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Kinetics space coordinates

The total catalysis situation is reached when Xe — oo and Xe/y oo. a is not longer independent of the space coordinate. Since Xe is large, pure kinetic conditions are achieved and the q profile is squeezed into a thin reaction layer within which a is a constant equal to its value at the electrode surface, ay=q. Equation (6.77) may thus be simplified into... [Pg.405]

In view of the fact that the interpretation of data from the above-described reaction systems involves kinetics so heavily, it is logical to seek an experimental reaction system in which an attempt is made to fix the concentrations of reactants and products in terms of time as well as the space coordinate so as to obtain measurable reaction rates more directly relatable to the intrinsic reaction velocity constant, k. [Pg.154]

Cell concentration in the recycle stream, M L"3 Space coordinate, L Enzyme penetration depth, L Organism yield coefficient, i.e. mass of cells formed/mass of nutrients Axial distance from the inlet of the reactor to achieve a given conversion, L Dimensionless axial coordinate Dimensionless reactor length characteristic of operation under diffusion control Dimensionless reactor length characteristic of operation under kinetic control Dimensionless transversal coordinate Dimensionless axial coordinate. [Pg.407]

These equations differ from the kinetic equations (5.152) only by the additional terms DjAcj, which take into account the transfer of aggregates in the solution. However, the presence of the Laplace operator A indicates another essential difference all variables cj are functions not only of time but of the space coordinates too. [Pg.464]

Closed models exclude any participation of flow and preprogrammed change of the environment. For this reason they are sometimes called hydrochemical reaction models. Thus, they do not require space coordinates and their processes may be considered only relative time scale and those events, which are associated with physicochemical processes. These models, in their turn, are subdivided into full chemical balance models and chemically imbalanced. In the former case kinetics of the physicochemical processes are ignored, and in the latter is accounted for but only relative to the processes of mass transfer between water and the host rock. The latter closed models of chemical nonequilibrium... [Pg.551]

In this equation, the kinetic energy on the left-hand side is the second derivative in terms of the space coordinate, while the right-hand side is the first derivative in terms of time. That is, the space and time coordinates are not equivalent to each other in this equation. This indicates that the SchrOdinger equation is not invariant for the Lorentz transformation, and therefore it is relativistically incorrect. [Pg.145]

On the other hand, bulk concentrations are required for estimation of the respective surface concentrations that are the terms of kinetic equations. To obtain the data for the solution layer adjacent to the electrode surface, mass transport of chemically interacting species should be considered. Quantitative formulation of this problem is based on differential equations representing Pick s second law and supplemented with the respective kinetic terms. It turns out that some linear combinations of these equations make it possible to eliminate kinetic terms. So produced common diffusion equations involve total concentrations of metal, ligand and proton donors (cj j, c, and Cj4, respectively) as functions of time and space coordinates. It follows from the relationships obtained that the total metal concentration varies in the same manner as the concentration of free metal ions in the absence of ligand. Simultaneously, the total ligand concentration remains constant within the whole region of the diffusion layer. This proposition also remains valid for proton donors and acceptors. [Pg.278]

By integrating the above-mentioned equation, we get the Boltzmann equation, that is, the fundamental relation of kinetic theory of gases monoatomic gas molecules are assumed. For monoatomic gas, there is no internal degree of freedom (rotation), that is, the state of each molecule is completely described by three space coordinates and three velocity coordinates. The only mode of a monoatomic gas is translation, while for diatomic gases rotation also contributes. The fluid is also restricted to dilute gases and molecular chaos is assumed. [Pg.90]

The Hamiltonian again has the basic form of Eq. (63). The system is described by the nuclear coordinates, Q, which are relative to a suitable nuclear configuration Q. In conbast to Section in.C, this may be any point in configmation space. As a diabatic representation has been assumed, the kinetic energy operator matrix, T, is diagonal with elements... [Pg.285]

Explicit forms of the coefficients Tt and A depend on the coordinate system employed, the level of approximation applied, and so on. They can be chosen, for example, such that a part of the coupling with other degrees of freedom (typically stretching vibrations) is accounted for. In the space-fixed coordinate system at the infinitesimal bending vibrations, Tt + 7 reduces to the kinetic energy operator of a two-dimensional (2D) isotropic haiinonic oscillator. [Pg.480]

Free energy calculations rely on the following thermodynamic perturbation theory [6-8]. Consider a system A described by the energy function = 17 + T. 17 = 17 (r ) is the potential energy, which depends on the coordinates = (Fi, r, , r ), and T is the kinetic energy, which (in a Cartesian coordinate system) depends on the velocities v. For concreteness, the system could be made up of a biomolecule in solution. We limit ourselves (mostly) to a classical mechanical description for simplicity and reasons of space. In the canonical thermodynamic ensemble (constant N, volume V, temperature T), the classical partition function Z is proportional to the configurational integral Q, which in a Cartesian coordinate system is... [Pg.172]

In its most elementary aspects, kinetic theory is developed on the basis of a hard sphere model of the particles (atoms or molecules) making up the gas.1 The assumption is made that the particles are uniformly distributed in space and that all have the same speed, but that there are equal numbers of particles moving parallel to each coordinate axis. This last assumption allows one to take averages over... [Pg.1]

In its more advanced aspects, kinetic theory is based upon a description of the gas in terms of the probability of a particle having certain values of coordinates and velocity, at a given time. Particle interactions are developed by the ordinary laws of mechanics, and the results of these are averaged over the probability distribution. The probability distribution function that is used for a given macroscopic physical situation is determined by means of an equation, the Boltzmann transport equation, which describes the space, velocity, and time changes of the distribution function in terms of collisions between particles. This equation is usually solved to give the distribution function in terms of certain macroscopic functions thus, the macroscopic conditions imposed upon the gas are taken into account in the probability function description of the microscopic situation. [Pg.2]

Starting with the partition function of translation, consider a particle of mass m moving in one dimension x over a line of length I with velocity v. Its momentum Px = mVx and its kinetic energy = Pxllm. The coordinates available for the particle X, px in phase space can be divided into small cells each of size h, which is Planck s constant. Since the division is so incredibly small we can replace the sum with integration over phase space in x and Px, and so calculate the partition function. By normalizing with the size of the cell h the expression becomes... [Pg.88]


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See also in sourсe #XX -- [ Pg.252 , Pg.282 ]




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Kinetic space

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