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Diffusion, effective

Ahn C B and Cho Z H 1989 A generalized formulation of diffusion effects in pm resolution nuclear magnetic-resonance imaging Med. Rhys. 16 22-8... [Pg.1545]

Thermal transpiration and thermal diffusion effects have been neglected in developing the dusty gas model, and will be neglected throughout the rest of the text. The physics of these phenomena and the justification for neglecting them are discussed in some detail in Appendix I. [Pg.24]

Thermal diffusion effects will be neglected throughout, so the flux relations are given by equations (3.17) - (3.19), which are repeated here for convenience ... [Pg.34]

Synthesis ofp-Ethyltoluene. j )i7n7-Ethyltoluene, the feedstock for j )-methylstyrene, is difficult to separate from the products of toluene alkylation with ethane using conventional acidic catalysts. The unique configurational diffusion effect of ZSM-5 permits -dialkylbenzenes to be produced in one step. In the alkylation of toluene with ethene over a chemically modified ZSM-5, -ethyltoluene is obtained at 97% purity (58). [Pg.459]

A second type of apparatus based on the pressure diffusion effect is the separation nozzle. Pressure gradients in a curved expanding jet produce an isotopic separation similar to that in a centrifuge. The separation effect obtained with a single jet is relatively small, and separation nozzle stages, similar to gaseous diffusion stages, must be used in a cascade to realize most of the desired separations. [Pg.88]

Mass Transport. An expression for the diffusive transport of the light component of a binary gas mixture in the radial direction in the gas centrifuge can be obtained directly from the general diffusion equation and an expression for the radial pressure gradient in the centrifuge. For diffusion in a binary system in the absence of temperature gradients and external forces, the general diffusion equation retains only the pressure diffusion and ordinary diffusion effects and takes the form... [Pg.92]

Binary Electrolyte Mixtures When electrolytes are added to a solvent, they dissociate to a certain degree. It would appear that the solution contains at least three components solvent, anions, and cations, if the solution is to remain neutral in charge at each point (assuming the absence of any applied electric potential field), the anions and cations diffuse effectively as a single component, as for molecular diffusion. The diffusion or the anionic and cationic species in the solvent can thus be treated as a binary mixture. [Pg.599]

Driven by the concentration gradient, solutes naturally diffuse when contained in a fluid. Thus, a discrete solute band will diffuse in a gas or liquid and, because the diffusion process is random in nature, will produce a concentration curve that is Gaussian in form. This diffusion effect occurs in the mobile phase of both packed GC and LC columns. The diffusion process is depicted in Figure 6. [Pg.247]

Diffusion effect The capture of particles due to Brownian motion. [Pg.1429]

Diffusion effects can be expected in reactions that are very rapid. A great deal of effort has been made to shorten the diffusion path, which increases the efficiency of the catalysts. Pellets are made with all the active ingredients concentrated on a thin peripheral shell and monoliths are made with very thin washcoats containing the noble metals. In order to convert 90% of the CO from the inlet stream at a residence time of no more than 0.01 sec, one needs a first-order kinetic rate constant of about 230 sec-1. When the catalytic activity is distributed uniformly through a porous pellet of 0.15 cm radius with a diffusion coefficient of 0.01 cm2/sec, one obtains a Thiele modulus y> = 22.7. This would yield an effectiveness factor of 0.132 for a spherical geometry, and an apparent kinetic rate constant of 30.3 sec-1 (106). [Pg.100]

Accumulatory pressure measurements have been used to study the kinetics of more complicated reactions. In the low temperature decomposition of ammonium perchlorate, the rate measurements depend on the constancy of composition of the non-condensable components of the product mixture [120], The kinetics of the high temperature decomposition [ 59] of this compound have been studied by accumulatory pressure measurements in the presence of an inert gas to suppress sublimation of the solid reactant. Reversible dissociations are not, however, appropriately studied in a closed system, where product readsorption and diffusion effects within the product layer may control, or exert perceptible influence on, the rate of gas release [121]. [Pg.19]

The relative magnitudes of the thermal diffusion and diffusion effects are represented by the dimensionless ratio ... [Pg.589]

If a local concentration of solute is placed at the midpoint of a tube filled with either a liquid or a gas, the solute will slowly diffuse to either end of the tube. It will first produce a Gaussian distribution with a maximum concentration at the center and finally, when the solute reaches the end of the tube, end effects occur and the solute will continue to diffuse until there is a constant concentration throughout the length of the tube. This diffusion effect occurs in the mobile phase of a packed LC column but the end effects are never realized. The diffusion process is depicted in figure 2. [Pg.99]

Weisz, P. B. and Hicks, J. S., The behaviour of porous catalyst particles in view of internal mass and heat diffusion effects, Chem. Eng. Sci., 17, 265-275 (1962). [Pg.380]

It has been reported by Lewis et al. [1] that the equivalence ratio where the minimum ignition energy has a minimum is dependent on the fuel property for hydrocarbon fuel and air mixtures, and that it moves to the rich side as the molecular weight of the fuel increases. This equivalence ratio dependency has been explained by the preferential diffusion effect. [Pg.33]

When both hydrodynamic and thermo-diffusive effects are simultaneously taken into account, it is found that the growth rate a of wrinkling is given by the roots of the dispersion relation [11,12] ... [Pg.71]

Bechtold, J.K. and Matalon, M., Hydrodynamic and diffusion effects on the stability of spherically expanding flames. Combust. Flame, 67, 77,1987. [Pg.127]

In order to eliminate the possibility that the observed FRC signal was due to diffusion effects or other experimental artifacts, two types of blank runs were performed with each catalyst. In one set of experiments, Ife was used as the "adsorbing" gas with a reduced catalyst while in a second set, H2 was used with a non-reduced catalyst. Neither type or experimental led to any observable FRC signal. [Pg.70]


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Acid diffusion effect

Additional base component effect acid diffusion

An Effective Diffusion Model

Anomalous diffusion effective temperature

Apparent effective hydrogen diffusivity

Arrhenius behavior, effective diffusivity

Assessment of relaxation times, MT effects and diffusion characteristics

Boundary conditions effective diffusivity model

Calculation of effective diffusivities

Capillary waves diffusion, effect

Carrots effective diffusivity

Carrots effective moisture diffusivity

Catalysts, general diffusion effects

Catalytic effective diffusivity

Catalytic reactions pore diffusion effects

Coked zeolite, diffusivity effect

Cross-diffusion effect

Deactivating catalysts pore diffusion effects

Diffuse double-layer effects, electrical

Diffuse functions, effect

Diffuse functions, effect acidities

Diffuse functions, effect anion geometries

Diffuse functions, effect bond separation

Diffuse functions, effect energies

Diffuse interface effective width

Diffusion Effectiveness factor)

Diffusion Effects During Cure

Diffusion Kirkendal effect

Diffusion Kirkendall effect

Diffusion and Mass-transfer Effects

Diffusion and reaction in pores. Effectiveness

Diffusion catalyst effectiveness

Diffusion classical aging effects

Diffusion coefficient absorption effect

Diffusion coefficient effective

Diffusion coefficient effective diffusivity

Diffusion coefficient effective transition region

Diffusion coefficient effects

Diffusion coefficient hydrodynamic effect

Diffusion coefficient ionic atmosphere effect

Diffusion coefficient solvent viscosity effect

Diffusion coefficient, effective axial

Diffusion coefficient, effective dual-mode

Diffusion coefficient, effective thermodynamic

Diffusion coefficients, effects Brownian motion

Diffusion coefficients, effects dynamical friction

Diffusion coefficients, effects theory

Diffusion concentration effect

Diffusion constant viscosity effects

Diffusion controlled reaction, transient effects

Diffusion crosslinking effect

Diffusion current absorptive effects

Diffusion current kinetic effects

Diffusion density effect

Diffusion effect

Diffusion effective binary

Diffusion effective charge

Diffusion effective diffusivity

Diffusion effective temperature

Diffusion effective thickness

Diffusion effects Nemst

Diffusion effects analysis

Diffusion effects burning within particle

Diffusion effects carbon burning reaction

Diffusion effects determination

Diffusion effects diffusivity

Diffusion effects diffusivity

Diffusion effects elimination

Diffusion effects experimental verification

Diffusion effects external

Diffusion effects first order reactions

Diffusion effects gaseous

Diffusion effects independence

Diffusion effects internal

Diffusion effects intraparticle

Diffusion effects involving reaction rates

Diffusion effects irregularly shaped particles

Diffusion effects laminar flow

Diffusion effects longitudinal

Diffusion effects measurements

Diffusion effects on biomoleeular reactions

Diffusion effects outside catalyst particle

Diffusion effects reactant concentration

Diffusion effects through catalyst particles

Diffusion effects through particle

Diffusion effects velocity constant

Diffusion effects within catalyst

Diffusion effects within catalyst particle

Diffusion effects, electron-transfer

Diffusion effects, electron-transfer bulk reaction

Diffusion effects, electron-transfer reactivity

Diffusion effects, electron-transfer structure

Diffusion effects, surface

Diffusion flames buoyancy effects

Diffusion flux/effective coefficient

Diffusion internal effectiveness factor

Diffusion internal viscosity effect

Diffusion layer effective boundary

Diffusion limitation effects

Diffusion limited current density effective

Diffusion magnetic field effects

Diffusion microstructure effects

Diffusion model, structure effect

Diffusion modified effective binary

Diffusion overall effectiveness factor

Diffusion overlapping effect

Diffusion polarization, solution velocity effect

Diffusion polymerization rate, effect

Diffusion quantum aging effects

Diffusion saturation effect

Diffusion shielding effect

Diffusion skin effect

Diffusion temperature effects

Diffusion terminal velocity, effect

Diffusion wall effect

Diffusion, bulk Effectiveness factor

Diffusion-controlled processes, pressure effects

Diffusion-limited regime effectiveness factor

Diffusion-reaction problems potential effects

Diffusion-thermo effect

Diffusivities effectiveness factor

Diffusivities structure effect

Diffusivity correlation effects

Diffusivity effective medium approximation

Diffusivity effectiveness factor

Diffusivity pressure effect

Diffusivity temperature effect

Diffusivity, bulk effective

Diffusivity, effective, polymer fractionation modeling

Drying supported catalyst diffusion, effect

Dufour effect, thermal diffusion

Edge diffusion effects

Effect of Diffusion and Exchange

Effect of Diffusion on Rate

Effect of Unequal Diffusion Coefficients

Effect of diffusion

Effect of diffusion resistance

Effect of external diffusion limitation

Effect of internal diffusion limitation

Effect of intraparticle diffusion on experimental parameters

Effect of longitudinal diffusion

Effect of sucrose on the bimolecular diffusion constant

Effect on diffusivity

Effective Diffusivities in Biological Gels

Effective Diffusivities in Multicomponent Mixtures

Effective Ionic Diffusivities

Effective Theories of Diffusion

Effective binary diffusivity

Effective catalyst layer Knudsen diffusion

Effective catalyst layer diffusivity

Effective coefficient of diffusion

Effective diffusion coefficient Brownian dynamics

Effective diffusion coefficient continuum

Effective diffusion coefficient definition

Effective diffusion coefficient discrete phase

Effective diffusion coefficient empirical expressions

Effective diffusion coefficient material

Effective diffusion coefficient penetrant concentration

Effective diffusion coefficient polymer degradation

Effective diffusion coefficient porous layer

Effective diffusion coefficient procedures

Effective diffusion coefficient relations from different equations

Effective diffusion coefficient volume

Effective diffusion coefficient, Df

Effective diffusion models

Effective diffusion time

Effective diffusivities

Effective diffusivities

Effective diffusivities calculated

Effective diffusivities in porous catalysts

Effective diffusivity

Effective diffusivity

Effective diffusivity concept

Effective diffusivity film model

Effective diffusivity ionic

Effective diffusivity limiting cases

Effective diffusivity methods

Effective diffusivity model

Effective diffusivity model endothermic reactions

Effective diffusivity multicomponent liquid mixtures

Effective diffusivity stagnant mixture

Effective diffusivity steady-state diffusion

Effective diffusivity, definition

Effective diffusivity, measurement

Effective diffusivity, polymer

Effective diffusivity, porous media

Effective gas diffusivity

Effective length, diffusion

Effective moisture diffusivity

Effective molecular diffusion coefficient

Effective single-file diffusion

Effective surface diffusivity

Effective terms diffusion

Effective theory diffusion

Effective thermal diffusivity

Effective thickness, of diffusion

Effectiveness factor diffusion, porous catalyst

Effectiveness factor effective diffusivity model

Effectiveness factor for first-order irreversible reaction-diffusion system

Effects of Brownian Diffusion on Deposition

Effects of Diffusion within Catalyst Particles

Effects of Diffusion within Immobilized Enzyme Particles

Effects of Rotational Diffusion on Fluorescence Anisotropies The Perrin Equation

Effects of intraparticle diffusion on the experimental parameters

Effects of pore diffusion

Electron-transfer . nonadiabatic solvent diffusion effects

Electrostatic potential diffusion effect

Energy transfer diffusion effects

Experimentation, effective diffusivity

Experimentation, effective diffusivity determination

Experimentation, effective diffusivity isolation method

Experimentation, effective diffusivity residence time determination

Experimentation, effective diffusivity temperature control

Extraction effective diffusivity method

Factor effective diffusion

Film theory effective diffusivity method

Fischer—Tropsch synthesis diffusivity effects

Fluxes with an Effective Diffusivity Model

Fractional rotational diffusion inertial effects

Heat diffusion effect

Heterogeneous reactions external diffusion effects

Intraparticle diffusion effectiveness factor

Intrinsic Diffusion Coefficient The Kirkendall Effect

Isobutylene, effective diffusivity

Lateral diffusion cholesterol, effect

Lemon effective diffusivity

Liquid diffusion pressure effects

Liquid diffusion temperature effects

Mass transfer coefficient liquid phase diffusivity effect

Mass-transfer measurements effective diffusivities

Mechanical behavior diffusion effects

Medium effects diffusion

Medium effects self-diffusion

Mixing and Diffusion Effects

Modeling effective diffusion coefficient

Moisture, diffusion effects

Molar flux in terms of effective diffusivity

Molecular diffusion, effect

Molecular diffusion, effect dispersivity

Molecular diffusivity, effect

Molecular diffusivity, effect model selection

Multicomponent diffusion, effective binary

Multicomponent diffusion, effective binary diffusivity

Nitrogen effective diffusivity

Nuclear Overhauser effect spin diffusion

Organic matter degradation, effects diffusion

Oscillations diffusion effects

Oxygen diffusion coefficient temperature effect

Oxygen diffusion effects

Oxygen diffusion effects degradation

Oxygen diffusion effects oxidation

Oxygen diffusion effects oxidation depth

Oxygen diffusion effects polymer

Para-xylene selectivity diffusivity effects

Pellets effective diffusivity

Poly , size effects diffusion

Pore Diffusion Resistance and Effective Reaction Rate

Pore diffusion effects

Pore diffusion, mass transport effect

Pore effective diffusion coefficient

Porous solids effective diffusivity

Propylene, effective diffusivity

Pulsed gradient spin echo diffusion effect

Ratio apparent effective diffusivities

Reaction diffusion solvent effects

Reaction diffusion substituent effects

Reaction diffusion template effects

Reaction effective diffusivity

Reaction rate pore diffusion effect

Reducing the Effect of Longitudinal Diffusion

Reduction diffusion effects during

Response time effective diffusion length

Role of diffusion in pellets Catalyst effectiveness

Rotational diffusion effects

Self-diffusion topological effect

Single effective diffusivity

Solvent diffusion polymer effect

Soret effect, thermal diffusion

Spherical catalyst pellets effective diffusivity

Spin diffusion effect

Taylor dispersion effective diffusivity

Temperature effect on diffusivity

Temperature effects and diffusion

The Effect of B-Site Cation on Oxygen Diffusivity

The Effect of Diffusion Limitation

The Effective Diffusion Coefficient

The Effective Diffusivity—Closing Remarks

The effective diffusivity

Thermal diffusion effects

Thermal diffusion length, effect

Thermal diffusion length, effect experiment

Tracer diffusion effect

Two Bulb Diffusion Cell A Test of the Effective Diffusivity

Viscosity effect upon diffusion

Water, effective diffusivity

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