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Explore the change in concentration inside a cell over time using mass conservation equations, initial and boundary conditions. Learn about non-dimensional variables, radial coordinates, and normalized concentrations. Investigate the separation of variables and the unique solution for boundary conditions.
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Unsteady Diffusion into a Sphere Steven A. Jones BIEN 501 Wednesday, May 16, 2007 Louisiana Tech University, Ruston, LA 71272
Diffusion into a Cell Outside: How does the concentration inside the cell change with time? Louisiana Tech University, Ruston, LA 71272
Equations Mass conservation Initial Conditions Boundary Conditions Louisiana Tech University, Ruston, LA 71272
Non-Dimensional Variables Radial Coordinate Normalized Concentration Time coordinate Louisiana Tech University, Ruston, LA 71272
Non-Dimensional Equations Mass conservation Becomes Initial Condition Becomes Boundary Conditions Become Louisiana Tech University, Ruston, LA 71272
Separation of Variables Becomes Louisiana Tech University, Ruston, LA 71272
Difference from Bessel Because of the factor of 2 in the second term this is not the standard Bessel equation. Louisiana Tech University, Ruston, LA 71272
Solution BC at h = 0 Louisiana Tech University, Ruston, LA 71272
Boundary Condition at 0 So B = 0 Louisiana Tech University, Ruston, LA 71272
BC at Cell Wall So Substitute back: Louisiana Tech University, Ruston, LA 71272
Initial Condition in Gives Louisiana Tech University, Ruston, LA 71272
Solution Louisiana Tech University, Ruston, LA 71272