Dynamic Environmental Processes
This page provides links to computer programs and database, for the computation of dynamic physico-chemical processes in environmental systems. Such processes commonly called "dynamic speciation" are linked to biouptake, bioavailability and dynamic sensor functionning. They are modelled in terms of nonlinear diffusion-reaction equations.
MHEDYN (Multiligand Heterogeneous Dynamics):
The computer code MHEDYN enables to compute (metal) fluxes towards consuming interfaces, like organisms or sensors, by considering the diffusional processes and chemical kinetics with "simple" ligands, humic substances and/or colloidal particles, in complicated (natural) mixtures of aquatic complexing agents. In addition to the data also provided by FLUXY v2.01 or v3.11, it enables to compute transcient and steady-state fluxes as well as concentration profiles at the interface. It can also be used without excess of ligand. It may be more computer-time consuming than FLUXY. It includes a user friendly interface and an important database.
Please, read the document "Getting_Started.pdf
" before downloading MHEDYN: it will help you step by step in the installation procedure. The user guide of MHEDYN is available on this link
. The computer code can be freely downloaded here
The computer code FLUXY, which has the same goals and also includes a user friendly interface and a database. MHEDYN and FLUXY however are complementary in a few respects. For instance FLUXY requires an excess of ligand, but can work with both spherical and planar diffusion.
Complete code for the calculation of steady-state metal fluxes at interfaces, in complexing solutions containing simple ligands, fulvics, particulate/aggregate complexants or their mixtures. It incorporates the calculation of the equilibrium concentrations of free cations and ligands, required as input parameters. A database for metal complexes, cations and ligands, with thermodynamic constants, chemical rate constants, diffusion coefficients, and other parameters required for flux computation of metals at interfaces is included. A Fluxy user manual is available and the program can be freely downloaded.
FLUXY v 3.11:
Complete version equivalent to the version 2.01. As the version 2.01, it includes two modes of calculation: FLUXY-RS and FLUXY-RLA. FLUXY-RS is the same as in v. 2.01. FLUXY-RLA is based on the same concepts as in v. 2.01, but the reaction layer thickness is computed from an equation more generally applicable as in v. 2.01, as explained in the "Addendum to the FLUXY user manual, for version 3.11". This version is recommended. Also this version of the program can be freely downloaded.
Besides the programmes and manuals the CABE web site also provides references to publications related to the modelling.