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katezat

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  1. katezat

    SIT database

    Hello Joel, You can calculate activity coefficients using the B-dot model (an extended form of the Debye-Huckel equation), or you can implement the virial methods (Pitzer equations) for better accuracy at high ionic strength. Currently, there is no way to incorporate the Specific ion Interaction Theory (SIT database). Kind regards, Katelyn Aqueous Solutions LLC
  2. katezat

    Activity

    Hello, Act2 works in terms of species’ activity, which is technically unitless, but close to the molal concentration. Remember, the activity is equal to the molal concentration of a species times its activity coefficient. When people construct diagrams by hand they typically assume the activity is equal to the concentration, but if you have a fluid of a certain composition in mind you can use SpecE8 to calculate the activity of the main species. Hope this helps, Katelyn Aqueous Solutions LLC
  3. katezat

    suppressed basis entry

    Hello Lauren, You can't swap a species that is suppressed into the basis. The “suppress” command is used to control which minerals are allowed to precipitate when saturated or suppress any that might be unlikely to form. To unsuppress a mineral, you go to Config – Suppress, select the species or mineral and click unsuppress then apply. For more information, see section 3.61 unsuppress and section 6.98 suppress in the GWB Reference Manual. You can access PDFs of the user's guides or the reference manual from the Help menu of any GWB program, or from the Docs pane of the GWB dashboard. Hope this helps, Katelyn Aqueous Solutions LLC
  4. Hi Tom, If you go to https://www.gwb.com/update.php you can find the latest patch for GWB11, release 11.0.5. Please let us know if this takes care of the issue. Kind regards, Katelyn Aqueous Solutions LLC
  5. Hi Tom, Thank you for the clarification. Unfortunately, we weren't able to recreate the issue you're experiencing with the default IonEx.sdat file. Could you please try reinstalling the software and let us know if this fixes the issue? If you’re still having trouble can you please send us the default file? Thank you, Katelyn Aqueous Solutions LLC
  6. Hi Tom, Can you please attach your revised surface data set (IonEx_revised.sdat), so we can take a better look at the issue you are experiencing? Thank you, Katelyn Aqueous Solutions LLC
  7. katezat

    Calculate EC in GSS 9.0

    Hello Paulina, I also wanted to mention that our latest release, GWB11, offers an alternative method for calculating electrical conductivity*. The USGS electrical conductivity model is valid over a much larger temperature (0 – 95 ⁰C) and ionic strength (0 – 1 molal) range, so you would be able to calculate the conductivity for all of your samples. Please visit http://gwb.com/requests.php to request an upgrade quote or free 30 day demo. *Reference: McCleskey, R. Blaine, Nordstrom, D. Kirk, Ryan, Joseph N., and Ball, James W., 2012, A new method of calculating electrical conductivity with applications to natural waters: Geochimica et Cosmochimica Acta, v. 77, p. 369-382. Kind regards, Katelyn Aqueous Solutions LLC
  8. katezat

    Calculate EC in GSS 9.0

    Hello Paulina, Thank you for sharing your spreadsheet. I would recommend you take a look at conductivity.dat (File - View - conductivity.dat from within GSS) and the reference mentioned for explanation of calculating electrical conductivity. You’ll notice the calculation is temperature dependent, and limited to values between 20⁰C and 30⁰C, which is why it was only calculated for some of your samples. Kind regards, Katelyn Aqueous Solutions LLC
  9. katezat

    Calculate EC in GSS 9.0

    Hello Paulina, Can you please attach your GSS file? Then I'd be happy to take a look and will have a better understanding of what you're trying to do. Thank you, Katelyn Aqueous Solutions LLC
  10. katezat

    SRB modeling

    Hello Zied, The error message you received is because you need to change your working directory to another location, where you have permission to write and save files. In the top left corner of React and the other GWB programs you'll find the path to a folder - this is your working directory. When you double-click on an input file (a saved .rea script, for example) the working directory will be set to the location of that file. If you open a file saved on the desktop, for example, the directory will be set to the desktop. You can change the working directory by going to File -> Working directory and browsing to another location. Kind regards, Katelyn Aqueous Solutions LLC
  11. katezat

    SRB modeling

    Hello Zied, You can find any of the input files from the Geochemical and Biogeochemical Reaction Modeling text in the GWB installation directory (commonly C > Program files > Gwb > Scripts > GBRM scripts). To load a thermo dataset into a GWB application, simply drag and drop the file. For more information on the drag and drop feature see section 1.7 of the GWB Essentials Guide. Kind regards, Katelyn Aqueous Solutions LLC
  12. Hello Michael, With plot output you can determine what dataset was used if it’s in character format. If you’re unsure of a text output file, you would need to compare the included species or reactions and log Ks with your thermo datasets, or run the model with different datasets. It’s often helpful to keep a detailed lab notebook and use the suffix feature to help clear up confusion. Hope this helps, Katelyn Aqueous Solutions LLC
  13. Hello, SUPCRT92 is a program used to calculate thermodynamic properties (log Ks, equilibrium reactions, etc.) at almost any temperature or pressure. Most GWB users are able to utilize the thermodynamic datasets distributed with the software. However, a user may want to account in their calculations for species or minerals not included in the GWB datasets, or to use data derived from more recent and higher quality experiments, or a user might want to run calculations at P-T conditions that are different from those set in the GWB’s defaults datasets. In these cases, a user might search for log K values in a different dataset or in the literature or use a program like SUPCRT92 to calculate the log Ks from other types of thermodynamic data. Hope this helps, Katelyn Aqueous Solutions LLC
  14. Hello, I have manually reset your license and you should now be able to activate it again. In the future, if you need to replace or reformat you computer be sure to first deactivate your license. Please let me know if you have any trouble. Kind regards, Katelyn Aqueous Solutions LLC
  15. katezat

    Dolomite

    Hello Ilona, Most of the thermo datasets have a bibliography which you can find on the Header section in TEdit or at the end of the dataset if you view the file with a text editor. The GWB’s default thermodynamic dataset (thermo.tdat) was compiled at LLNL, but other thermo datasets also come installed with the software. The expanded LLNL dataset, thermo.com.V8R6+.tdat, specifies which references were used for many of the species and minerals. The log K values for dolomite, dolomite-ord, and dolomite-dis are pretty close in the two datasets, so it’s likely they’re referencing the same data. Hope this helps, Katelyn Aqueous Solutions LLC
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