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  1. Hello, I'm wondering if you could provide some information about the water activity calculation in Debye-Huckel/Bdot thermodynamic datasets. How exactly are the coefficients in the header of the file derived and utilized? I have scanned the reference manual and the Bethke (2010) book, but cannot find this information in either. Any relevant reference would be greatly appreciated. Thanks, Ben
  2. Hi Brian, Thanks for the response. The only problem I see with this solution is that it requires the basis to be in equilibrium with the initial mineralogy (quartzite in Ex. 3.3), which is not possible for minerals with no stability in the presence of water at the reaction conditions you are examining. This is how I ended up with the "backward" configuration (minerals reacting with water, rather than water reacting with minerals). Is there a workaround for this? Thanks! Ben
  3. Is there a convenient way to perform and plot water-to-rock ratio calculations in React? In other words, repeatedly reacting 1 kg of solution with fixed composition (i.e., seawater) with 1 kg of "rock" of fixed mineralogy to achieve ever-increasing water-to rock ratios and plotting the precipitated minerals (y axis) vs. water-to-rock mass ratio (x-axis). This is a typical calculation to do with EQ3/6 and it is intuitively possible with GWB, but I can't come up with a way of doing it that isn't either "backwards", i.e., repeatedly reacting a rock (reactants tab) with a solution of fixed init
  4. Thanks, Brian. I ended up producing a GSS spreadsheet with the appropriate Trailer lines, and then wrote a Matlab script that extracts the pH from the output files.
  5. Is there a way, using GSS/React, to add a reactant to every sample in a GSS spreadsheet and have the resultant pH output in a separate column of the spreadsheet? Or, alternatively, is there a way to extract only the final pH from a React output file? I need to perform thousands of calculations, so it isn't practical to go into every file and copy and paste the final pH into a spreadsheet.
  6. You are correct about the factor of 10^8 on B. GWB tabulates them without the factor, but they are indeed all multiplied by 10^8 in the calculations. To calculate A and B, I would suggest using: Helgeson, H. C., Kirkham, D. H., 1974b. Theoretical prediction of the thermodynamic behavior of aqueous electrolytes at high pressures and temperatures: II. Debye-Huckel parameters for activity coefficients and relative partial molal properties. Am. J. Sci. 274 (10), 1199–1261. Density and dielectric constants are calculable using algorithms implemented in SUPCRT92 (Johnson et al, 1992).
  7. All of the source code and executables for DBCreate can be downloaded from the journal in which the article was published, Computers & Geosciences as an "Application" file. Kong, X. Z., Tutolo, B. M., & Saar, M. O. (2013). DBCreate: A SUPCRT92-based Program for Producing EQ3/6, TOUGHREACT, and GWB Thermodynamic Databases at user-defined T and P. Computers & Geosciences 51: 415–417. http://www.sciencedirect.com/science/article/pii/S0098300412002828 If there are any problems, we can work with you to produce a new GWB-formatted data set. Please be sure to cite DBCreate whe
  8. Our code, DBCreate, is now available to produce GWB-formatted database at user-defined temperature and pressure. Users may find this useful if they are interested in high pressure applications, or for implementing new or revised thermodynamic data into their GWB simulations. The paper and software can be found here.
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