Mass transfer schematic representation

Schematic representation of shift in activation energy when intraparticle mass transfer effects become significant.

Schematic representation of reactant concentration profiles in various global rate regimes. I External mass transfer limits rate. II Pore diffusion limits rate. Ill Both mass transfer effects are present. IV Mass transfer has no influence on rate.

Fig. 5. Schematic representation of a screw channel that is partially filled with liquid. Mass transfer occurs from the film on the barrel wall and the surface of the nip.

Figure 9.3 Schematic representation of possible reaction sites for PoHNL-catalyzed cleavage/synthesis of mandelonitrile (MN) (a) adsorbed enzyme model [24] and (b) mass transfer model [27]. BA benzaldehyde white dots enzyme.

Fig. 10.1. Schematic representation of the reaction zone appropriate to our simple ther-mokinetic model. The end walls (r = 0 and r = a0) are perfectly insulated against both mass and heat transfer. The side walls are impermeable to mass, but allow heat transfer such that there are no spatial gradients perpendicular to the long axis.

FIGURE 16 Schematic representation of the origins of zone-broadening behavior and mass transfer effects of a polypeptide or protein due to Brownian motion, eddy diffusion, mobile phase mass transfer, stagnant fluid mass transfer, and stationary-phase interaction transfer as the polypeptide or protein migrated through a column packed with porous particles of an interactive HPLC sorbent. 

FIGURE 3-11. Schematic representation of the contributions to bandspreading and the chromatographic result. Contribution of flow inequality (A term) A, is the effect of particle size and A2 is the effect of packing nonuniformity. Contribution of diffusion (B term) Bi is at very slow flow and B2 is at typical flow. Contribution of mass transfer (C term) C is in a large particle and C2 is in a small particle. 

Figure 1 A schematic representation of the ocean reservoir. The source and sink fluxes are designated as g and n, referring to gross and net fluxes, thereby indicating that interactions within the boundary regions can modify the mass transfer. Within seawater, the p d term signifies that substances can undergo particulate-dissolved interactions. However, it must be appreciated that several transportation and transformation processes might be operative (Adapted from Chester, 1990. )...

In a heterogeneous reaction sequence, mass transfer of reactants first takes place from the bulk fluid to the external surface of the pellet. The reactants then diffuse from the external surface into and through the pores within the pellet, with reaction taking place only on the catalytic surface of the pores. A schematic representation of this two-step diffusion process is shown in Figures 10-3 and 12-1. 

Figure 1. Schematic representation of the electrochemical cell. First insert concentration profile of the reactant in the stagnant layer in the vicinity of the electrode. Second insert mass transfer black box at the boundary between the stagnant layer and the bulk solution (x = (5).

Figure 10.11 Schematic representation of mass-transfer controlled reaction by an ionic species formed through an adsorbed intermediate.

The rotating cylinder is a popular tool for electrochemical research because it is convenient to use and both the primary and mass-transfer-limited current distributions are uniform.A schematic representation of the rotating cylinder is presented in Figure 11.12. At very low rotation speeds, the fluid flows in concentric circles around the rotating cylinder, satisfying a no-slip condition at the rotating inner cylinder and at the stationary outer cylinder. Since there is no velocity component in the radial direction, there is no convective enhancement to mass transfer. 

Figure 11.12 Schematic representation of a rotating cylinder electrode a) entire cylinder used as working electrode. This geometry provides a uniform current and potential distribution at and below the mass-transfer-limited current, b) band-shape cylindrical coupon used as a working electrode. This geometry is useful for studies conducted at the open-circuit condition.

Looking at the schematic representation of the flow profile within the fiber shown in Fig. 3-39, it becomes apparent that a further sensitivity increase can be accomplished by changing the parabolic flow profile. When the fiber is packed with inert Nafion beads, the translational diffusion of ions is favored over longitudinal diffusion. This, in turn, improves the mass-transfer across the membrane which leads to a further increase in sensitivity, particularly pronounced in the case of orthophosphate as the salt of a weak acid. 

FIGURE 21.1 Schematic representation of an electrode-solution interface. MT, mass transport CT, charge transfer Cas and Cbs> concentration of A and B in a bulk solution Cae and Cbe> concentration of A and B at the electrode surface. 

Figure 2.6. Schematic representation of the inverse mass balance model. If we know that the spring at the foothill is evolved from rain water, possible mass transfer reactions can be modeled from the mass balance principle.

Figure 18.2.6 Schematic representation of the variation of electron-transfer rate, and transfer coefficient, a, with electrode potential for an ideal semiconductor electrode. The current is is equivalent to that defined in (18.2.9) or (18.2.10). At sufficiently extreme potentials (not shown) mass transfer would lead to a limiting current on the right side of the diagram. [Reprinted with permission from B. R. Horrocks, M. V. Mirkin, and A. J. Bard, 7. Phys. Chem., 98, 9106 (1994). Copyright 1994, American Chemical Society.]...

FIGURE 18.48 Schematic representation of a typical quenching curve illustrating surface temperature variation with time. From 1. Tanasawa and N. Lior, Heat and Mass Transfer in Materials Processing, pp. 455-476. Taylor and Francis Group, New York. Reproduced with permission. All rights reserved. 

Figure 4.10 is a schematic representation of one tray of a multitray tower. The tray n is fed from tray n - 1 above by liquid of average composition x and it delivers liquid of average composition xn to the tray below. At the place under consideration, a pencil of gas of composition yn+, local rises from below and, as a result of mass transfer, leaves with a concentration yn local. At the place in question, it is assumed that the local liquid concentration xlgcal is constant in the vertical direction. The point efficiency is then defined by... 

Fig. 10 Schematic representation showing the formation of a composite zeolite adsorbent and the various resistances to mass transfer. From Ruthven and Post [35]...

Figure 13.3 A schematic representation of a two-compartment model. 2/1 21/ transfer rate constants /Cio, elimination rote constant X, mass of drug in o compartment.

A schematic representation of HFSLM system is shown in Figure 31.3. A detailed description of Equation 31.4 has been given in the mass transfer modeling section, later in this chapter. 

As indicated by lUPAC definition [5], a membrane can be described as a structure having lateral dimensions much greater than its thickness through which mass transfer may occur under a variety of driving forces such as gradient of concentration, pressure, temperature, electric potential, etc. A schematic representation of a two-phase system separated by a membrane is given in Fig. 2.3, where the Phase 1 is usually considered as the feed, while the Phase 2 as the permeate. 

Figure 3.31 Schematic representation of the induced mesophases in amorphous discoid donor polymers via charge transfer interactions with low molar mass acceptors (permission being sought from [71]).

Figure 8.8 Mass transfer in dispersed phase microstructured reactors where gas solute diffuses through liquid toward solid surface, (a) Schematic representation, (b) Resistance model.

Figure 2 Schematic representation of (A) passive membrane mass transfer and (B) facilitated membrane mass transfer (A is the analyte anion and is a cationic carrier).

Figure 2.5. Schematic representation of the Film Model. The mass and heat transfer fluxes are assumed to be positive in the direction Uquid —> vapor.

A schematic representation of this polarisation curve is given in Rg. 15.2. The first part of the curve corresponds to activation loss, mainly the kinetics of oxygen reduction (with jo = 10 -10 A cm ) involved the second part is linear and due to ohmic loss, mainly the electrolyte resistance the third part is due to mass transfer or diffusion loss when the value of becomes close to /umcat or E(j) tends to zero. The optimal operating point is located in the linear part of the curve. These current-density-potential curves are very important for any type of fuel cell, because they summarise the influence of all the important parameters on the performance of a cell. Even though the equation is more complex in the case of high-temperature fuel cells, the general features of the current density vs potential characteristics are similar. 

Fig. 4. Schematic representation of and various steps involved in mass transfer of petroleum sulfonate from aqueous solution to the interface and then to the oil phase. The right hand side of the diagram illustrates the role of preferentially water soluble and oil soluble surfactant species in partitioning of the petroleum sulfonate.

Figure 3.16 Schematic representation of a hybrid FT-ICR mass spectrometer. It consists of a QMF, a collision cell/ion trap, and a long ion guiding device for transferring ions to the ICR cell...

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