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Fick's Second Law Unsteady-State Diffusion Calculator

Calculates transient concentration profiles and dimensionless penetration parameters for 1D diffusion in semi-infinite media using Fick's Second Law.

📖 Need the theory? Read the methodology, assumptions, and equations in the full reference guide.
Read Fick's Second Law Unsteady-State Diffusion Calculator Guide →

1. Define Input Parameters

2. Engineering Output

Dimensionless Variable (η) (eta)
-
Error Function Value (erf_eta)
-
Concentration at Depth z and Time t (C_zt)
- kg/m³

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Context & Assumptions

Fick's Second Law describes unsteady-state mass transfer where solute concentration varies with position and time in non-equilibrium systems. It is commonly applied in process engineering to predict transient diffusion fronts in stagnant fluids, solid matrices, and containment boundaries. Understanding these transient concentration profiles is critical for safety assessments, barrier designs, and environmental containment modeling.

Understand the Engineering Principles

Review the step-by-step derivations, typical industrial limits, and scale-up rules.

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