Concentration profiles simulations

Fig. 5.17 Simulated concentration profiles at a diffusion domain containing a spherical particle. Category 1 = 1CT3. Category 2 1% = 0.1. Category 3 1% = 1. Category 4 = 100. For all categories, the distance between particles is two times the radius. Reproduced from [57] with permission...

A voltammetric experiment in a microelectrode array is highly dependent on the thickness of the individual diffusion layers, <5, compared with the size of the microelectrodes themselves, and with the interelectrode distance and the time experiment or the scan rate. In order to visualize the different behavior of the mass transport to a microelectrode array, simulated concentration profiles to spherical microelectrodes or particles calculated for different values of the parameter = fD Ja/r s can be seen in Fig. 5.17 [57] when the separation between centers of... 

No details on mixer in [109]) [P 25] By use of confocal microscopy, cross-sectional concentration profiles were derived in a Y micro mixer (see Figure 1.58) [70]. At the top and bottom of the channel large fluorescent areas were found, while this region thinned in the channel center. The experimental images perfectly match the simulated concentration profiles. 

Figure 9.9 shows a comparison of the simulated and measured gas-phase concentrations of NO and NO2 throughout the whole absorption plant. The zigzag form of the simulated concentration profiles results from switching different sections of each single column (see Ref. [35]). Good agreement between experimental and simulation results can be definitely observed here. 

Figure 2 simulated concentration profile in a TMB with or without a pressure gradient [14]... 

From a process-engineering point of view, there is now a better understanding of the development of concentration profiles in chromatographic columns under overloaded conditions available. This includes in particular the quantitative description of displacement and tag-along effects caused by competitive adsorption. Since it is now possible (as mentioned before) to simulate concentration profiles on a personal computer, the choice of the appropriate mode... 

The basic principle of one-column process is identical to four-zone SMB. The performance of the process for the amino acids separation was compared with four-zone SMB by computer simulation using Aspen Chromatography. The system and operating parameters are listed in Table 1. It was set that T2, T3 and T4 are initially filled with desorbent and T1 is empty in the simulation. Liquid in each tank is ideally mixed. Liquid of the average solute concentration in a tank is introduced into the column. The simulated concentration profile of two amino acids in the one-column process is presented in Figure 3. 

Figure 3. Simulated concentration profile of one-column process. Solid line is for tryptophan and dashed line is for phenylalanine.

In Fig. 6.15 two different models for parameter estimation are used and the resulting simulated concentration profiles are compared with the measurements. In one case ideal plug-flow (Eq. 6.116) and in the other axial dispersive flow (Eq. 6.117) is assumed for the pipe system, while both models use the C.S.T. model (Eq. 6.121) to describe the detector system. Figure 6.15 shows that the second model using axial dispersion provides an excellent fit for this set-up, while the other cannot predict the peak deformation. Because of the asymmetric shape a model without a tank would also be inappropriate. 

Fig. 6.42 Measured and simulated concentration profile in the SMB for EMD53986 (cycle 8, Cfej = 5 g I 1 for additional data see Appendix B.l. (Reproduced from Jupke et al., 2002.)...

Fig. 6.44 Measured and simulated concentration profile in the SMB for Troger s base (10th cycle,...

At steady-state cadmium transport permeation is motivated mostly by an external driving force and the fluxes are about an order lower. A much more effective HLM module, with continuously flowing feed (open system), can be designed if the feed side membrane area Sp and the feed flow rate Up enable us to obtain a fixed cadmium feed outlet concentration (e.g., 1 ppm) at a contact time, less than that at the maximum on the simulated concentration profile of the carrier solution. 

Microscopically, the peak potential increases with metal (microparticle) center radius rj, but not (as found by Brainina [51]) linearly with In(/-, ). As can be explained on the basis of the simulated concentration profiles, this is due to the nature of diffusion that is, with increasing rj the spherical nature of diffusion decreases in favor of the planar one. The resultant slower transport provides a better chance for a re-deposition, thus shifting Ep to more positive values (Figure 6.25). 

Fig. 17. Simulated concentration profiles of selected products on the initial stage of methane oxidation (Arutyunov, 2004) (T= 733K, P=84bar, CH4 02 = 21 1). (1) CH20, (2) H20, (3) H202, (4) CH3OH, (5) CO, (6) H2, (7) C02, (8) C2H6, (9) C2H5OH.

The simulated concentration profile in Figure 2 was obtained using a weighted sorption coefficient (K = 0.15) for the 0 to 7 meter zone of Borehole 3. Use of a weighted value is an undesirable simplification, especially when the sorption coefficient changes so rapidly with depth (Table I). However, we were constrained by the analytical model to use a single sorption coefficient for the entire profile. The simulated DBCP concentration profile has the shape of Borehole 5 data and the concentration range of Borehole 3 data. 

Figure 3.20. Experimental a and simulated b response curves for formation of a Cu(II)-TAMSB complex in a straight tubular reactor. Values of (0 + L)/0 and Q were (1) 2.0, 0.58 (2) 3.0, 0.29 (3) 3.5, 0.23 (4) 4.3, 0.17 and (5) 6.0, 0.12. Note the presence of the humped peak at t = 2 for both the simulated and the experimental curves. The simulated concentration profiles c for t = 2 show the concentration maxima, which, when perpendicularly viewed by the detector, yield a humped peak. (According to Ref. 1065 by permission of Elsevier Scientific Publishing Co.)...

Figure 6.43 Measured and simulated concentration profiles in the SMB for EMD53986 during start-up (one and two cycles for other data see Figure 6.39).

Figure 6.45 Measured and simulated concentration profiles in the gradient SBM for separation of P-lactoglobulin A and B (reproduced from Wekenborg, 2009).

FIGURE 17.8 Simulated concentration profiles at the given four time points for the sample containing (a) 10 mM, (b) 20 mM, (c) 40 mM, and (d) 100 mM chloride. Left concentration axis relates to the macrocomponents chloride (Cl, dotted line), phosphate and lactate (P and L, respectively, both thin lines). Right concentration axis relates to the microcomponents citrate, malate, and acetoacetate (thick lines). Simulations were performed with Ax = 62 pm at a field strength of 40.54 V/cm. (Reproduced from Kfivankova, L., et ah. Electrophoresis, 24, 505, 2003. With permission.)... 

Fig. 27 Simulated concentration profile (black circles correspond to left axis) and electrostatic potential (white circles correspond to right axis) in PS-PMA micelles as a function of the distance from the micellar center for pH 5 and ionic strength 0.001...

Figure 10 Effect of mass transfer coefficient on deviation of simulated concentration profiles from experimental data. The minima correspond to the best fitting curves and the corresponding coefficients are considered to be the true mass transfer coefficients for the given experimental condition. (Actual measurements with the MIBK/water/acetic acid system are shown).

Figure 11 Comparison of simulated concentration profiles with experimental data for a system with immiscible solvents o-xylene/ water/acetone).

Figure 12 Comparison of simulated concentration profiles with experimental data for a system with partially miscible solvents, x - solute concentration in heavy phase, y - solute concentration in light phase, xb - concentration of light solvent in heavy phase, yf - concentration of heavy solvent in light phase. Broken lines equilibrium values.

Figure 5.4 Open-loop simulations concentration profiles of key component and biomass for different dilution rates.

Figure 2.16 (a) Schematic of the simulation geometry model for a Nafion-coated HOPG surface (i), where the numbers are indicative of the film-solution interface (1), periodic boundaries from which the step array response can be determined (2a, 2b), step-edge plane (3), and basal plane (4a, 4b), respectively, and simulated concentration profiles for a Nafion-Ru(bpy)3 +... 

Figure 9.16 Simulated concentration profiles during wave reversal. (Adapted from Sevcikova and Marek, 1986.)...

Figure 1 shows the simulated concentration profile of hydroxyl radicals (Eq. 14 and 15) during oxygen evolution as a function of the distance from the electrode surface. It can be seen that, for a ciurent density of j = 300 A m, the thickness of the reaction layer is about 1 pm, whereas the maximum (siuface) concentration of hydroxyl radicals reaches values in the range of several tenths of pM. 

The thickness of the reaction layer (reaction cage) depends on the concentration of organic compounds, the rate constant of organic oxidation (via hydroxyl radicals), and the applied current density. As a typical example. Fig. 2 shows the simulated concentration profile during the oxidation of formic acid (0.25 1 M) at 300 A m . ... 

Organic Pollutants, Direct Electrochemical Oxidation, Fig. 1 Simulated concentration profile of hydroxyl radicals during oxygen evolution according to Eq. 14 and... 

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