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Bottleneck defined

A situation that arises from the intramolecular dynamics of A and completely distinct from apparent non-RRKM behaviour is intrinsic non-RRKM behaviour [9], By this, it is meant that A has a non-random P(t) even if the internal vibrational states of A are prepared randomly. This situation arises when transitions between individual molecular vibrational/rotational states are slower than transitions leading to products. As a result, the vibrational states do not have equal dissociation probabilities. In tenns of classical phase space dynamics, slow transitions between the states occur when the reactant phase space is metrically decomposable [13,14] on the timescale of the imimolecular reaction and there is at least one bottleneck [9] in the molecular phase space other than the one defining the transition state. An intrinsic non-RRKM molecule decays non-exponentially with a time-dependent unimolecular rate constant or exponentially with a rate constant different from that of RRKM theory. [Pg.1011]

Whether or not a team effort is feasible, defining goals for your efforts helps you stay on track, anticipate bottlenecks and obstacles, and assure that the end results reflect the real world of your particular company. [Pg.45]

For the ZW (zero wait) policy idle times (slacks) between consecutively produced batches may appear in all stages including the one that defines the bottleneck. It should be noted that the slacks are only a function of consecutive pairs of batches. Therefore, the slacks for each pair of batches can easily be calculated a priori with the binary variable for any two consecutive batches ... [Pg.509]

Allocation defines the time span between the first and the last usage of a station including unproductive waiting times. Utilization sums the times when a station is used for processing. The small difference (delta) between the degrees of allocation and utilization of station 2 shows that this station is working almost to full capacity. In contrast, the other stations have a significantly lower utilization because the vessels have to wait for station 2, which means that station 2 turns out to be a bottleneck. [Pg.50]

The activation energy represents the ease of ion hopping, as already indicated above and shown in Fig. 2.5. It is related directly to the crystal structure and in particular, to the openness of the conduction pathways. Most ionic solids have densely packed crystal structures with narrow bottlenecks and without obvious well-defined conduction pathways. Consequently, the activation energies for ion hopping are large, usually 1 eV ( 96 kJ mole ) or greater and conductivity values are low. In solid electrolytes, by contrast, open conduction pathways exist and activation energies may be much lower, as low as 0.03 eV in Agl, 0.15 eV in /S-alumina and 0.90 eV in yttria-stabilised zirconia. [Pg.18]

The 7-shifting method depends on our ability to identify a unique bottleneck geometry and is particularly well suited to reactions that have a barrier in the entrance channel. For cases where there is no barrier to reaction in the potential energy surface, a capture model [149,150,152] approach has been developed. In this approach the energy of the centrifugal barrier in an effective onedimensional potential is used to define the energy shift needed in Eq. (4.41). For the case of Ai = 0, we define the one-dimensional effective potential as (see Ref. 150 for the case of AT > 0)... [Pg.271]

Ashkenazi Jewish (both parents CJA). Ashkenazi Jews, who are defined as those bom of Jews of European origin where both parents were Ashkenazi, have hereditary disease risk characteristics different from those of other groups. Because there has been little outbreeding in the group for at least several hundred years, this group is an effective bottleneck for several characteristic genetic lesions. [Pg.200]

Counting the Trajectories. The generation of tra-jectories and the estimation of the overall transition rate are facilitated by defining an arbitrary 6N-1 dimensional dividing surface S in the bottleneck region, and counting the trajectories as they cross through it. [Pg.78]

A new issue arises when one makes a solute-solvent separation. If the solvent enters the theory only in that V(R) is replaced by TT(R), the treatment is called equilibrium solvation. In such a treatment only the coordinates in the set R can enter into the definition of the transition state. This limits the quality of the dynamical bottleneck that one can define depending on the system, this limitation may cause small quantitative errors or larger more qualitative ones, even possibly missing the most essential part of a reaction coordinate (in a solvent-driven reaction). Going beyond the equilibrium solvation approximation is called nonequilibrium solvation or solvent friction [4,26-28], This is discussed further in Section 3.3.2. [Pg.341]

The overall throughput, as within any chain or cycle, is constrained by the slowest steps and it is essential to focus on and eliminate these successively. Overcoming key bottlenecks to enable a fully automated system requires considerable work on the chemical development of the various steps that are often done offline, such as isolation and washing. This can be overcome partially by a systematic approach in the design stage where the conditions for each of the reaction stages must be defined such that yields are optimised across the range of substrates represented by the library. [Pg.108]


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See also in sourсe #XX -- [ Pg.5 , Pg.50 ]




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Bottlenecks

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