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  1. From: Tiziano Boschetti Subject: Processing multiple samples I'm using a GWB 4.0.3 version. I've a database of 200 water samples and I'd like to calculate the saturation indexes. It's possible to copy at the same time more of one sample data in the spreadsheet form (edit--> Paste From Spreadsheet)? It's possible to include in the dataset, other than basis concentrations, a parameter as density?" From: Tom Meuzelaar Subject: Re: Processing multiple samples The ability to process multiple samples is not available in GWB version 4, but is available in GWB version 6 via TCL scripting. I
  2. From: Andrew L. Scott Subject: ACT2 and REACT not in agreement I have been trying to model the Yucca Mountain J-13 well water in preparation for performing a sensitivity analysis for U speciation. Attached you will find the Statement of the Problem, some REACT output, the thermo dB, scripts for ACT2 and REACT and some calculation macros. I updated the thermo.com.v8.r6+ dB with the NEA 2003 numbers for U species only at 25 deg C. I hope someone is able to understand and help with my problem. I have tried to be as complete as possible with the materials I have provided, but if there is anyth
  3. From: Biniam Zerai Subject: Info on CO2(aq) I am trying to model the possible reaction of CO2 gas, albite, annite, siderite, calcite and dolomite in 2 molal of brine solution. I made the correction for fugacity of the gas using Duan and Sun equation of state but I am not sure what is the right way as how to correct the salting-out effect using GWB. I have been told to change the the ionic size in the thermodynamic database that contains the aqueous species, CO2(aq) to -0.5 in order to correct the effect of salinity on CO2(g) solubility. Is this the right way to do it? I did it using the abov
  4. From: Tiziano Boschetti Subject: Correct formula for hydrated minerals I've noted that the water of hydrated minerals in the database thermo_phrqpitz is written as: H2O or ^H2O. So, if I add a new mineral, what's the correct form? From: Tom Meuzelaar Subject: Re: Correct formula for hydrated minerals As far as the software is concerned, the notation you use doesn't matter- what is important is that the formation reaction for the mineral is written only in terms of the 16 basis species in the thermo_phrqpitz database. Maybe another user can shed light as to whether or not there's any
  5. From: GOLDEN, D. C. Subject: Evaporation of saline solutions containing Al3+ and Fe3+ I am trying to simulate the evaporation of acidic aqueous solutions containing Na, K, Mg, Ca, Mg, sulfate, Al and Fe. I use the flow through model of the React2 in GWB 4.0.3. I tried to use the data base for the Harvie-Moller-Weare activity model provided in the above package. When I include Al and Fe in the Basis, it responds : Al3+ not in the database, and similarly for Fe3+. Is there a data base for high ionic product solutions which takes into account these ions? How do I update the existing database to
  6. From: Hlanganani Tutu Subject: Modelling geochemical speciation of uranium in sediments I need your help and advice on how I can do thermodynamic modelling of uranium speciation in sediments. Is it proper for instance if I measure the temperature, pH and redox potential of the moist sediment and then leach with deionised water (shake test) and measure sulphates and uranium in the leachate. Finally, I use these results to construct the Eh-pH diagrams. I'm studying the geochemical speciation of uranium in mine tailings and am using GWB release 4.0.1 for modelling. From: Armand R. Groffman
  7. From: Andrew L. Scott Subject: Database Conversion Routines Does anyone have any conversion programs for converting some other database format to that of GWB? I am particularly interested in converting the NIST Standard Reference Database 46- Critically Selected Stability Constants of Metal Complexes- Ver 8, Martell, et al.
  8. Since GWB does not natively run on Linux you have emulate Windows to get GWB running. So far I have tested two options: VMWare and Crossover Office. There is a slight difference between the two. In VMWare you install Windows as your virtual machine and then install GWB as you would in Windows. There are no major problems I know about, however, I recommend a fast machine for VMWare to operate fast enough. The cost is ~190USD (http://www.vmware.com). Crossover Office (based on Wine), on the other hand, will trick GWB (and a lot of other Windows programs) into believing it is being inst
  9. Edward Grew Subject: Cerium redox equilibria Is anybody aware of experimental work on CeO2 - Ce2O3 equilibria? I am looking for a T - f(O2) diagram for Ce oxides. From: J. Michael Palin Subject: Re: Cerium redox equilibria I seem to remember various multiple valence oxide pairs, including CeO4-Ce2O3 and Eu2O3-EuO, shown on a T-fO2 diagram in: Carmichael, I.S.E. & Ghiorso, M.S. (1990): The effect of oxygen fugacity on the redox state of natural liquids and their crystallizing phases. in ¨Modern methods of igneous petrology: Understanding magmatic processes¨, J. Nicholls & J.
  10. From: Henry B. Kerfoot Subject: Request for kinetic data (calcite) I am looking for kinetic data on the reaction of calcite with low-pH water. In particular, I wish to be able to estimate an appropriate residence time for pH 3.5 water in commercially available limestone gravel.
  11. From: Kirk J Cantrell Subject: Pitzer and React I am using React to calculate the solubility of a mineral at high ionic strength using the Phrqpitz thermo database. I modified the database to include a solubility constant for a mineral I am interested in, as well as some associated Pitzer parameters. Without giving you all the details, I have determined that the model is not using the new theta parameters for the interaction of two anionic species that I added to the Phrqpitz thermo database. The reason I know this is that at zero ionic strength, React is calculating the solubility correc
  12. From: Burnol Andre Subject: Convert Phreeqc format to GWB format or EQ3 format I am wondering wether a code converting Phreeqc to EQ3 format for the thermodynamic database is available ? I know that, recently, thermo_phreeqc.dat - The thermodynamic database from PhreeqC release 2.8 - is ready for use with GWB. But I don't know how the conversion was made ?! if a code was developed for this purpose, it will be not very difficult for me to adapt this convertor if the sources are available. I am currently using a modified llnl.dat in Phreeqc format and I would like to convert it in EQ3 format.
  13. From: Andrew L. Scott Subject: 'Best' database I am performing uranium speciation of natural ground waters under various conditions, including speciation with organic and inorganic ligands. What are your opinions on the 'best' database to use for this application (please also consider databases that are not necessarily in GWB format, as I can convert if necessary). I am currently using thermo.com.v8.r6+, but want to ensure I am using the 'best' available data. I have available, for example, NIST standard reference database 46, critically selected stability constants of metal
  14. From: Brian Gibney Subject: Fe/As redox and sorption I am modeling the sorption of arsenic to Fe(OH)3 under the following circumstances: 1) Arsenic consistently oxidized, Fe redox slides from reduced to oxidized 2) Fe consistently oxidized, As redox slides from reduced to oxidized The basis for my reaction has been set up as below: hematite/Fe+++ = 1 free gram e-/O2 = 0 Eh Na = 100 mmolal Cl- = 100 mmolal (charge balance) SO4- = 10 mmolal Ca++ = 10 mmolal As(OH)4- = 0.1 mmolal H+ = 7 (pH) Reactants: react 1 g Fe(OH)3 ppd slide Eh to 1 Plots of reactions don't show a
  15. From: "Brugger, Joel (SAM)" Subject: Speciate different components over x-y I'm trying to calculate a log f O2(g) vs pH diagram to show relationships between Fe-Ni sulfides. I therefore speciate SO4-- and Fe++ over x-y and make the diagram for Ni++. I get a nice diagram, but something disturbs me. The dashed boundaries correspond to the overlap of the boundaries for the pure Fe-O-H and S-O-H systems. It seems more appropiate that the boundaries for Fe should take into account Fe sulfides (e.g. pyrite), i.e. the Fe should be speciated in the Fe-S-O-H system. So my question is: is there any
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