Gradient forms

Estimate the interfacial tension gradient formed in alcohol-water mixtures as a function of alcohol content. Determine the minimum alcohol content necessary to form wine tears on a vertical glass wall [174] (experimental veriflcation is possible). 

The most commonly used gradients are linear gradients where the starting solvent is gradually mixed with a second gradient-forming solvent at the column entrance to yield a volume fraction

mobile phase modulator that increases huearly with time ... 

The equations above describe how solutes in the soil will move in response to concentration or water potential gradients. Such gradients form when the rhizo-sphere is perturbed by the activities of the root including water and MN abstraction and carbon deposition. These activities need to be mathematically described and form one of the two boundary conditions required to solve the initial-value problem. 

Antonenko et al. [540] considered pH gradients forming in the UWL under bulk solution iso-pH conditions. They elegantly expanded on the buffer effect model and made it more general by considering multicomponent buffer mixtures. Direct measurements of the pH gradients (using wire-coated micro-pH electrodes) near the membrane-water interface were described. 

The first of these is the ohmic potential gradient, characteristic for charge transfer in an arbitrary medium. It is formed only when an electric current passes through the medium. The second expression is that for the diffusion potential gradient, formed when various charged species in the electrolyte have different mobilities. If their mobilities were identical, the diffusion electric potential would not be formed. In contrast to the ohmic electric potential, the diffusion electric potential does not depend directly on the passage of electric current through the electrolyte (it does not disappear in the absence of current flow). 

In dilute solutions of surfactants adsorption processes are controlled by transport of the surfactant from the bulk solution towards the surface as a result of the concentration gradient formed in the diffusion layer the inherent rate of adsorption usually is rapid. For non-equilibrium adsorption the apparent (non-equilibrium) isotherm can be constructed for different time periods that are shifted with respect to the true adsorption isotherm in the direction of higher concentration (Cosovic, 1990) (see Fig. 4.10). 

After a period of time, a steep concentration gradient forms around the electrode since the solution immediately adjacent to the HMDE is entirely depleted of Cu. In response, (solvated) Cu analyte ions from the bulk of the solution will diffuse toward the HMDE and themselves be reduced. After a further period of time, all of the copper ions will have been removed from solution and accumulate on the surface of the drop (Figure 5.6(b)). Here, we say that we have exhausted the solution. ... 

During dissolution, the concentrations of X and AgY2 increase at the phase boundary, the concentration of Y decreases and, as a consequence of the concentration gradient formed, mass transport occurs, as indicated in fig. 3.6. If the electrolyte is not stirred [1,38,39,40], diffusion and natural convection are the only driving forces of transport. 

If the sample was denatured by extraction from cell lysates, a renaturation is possible while the protein is bound to the column Wash the column with Soln. B and elute with a gradient formed by Soln. C (starting buffer) and Soln. E. 

The ion gradients formed by primary transport of Na+ or H+ can in turn provide the driving force for cotransport of other solutes. Many cell types contain transport... 

C Isopycnic centrifugation the density gradient forms during centrifugation. Illustration courtesy of Beckman Instruments, Inc. 

Figure 4.1 Concentration gradients formed when a dialysis membrane separates two solutions of different concentrations...

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