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Frank Bok

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About Frank Bok

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    http://www.thereda.de www.hzdr.de/res3t

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    Helmholtz-Zentrum Dresden-Rossendorf
  • Interests
    high salinar solution modelling
    sorption (SCM)
    providing thermodynamic data:
    and sorption data:

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  1. Hi! I would like to model a 2D transport calculation with two spatially separated mineral phases. Is this possible to set up a model with different minerals in different blocks? And, due to the effects of grain boundaries and surface roughness, is it somehow possible to have different surface areas for the minerals in different blocks? Thanks in advance and best regards, Frank
  2. Hi Brian, thank you very much for your comment! 😀 Best regards, Frank
  3. Dear Forum members, recently I tried to model a seawater evaporation and I ended up with different results (using the same Pitzer database) with the identical .rea-files input just with different order of entries n(concerning the species in Basis) in the two files. One file I had created in my own in React (Working_example.rea), the other one (Aborting_example.rea) was created by launching React from GSS. The chemical composition is the same in both files but the one from the GSS-launched React instance stops much earlier. I would like to understand the different behavior, in principle, it shouldn't do that. Thank you in advance and best regards, FrankTHEREDA_PIT_GWB_r03.dat Working_example.rea Aborting_example.rea React_output_aborting.txt React_output_working.txt
  4. Hi Brian, thank you for the information. Acutally I wanted to use the activity model "phreeqc" so this is one of the reasons I got in this trouble. I should more often remember to "RTFM"... ;-) Thank you and best wishes! Frank
  5. Hello, I have prepared a database (attached) and both TEdit and React are loading the file without any warning. But even the simplest calculations fail and give an error message like this: Is there a way to locate the error to make it work? Thank you in advance and best regards, Frank thermo_test.tdat Test.rea
  6. Hi Brian et al. I would like to learn using the new Phase2 program and to do so, I started with something simple: the Eh-pH diagram of Uranium using thermo.tdat. With Act2 this works over the whole range (pH = 0 to 14, Eh = -0.9 to 1.25 V). Trying to do the same with Phase2, I run into several problems: If I try the whole pH range (starting at pH = 0), the initial system cannot be solved: Newton-Raphson did not converge after 999 iterations, maximum residual = 5.42e-15, Xi = 0.0000 Largest residual(s): Resid Resid/Totmol Cbasis --------------------------------------------------------- Na+ 3.338e-05 5.422e-15 7.396e+05 --------------------------------------------------------- Reducing the pH range to 4-10 and deactivating charge balancing, the diagram can be calculated. But: The resulting diagrams of Act2 and Phase2 does not match. If I try to go higher, either GWB runs with full CPU workload and does not respond (Windows then kills the program if I try to close it) or produces an incorrect *.p2p file. Can you give me a hint how to correctly use Phase2?! Thank you in advance and best regards, Frank Phase2-Test.ac2 Act2_output.txt Phase2-Test_error.ph2 Phase2-Test.ph2 p2plot_conf.p2c
  7. Hello! I try to model the alteration of Ferrihydrite to Goethite (including it's effect on sorption). I have suppressed all Fe minerals beside Fe(OH)3(ppd) and Goethite. Since Goethite has a much lower solubility, GWB uses Goethite as stable mineral phase and instantantiosly forms Goethite from all the Fe(OH)3(ppd) I give into the system. My only idea is to remove all the Fe(OH)3(ppd) first from the system and then add the same molar amount of Goethite. But this is somehow inelegant. I also found some kinetic data on the Ferrihydrite-to-Goethite alteration, that I would like to use (http://pubs.acs.org/doi/pdf/10.1021/ie010931z). My question is: Is there a way to handle two mineral phases with the same basis species / redox species (in this case Fe+++) in coexistence? Thank you in advance! Frank
  8. Dear Melika, thank you forthe quick answer. With your help I got the points into Gtplot. The main problem was that I am not using the MS Windows Editor but another ASCII editor. And the Windows editor handles columns a little bit different than Notepad++. Again thank you and best regards, Frank
  9. Hello, I have done a small sorption modelling (works fine) and I wanted to add some experimental points to the graphic output using the File > Open > Scatter data. I have my data points (ok, not my data points but from a paper) as ASCII file (tab seperated values, BB93.txt), but no points were displayed. Is there a way to import ASCII files as scatter data or do I have to create an .gss file? Thank you! FeOH_Np.sdat Np-Sorption.rea BB93.txt
  10. Hi Brian, thank you for the answer. Are there future plans zu include a fugacity coefficient model? Best regards, Frank
  11. Hi, I plan to create a dataset for the calculation of Hydrogen solubility in water and brines at elevated temperature (0-100°C) and pressure (≤ 50 bar). So my question is: How is the pressure dependecy of gases implemented in GWB? I know that PHREEQC calculates the fugacity coefficient with the Peng-Robinson equation of state and I would like to know whether GWB uses the same model or another. And if there is a model for the pressure dependecy implemented, where can I enter the corresponding parameters for a new gas? Thanks in advance! Frank
  12. Hi Brian, thank you for the comment. Actually I have created a model using React and it works fine. I just wanted to create a "nice picture" with Act2. Regards, Frank
  13. Hello, I try to ceate a Eh-pH diagram for neptunium in the presence of the mineral siderite (and vice versa the diagram if iron in presence of neptunium). Both cations should be able to form complexes with carbonate - and such complexes are within the thermo.dat. But I can't get Act2 (Version 10.0.4) to manage both carbonate complexations. I attached and example and the carbonato-complexes of neptunium are not taken into account allthough they should be formed as dominant species in the alkaline range then carbonate is present. Is there a way to inlcude both complexations? Thanks in advance! Frank Demo.ac2
  14. Hi Brian, thank you for the information. Beside of the oscillation I get the invariant point. Best regards, Frank
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