4.2.1. Millington Quirk’s Expression

Try these first

1. 1.

   What is effective diffusivity?

   Hint

   Think about how substances move through soils.

2. 2.

   Define the local equilibrium assumption.

   Hint

   Consider how quickly changes happen in both phases.

3. 3.

   What does Millington Quirk's expression calculate?

   • Effective diffusion rate
   • Concentration of solids
   • Adsorption rate

   Hint

   Focus on the context of material movement in sediments.

4. 4.

   True or False: The local equilibrium assumption holds even in fast-flowing fluids.

   • True
   • False

   Hint

   Think about the speed of water movement versus the rate of molecular interactions.

5. 5.

   How would you apply Millington Quirk's expression to predict contaminant movement in a layered soil profile? Identify key factors.

   Hint

   Consider how each layer's characteristics impact the model.

6. 6.

   Critically assess the viability of Millington Quirk's expression in a highly variable sediment environment. What adaptations could be made?

   Hint

   Reflect on the complexities of real-world sediment structures.