Partial pressures profiles

FIG. 20. The partial-pressure profile of S1H4 calculated with the 2D model. Discharge settings are a total pressure of 20 Pa. a power of 5 W. and an RF frequency of 50 MHz. (From G. J. Nienhuis, Ph.D. Thesis, Universiteit Utrecht, Utrecht, the Netherlands, 1998. with permission.)... 

For microporous membranes, the partial pressure profiles, in the case of gas (vapor) systems, and concentration profiles are continuous from the bulk feed to the bulk permeate, as illustrated in Figure 10.10a. Resistance to mass transfer by films adjacent to the upstream and downstream membrane interfaces create partial pressure and concentration differences between the bulk concentration and the concentration adjacent to the membrane interface. Permeability for microporous membranes is high but selectivity is low for small molecules. 

Figure 18. Pseudo-2-D simulation results at 0.4 A/cm where the feed gases are dry and countercurrent, (a) Water partial pressure profiles at four positions in the fuel-cell sandwich as a function of distance along the channel the positions are at the anode and cathode gas channels (I and IV) and catalyst layers (II and III), respectively. Also plotted is the value of fS, the net flux of water per proton flux, as a function of position. The data are from Janssen. (Reproduced with permission from ref 55. Copyright 2001 The Electrochemical Society, Inc.) (b) Membrane water content as a function of position both along the gas channel and through the thickness of the membrane for the same simulation conditions as above. The data are from Weber and Newman. (Reproduced with permission from ref 55 and 134. Copyright 2004 The Electrochemical Society, Inc.)...

For flat plate geometry, the overall mass trasnfer flux,y (moles/area/ time), resulting from the total partial pressure profile over the boundary layer and across the pores is given by... 

From the gas pressure which includes the partial pressure profile, the temperature profile, and local capillary pressure which is a fvmction of the volume fraction profile and the liquid radius of curvature profile inside the green body, the average stress can be determined. The partial pressure profile is determined by the flux, J, and the effective pore diffusion coefficient, as follows ... 

The resistance to oxygen diffusion at the blood-tissue interface is negligible (21, 22). The oxygen partial pressure profile is continuous at the blood-tissue interface, and transport across the blood-tissue interface can be described by Ficks first law (22). 

Figure 5. Axial partial pressure profiles in the fetal capillary for various maternal to fetal volumetric flow rate ratios. Maternal volumetric flow rate...

Figure 6 shows the effects of reduced fetal blood volumetric flow rate on the maternal blood axial oxygen partial pressure profile. As fetal blood flow rate decreases and fetal blood oxygen partial pressures increase,... 

Figure 8 shows the effects on the fetal blood axial oxygen partial pressure profile when the maternal blood flow rate is decreased. As the maternal blood flow rate decreases, the fetal profile is shifted downward, resulting in fetal blood oxygen partial pressure values in the fetal capillary that are lower than normal. 

Figure 9 shows the effects of decreasing the oxygen capacity of maternal blood on the maternal axial oxygen partial pressure profile. In the normal case (N2 — 16 ml oxygen/100 ml blood) maternal arterial blood enters the exchange unit at an oxygen partial pressure of 90.5 mm... 

The effects of decreasing the maternal blood oxygen capacity on the fetal blood axial partial pressure profiles are shown in Figure 10. As the oxygen capacity of maternal blood decreases, the fetal axial oxygen partial pressure profile is shifted downward. 

Figure 13. Axial partial pressure profiles in the maternal channel for various fetal blood oxygen capacities. Maternal blood oxygen capacity held constant.

Oxygen Diffusivity. A study was also made to determine the effects of simultaneously decreasing the oxygen diffusivity of maternal and fetal blood. Figures 15 and 16 show the effect on the maternal and fetal axial oxygen partial pressure profiles, respectively. For comparison purposes, normal conditions are represented by a blood diffusivity of D = 0.112 X 10"4 cm2/sec. 

Figure 17. Axial oxygen partial pressure profiles in the maternal capillary for various maternal entrance oxygen partial pressures...

Figure 9.1 Concentration and partial pressure profiles for transport through dense membranes (a) liquid mixture, (b) gas mixture.

Figure 4.25 Typical temperature and partial pressure profiles for nonisothermal reactor operation with the highly exothermic naphthalene oxidation reaction. (After R.J. Van Welsenaere and G.F. Froment, Chem. Eng. Sci., 25, 1503, with permission of Pergamon Press, Ltd., London, (1970).]...

Consider the idealized picture of a mass-transfer process based on the two-film theory as shown in Figure 7.27. The partial pressure profile in the gas film is linear, as called for by steady-state diffusion, but the concentration profile in the liquid film falls below a linear measure as a result of a first-order chemical reaction removing the absorbed gas. A normal mass balance over the differential segment dz (we may assume unit area normal to the direction of diffusion) produces a familiar result ... 

Figure 9.n Hydrogen partial pressure profiles at the shell and lumen sides for co-current (solid symbols) and counter-current (open symbols) flow modes. Co-current con-... 

Figure 11.5.h-1 Partial pressure profiles in the reactor illustrating the sensitivity with respect to the inlet partial pressure (from van Welsenaere and Froment [20]). 

Figure H.5.f-6 Pentane isomerization. Partial pressure profiles of n-pentane versus... 

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