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D is the diffusion constant of the solute unit m 2 ⋅s −1, t is time unit s, c 2, c 1 concentration should use unit mol m −3, so flux unit becomes mol s −1. The flux is decay over the square root of time because a concentration gradient builds up near the membrane over time under ideal conditions.
Tracer diffusion and Self-diffusion, which is a spontaneous mixing of molecules taking place in the absence of concentration (or chemical potential) gradient. This type of diffusion can be followed using isotopic tracers, hence the name. The tracer diffusion is usually assumed to be identical to self-diffusion (assuming no significant isotopic ...
Facilitated diffusion may occur through three mechanisms: uniport, symport, or antiport. The difference between each mechanism depends on the direction of transport, in which uniport is the only transport not coupled to the transport of another solute. [4] Uniporter carrier proteins work by binding to one molecule or substrate at a time ...
Simple diffusion of colloids is fast on length scales of a few micrometres, and so diffusiophoresis would not be useful, whereas on length scales larger than millimetres, diffusiophoresis may be slow as its speed decreases with decreasing size of the solute concentration gradient. Thus, typically diffusiophoresis is employed on length scales ...
The concept of diffusion is widely used in many fields, including physics (particle diffusion), chemistry, biology, sociology, economics, statistics, data science, and finance (diffusion of people, ideas, data and price values). The central idea of diffusion, however, is common to all of these: a substance or collection undergoing diffusion ...
Whereas sedimentation seeks to concentrate the solute near the outer radius of the cell, diffusion seeks to equalize the solute concentration throughout the cell. The diffusion constant D can be estimated from the hydrodynamic radius and shape of the solute, whereas the buoyant mass m b can be determined from the ratio of s and D
Figure 1: Diagram of Mason–Weaver cell and Forces on Solute. A typical particle of mass m moving with vertical velocity v is acted upon by three forces (Fig. 1): the drag force, the force of gravity and the buoyant force, where g is the acceleration of gravity, V is the solute particle volume and is the solvent density.
As mentioned above, passive diffusion is a spontaneous phenomenon that increases the entropy of a system and decreases the free energy. [5] The transport process is influenced by the characteristics of the transport substance and the nature of the bilayer. The diffusion velocity of a pure phospholipid membrane will depend on: concentration ...