j.mino.mobi
init…
t = 0 s filled 0%

Cross-section

50%
1.0

Temperature (Arrhenius)

D(T) = D₀·exp(−Eₐ/RT). Heat it up and watch the front race inward.
298
D(T)—

Regime — when Fick isn't enough

0.22
0.12
0.0
Each regime makes the diffusivity vary in space (or adds reaction k) — the cross-section profile then matches the corresponding /model fit.

Fundamental parameters

1.0
0
4

What you're seeing

  • The sphere starts empty; everything outside its surface is a reservoir at the surface concentration.
  • Explicit finite-difference Fickian diffusion runs on the GPU; the front obeys the same √(Dt) law you fit on the Model page.
  • First-order reaction k consumes the species inside, giving a reaction–diffusion (Thiele) steady state instead of full saturation.
  • Drag the cross-section to look inside the volume.