[Site occupancies on exchanger phase]

Hi Tom

 

Thanks for the additional information.

 

However, I'm still not entirely clear how to proceed with this.

 

For example, if I want to model exchange on smectite, which say has 4 exchange components (e.g. Na, K, Ca, Mg), do I need to have 4 versions of the IonEx database for each of the components, i.e. one each for Na, K, Ca and Mg?

 

It would be a lot easier to do this if the input requirements for GWB were like those in PHREEQC - presumably this would be easy to implement? Also, in PHREEQC you can calculate the exchanger composition in equilibrium with a given water composition, which is also a very useful feature.

 

Whilst I'm on the subject of GWB developments, I'm really surprised that there's no capability for modelling solid-solutions. Again, this capability is in PHREEQC, and as I recall, was available in EQ3/6 (albeit for ideal solid solutions) about 20 years ago. Is this something that you can include for the next version?

 

Many thanks for your help.

 

best regards

 

Dave

[Site occupancies on exchanger phase]

Hi Dave:

 

Two ways to do this:

 

1. Set a non-reactive rock volume using the inert variable (Config - Variables menu). GWB will convert the volume to rock mass using a standard rock density of 2.65 g/cm3.

 

2. Define a reactive mineral mass either in your Basis setup, or make sure one precipitates during the course of a reaction path model. GWB will exchange mass between rock and fluid independent of mineral composition. That is, minerals that are not clays will exchange with the fluid if they are present in the system.

 

If you are using ionex.dat as a database template, GWB assumes that the sorbed cations are all Na+ cations. You can change this by re-writing the dataset. Refer to the instructions in ionex.dat for more detail.

 

Hope that helps,

 

Tom Meuzelaar

RockWare, Inc.

 

Hi Tom

 

Many thanks for the pointers.

 

I think I understand what you mean, but it does seem a bit of an obtuse way of doing it!

 

Is this something that you might address in the next GWB update? I think a more transparent way of specifying the exchange composition would benefit a lot of users.

 

best regards

 

Dave

[Site occupancies on exchanger phase]

How do I set the occupancies on the (solid) exchanger phase when I'm using the ion exchange option in SpecE8 and React?

 

I can see how to set the total CEC and exchange constants, but not the site occupancies.

 

Any ideas?

[Scatter data character set problem]

Hi Dave:

 

This sounds like a problem with the GWB fonts not being installed on your Mac desktop. The fonts are not embedded in the image files you mention. GWBSymbol.ttf is found in the font folder of your installation CD, and is freely distributable, however, I would be surprised if it installed properly on Mac. You are welcome to try it though...

 

Hope that helps,

 

Tom Meuzelaar

RockWare, Inc.

 

Hi Tom

 

Your suggestion worked! Many thanks!

 

best regards

 

Dave_S

[Scatter data character set problem]

I'm running GWB on a Mac through a VMWare virtual machine. It works fine.

 

However, when I include scatter data on an ACT2 plot, although the plot looks OK on my PC window, when I transfer the plot to my Mac desktop and open with Illustrator, the scatter data symbols appear as odd characters (e.g. 'J's' instead of dots). (see attached file).

 

This happens with .svg, .eps, and .emf files (I haven't tried any others).

 

Is there a scatter data character I can choose that will be recognised on both operating systems?