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La Place equation

Consider a reaction represented by A +. . . - products taking place in a PFR. Since conditions may change continuously in the direction of flow, we choose a differential element of volume, dV, as a control volume, as shown at the top of Figure 2.4. Then the material balance for A around dk is, from equation 1.5-la (preceding equation 2.3-3) ... [Pg.34]

The Boltzmann equation, S = kXxiW, establishes the zero point for entropies. Because ln(l) = 0, this equation predicts that the entropy will be zero for a system with only one possible description. Figure 14-1 la shows a system with W =, nine identical marbles placed in nine separate compartments. The figure also shows two types of conditions where > 0. Figure 14-llZ) shows a condition when the marbles are not identical. If one marble is a different color than the other eight, there are nine different places to place the different marble. Figure I4-IIc shows a condition where there are more compartments than marbles. If there are more places to put the marbles than there are marbles, there are multiple ways to place the marbles in the compartments. [Pg.988]

Dirac-Fock-Breit (DFB) functions. The spherical symmetry of atoms lejwis to the separation of the one-electron equation into radial and spin-angular parts [11]. The radial four-vector has the so-called la,rge component in the upper two places and the small component Q k in the lower two. The quantum number K (with j/cj — j +1/2) comes from the spin-angular equation, and n is the principal quantum number, which counts the solutions of the radial equation with the same k. Defining... [Pg.316]

When two isolated and electrically neutral conductors A and B with electrochemical potentials fiA and /la, respectively, are placed in electrical contact, iiA and fLa change in value so that at equilibrium fiA = Ms. This effect is due to the transfer of electrons from the conductor with the higher electrochemical potential until (0 — inner is equal to the initial difference Ha — Mb, Mi the chemical potential, being insensitive to variations in electron density. Thus from Equation (1) it follows that an electrical potential difference Vab, equal to (0 — 0B)outor > and hence to the difference in work function A, appears between points just outside the surface of the two conductors, i.e.,... [Pg.76]

We want to introduce a diagrammatic description of these processes, equation (9.1.14). A process takes place on the site , whereas the symbol means that this site plays no role for the determination of the state of another site. Therefore the first two terms correspond to the cases (la) and (lb) and the third term represents the bimolecular step. The diagrams of type (la) and (lb) are of the form (9.1.17), the second term on the right hand side... [Pg.569]

Thus, with each system there is now associated a function, its empirical temperature function, such that two systems can be in equilibrium if and only if their empirical temperatures (i.e., the values of then empirical temperature functions) are equal. Write t — ( ) so that one has the equation of state of KA. Also, t may be introduced in place of any one of the xt. Note that the empirical temperature is not uniquely determined since lA = tt, may be replaced by is monotonic but otherwise arbitrary one has a choice of temperature scales. For a system not in equilibrium, temperature is not defined. [Pg.1606]

Anodic reactions Equation (la,b) lead to dissolution of metal (copper-nickel 90/10). At the beginning of pit initiation, the reactions of Equation (2a,b) might take place,... [Pg.488]

In Tables la and lb we have placed all equations which are correlated by the single parameter, log P. Except for those equations in which activity could not be defined by pC (i.e., log 1/C), all equations have... [Pg.166]

This gas-phase reaction is carried out over a zeolite catalyst and follows an elementary rate law. The catalyst is packed in a tubular PBR that is 2 m in diameter and 22 m in length. Pure methanol Is fed at a molar flow rate of 950 mol/s, a pressure of 1500 kPa, a concentration of 0.4 mol/ dm, and 490°C. The conversion and pressure at the exit are 0.5 and 375 kPa, respectively. Flow throughout the bed is known to be such that the mrbulem contribution in the Eigun equation (i,e., G ) can be neglected. The tubular PBR is to be replaced with a spherical PBR containing an equal amount of identical catalyst. The spherical PBR measures 5.2 m hi diameter and has screens placed 2 dm from each end (i.e., L= L lA dm). [Pg.125]

It is clear, from the examples cited above, that lower crustal delamination takes place. What is less certain is the relative importance of this process, for the number of convincing examples of lower crustal delamination is small. Kramers and Tolstikhin (1997) argued on the basis of their Pb-isotope forward transport model that lower crustal delamination is a minor process and not important in modifying crustal compositions. In contrast, Plank (2005) argued that between 40 and 50% lower crustal loss is required over geological time, to achieve the present-day Th/La ratio of the bulk crust. Whilst this volume equates to only 0.3% of the mantle mass, and less than 10% of the mass of subducted slabs over geological... [Pg.170]

As a result, there is no need to describe the fluorescence response from a sub-ensemble of donor and acceptor molecules separately, i.e. it is unnecessary to create two systems of equations (one for a donor sub-ensemble and one for an acceptor sub-ensemble) similar to (la), as it takes place in the conventional approach. Instead of this, the system of equations that describes the populations of the collective states can be written. The dynamics of variation in the concentrations of these four collective states of the LDA pair (nonmetering the process of intersystem crossing in molecules of the donor and acceptor) is mathematically described by the following system of kinetic equations ... [Pg.187]


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See also in sourсe #XX -- [ Pg.64 ]




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