GEMS Links to Third-Party Databases 

Many modelling applications of GEMS result in a published extension of thermodynamic database that may be of great value for other people. The related modelling projects can be used as tests or good tutorial examples for the specific field of research.

Our policy is that an owner (contributor) of the respective application that required intensive use of GEM-Selektor package can provide the GEMS-compatible files on her/his own web page for download. It is assumed that the owner is responsible for the content and maintains the contributed files independently of us. If this is the case, we provide all necessary links here on this web page.

Alternatively, the owner who has no web page may wish to provide the contributed files with associated comments and instructions for download through this page from GEMS web site. In this case, we are not responsible for the correctness and content of modelling project or thermodynamic database files.

AqTDB16 - internally consistent thermodynamic database for fluid rock interaction

System: Na-K-Al-Si-O-H-Cl

AqTDB16 files in GEMS format can be downloaded here.

The detailed description related to the selection of experimental data and database generation can be found in: Miron G.D., Wagner T., Kulik A.D., Heinrich C.A. (2016) Internally consistent thermodynamic data for aqueous species in the system Na-K-Al-Si-O-H-Cl. Geochimica et Cosmochimica Acta 187: 41-78. DOI: 10.1016/j.gca.2016.04.026.

The thermodynamic database was generated by simultaneous global optimization of Gibbs energies of aqueous species against a critically selected large collection of solubility experiments. The thermodynamic properties of the solubility-controlling minerals were adopted from the internally consistent data-set of Holland and Powell (2002; Thermocalc dataset ds55).

The database uses the thermodynamic framework of the revised Helgeson-Kirkham-Flowers (HKF) (Tanger and Helgeson, 1988) equation of state and the Extended Debye-Hückel (Helgeson et al. 1981) activity coefficient model. The database is applicable at temperatures from 25 to 800°C, pressures from 1 bar to 5 kbar, and salt concentrations up to 5 molal.

To use the AqTDB16 data base with the GEM-Selektor package, please, download it (as a .zip file) to your hard disk and perform the following steps:

1. Unzip the downloaded zip file (contains a directory named "TDB_Miron_etal_2016/") into a temporary directory, e.g. as Tempfiles/TDB_Miron_etal_2016/

2. Find where you have GEMS installed (on Windows, usually under C:\Selektor\Gems3-app\Resources\) the DB.default/ directory.

3. Copy all files from Tempfiles/TDB_Miron_etal_2016/ into the /Resources/DB.default/ folder.

4. Start GEM-Selektor and create a new modelling project. In the project configuration wizzard select only Aqueous electrolyte and Crystalline solids. Check that "supcrt", "psi-hagra" and other entries except "AqTDB16" in "3rdparty" are turned off. Click "Next>" when ready.

 5. Select Independent Components to define the system, and proceed as usual.

CEMDATA18 - thermodynamic data for hydrated solids in Portland cement system

(CaO-Al₂O₃-SiO₂-CaSO₄-CaCO₃-Fe₂O₃-MgO-H₂O) 

Contributed and supported by Cement Chemistry Group at EMPA, Switzerland. CEMDATA database files in GEMS binary format can be downloaded here. Details are available in a paper:

Lothenbach B., Kulik D.A., Matschei T., Balonis M., Baquerizo L., Dilnesa B.Z., Miron G.D., Myers R. (2019): Cemdata18: A chemical thermodynamic database for hydrated Portland cements and alkali-activated materials. Cement and Concrete Research 115, 472-506. doi.

The composition of hydrated cementitious systems can be quite complex. Thermodynamic modelling of such multicomponent-multiphase systems can promote our understanding of the impact of different factors such as composition, hydration, leaching, or temperature. For the purpose of such modelling, the thermodynamic data for a number of solids present in Portland cement systems have been compiled from literature and critically reviewed. Wherever necessary, additional solubility data have been measured in a range of temperatures between 0 and 100 °C.

The resulting CEMDATA data base covers hydrates commonly encountered in Portland cement systems in the temperature range 0-100 °C, including C-S-H, hydrogarnets, AFm and AFt phases and their solid solutions. This dataset is consistent with the auxiliary thermodynamic data for aqueous species, gases, and common minerals such as portlandite or gypsum, provided in the GEMS default kernel database (GEMS version of Nagra-PSI 01/01 data base). Hence, the CEMDATA files comprise a specific extension to the GEMS kernel data base.
 
CEMDATA contains thermodynamic data for solids found in Portland cement systems, evaluated as described in publications. In order to model other systems, e.g. blended cements, cement degradation in contact with clay, or sorption of metals in cement matrix, the CEMDATA must be critically evaluated and extended with additional pure solids and/or solid solutions.

More details, literature and downloads are provided in the contributors web page www.empa.ch/cemdata. In future, some test modeling projects may also be provided there.

To use the CEMDATA data base in GEM-Selektor package, please, download it (as a .zip file) to your hard disk and perform the following steps:

1. Unzip the downloaded zip file (contains a directory named "DB.default/") into a temporary directory, e.g. as Tempfiles/DB.default/

2. Find where you have GEMS installed (on Windows, usually under C:\GEMS350\Gems3-app\Resources\) the DB.default/ directory.

3. Copy all files from Tempfiles/DB.default/ into the /Resources/DB.default/ folder.

4. Start GEMS and create a new project. In the "Basis configuration of a new Modelling Project" dialog, turn on "support", "psi-nagra" and "3rdparty" entries (check that "supcrt" and other entries except "cemdata" in "3rdparty" are turned off). This will link the CEMDATA database files as a third-party extension to the kernel PSI-Nagra database. Do not turn on "Skip solid solutions" in the lower-left corner. Click "Next>" when ready.

 5. Select Independent Components to define the system, and proceed as usual.

MINES thermodynamic database

Contributed and supported by Prof. Alexander Gysi at at the Bureau of Geology and Mineral Resources, New Mexico Tech, USA. 

MINES TDB files in various versions in GEMS format can be downloaded here.

MINES (currently version 19.1) is a thermodynamics dataset prepared for modeling magmatic-hydrothermal ore forming processes. The dataset includes the most recent experimental data for REE-bearing minerals and the data for rock forming minerals from the Holland and Powell (1998) and Robie and Hemingway (1995) datasets. Aqueous species are from SUPCRT92 (slop98.dat) and were updated to include recent experimental data for REE-, Zr- and Al-bearing aqueous species and much more.

This open access dataset is meant to be used with the GEM-Selektor v.3.9 or later versions. In addition, several modeling project files (Modules) have been prepared to get you started with GEMS.package for geochemical modelling. More details and the file download are provided in the contributor's web page geoinfo.nmt.edu/mines-tdb.

To use the MINES data base with the GEM-Selektor package, please, download it (as a .zip file) to your hard disk and perform the following steps:

1. Unzip the downloaded zip file (contains a directory named "DB.default/") into a temporary directory, e.g. as Tempfiles/DB.default/

2. Find where you have GEMS installed (on Windows, usually under C:\Selektor\Gems3-app\Resources\) the DB.default/ directory.

3. Copy all files from Tempfiles/DB.default/ into the /Resources/DB.default/ folder.

4. Start GEM-Selektor and create a new modelling project following module 1 on the tutorial gitbook (https://apgysi.github.io/gems-mines-tutorial/). Check that "supcrt", "psi-nagra" and other entries except "mines" in "3rdparty" are turned off. Click "Next>" when ready.

 5. Select Independent Components to define the system, and proceed as usual.

HERACLES database for U, TRU and FP speciation

The HERACLES-TDB, available from NES PSI, has been compiled to support modeling of U and fission products (FP) solid and gaseous speciation during pyroreprocessing of spent nuclear fuel in nuclear engineering. The database covers standard molar thermodynamic properties of compounds of actinides, fission products, and minor actinides, covering most of chemical elements. At present, the data for over 340 condensed compounds (including melts and liquid condensates and over 290 gaseous (also charged) species are provided. The gas phase is treated as an ideal mixture of ideal gases; for melts, the non-ideality of mixing is taken into account.

After downloading the database archive:

• unpack it  into a temporary directory; e.g. as Tempfiles/DB.default/ ;
• find where you have GEMS installed, and locate there the Resources/DB.default/ directory. Remove in that directory all files that contain "specific" as part of the file name (if any present);
• copy all files from Tempfiles/DB.default/ into the /Resources/DB.default/ folder;
• start GEMS and create a new project. In the "Basis configuration of a new Modelling Project" dialog, turn off "psi-nagra", "supcrt" (if no aquatic systems should be modelled) and turn on "3rdparty" and "support". Check that in "3rdparty", other entries except "heracles" are turned off. Click "Next>" when ready. This will make HERACLES database files available for creating new projects;
  
• select Independent Components to define the system, and proceed as usual.

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