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FRS studies of molecular mass diffusion are somewhat more involved than studies of thermal diffusion or thermophoresis because the ground and excited dye states may have different diffusion coefficients. [6] [7] When this is the case, two gratings differing in phase by 180 degrees are present: the excited state grating and a complementary ...
The way that a Stefan tube is modelled, mathematically, is very similar to how one can model the diffusion of perfume fragrance molecules from (say) a drop of perfume on skin or clothes, evaporating up through the air to a person's nose. There are some differences between the models.
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 ...
The self-diffusion coefficient of neat water is: 2.299·10 −9 m 2 ·s −1 at 25 °C and 1.261·10 −9 m 2 ·s −1 at 4 °C. [2] Chemical diffusion occurs in a presence of concentration (or chemical potential) gradient and it results in net transport of mass. This is the process described by the diffusion equation.
The rate of diffusion of each ion will be roughly proportional to its speed in an electric field, or their ion mobility. If the anions diffuse more rapidly than the cations , they will diffuse ahead into the dilute solution, leaving the latter negatively charged and the concentrated solution positively charged.
Specifically, Matano proved that the diffusion rate of A atoms into a B-atom crystal lattice is a function of the amount of A atoms already in the B lattice. The importance of the classic Boltzmann–Matano method consists in the ability to extract diffusivities from concentration–distance data.
A Utah man is said to have killed his son following an argument on Christmas Eve, in which he accused him and his fiancée of "withholding information" about his wife’s alleged affair.
Diffusion-controlled (or diffusion-limited) reactions are reactions in which the reaction rate is equal to the rate of transport of the reactants through the reaction medium (usually a solution). [1] The process of chemical reaction can be considered as involving the diffusion of reactants until they encounter each other in the right ...