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  2. Algo, as i have more water samples and the real isotopic composition of these samples while they loss water (by evaporation). I want to compare the simulation with the real samples, so i can take conclusions about samples that do not evaporate in the zone because they are underground (so with the simulation i can make and idea of the evaporation process for those samples). Greetings 😛 Mauricio
  3. Hi, I took a look at the database, but i found the species there). Below is the input script. It contains the chemical composition, deuterium and oxygen 18 of a water sample (superficial). What I hope is to be able to simulate the increase in oxygen 18 and deuterium as the water evaporates up to 100% (almost). My result is that simulation gives me a very small isotopic enrichment of oxygen 18 (that is what I think of, based on more samples that I have from the sector); and also theres no hydrogen enrichment in almost the entire simulation. Thanks for the help and best regards! Mauricio Test.rea
  4. Hello Muhammet, Thank you for attaching your input file. I wasn't able to reproduce your exact diagrams because I don't have your custom thermodynamic dataset, but here are a couple of suggestions that might help clear up some confusion. The cross section view plots variables on an XY grid for a row or column from the 2D phase diagram. I suggest that you double check the XY plots to make sure that they are plotting the row you are expecting from the phase diagram. In the XY plots, I see on the y-axis label "Xi, 0", which in this case means that you're plotting the cross section values in the bottom row of your phase diagram, where the pH is 1.004 and not 1.481. In the configuration dialog (under the tab "Step"), you can also change the Progress variable to display the "pH" instead of the "Rxn progress (y)", which might be helpful to see pH of the corresponding row you're plotting more clearly. If you would like to see more information and some examples of P2plot, refer to section 8.2 Cross-section Plot configuration in the GWB Reaction Modeling User Guide. Also note that the predominance diagram shows the species in the highest abundance. For example, if Ca++ , CaSO4, and Gypsum are present in the same node, the predominance diagram will color the node and assign subsection label according to the Ca containing species with the highest concentration. If you want to display fields where a mineral or group of minerals exist in the calculation, you can use an "Assemblage map" instead. You can also add a color mask of a variable's value range over the diagram axes, that would overlay onto either a predominance or assemblage map. If you're interested in the different the types of diagrams in P2plot, please take a look at section 8.1 2D Diagram in the GWB Reaction Modeling User Guide. It sounds like you're making progress with the software and your work. I hope this helps. Best regards, Jia Wang Aqueous Solutions LLC
  5. Hello, You're welcome. I am not sure the exact details of your file setup so it's difficult to know. One suggestion is to check the isotope data file for the species that are important in your simulation. The isotope.dat file provided with the installation is a good start but you may have to add to it fractionation factors for species that are not accounted for but expected in your simulation. If the species is missing in the database, the program assumes a fractionation factor of 0. If you are still encountering issues, please attach your input script so we can take a closer look. It would also be very helpful if you can provide more explanation of what you're trying to model and the trends you expect. Best regards, Jia Wang
  6. Hi, First of all, thank you for being very supportive so far. I have a question related to Phase2. I used the phase2 file attached to generate diagrams shown in the image file, I have meaningful results from Phase2 cross-section and confirmed with React and also experiments for the particular condition. However, 2D diagram does not match with the cross-section and React results (Please see the attached photo for more information). Could you help me to find the reason behind the inconsistent values, please? Many thanks, Muhammet 25C__ph1.ph2
  7. Hey Karen, I was attempting to input the above script into my model, and I stumbled across a "node by node" function in the mineral "mass" box. If you select "node by node", where you select "volume%" as your units, you can change the volume percent of the mineral in each node of your model. Maybe this was part of a recent update. Cheers,
  8. Hello, Thanks for attaching your input file. If you are only looking at one node, then I am not sure that you need a reactive transport modelling application as you have used here. X1t and X2t are set up to trace chemical reactions that occur over a region of space represented by a system of nodes. If this is the type of simulation that you're interested in, then you should build a reactive transport model. If you are only interested in reactions that are occurring in a single node, then you may want to consider using React. In React, you can just as easily add kinetic reactions to the flush model as you did in X1t. I also see that the specific surface area of forsterite is set to vary according to a random distribution. Since your X1t model has only one node, I am not really sure that it is very useful here. It might be more straightforward to set a constant specific surface area and vary that in different simulations. Just to note, the program does not factor grain size into the equilibrium or transport equations. For kinetic reactions, you can designate a specific surface area for the mineral of interest and that is taken into account for the kinetic dissolution/precipitation of that mineral. If you are using surface area as a proxy for grain size, that would be something that you need to consider carefully. You can find information regarding reactants under Reactant properties when you plot your results. React and X1t will both report the mass of minerals reacted, rate of reaction, and etc. You can find the pore volume displaced under the Physical parameters in the Gtplot or Xtplot. Hope this helps, Jia Wang Aqueous Solutions LLC
  9. Hi Jia, Thank you for your reply. I added the reaction path correctly for y-axis and it works now! Since I couldn't open my previous file and individual p2plot module, I thought there might be an issue. However, adding the reaction path and re-running phase2 made it working again. Many thanks, Muhammet
  10. Hello, thanks for the answer. Im modeling as you told me but when i see the results, only Oxygen 18 get enriched, not Deuterium (it ends with the same inicial composition at the end of simulation, with almost all water removed). Any idea of what im missing?, i believe both isotopes must grow while water is still evaporating.
  11. Hello Muhammet, The issue here is that your input file for Phase2 is missing a reaction path for the y-axis. In the video posted, you can check under the "Y Axis" tab and see that there is nothing set. The Results pane also indicates that there is no reaction path set for your simulation after the run as well. The resulting output file does not enough information to plot a phase diagram in P2plot. Can you double check that you are running the correct file? The video shows your input files contain the .rea extension, which indicates that these are really meant for the React application. In certain cases, you may use a React input file as a starting point (i.e. for setting up the basis constraints) but you should also check that the reaction paths in both x and y axes are set up correctly. For more information on setting up a Phase2 input file, please see the examples in section 7 Using Phase2 in the GWB Reaction Modeling User Guide. Hope this helps, Jia Wang Aqueous Solutions LLC
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  13. Hi, I am using GWB 12 Professional. I have a problem with P2plot which was not there before. Please see the video below. I can't open p2plot window from the main interface, my previously created p2plot plot, and I cant create a new plot using phase2 module. I installed the latest GWB update but nothing changed. Could you help me to fix the issue, please? Many thanks, Muhammet GWB p2plot error.mp4
  14. Hello, I think a good place for you to start is the section working with isotope fractionation in SpecE8. You would need to define the isotope system and then allow the program to calculate the composition of the solvent and dissolved species to honor the fluid's bulk composition assuming isotopic equilibrium. If you require evaporation in your simulation, then you would need to use the React application to simulate reaction path changes. For more information and examples, please take a look at section 7.7 Fractionation of stable isotopes in the GWB Essentials Guide and section 3.9 in the GWB Reaction Modeling Guide. Hope this helps, Jia Wang
  15. Dear Jia Wang, Thanks for your patient explanation and checking. But I don't think it should be ascribed to the lack of constants of KH2PO4 and KPO42-. Actually, I had added these 2 constants before I posted to you, but there was no change in the result. Perhaps, like what you said, it's better to consult with the corresponding author concerning the activity model, charge balance and molal units. It's really helpful, thank you!
  16. Hello Zixuan, Thanks for providing your updated script. By setting up kaolinite as a kinetic mineral with a zero dissolution rate, you have prescribed a surface available for surface complexation for your experiment without precipitation or dissolution of kaolinite to maintain equilibrium with the fluid. Also, the initial method of setting a Al+++/SiO2(aq) activity ratio to a constant value was causing a large amount of dissolved Al and P species to form aqueous complexes that were not considered as a part of the complexation reaction. Here are a few suggestions for you after looking at the paper. If you are using the default thermo.tdat for your run, you would want to double check that the thermodynamic data is consistent. For example, the default dataset doesn't include the reaction for KPO3-- or KH2PO4-. You should also check that the log K data is consistent with those provided in the paper. You will also notice that species not included in the reactions listed in the paper may form because the GWB considers all the reactions possible in the dataset unless it is suppressed. You may find it helpful to either suppress all the species other than the one considered in the paper or can create a new thermo dataset by extracting a subset of the relevant reactions from thermo.tdat. The paper did not provide the activity model used in its modeling with FITEQL. thermo.tdat uses the B-dot activity model, an extended version of the Debye-Huckel equation, to calculate the activity of species. You can find this information in the Headers pane when you open the dataset in TEdit or the activity model line if you open the file in a text editor. If a different activity model was used in the paper, then it may explain some of the differences observed. Other details include whether or not charge balancing was utilized in the original calculation and if so, was the simulation charge balanced with an anion or cation. The GWB uses a molal or mole fraction (for polydentate complexes) standard state in surface complexation reactions. Some programs may use a molar standard state instead, which may result in a small difference when comparing simulation results across software. I would recommend communicating with the corresponding author(s) to see if you are able to obtain more details regarding their model if you would like to improve your results. Hope this helps, Jia Wang
  17. Hi GWB team, I'm attempting to react a specified volume of fluid with a certain chemistry through a mass of olivine with a certain grain size over a year. I am able to do this using X1t, such that olivine dissolves into the fluid as the fluid migrates through. However, I'd like to essentially add more olivine as the initial olivine is dissolved away. Is there a way to do this? I played around with doing this in React - like the "Flush.rea" tutorial - however that does not let you specify grain size. Another example is this quartz aquifer one: https://academy.gwb.com/dissolution.php which is what I’m sort of aiming to do but I’d like to specify grain size of the aquifer. As part of this experiment, I'm hoping to keep track of total olivine dissolved, total fluid passing through the system, and chemistry of that fluid. I've attached an initial script and database to give an idea of what I'm trying to do. Thanks for all the help! thermo.presaltnov2017.dat forsterite_large_v1.x1t
  18. Hello everyone, I have chemical (major and some minor elements) and isotopic (deuterium, 18O) data from water samples. With this i want to know if is it possible to simulate evaporation, with both components at the same time, so that way i could know isotopic enrichment and final chemical concentration. Thanks for this forum 😄
  19. Thanks for your help! I edited the data and simulated again, though the convergence in my last graph disappeared and the tendency was very close to that on paper, the total sorbed fraction was still incorrect. In 0.01KNO3 it should begin with 90% and in 0.1KNO3 it should begin with about 70%. I had no idea about these differences. p.rea
  20. Hello Zixuan, I think you're pretty close with your script. The software calculates the speciation of your fluid based on the component concentrations prescribed in the basis pane. I noticed that you had set the activity ratio of SiO2(aq)/Al3+ to 1. This is not a particularly robust way of performing these simulations as each component may speciate to different extents. Holding these ratios constant might not be particularly realistic and probably contributed to your convergence issue initially. Since the paper did not provide initial SiO2(aq) and Al3+ concentrations in the fluid, you can try setting a negligible concentration for both and set up Kaolinite as a kinetic mineral with a zero rate constant. This way, you are effectively setting up kaolinite as an inert surface, as it will not dissolve or precipitate with a reaction rate of 0 but available for surface complexation. Hope this helps, Jia Wang
  21. Hello Kerstin, The GWB example for Fe2+ oxidation adds OH-, O2(aq), and Fe2+ as promoting species based on the rate law. If you want to use the same rate law as described in Stumm and Morgan, you can substitute O2(g) for O2(aq) as a promoting species. For the rate constant, you would need to convert from /min to /s. For more details regarding kinetic rate laws, please refer to chapter 4 Kinetic Reaction Paths in the GWB Reaction Modeling User Guide. In particular, I think you will be interested in section 4.6 Kinetics of Redox Reactions. If a constant value is provided in the rate constant field, that value is applied across the temperature range of your simulation and does not vary. Note the example input file is set at 10 C, not 25 C. The rate constant used in the example is for demonstrating the principles for kinetic redox reactions, not presenting kinetic parameters as facts. Hope this helps, Jia Wang
  22. Hi, As part of my lecture on reaction kinetics at University of Bayreuth, I have discussed the rate law of the abiotic oxidation of Fe(II) by molecular oxygen (Stumm, W., Morgan, J.J., 1996. Aquatic Chemistry: Chemical Equilibria and Rates in Natural Waters Wiley-Interscience, New York ) with my students. The reaction is Fe++ + .25*O2(aq) + 2.5*H2O -> Fe(OH)3(ppd) + 2*H+ and the rate law is given by: rate_con * activity("OH-")^2 * pO2 * molality("Fe++") with a rate constant of 8 * 10^13 M-2 atm-1 min-1 (at 20°C). I am now trying to simulate the kinetic oxidation of Fe(II) according to this rate law using GWB with my students. For initial rates, the rate law above should equal the example presented at the GWB academy which uses the buit-in rate equation rate_con * activity("OH-")^2 * molality("O2(aq)") * molality("Fe++") * (1-Q/K). The rate constant provided by GWB for this reaction is 7*10^2 kg mol-1 s-1. I understand that the latter rate constant refers to reaction with dissolved O2 on a basis of seconds at (probably?) 25°C, while the constant given above refers to a rate law expression with at O2 in air, on a basis of minutes at 20°C. I was wondering how these tow values compare, i.e. how I can calculate the rate constant from Stumm and Morgan in the units given by GWB. I tried to consider Henry’s constant (again, at 25 °C?) and the transformation from min to seconds, but this gives a completely different number. Also, I was wondering if the rate constant given by GWB refers to a temperature of 25°C (which is then adjusted by Arrhenius’ law, I assume?). If both rate constants cannot be readily compared, do you have a reference for the value used in GWB? The script I want to use with my students is given below, and it pretty much aligns with the file provided on the GWB homepage. Thanks a lot Kerstin Script FeII oxidation_built_in_RxRate.rea
  23. Excuse me, I cannot get an ideal simulation result as for PO43- sorption. In the paper, it took a TLM model to simulate this process with inner-sphere species(>AlOPO32-) and outer-sphere species (>AlOH2+:HPO42-). But the result was still not optimum. I have attached my sdat, this was established on the base of thermo.dat. Meanwhile, the result, solution settings and paper also have been attached. doi:10.2136/sssaj2016.12.0402 The reference result of paper is Fig.7.(b) I would be appreciate if someone could help me. Thanks! Kaolinite-p-original.sdat p.rea
  24. Hello Carlos, I am sorry to hear that you're having issues with your installation. Can you try these general tips for installation issues and see if one works? Restart computer Reinstall the software Reinstall the software as an administrator (right-click on installer "Run as administrator") Run the software as an administrator (right-click on dashboard or GWB app "Run as administrator") Temporarily disable antivirus software, if any Temporarily disable firewall, if any Please let me know if this helped. Best regards, Jia Wang
  25. necesito que me ayuden a instalar el GWB, quiero abrirlo pero me dice que lo reinstale y lo hago pero sigue el mismo problema
  26. Thanks, Jia. I will check this out. I have a question about the error window. Sometimes when the script is too long, the error window would be too long to fully show up on my computer screen. There is no minimize or maximize button on that error window, only close "x". I move the window around but it won't let me see the bottom part. I cannot copy and paste the error information to a text file either. Did you have this issue with the error window?
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