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Tom Meuzelaar

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Posts posted by Tom Meuzelaar


  1. Hello:

    This isn't necessarily an issue with charge balance. It could be that you've defined a system that is far from equilibrium, and thus has trouble converging. If the pH value is important, I recommend starting with 3.5, so the system initially converges, then sliding the pH (in the Reactants pane) down to 3.1, so that you have a stable chemistry.

    Hope that helps,

    Tom Meuzelaar

    RockWare, Inc.


  2. Hi Olivia:

    We are wondering if a firewall or anti-virus program are temporarily disabling the software that runs your hardware lock. Is it possible to disable your firewall and/or antivirus software to see if that makes a difference?

    If it does not, can you go to the following address on your browser: http://localhost:1947, and click on the HASP keys menu on the left hand side? Please send the resulting screenshot to my attention via email.

    Regards,

    Tom Meuzelaar

    RockWare, Inc.


  3. Hi Ken:

    I'd start by taking a look at polythermal reaction path models in the Reaction Modeling User's Guide. You should be able to view the pH vs. temperature trends in Gtplot. Dealing with variable pressures is going to be a bit trickier, given that the database is compiled for a single confining pressure (1 atm). For most aqueous species and minerals, the equilibrium constant data does not change significantly, but for gases it is a different story altogether, and you may need to make some database modifications.

    Hope that helps get you started,

    Tom Meuzelaar

    RockWare, Inc.


  4. Hello:

    Yes, I've used the RC_helper.h and RC_helper.cpp source files without too much trouble using Visual Studio. I had to adjust a few settings in the default setup for VS, including:

    1. In project settings, remove explicit use of the Unicode character set.

    2. Turn off use of precompiled headers

    However, these settings are specific to Visual Studio, so they may or may not help you. I can tell you that there is nothing wrong with the RC_helper.h and RC_helper.cpp code, and that your problem is probably somewhere in the configuration of the application you are using for code development.

    Unfortunately, my response time will be much slower after this, as I am about to step out for a 4-day holiday weekend.

    Regards,

    Tom Meuzelaar

    RockWare, Inc.


  5. Hello:

    I recommend checking your syntax- as the error messages suggest,this is likely cause by missing a semicolon somewhere. If this occurs in one line of code, all of the other lines of code can become uninterpretable.

    I hope that helps,

    Tom Meuzelaar

    RockWare,Inc.


  6. Hi Ruth:

    This should work fine- just be sure to:

    • constrain the oxygen concentration in the system
    • specify a pH
    • convert your total As concentration to the arsenic basis species

    GWB will speciate all of your arsenic among all dissolved arsenic species in the thermo database according to their equilibrium constants.

    Let me know how I can be of further help.

    Regards,

    Tom Meuzelaar

    RockWare, Inc.


  7. Dear Christoph:

    The reason for this is that the temperature dependence of the rate constant is defined as a function of the activation energy (Ea) and pre-exponential factor (A) as follows:

    kinetic_temperature_dependence.jpg

    If you have a kinetic rate law that includes both a rate constant and activation energy, you might consider using the Custom Rate Law features in GWB.

    Hope that helps,

    Tom Meuzelaar

    RockWare, Inc.


  8. Hi Adam:

    You can do this using React, a simple mixing model, and the Pickup command. First add your acid groundwater to the React Basis. Speciate this water, and use the Config - Pickup - Reactants command to load the speciated water into the Reactants tab. Next load your surface water into the Basis tab. You now have a model simulating gradual titration of acidic groundwater into surface water.

    You'll run into a problem due to the fact that your surface water does not have all the components of your acid groundwater (Br-, Al, Fe, Mn). Remedy this by either excluding these components from your acid groundwater analysis, or by adding acceptably low concentrations for these components to your surface water in the Basis.

    I hope that helps,

    Tom Meuzelaar

    RockWare, Inc.


  9. Hi Ross:

    It turns our that the rate law script, as written in the v8 Reaction Modeling user's guide (page 56), reflects command line syntax. The actual code for the direct script editor looks exactly like the code you would put in a .bas file- you only need the code in between the brackets- not the 'kinetic Albite rate_law = { }' part.

    I hope that makes sense...

    We'll update the User's Guide to be a little more clear.

    Regards,

    Tom Meuzelaar

    RockWare, Inc.


  10. Hi Ross:

    I simplified the script quite a bit, and am still getting a syntax error in line 1, even though the format appears to be correct. I'll need to check with the developers to see if I'm doing something wrong here.

    However, there's a simple work-around. Save the file in notepad with a .bas extension, and load it in as a Rate law script file.

    Let me know if that resolves the issue.

    Regards,

    Tom Meuzelaar

    RockWare, Inc.


  11. Dear GWB users:

    We are pleased to announce a workshop in Golden, CO for GWB Essentials, Standard and Professional users this fall.

    The July 7-8, 2011 workshop is designed for:

    • Current users of GWB Essentials, GWB Standard and GWB Professional who wish to become more familiar with the software's interface and features.
    • Those interested in reviewing the basics of geochemical modeling (speciation models, activity models and activity diagrams)
    • Those interested in learning detailed reaction path modeling (using redox disequilibrium, kinetics, and surface complexation)
    • Those interested in learning the basics of 1D/2D reactive transport modeling

    Registration fees are $799 (commercial) / $699 (academic). Students can register on stand-by for $299.

    RockWare will be hosting the workshop in their newly remodeled conference room. The advantage of this venue is a smaller classroom size and teacher to student ratio. This does, however, require that students bring their own laptops. RockWare will provide temporary licenses for GWB Pro v8 to each participant.

    There conference room seats up to 7 participants. If the course is sold out, and significant interest remains, we will consider holding a second workshop later in the year.

    For all the details, visit the GWB workshop page on the RockWare website.

    Please don't hesitate to contact me with any questions.

    Regards,

    Tom Meuzelaar

    RockWare, Inc.

    2221 East Street Golden, CO 80401

    ph. 303 640 5526

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