Pressure coefficient, transition region

If equimolecular counterdiffusion takes place N = -N B (see Volume 1, Chapter 10) and the total pressure is constant, we obtain from equation 3.5 an expression for the effective self-diffusion coefficient in the transition region ... 

Figure 1 represents the isotherms for two lipid components which are miscible in the condensed monolayer state. The major feature of the isotherms for the pure components (1 0, 0 1) is the transition region in which the surface pressure is independent of surface area here the limits of the transition region are at the low area end, Ac, and at the high area end, Ax. These areas are characteristic of each lipid and represent the area per molecule of the lipid in the condensed and vapor states (10). For an equimolar mixture of the two components (1 1), the surface pressure in the transition region depends on the surface area according to the phase rule (11, 12, 13, 14), two surface phases coexist here a condensed phase of lipids and the surface vapor phase. To obtain the activity coefficient of the ith component in the condensed phase the following relation may be used ... 

Further information on the rate coefficients for the reactions in Eqs. 2a and 2b is given in some recent papers. Gutman and Nelson (1983) used laser-induced fluorescence to study the addition reactions of the (32H3O radical with O2 and NO. The bimolecular rate coefficients for the reaction with NO were observed over the major portion of the transition region from the low- to high-pressure limits and give at room temperature hP = (2.36 0.31) X 10 ilf -sec with N2 as a chaperone and k" = (1.51 0.18) x 10 ° A/ -sec . However the C2H3O radical has two resonance forms. 

An accurate determination of a and c in the low-pressure region is crucially important. To avoid the effect of the well-known anomaly in the immediate vicinity of the NI transition point, the values estimated in the stable region are extrapolated to the phase boundaries. Thermal pressure coefficients can thus be calculated from the relation... 

Transonic Airfoil Flow. In Fig. 5(a) the time- and spanwise averaged distributions of the pressure coefficient Cp for the zonal RANS-LES and the pure LES are presented. The averaging time was about two shock-oscillation cycles. The gray shaded areas represent the overlapping regions of the zonal RANS-LES approach. The average shock position is located at x/c 0.57 for the zonal RANS-LES and the pure LES result. A smooth RANS-to-LES transition of the pressure coefficient at the upper and lower side of the airfoil is evident. 

Stigter and Dill [98] studied phospholipid monolayers at the n-heptane-water interface and were able to treat the second and third virial coefficients (see Eq. XV-1) in terms of electrostatic, including dipole, interactions. At higher film pressures, Pethica and co-workers [99] observed quasi-first-order phase transitions, that is, a much flatter plateau region than shown in Fig. XV-6. 

To observe ammonia oxidation on platinum in the kinetic region, the reaction must be carried out at low pressures since the decrease in pressure increases the diffusion coefficient and slows down the reaction, both factors favoring the transition to the kinetic region. 

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