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Jia Wang

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  1. Hello Johan, I think your rate law is ok when I tried to read in the script with a different dataset. However, I think your command for report Eh(Fe+++/Fe++) is not quite right. For the Nernst Eh value of a redox pair, you would want to use the keyword "Eh" followed by the arguments "couples" and the name of the couple exactly as shown from the report ('couples') command enclosed in double quotes. For example, to retrieve the Nernst Eh value for the redox pair Fe+++/Fe++, it'll be like this: cp.Report1('Eh couples "Fe+++ /Fe++ "') For a more detailed list of keywords and arguments accepted by the report command, please refer to the Appendix: Report Function section in the ChemPlugin User Guide. Hope this helps, Jia Wang Aqueous Solutions LLC
  2. Hello Jason, I am sorry to hear you're having issues with the installation of the new update. That error typically means the file that the installer is trying to write to is in use by another application or anti-virus software. Please try installing again after rebooting your computer. If you still encounter the same errors, try disabling any anti-virus type software briefly and run the installation again. Hope this helps, Jia
  3. Hello Jon, The GWB apps will report the water type based on the highest electrical equivalents of cation and anion species of a sample after calculating speciation. Best regards, Jia Wang Aqueous Solutions LLC
  4. Hello Wen Qiu, The GWB applications themselves do not carry species, minerals, or gasses. The applications draw reactions from the thermo dataset loaded for your calculation. In React, you can go to File -> View -> select the file that ends in .tdat (or .dat for really old datasets) to view the thermo dataset loaded. thermo.tdat, the default dataset in The GWB does not contain Lactate, you can add the reaction using values in literature or copy and paste it from another database to thermo.tdat and save it as a custom dataset with a new name. You might also find the GWB academy lesson on Microbial Population helpful. The dataset used in this example is a modified thermo.tdat with the addition of the Lactate reaction. For more information on how to alter thermo datasets in the GWB, please refer to section 9 in the GWB Essentials User Guide. Hope this helps, Jia Wang Aqueous Solutions LLC
  5. Hello Erik, If a mineral is known to be in equilibrium with the fluid in your system at the start, then you would swap in the mineral in the basis and allow the program to calculate the dissolved concentration in equilibrium with that mineral. You shouldn't convert a mineral into aqueous species and then sum those concentrations into the basis pane. For example, if your fluid is in equilibrium with Quartz, add SiO2(aq) into the basis and then swap it for Quartz and set the volume of quartz. The speciation calculation in the GWB will calculation the dissolved silica component in addition to the mineral you input. In your input file, it'll look like this: swap Quartz for SiO2(aq) Quartz = 1 free cm3 Also, you don't have to keep to mg/kg as the unit. The GWB accepts many units for minerals and dissolve species concentration. To see all units recognized by the GWB, see the GWB Reference Manual. I think it would be really helpful for you to revisit the sections in the Essentials User Guide on how The GWB configures its geochemical system. The best place to start would be in section 2.1 Configuring a calculation and 2.2 Setting and constraining the basis. You can find the commands accepted by each GWB app in the GWB Command Reference. Hope this helps, Jia
  6. Hello Eden, Act2 draws its species, minerals, and gases from the thermodynamic dataset loaded in the run. You can view the thermodynamic dataset loaded by going to File -> View -> open the file that ends in .tdat (or .dat for really old datasets). thermo.tdat is the default dataset used in The GWB apps and does not contain Antimony. You can add in Antimony and the desired reactions to create a customized thermo dataset tailored for your needs. Here is a similar thread which discusses how to do so. Hope this helps, Jia Wang Aqueous Solutions LLC
  7. Hi Erik, You're welcome. I am not sure what you mean by breaking down each input species to basis species. A good example of a free quantity is pH. pH is a measure of the activity of H+ alone. When you enter a pH, you're describing the hydrogen only in the H+ form and not including any H that's part of other aqueous species (e.g. CH4) or minerals. A typical use of a free quantity is when a user is setting the fluid in equilibrium with a mineral. For example, if the silica component in your system is in equilibrium with the mineral quartz, you should swap in Quartz for SiO2(aq) in your system. Minerals like this are typically set as a free unit since the amount entered represents only the silica that exists as quartz not the silicia in dissolved species such as SiO2(aq). On the other hand, most chemical lab analysis of a water sample provides bulk quantities. In natural waters, sodium may exist in fluid as Na+, NaCl, NaHCO3-, NaOH, and more but the measured concentration only reports the total quantity of Na+. When you enter this bulk concentration in the basis, the software solves a set of matrix equations to distribute the total mass of Na+ amongst all Na-bearing species. The bulk concentration is not just the dissolved Na+ ion alone. Please see section 7.2 Equilibrium models in the GWB Essentials User Guide to see a seawater speciation example. Hope this helps, Jia
  8. Hello, I am glad to hear that you were able to copy the reaction for H2(aq) and H2(g) to thermo_minteq. If you like, you can use Rxn to calculate the log K values for the intermediate temperatures, similar to how it is done for H2(aq). You can load thermo.tdat into Rxn and select H2(g) in the "balance reaction for" section. The program by default populates the "in terms of" section with the basis species that reacts to form H2(g). Since you want the log Ks for the reaction H2(g) = H2(aq), swap H2(aq) for O2(aq) to rebalance the reaction. Then enter the desired temperature and run the calculation. You can find the log K at your desired temperature in the Results pane. Hope this helps, Jia Wang Aqueous Solutions LLC
  9. Hello Erik, Please find my response to your earlier post here. I had already included some explanation regarding bulk vs. free quantity there before seeing this post. Best regards, Jia Wang Aqueous Solutions LLC
  10. Hello Erik, The GWB does not account for species that are not defined in the thermo dataset. In a speciation calculation, you supply the composition of your system and the software calculates the distribution of mass amongst species using thermodynamic information provided in the thermo database loaded. For example, if a system’s composition consists of sodium, chloride, and solvent water at a given temperature, then the program will calculate the mass distributed amongst the dissolved species and minerals given the bulk quantity of each component. If we use thermo.tdat with the system above, the software will calculate the amount of the sodium component distributed between the free sodium ion (Na+), NaCl complex, and the halite mineral if it precipitates (assuming that you are using React). NaCl is not part of the basis species in the thermo.tdat but instead a secondary species that forms from reacting the basis species of Na and Cl, you will find it in the Aqueous Species section. You should never see GWB report a species that doesn’t exist within the dataset loaded. Users can easily edit datasets in TEdit or in a text editor, like Notepad, before the run to account for reactions not in the dataset. For more details, please see section 9 TEdit in the GWB Essentials User Guide. You set the composition of your initial system using a set of basis species. The basis is the set of aqueous species that appear at the beginning of the thermodynamic database. You can alter the basis by swapping in aqueous species, minerals, or gases that you wish to use to constrain your geochemical system. For example, if your system is in equilibrium to quartz, you will add the component SiO2(aq) to your basis and then swap it for Quartz. For more information on setting up your basis, please see section 2 Configuring the Programs in the GWB Essentials User Guide. An important point to note is setting a bulk vs. free quantity in the basis. For example, you can constrain the sodium component in your basis pane by setting a bulk quantity, which would include the total amount of sodium present in all sodium bearing species. Alternatively, you can also set a quantity for the free sodium ion, which does not include the mass of sodium in Na-complexes, and have the software calculate bulk composition. For more details and examples, please refer to section 7.2 Equilibrium models in the GWB Essentials User Guide. Hope this helps, Jia Wang Aqueous Solutions LLC
  11. Hello Karen, Johan, I want to let you know that this issue has been fixed with the release of GWB 15.0.1 for all GWB subscribers. Existing 15.0.0 installations should automatically update if auto-update is enabled. If disabled, you can update your installation under the Help menu in any GWB app. Best regards, Jia
  12. Hello again, I want to let you know that this issue has been fixed with the releases of GWB 15.0.1 and GWB 12.0.8. Existing GWB 15 and GWB 12 installations should automatically update if auto-update is enabled. If disabled, you can update your installation under the Help menu in any GWB app. Best regards, Jia
  13. Dear GWB users, We are pleased to announce our latest maintenance release for GWB subscribers, GWB 15.0.1. The 15.0.1 update fixes tab delimiting issue in thermo datasets, improves presentation of some dialogs on high-resolution monitors, improves messaging in TEdit, enables "report" command to list entries in current thermo database, resolves last-digits inconsistency in reported solvent mass, fixes an issue arising when importing some PhreeqC datasets, allows user-defined analytes to share names with basis entries in GSS, and provides fixes for all known issues. Update from 15.0.0 at no charge to ensure you have all the newest features and bug fixes. Existing installations should automatically update to this release, unless auto-update is disabled. In that case, users should update their installations from the Help menu of any GWB app. Best regards, Jia Wang Aqueous Solutions LLC
  14. Hello Juro, The default GWB dataset (thermo.tdat) is based on the Lawrence Livermore National Laboratory database. Thermo.tdat is converted from the file data0.3245r46 from EQ3/6. You can find information regarding the origin of the dataset at the top of the text file and sources cited at the end of the text file. Or, if you open the dataset in TEdit, you can find both sections in the Header pane. You can contact the original authors regarding compilation method and discrepancies. Also, I wasn't able to verify the Log k value for the reaction stated above in thermo.tdat. Perhaps, you are looking at a different dataset? The expanded variant of LLNL dataset, thermo.V8.R6+.tdat, does contain thermo data for H2AsO3- with Log Ks spanning from 0 to 300C. The Log K at 300C is 13.8282 and not 11.92. Perhaps your reaction data was altered at some point? You can download the version installed with the software from the thermo webpage. SUPCRTBL and SUPCRT uses mostly the same data sources for their compilation but they are not entirely the same. You can view a summary of their differences here. If you would like to use a dataset that's consistent with SUPCRTBL, you can convert one of the ready-to-go PhreeqC datasets to GWB format using the TEdit application. There are several default datasets published that you can choose from. Geothermal.dat is compiled from 0 to 300C using the debye huckel b-dot activity model. To convert geothermal.dat to GWB format, you would need to edit the llnl_aqueous_model_parameters block so that there are only 8 principal temperatures spanning the desired range. For more information on converting datasets, please see section 9.3 Importing PhreeqC datasets in the GWB Essential User Guide. Hope this helps, Jia Wang Aqueous Solutions LLC
  15. Hello Zixuan, GWB does not fit surface data to calculate surface reaction equilibrium constants. However, you may be able to use the Alter Log K dialog to manually alter the log k values for your surface reactions to and find the value that best reproduces your data by trial and error. Overlaying your data on your plot may help to visually assess this. For more information on Altering Log Ks, please refer to the alter command in the GWB Command Reference. In GWB applications (except GSS, TEdit, and the plotting apps), you can find the Alter Log K under Config -> Alter Log Ks... For examples of scatter data, please refer to section 6.5 in the GWB Reaction Modeling Guide. Alternatively, you can also write your own scripts and use React's plugin feature to run the models and retrieve the data, assess the fit quality, update your Log K with a better estimate and rerun the model. Please refer to section 7 of the Command Reference for details regarding the Plugin feature. Best regards, Jia
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