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This section lists past changes related to AIOMFAC-web in reverse chronological order.

  • Back to recent announcements.

  • November 22, 2017: Recent hardware issues and related repairs of the server at Caltech have caused temporary unavailability of this website. To avoid longer unavailabilities in future, the AIOMFAC model website is now also hosted on a server at McGill University, currently accessible via the following URL: The Caltech-hosted website ( remains available.

  • May 15, 2015: A search tool has been added to the navigation menu to aid you in finding relevant information on this website.

  • April 24, 2014: Initial input data validation, error, and warning checks have been further improved (including the blocking of automated spam upload). The model version was changed to 2.18. However, these changes do not affect the actual AIOMFAC code nor model output.

  • June 19, 2013: The AIOMFAC model has been corrected for a typo in the supplementary tables of Hansen et al. (1991) for the relative surface area parameter of the ketone subgroup CH3CO. The previously used value (1.448 instead of 1.488) led to slight deviations of activity coefficients in affected systems, e.g., noticeable at conditions of very high dilution in the system of water + acetone. We thank Steven Compernolle for the hint. The AIOMFAC-web version has been changed to 2.16.

  • December 10, 2012: Additional error and warning checks have been implemented in the AIOMFAC-web model to prevent certain types of incorrect input data. The model version was changed to 2.15.

  • October 16, 2012: The webpages have been updated to be compliant with HTML5 syntax and features. The AIOMFAC-web model has been updated to version 2.14 (including output of results in HTML5 syntax and internal performance upgrades).

  • August 17, 2012: The model input page has been updated to fix compatibility issues with older web browsers (and their interpretation of JavaScript code).

  • June 06, 2012: AIOMFAC-web version bug-fix update to 2.11. A bug in the model code slightly affecting activity coefficients in mixtures containing organic compounds and non-1:1-electrolytes has been corrected. Thanks to Steven Compernolle for pointing out this error.

  • May 11, 2012: AIOMFAC-web version update to 2.10. New functional groups are made available in AIOMFAC-web: hydroperoxide, peroxyacid, peroxide, peroxyacyl nitrate (PAN), and organonitrate. The new functional groups and the parameterization of their interactions with other functional groups and inorganic ions are described in Zuend and Seinfeld (2012). The list of available functional groups and the interaction matrix shown on the page About AIOMFAC have been updated accordingly.

  • April 01, 2012: AIOMFAC-web version update to 2.02. The version update includes a minor correction in TeX format of model output in text files, allows now 101 data points per model run, and addresses numerical issues at extremely high electrolyte concentrations.

  • February 17, 2012: Additional examples of AIOMFAC-web calculations have been added to the Hints & Examples page. It is demonstrated how the water content and mixture composition at a given RH can be computed and how the solubility and deliquescence RH of a component in a multicomponent solution can be determined with AIOMFAC.

  • January 10, 2012: The AIOMFAC website has been launched with AIOMFAC-web version 2.0 available for online calculations.

    AIOMFAC-web 2.0 covers water, inorganic ions and the following organic functional groups: hydroxyl, carboxyl, ketone, aldehyde, ether, ester, alkenyl, aromatic hydrocarbon, aromatic carbon-alcohol, and different alkyl groups. The inorganic ions available are: H+, Li+, Na+, K+, NH4+, Mg2+, Ca2+, Cl-, Br-, NO3-, HSO4-, and SO42- (see further here).

© 2012 – 2023 Andreas Zuend, California Institute of Technology | McGill University last page update: 2019-10-21