV 41 591,... 

Fig. 12.15. Computational comparison of reactants (adducts) and transition structures for Baeyer-Villiger oxidation of 2-(trifluoromethyl)cyclohexanone by peroxytrifluo-roacetic acid. Reproduced from Org. Lett., 5, 4803 (2003), by permission of the American Chemical Society.

On the other hand, there is considerable interest to quantify the similarities between different molecules, in particular, in pharmacology [7], For instance, the search for a new drug may include a comparative analysis of an active molecule with a large molecular library by using combinatorial chemistry. A computational comparison based on the similarity of empirical data (structural parameters, molecular surfaces, thermodynamical data, etc.) is often used as a prescreening. Because the DFT reactivity descriptors measure intrinsic properties of a molecular moiety, they are in fact chemical fingerprints of molecules. These descriptors establish a useful scale of similarity between the members of a large molecular family (see in particular Chapter 15) [18-21],... 

This system of equations allows us to take account of the flow in the frontal zone and the influence of the fountain effect on the distributions of variables in the main stream zone. The equations for this rather complicated model can be solved numerically by computer. Comparison of the calculations with experimental data shows that the maximum deviations of the predicted values from the experimental points do not exceed 15 % (Fig. 4.60). 

A computational comparison between ADN and the oxidizers AP, AN, CL-20 and hydrazine nitroformate (HNF) in an HTPB-IDP binder showed that only HNF had a higher specific impulse than ADN at 70% (volume) oxidizer. CL-20 outperformed ADN only at very high levels of oxidizer. At these levels, the viscosity and sensitivity would be problems... 

For the definition and analysis of molecular similarity, a reference frame is needed that relates molecular structures to each other and facilitates computational comparisons. Hence, an important aspect of similarity analysis is the definition of theoretical chemical spaces into which compounds are projected. 

Burkard, R.E., Hatzl, J., 2005. Review, extensions and computational comparison of MILP formulations for scheduling of batch processes. Comp. Chem. Eng. 29(8), 1752-1769. 

Ouzounis, C., G. Casari, C. Sander, J. Tamames, and A. Valencia. 1996. Computational comparisons of model genomes. Trends Biotechnol 14 280-5. 

The most wide-ranging and internally consistent computational comparison of substituent effects on carbocation was reported by a group working in The... 

Note also the preference for [2 + 2] rather than [2+4] cycloaddition with cyclopentadiene. A computational comparison of the [2 + 2] and [2 + 4] modes of reaction between cyclopentadiene and ketene found the former to have a lower (by about... 

Since the necessary cell kinetics and the pharmacokinetics have been described, they can be combined in an attempt to show the results of drug treatment. Several general solutions to Equations (la-3a) have been developed by Himmelstein (20) only one will be described here. A search for experimental data with which to test the models revealed that too little was available to utilize the full cell cycle specific provisions in the model. Computational comparisons (20) indicated that a time-dependent rate constant, Ki(t), would give results similar to the cell cycle effects although much biological input might be lost with this semiempirical approach. For this case the loss function is a function only of time, A = A(f), and the solutions to Equations (la-3a) are par-... 

Table 3. ENERGY FLOWMETER FLOW COMPUTER COMPARISON...

The BFGS formula is generally preferred to (26) since computational results have shown that it requires considerably less effort, especially when inexact line searches are used. Quasi-Newton methods, also referred to as variable metric methods, are much more widely used than either the steepest descent or Newton s method. For additional details and computational comparisons, see Fletcher (1987, pp. 44-74). 

Munsell book notation n. The Munsell color notation of a specimen obtained by visual or computational comparison with the Munsell hue, value, and chroma scales of the Munsell Book of Color. 

Interiaboratory Computational Comparisons of Critical Fast Test Reactor Pin Lattices, J. F. 

A summary of the initial calculational results is given in Table I. Three sets of computations are compared each set utilizes virtually, the same KENO-IV code and geomet-. rical model but different cross-section libraries. As noted in Table I, two of the experimental lattice grids were recently discovered (by PNL personnel) to have slifditly smaller pitches than values used in these three sets of calculations. Updated calculations are in progress meanwhile, the slight corrections to the pitches do not affect present computational comparisons since the pitch values among the three calculational sets are consistent. 

---