Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Stages statistical derivation

The final stage involves integration of the results of the preceding stages to derive a probability of the occurrence of the adverse effect in humans exposed to the chemical. The biological, statistical, and other uncertainties will have to be taken into account. [Pg.30]

The factor of 0.75 in the denominator of Eq. 7 for alite birefringence was statistically derived to account for deviations between true and observed birefrin gences of an alite crystal in which the X vibration direction is not exactly parallel to the microscope stage and the Y and Z directionsarenotpreciselyknown. In order to minimize this deviation, which lessens the birefringence, a crystal thickness-to particle width ra tio of 3/4 is assumed (Ono, letter, 1978). The clinker particle, in this case, was illustrated to contain only part of an alite crystal. [Pg.55]

The plan of this chapter is the following. Section II gives a summary of the phenomenology of irreversible processes and set up the stage for the results of nonequilibrium statistical mechanics to follow. In Section III, it is explained that time asymmetry is compatible with microreversibility. In Section IV, the concept of Pollicott-Ruelle resonance is presented and shown to break the time-reversal symmetry in the statistical description of the time evolution of nonequilibrium relaxation toward the state of thermodynamic equilibrium. This concept is applied in Section V to the construction of the hydrodynamic modes of diffusion at the microscopic level of description in the phase space of Newton s equations. This framework allows us to derive ab initio entropy production as shown in Section VI. In Section VII, the concept of Pollicott-Ruelle resonance is also used to obtain the different transport coefficients, as well as the rates of various kinetic processes in the framework of the escape-rate theory. The time asymmetry in the dynamical randomness of nonequilibrium systems and the fluctuation theorem for the currents are presented in Section VIII. Conclusions and perspectives in biology are discussed in Section IX. [Pg.85]

In fact, Waite s approach needs a kind of demon to mark (enumerate) pairs of particles at moments of their birth and then following the time development w(r,t) of all such geminate pairs - even when these pairs already completely have mixed at the bimolecular reaction stage What is said above demonstrates quite well how the violation of statistical principles in deriving kinetic equations can lead to unphysical paradoxes (discussed in detail in [14, 15]). [Pg.181]

Equation (88) was used to demonstrate [44] the differences in distributions of molecular sizes in pre-gel stages of an RA3 polymerization with substitution effects as calculated according to a statistical and a kinetics model. The moments of distribution and the gel points were calculated by the numerical solution of a few ordinary differential equations that were derived from Eq. (88) and compared with analogous quantities calculated from a statistical model. [Pg.160]

The Flory model is the version where the equivalence between kinetics and statistical descriptions is extended to the post-gel stage of polymerization. Consequently, the functional groups are assumed to continue to react at random with no distinction on whether they belong to sol molecules or to gel. To analyze this version one can use the explicit form of function H. As usual, the moments are available through successive derivatives of H (Eq. 76) with respect to x calculated at x=l. We may rewrite Eq. (77) in the form... [Pg.163]

To derive statistical parameters in the postgel stage, we have to determine the probability of having a finite continuation when leaving a fragment from (+) bonds, (—) bonds, (+)bonds, (—)bonds and arrows. We will call these probabilities Z(+), Z(—), Z (+), Z (—) and Z(A), respectively. For example, Z(—) is defined as... [Pg.123]

At this stage, we are confident that a clear connection between Levy statistics and critical random events is established. We have also seen that non-Poisson renewal yields a class of GME with infinite memory, from within a perspective resting on trajectories with jumps that act as memory erasers. The non-Poisson and renewal character of these processes has two major effects. The former will be discussed in detail in Section XV, and the latter will be discussed in Section XVI. The first problem has to do with decoherence theory. As we shall see, decoherence theory denotes an approach avoiding the use of wave function collapses, with the supposedly equivalent adoption of quantum densities becoming diagonal in the pointer basis set. In Section XV we shall see that the decoherence theory is inadequate to derive non-Poisson renewal processes from quantum mechanics. In Section XVI we shall show that the non-Poisson renewal properties, revealed by the BQD experiments, rule out modulation as a possible approach to complexity. [Pg.361]

To close this Section we comment on two papers that do not fit under any neat heading. The first of these is by Xiao et al,261 who study the final stages of the collapse of an unstable bubble or cavity using MD simulations of an equilibrated Lennard-Jones fluid from which a sphere of molecules has been removed. They find that the temperature inside this bubble can reach up to an equivalent of 6000 K for water. It is at these temperatures that sonolumines-cence is observed experimentally. The mechanism of bubble collapse is found to be oscillatory in time, in agreement with classical hydrodynamics predictions and experimental observation. The second paper, by Lue,262 studies the collision statistics of hard hypersphere fluids by MD in 3, 4 and 5 dimensions. Equations of state, self-diffusion coefficients, shear viscosities and thermal conductivities are determined as functions of density. Exact expressions for the mean-free path in terms of the average collision time and the compressibility factor in terms of collision rate are also derived. Work such as this, abstract as it may appear, may be valuable in the development of microscopic theories of fluid transport as well as provide insight into transport processes in general. [Pg.355]

Results of DDM refinement for simulated XRD pattern with randomly modulated background and statistical noise added. The simulated (1), calculated (2), difference (3), difference first derivative (4) and difference second derivative (5) profiles are shown at the initial stage (a) and after 15 cycles of DDM (b). The bold dashed line depicts the background curve added. [Pg.289]


See other pages where Stages statistical derivation is mentioned: [Pg.674]    [Pg.257]    [Pg.52]    [Pg.238]    [Pg.14]    [Pg.105]    [Pg.106]    [Pg.270]    [Pg.218]    [Pg.152]    [Pg.344]    [Pg.452]    [Pg.242]    [Pg.3]    [Pg.52]    [Pg.273]    [Pg.165]    [Pg.222]    [Pg.127]    [Pg.64]    [Pg.405]    [Pg.455]    [Pg.34]    [Pg.38]    [Pg.179]    [Pg.86]    [Pg.241]    [Pg.540]    [Pg.327]    [Pg.275]    [Pg.186]    [Pg.219]    [Pg.471]    [Pg.305]    [Pg.172]    [Pg.3]    [Pg.80]    [Pg.1724]   
See also in sourсe #XX -- [ Pg.43 , Pg.44 ]




SEARCH



Statistical Derivation

© 2024 chempedia.info