Diffusion speed

As measured, the Hs term means that a smaller particle size reduces the distance between particles, and thus the spreading due to diffusion of sample molecules is minimized. From Equations 5.18 and 5.19, a decrease in H value is achieved by increasing the diffusion speed (elevating the column temperature,... 

The other major route of chemical hazards to plant workers is penetration through the skin, which has a surface area of about 1.8 m for a male adult, and is lined with a tough horny layer of densely packed cells without nuclei. So the skin is reasonably impervious to the penetration of chemical substances, and penetration depends on the lipid solubility of the compound, where the diffusion speed is inversely related to molecular weight. Skin penetration hazard becomes relatively more important than breathing for high boiling point liquids, which have lower vapor pressures. 

There are several different approaches that are commonly used to determine particle size distributions in air. One of them, impaction, has been discussed earlier. Multistage impactors with different cut points are used extensively to obtain both mass and chemical composition data as a function of size for particles with diameters > 0.2 /xm. Others, including methods based on optical properties, electrical or aerodynamic mobility, and diffusion speeds, are described briefly in the following section. The condensation particle counter (CPC) is used as a detector in combination with some of these size-sorting methods. 

C02 assimilation. The amount of C02 available for photosynthesis decreases with decreasing C02 partial pressure at higher elevations, but this effect is offset by the increase in diffusion speed at lower air pressure (Gale 1972, 1973). The lower temperature at higher altitudes, however, decreases diffusion speed, and therefore the temperature lapse rate of the particular mountain determines whether C02 availability decreases (dry-moist lapse rate) or stays relatively constant (very wet lapse rate) (Smith and Donahue 1991). The lower air pressure at altitude does not just decrease C02 partial pressure but also 02 partial pressure, which results in lower photorespiration rates and more efficient photosynthesis. When all these effects are modeled, photosynthetic rates generally decrease with altitude, unless the temperature lapse rate is very low (which could occur in extremely wet mountain ranges), but the photosynthetic limitation is much less than expected based on just the partial pressure decrease (Terashima et al. 1995 Smith and lohnson 2007). 

The speed of crystal growth [2] depends on the diffusion speed of the water molecules to the crystal surfaces, which depends on the viscosity of the solution at the time of crystallization and on the transport of the crystallization energy from the crystal to the heat sink, which, again, depends on the viscosity, among other factors. 

The viscosity of the solution (determines the diffusion speed of the reactants)... 

Fig. 1.13. Diagram illustrating the importance of the diffusion speed of THK aggregates towards the soUd/liquid adsorption interface for the growth of nuclei FA, adsorption film X, molecular aggregate of THK diffusing towards the interface IS/L, solid/liquid interface N, nuclei C, THK concentration in the liquid phase Q, THK concentration at the solid/liquid interface S, theoretical solubility of THK C — S, supersaturation of the wine C > > S...

For ions of equal mobility, the diffusion speed at any E/N is inversely proportional to the charge state z (2.2.4). This does not affect FAIMS metrics at short t s where diffusion is inconsequential (4.2.1). At long t es, both s by Equation 4.13 and R by Equation 4.16 should increase at higher z, with the latter scaling as Same scaling... 

Discrimination of Ions Based on Diffusion Speed AND Its Reduction in Field-Driven Systems... 

Decreased amount of copper diffusing into tin/time and reduced overall diffusion speed... 

Moreover, it is interesting to note that for both Ag and Pd composite particles the catalytic activities of metal nanoparti-cles immobilized in SPEB are higher than that of a core-shell miaogel system. This can be explained by the diffusion speed of reactant molecules to metal nanopartides encapsulated in both carrier systems. For the microgels, the cross-linked PNIPAM shdl restricts diffusion and the reactant molecules need a longer time to reach the catalytic active center. The SPEBs have an open structure, and reactant molecules can diffuse through to reach the metal nanopartides more quickly. This demonstrates that SPB can work as stable carrier systems for metal nanopartides used in catalysis. 

The decline in concentration arises from the reduction from A to A ". As A disappears from the solution in the same ratio as A " is formed, the following is true, provided that the diffusion speeds of A and A are equal ... 

NIR-Controllable Drug Release Through Increasing the Diffusion Speed... 

The high diffusion speed of small molecules (even under nearcritical conditions) in comparison with ordinary solvents and the dissolution selectivity of such systems can be used in the extraction of low-molecular organic products out of amorphous polymeric materials. Some results for acrylonitrile containing (co-) polymers/blends and thermoplastic polymers like ethylene-propylene-diene terpolymers are reported. 

The curing speed of PUR-Hybrid Sikaflex -555 is between those of MS-products and PUR-adhesives (Fig. 85), although the level of catalyst and diffusion speed through the polymer backbone have an effect on the curing speed. 

At low concentration, the temperature influence is more marked. It strongly decreases as the concentration increases, reaching a maximum level. It joins the previously suggested idea of a phenomenon of saturation of the corrosive diffusion. This saturation could explain the observed limitation of the diffusion speed. This limitation also depends on the gradual creation of decomposition products of chemical species during the mechanism of destruction of tissue by the corrosive agent. 

The classic method for isotope separation utilizes a gas diffusion method in cells. Each cell is divided into two parts, separated by a barrier pierced with a lot of tiny holes. On one side of the barrier an under-pressure is maintained, on the other side an over-pressure. The fluoride is fed in to the part with overpressure and diffuses through the barrier. The mean speed of the molecules of a gas is lower if the molecular weight is higher. It can be calculated that the diffusion speed for is 1.0043 times higher than that for When... 

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