Even at the lowest studied temperatures, grain boundary diffusion causes nitrogen to move relatively deep in the bulk sample.
Decreasing the activation energy for diffusion causes the minimum to move to higher temperatures.
As the oxygen tension falls, as it does in the tissues, oxygen dissociates from hemoglobin and is available to move by diffusion through the red cell membrane and the plasma to sites where it is used.
Molecules of a solute (e.g., salt, sugar) in water tend to move by diffusion from a region where they are in high concentration to one where they are in low concentration, and molecules of water tend to move in the opposite direction.
Turbulence, velocity gradients, and molecular diffusion-all these cause material to move at different speeds in a flowing stream.
Small barriers have been implemented into the flow field channels that force the gas flow to move through the gas diffusion layers in order to improve the supply of the catalyst with reactant gases.
The vertebrate cardiovascular system is designed to move a variety of molecules over considerable distances throughout the body faster than they would move by diffusion alone.
Also hypoechoic lesions of the spleen appear most often as progressive hypoenhancing nodules, in arterial and parenchymal phases, compared to adjacent splenic tissue, with increasing lesion-to-parenchyma contrast diffusion while moving to parenchymal phase [ 58, 65].
From this 'station', membrane bound molecules move by lateral diffusion to the surface of the cell body and the flagellum [ 16, 53].
This paper focuses on the use of a simple one-dimensional model considering moving boundary vapor diffusion to describe the ultrasonic assisted atmospheric freeze-drying of foodstuffs.
