Contribution of dispersion

It is desirable to calculate new bulk phase Z values for the four primary media which include the contribution of dispersed phases within each medium as described by Mackay and Paterson (1991) and as listed earlier. The air is now treated as an air-aerosol mixture, water as water plus suspended particles and fish, soil as solids, air and water, and sediment as solids and porewater. The Z values thus differ from the Level I and Level II pure phase values. The necessity of introducing this complication arises from the fact that much of the intermedia transport of the chemicals occurs in association with the movement of chemical in these dispersed phases. To accommodate this change the same volumes of the soil solids and sediment solids are retained, but the total phase volumes are increased. These Level III volumes are also given in Table 1.5.2. The reaction and advection D values employ the generally smaller bulk phase Z values but the same residence times thus the G values are increased and the D values are generally larger. 

In the first case it is necessary to know solubility parameters of both the solvent, 81, and the polymer, S2. A general rule for non - polar systems is that the solvent is better when its 81 values is closer to 82. In polar systems, contributions of dispersive... 

Examination of the Contributions of Dispersion and Electrostatic Terms to the Heat of Adsorption on Aluminosilicates... 

On the basis of Equation 4, the values of ya and y/ for a solid polymer surface can be calculated from the contact angles on it of two liquids, the surface tensions of which have been defined in terms of the respective contribution of dispersion and polar force components (5). In this case. Equation 4 is rearranged to two simultaneous equations, and solved for y/ and y/. 

Finally, the scale distinction is also recognized in the interpretation of contact angles. In secs. 2.5c and 2.11b we saw that surface tensions, and hence contact angles, can to a first approximation be Interpreted in terms of an additive contribution of dispersion forces and a non-dispersive contribution (say, hydrogenbridging in water). These forces act across the entire bulk of each phase tmd, at least for London-Van der Waals forces they have a colloided range. On the other hand, a limited adsorption of surfactants, which only act over a molecular range, drastically modifies the wetting behaviour. 

The linear relationships obtained could mean that the interfacial adhesion results principally from acid/base or acceptor/donor interactions, assuming that the dispersive interactions are of the same magnitude. The meaning of the value of x obtained by the intercept at the origin of the straight lines is not clear. It was first considered to be the contribution of dispersive interactions to the shear resistance of... 

Poggi, D., Katul, G., and Albertson, J. (2004) A note on the contribution of dispersive fluxes to momentum transfer within canopies, Boundary-Layer Meteor. Ill, 615-621. 

Effect of particle size. The size of the packing influences the Reynolds number and therefore influences the contributions of dispersion and external mass transfer. The contribution from internal diffusion to the total variance is also affected by the particle size. An increase in particle size from 10 pm to 40 pm increases the contribution from external mass transfer more than the other factors investigated here and this influence is dependent upon solute size. Solute displacement is not... 

Alternatively, when taking into account the contributions of dispersion and polar forces for deeper examination, one may write [62] ... 

Here the first term expresses the contribution of dispersion forces of repulsion 11 > 0, where A,30 is the composite Hamaker constant. The second term represents the forces of electrostatic attraction n, < 0. 

These successes give confidence in calculating the contributions of dispersion forces to the binding energies of materials in which the principal binding forces have other origins. 

That is, the dispersion energy of interaction between two dissimilar atoms I and 2 is given as the geometric mean of corresponding interaction energies between like atoms (1-1 and 2-2). The contribution of dispersion interactions to the adsorption energy of an atom of type 1 on a surface composed of atoms 2 may be obtained from Eqs. (3-Ia) or (3-lb) by summing the various atom-atom interactions between atom 1 and all the atoms of (he adsorbent ... 

For a given adsorbent the contribution of dispersion interactions to the adsorption energy of atom 1 is proportional to the polarizability of atom... 

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