Efficient chemical equilibrium calculations for geochemical speciation and reactive transport modelling

A chemical kinetics algorithm for geochemical modelling

A chemical kinetics algorithm is presented for geochemical applications. The algorithm is capable of handling both equilibriumand kinetically-controlled reactions in multiphase systems. The ordinary differential equations (ODEs) are solved using an implicit multistep backward differentiation formula (BDF) algorithm to ensure efficiency and stability when integrating stiff ODEs. An adaptive cont...

Modelling Chemical Speciation: Thermodynamics, Kinetics and Uncertainty

Chemical speciation refers to the distribution of an element amongst chemical species in a system. It is critical for understanding chemical toxicity, bioavailability, and environmental fate and transport. Despite the central importance of knowing the full speciation of a chemical in order to predict its behaviour in a system, it is generally not possible to determine a speciation analysis usin...

A Review of Computable General Equilibrium Modelling for Transport Appraisal

The traditional cost-benefit analysis (CBA) for transport appraisal has two key weaknesses. Firstly, by assuming static prices in markets external to transport, externalities cannot be considered other than in an ad-hoc, case-by-case manner. This approach is only valid under restrictive assumptions regarding perfect competition and the reflection of marginal costs in prices, which may not be ap...

Efficient wave-function matching approach for quantum transport calculations

Extraction of model parameters for reactive solute transport

In the present study, tried to examine the reactive solute relationships for transport and degradation processes through the rockfill media. By applying the analytical solution of reactive transport, the 1st to 3rd theoretical temporal moments have been extracted then, by using two methods of curve fitting and temporal moment matching, the coefficients of dispersion and degradation have been ex...