Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Faraday diffusion

Faraday diffusion current, 363 FES, 253 FID (GC), 35 FID (NMR), 137 Film resin, 68 Fischer-Snedecor, 391 Flame emission, 257 Flame ionisation detector, 35 Fluor, 333 Fluorophore, 230 Force constant, 163 Fourier transform, 170 FPD, 36... [Pg.442]

Courtney S H, Kim S K, Canonica S and Fleming G R 1986 Rotational diffusion of stiibene in alkane and alcohol solutions J. Chem. See. Faraday Trans. 2 82 2065-72... [Pg.867]

Lennard-Jones J E 1932 Prooesses of adsorption and diffusion on soiid surfaoes Trans. Faraday Soc. 28 333... [Pg.917]

Smit B, Loyens L D J C and Verbist G L M M 1997 Simulation of adsorption and diffusion of hydrocarbons in zeoWtes Faraday Disc. Ohem. See. 106 93-104... [Pg.2285]

Schinke R, Weide K, Heumann B and Engel V 1991 Diffuse structures and periodic orbits in the photodissociation of small polyatomic molecules Faraday Discuss. Chem. Soc. 91 31... [Pg.2327]

Rabinowitch E 1937 Collision, coordination, diffusion and reaction velocity in condensed systems Trans. Faraday See. 33 1225-33... [Pg.2850]

Caldin E F, de Forest L and Queen A 1990 Steric and repeated collision effects in diffusion-controlled reactions in solution J. Chem. See. Faraday Trans. 86 1549-54... [Pg.2850]

If the electrodes are moved closer together, the positive column begins to shorten as it moves through the Faraday dark space because the ions and electrons within it have a shorter distance through which to diffuse. Near the cathode, however, the electric-field gradient becomes steeper and electrons from the cathode are accelerated more quickly. Thus atom excitation through collision with electrons occurs nearer and nearer to the cathode, and the cathode glow moves down toward the electrode. [Pg.37]

The formation of carbon black in a candle flame was the subject of a series of lectures in the 1860s by Michael Faraday at the Royal Institution in London (23). Faraday described the nature of the diffusion flame, the products of combustion, the decomposition of the paraffin wax to form hydrogen and carbon, the luminosity of the flame because of incandescent carbon particles, and the destmctive oxidation of the carbon by the air surrounding the flame. Since Faraday s time, many theories have been proposed to account for carbon formation in a diffusion flame, but controversy still exists regarding the mechanism (24). [Pg.543]

These three terms represent contributions to the flux from migration, diffusion, and convection, respectively. The bulk fluid velocity is determined from the equations of motion. Equation 25, with the convection term neglected, is frequently referred to as the Nemst-Planck equation. In systems containing charged species, ions experience a force from the electric field. This effect is called migration. The charge number of the ion is Eis Faraday s constant, is the ionic mobiUty, and O is the electric potential. The ionic mobiUty and the diffusion coefficient are related ... [Pg.65]

Deuterium [7782-39-0] M 4. Passed over activated charcoal at -195° [Maciver and Tobin J Phys Chem 64 451 I960], Purified by diffusion through nickel [Pratt and Rogers, J Chem Soc, Faraday Trans 192 1589 1976], Always check deuterium for radioactivity to find out the amount of tritium in it (see D2O below). [Pg.417]

Glueckauf E. (1955) Theory of Chromatography Part 10 - Formula for Diffusion into Spheres and Their Application to Chromatography, Trans. Faraday Soc. 51 1540-1551... [Pg.250]

J = the average diffusion current in microamperes during the life of the drop n = the number of faradays of electricity required per mole of the electrode reaction (or the number of electrons consumed in the reduction of one molecule of the electro-active species) ... [Pg.596]

The constant 607 is a combination of natural constants, including the Faraday constant it is slightly temperature-dependent and the value 607 is for 25 °C. The IlkoviC equation is important because it accounts quantitatively for the many factors which influence the diffusion current in particular, the linear dependence of the diffusion current upon n and C. Thus, with all the other factors remaining constant, the diffusion current is directly proportional to the concentration of the electro-active material — this is of great importance in quantitative polarographic analysis. [Pg.597]

Danckwkrts. P. V. Trans. Faraday Soc. 46 (1950) 300. Absorption by simultaneous diffusion and chemical reaction. [Pg.655]

Haul, RA.W. and Stein, L.H. 1955 Diffusion in calcite crystals on the basis of isotope exchange with carbon dioxide. Faraday Society Transactions 51 1280-1290. [Pg.112]

According to Faraday s law, the current passing through the electrode is equivalent to the material flux of electroactive substances. The disappearance of electroactive substances in the electrode reaction is considered as their transport through the electrode surface. Consequently, only diffusion and migration but not convection flux need be considered at the electrode surface, as the electrode is impenetrable to the solution components. [Pg.290]

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. 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.
MJ Hayes, GS Park. The diffusion of benzene in rubber. Trans Faraday Soc 52 949-955, 1956. [Pg.481]

W Brown, K Chitumbo. Solute diffusion in hydrated polymer networks. Chem Soc Faraday Trans I 71 1-11, 1975. [Pg.555]

Here F is the Faraday constant C = concentration of dissolved O2, in air-saturated water C = 2.7 x 10-7 mol cm 3 (C will be appreciably less in relatively concentrated heated solutions) the diffusion coefficient D = 2 x 10-5 cm2/s t is the time (s) r is the radius (cm). Figure 16 shows various plots of zm(02) vs. log t for various values of the microdisk electrode radius r. For large values of r, the transport of O2 to the surface follows a linear type of profile for finite times in the absence of stirring. In the case of small values of r, however, steady-state type diffusion conditions apply at shorter times due to the nonplanar nature of the diffusion process involved. Thus, the partial current density for O2 reduction in electroless deposition will tend to be more governed by kinetic factors at small features, while it will tend to be determined by the diffusion layer thickness in the case of large features. [Pg.267]


See other pages where Faraday diffusion is mentioned: [Pg.470]    [Pg.470]    [Pg.1685]    [Pg.512]    [Pg.82]    [Pg.243]    [Pg.341]    [Pg.331]    [Pg.178]    [Pg.237]    [Pg.276]    [Pg.91]    [Pg.246]    [Pg.91]    [Pg.35]    [Pg.14]    [Pg.21]    [Pg.233]    [Pg.649]    [Pg.381]    [Pg.154]    [Pg.35]    [Pg.29]    [Pg.247]    [Pg.371]    [Pg.241]    [Pg.146]   
See also in sourсe #XX -- [ Pg.470 ]




SEARCH



Faraday

© 2024 chempedia.info