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Complex systems theory cycle model

Chemists have increasingly used computational chemistry to study aspects of organometallic chemistry. Although Chapter 2 and subsequent chapters make good use of qualitative molecular orbital theory, the ready availability of easy-to-use computational chemistry software and the powerful capability of modem desktop computers allow chemists to effectively model complex systems to obtain minimum energy geometry of molecules, determine transition state energies, and predict the course of chemical reactions, particularly if two or more isomeric products could form. Researchers have modeled entire catalytic cycles, which... [Pg.42]

Analytic performance modeling, using queueing theory, is very flexible and complements traditional approaches to performance. It can be used early in the application development life cycle. The actual system, or a version of it, does not have to be bmlt as it would be for a benchmark or prototype. This saves tremendously on the resources needed to bmld and to evaluate a design. On the other hand, a simulation shows the real world in slow motion. Simulation modeling tools allow us to observe the actual behavior of a complex system if the system is unstable, we can see the transient phenomena of queues building up and going down repeatedly. [Pg.729]

The potential energy surface for the hydroformylation of ethylene has been mapped out for several catalytic model systems at various levels of theory. In 1997, Morokuma and co-workers [17], considering HRh(CO)2(PH3) as the unsaturated catalytic species that coordinates alkene, reported free energies for the full catalytic cycle at the ab initio MP2//RHF level. Recently, in 2001, Decker and Cundari [18] published CCSD(T)//B3LYP results for the HRh(CO)(PH3)2 catalytic complex, which would persist under high phosphine concentrations. Potential energy surfaces for both Rh-catalyzed model systems were qualitatively very similar. The catalytic cycle has no large barriers or deep thermodynamic wells to trap the... [Pg.164]

The experiments and the simulation of CSTR models have revealed a complex dynamic behavior that can be predicted by the classical Andronov-Poincare-Hopf theory, including limit cycles, multiple limit cycles, quasi-periodic oscillations, transitions to chaotic dynamic and chaotic behavior. Examples of self-oscillation for reacting systems can be found in [4], [17], [18], [22], [23], [29], [30], [32], [33], [36]. The paper of Mankin and Hudson [17] where a CSTR with a simple reaction A B takes place, shows that it is possible to drive the reactor to chaos by perturbing the cooling temperature. In the paper by Perez, Font and Montava [22], it has been shown that a CSTR can be driven to chaos by perturbing the coolant flow rate. It has been also deduced, by means of numerical simulation, that periodic, quasi-periodic and chaotic behaviors can appear. [Pg.244]


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See also in sourсe #XX -- [ Pg.215 , Pg.220 ]




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