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Fick's first law relates the diffusive flux to the gradient of the concentration. It postulates that the flux goes from regions of high concentration to regions of low concentration, with a magnitude that is proportional to the concentration gradient (spatial derivative), or in simplistic terms the concept that a solute will move from a region of high concentration to a region of low ...
Therefore, the surface free energy increases right-to-left, which drives flow from right-to-left. For gradients that are not-too-large, the diffusioosmotic slip velocity, i.e., the relative flow velocity far from the surface will be proportional to the gradient in the concentration gradient [1] [12]
A diffusion gradient is a gradient in the rates of diffusion of multiple groups of molecules through a medium or substrate.The groups of molecules may constitute multiple substances, portions of the same substance that have different temperatures, or other differentiable groupings.
The standard logistic function is the logistic function with parameters =, =, =, which yields = + = + = / / + /.In practice, due to the nature of the exponential function, it is often sufficient to compute the standard logistic function for over a small range of real numbers, such as a range contained in [−6, +6], as it quickly converges very close to its saturation values of 0 and 1.
The horizontal axis is the concentration of the ligand. As the Hill coefficient is increased, the saturation curve becomes steeper. In biochemistry and pharmacology, the Hill equation refers to two closely related equations that reflect the binding of ligands to macromolecules, as a function of the ligand concentration.
In the case of dialysis, the driving concentration gradient in the membrane is reduced. [6] In the case of electromembrane processes, the potential drop in the diffusion boundary layers reduces the gradient of electric potential in the membrane. Lower rate of separation under the same external driving force means increased power consumption.
The negative sign arises because the concentration of A decreases as the distance x increases. Similarly, the variation in the concentration of gas B is -dC B /dx. The rate of diffusion of A, N A , depend on concentration gradient and the average velocity with which the molecules of A moves in the x direction.
Imbibition is a special type of diffusion that takes place when liquid is absorbed by solids-colloids causing an increase in volume. Water surface potential movement takes place along a concentration gradient; some dry materials absorb water. A gradient between the absorbent and the liquid is essential for imbibition.