Diffuse schematic representation

Figure C2.1.18. Schematic representation of tire time dependence of tire concentration profile of a low-molecular-weight compound sorbed into a polymer for case I and case II diffusion. In botli diagrams, tire concentration profiles are calculated using a constant time increment starting from zero. The solvent concentration at tire surface of tire polymer, x = 0, is constant.

Figure C2.7.13. Schematic representation of diffusion and reaction in pores of HZSM-5 zeolite-catalysed toluene disproportionation the numbers are approximate relative diffusion coefficients in the pores 1131.

Figure 7 is a schematic representation of a section of a cascade. The feed stream to a stage consists of the depleted stream from the stage above and the enriched stream from the stage below. This mixture is first compressed and then cooled so that it enters the diffusion chamber at some predetermined optimum temperature and pressure. In the case of uranium isotope separation the process gas is uranium hexafluoride [7783-81-5] UF. Within the diffusion chamber the gas flows along a porous membrane or diffusion barrier. Approximately one-half of the gas passes through the barrier into a region... 

Fig. 1. Schematic representation of the electrochemical or diffuse double layer showing the inner (IHP) and outer (OHP) Helmholtz planes and the...

FIGURE 18.5 Schematic representation of types of multienzyme systems carrying out a metabolic pathway (a) Physically separate, soluble enzymes with diffusing intermediates, (b) A multienzyme complex. Substrate enters the complex, becomes covalently bound and then sequentially modified by enzymes Ei to E5 before product is released. No intermediates are free to diffuse away, (c) A membrane-bound multienzyme system. 

Figure 9 The schematical representation of dispersion polymerization process, (a) initially homogeneous dispersion medium (b) particle formation and stabilizer adsorption onto the nucleated macroradicals (c) capturing of radicals generated in the continuous medium by the forming particles and monomer diffusion to the forming particles (d) polymerization within the monomer swollen latex particles, (e) latex particle stabilized by steric stabilizer and graft copolymer molecules (f) list of symbols.

Fig. 20. Schematic representation of the solid + solid reaction A + B -> AB in which constituents of the relatively mobile reactant (A) are transported to the outer surfaces of the product phase (AB) and rate is controlled by diffusion of constituents of A and/ or B across the barrier layer AB.

Molecules can passively traverse the bilayer down electrochemical gradients by simple diffusion ot by facilitated diffusion. This spontaneous movement toward equilibrium contrasts with active transport, which requires energy because it constitutes movement against an electrochemical gradient. Figure 41-8 provides a schematic representation of these mechanisms. 

Figure 3.1 Schematic representation of a generic excitatory synapse in the brain. The presynaptic terminal releases the transmitter glutamate by fusion of transmitter vesicles with the nerve terminal membrane. Glutamate diffuses rapidly across the synaptic cleft to bind to and activate AMPA and NMDA receptors. In addition, glutamate may bind to metabotropic G-protein-coupled glutamate receptors located perisynaptically to cause initiation of intracellular signalling via the G-protein, Gq, to activate the enzyme phospholipase and hence produce inositol triphosphate (IP3) which can release Ca from intracellular calcium stores...

Figure 15.2 Schematic representation of different electrochemical cell types used in studies of electrocatalytic reactions (a) proton exchange membrane single cell, comprising a membrane electrode assembly (b) electrochemical cell with a gas diffusion electrode (c) electrochemical cell with a thin-layer working electrode (d) electrochemical cell with a model nonporous electrode. CE, counter-electrode RE, reference electrode WE, working electrode.

Figure 4 Schematic representation of a small section of a diffusion profile illustrating the application of Fick s law to determine the concentration change in the central volume element as a result of the fluxes (F) across the two planes at L and R (see text for details).

FIG. 2 Schematic representation of different microhole geometries, (a) Recessed microdisk interface, spherical-linear, linear-spherical diffusion, (b) quasi-inlaid microdisk interface, spherical-spherical diffusion, (c) Long microhole with quasi-inlaid interface, spherical-linear diffusion. (Reprinted with permission from Ref. 13. Copyright 1999 Elsevier Science S.A.)... 

Fig. 2 A schematic representation of an HTRF assay for a protein-protein interaction. One protein is tagged with a fluorescent molecule whose emission spectra overlaps with the excitation of another fluorescent molecule. When they are in close proximity (above) the energy is transferred. When they diffuse apart (below) or are inhibited from coming together by a small molecule no FRET occurs...

Figure 3.3. Schematic representation of the adsorption, surface diffusion, and surface reaction steps identified by surface-science experiments on model supported-palladium catalysts [28]. Important conclusions from this work include the preferential dissociation of NO at the edges and defects of the Pd particles, the limited mobility of the resulting Nads and Oads species at low temperatures, and the enhancement in NO dissociation promoted by strongly-bonded nitrogen atoms in the vicinity of edge and defect sites at high adsorbate coverages. (Figure provided by Professor Libuda and reproduced with permission from the American Chemical Society, Copyright 2004).

Schematic representation of the experimental setup is shown in Fig 1.1. The electrochemical system is coupled on-line to a Quadrupole Mass Spectrometer (Balzers QMS 311 or QMG 112). Volatile substances diffusing through the PTFE membrane enter into a first chamber where a pressure between 10 1 and 10 2 mbar is maintained by means of a turbomolecular pump. In this chamber most of the gases entering in the MS (mainly solvent molecules) are eliminated, a minor part enters in a second chamber where the analyzer is placed. A second turbo molecular pump evacuates this chamber promptly and the pressure can be controlled by changing the aperture between both chambers. Depending on the type of detector used (see below) pressures in the range 10 4-10 5 mbar, (for Faraday Collector, FC), or 10 7-10 9 mbar (for Secondary Electrton Multiplier, SEM) may be established.

Figure 12 Schematic representation for reversibly changing drug permeation through membranes by external modulation. M, indicates the diffused amount of drug at time t. 

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.

Figure 7. Schematic representation ofprocesses of electromigration / diffusion of ions and formation of insulation passive layer on the boundary current collector / conductive polymer.

Figure 2.86 Schematic representation of variation in the diffusion layer thickness, 6, as a function of time for the reduction of an oxidant O at a fixed planar electrode. [O ] is the concentration of O in the bulk of the solution, [O]0, is the concentration at the electrode surface, x is the distance into the solution from the electrode surface, and du etc, are the diffusion layer thickness at various times etc.

Figure 3.97 Schematic representation or the conversion of radial to linear diffusion, as the density of specific electroactive surface sites increases. From Guo and Hill, Advances in Inorg...

Figure 14 shows a schematic representation of a mixed potential diagram for the electroless deposition reaction. Oxidation of the reductant, in this case hypophos-phite, is considered to be under 100% kinetic control. A mixed kinetic-diffusion curve is shown for the reduction of the metal ion, in our case Co2+, in the region close to the mixed potential, Em. Thus, since Co deposition occurs under a condition of mixed kinetic and diffusion control, features small relative to the diffusion layer thickness for Co2+ will experience a higher concentration of the metal ion, and hence... 

Fig. 4 Schematic representation of the diffuse reflectance sampling accessory. Key A, blocker device to eliminate specular reflectance B, path of IR beam.

Figure 5.3 Schematic representation of the penetration profile for bulk, grain boundary, and dislocation diffusion in a polycrystalline solid. The initial part of the curve is bell shaped, and the part due to short-circuit diffusion is made up of linear segments. The insets show the distribution of the tracer in the sample.

FIG. 23-44 Schematic representation of time-averaged distribution and spread for a continuous plume. and o2 are the statistical measures of crosswind and vertical dimensions 4.3oy is the width corresponding to a concentration 0.1 of the central value when the distribution is of gaussian form (a corresponding cloud height is 2.15o2). (Redrawn from Pasquill and Smith, Atmospheric Diffusion, 3d ed., Ellis Norwood Limited, Chichester, U.K, 1983). 

Figure 4. Schematic representation of the convective-diffusion problem for an active plane parallel to the direction of flow dealt with in Section 4.1. The liquid flow extends up to a — oo, where its free velocity is v in the direction of increasing y. The leading edge of the plane is the segment x — 0, y — 0, 0 < z

Figure 19. Schematic representation of the coupled diffusion of M (species taken up) and ML (bioinactive complex), with their interconversion kinetics involving the bio-inactive ligand L...

Figure 9. Schematic representation of concentration profiles at the biological surface in the case of a diffusion-limited uptake. Note that the ratio of bound metal to free metal is not drawn to scale in reality, the ratio at the biological surface is always larger than that in solution. The figure assumes that the total concentration of ligand is much greater than the total concentration of metal. For further details, refer to [142,331,333]...

For a triphasic reaction to work, reactants from a solid phase and two immiscible liquid phases must come together. The rates of reactions conducted under triphasic conditions are therefore very sensitive to mass transport effects. Fast mixing reduces the thickness of the thin, slow moving liquid layer at the surface of the solid (known as the quiet film or Nemst layer), so there is little difference in the concentration between the bulk liquid and the catalyst surface. When the intrinsic reaction rate is so high (or diffusion so slow) that the reaction is mass transport limited, the reaction will occur only at the catalyst surface, and the rate of diffusion into the polymeric matrix becomes irrelevant. Figure 5.17 shows schematic representations of the effect of mixing on the substrate concentration. 

Figure 9 Schematic representation of the conversion of the diffusive movement of a species towards the electrode from radial to linear with the increase of the number of microscopic sites present at the electrode surface. Electrode of radius r...

Figure 1. Schematic representation of remodelling mechanisms. (Adapted form Langst and Becker, 2004.) The schemes show nucleosomes from the top. (a) The twist diffusion model - Twisting of DNA moves it over the histone surface in one base pair increments. This changes the position of the DNA with respect to the histone, as shown by the open and closed circles, (b) The Loop recapture model - Extranucleosomal DNA is pulled into the nucleosomes to replace a DNA segment which consequently loops out. This loop is then propragated over the histone surface like ripples of a wave. The star,, indicates how this leads to a change in the position of DNA relative to the nucleosome. (See Colour Plate 4.)...

Figure 6.30 Schematic representation of a glucose sensor operating by diffusion across a perm-selective membrane (as represented by the vertical arrows) GOD is glucose oxidase.

Figure 6. Schematic representation of the relaxation of a diffusive mode in space and time toward the uniform equilibrium state.

Figure 14. Schematic representation of the diffusion process of particles in a conductor composed of L cells of volume AV between two particle reservoirs, A and B.

---