Creating and Editing Precipitate Removal Mass Flux Links

To create a precipitate removal mass flux link An interconnnection between two transport pathways that defines the rate at which species move between the pathways. between two pathways in GoldSim, you must specify a single input:

Precipitate removal mass fluxes can only originate from a Cell pathway A transport pathway element that is mathematically equivalent to a finite difference node. Cells are commonly applied to simulate discrete compartments in an environmental system (such as ponds, lakes, shallow soil compartments, or the atmosphere)., although they can be sent to any kind of pathway.

Note: Once the mass is transferred to another pathway, it will not necessarily remain precipitated, depending on properties of the pathway. If it is transferred to a Pipe pathway A transport pathway element that is intended to represent a feature that essentially behaves as a fluid conduit, such as a fracture. Pipes are primarily used for simualting matrix diffusion in fractured groundwater pathways., for example, all the mass will immediately be mobilized (i.e., assumed to be dissolved).

GoldSim provides two ways to create a precipitate removal flux link between two pathways:

The Outflows tab is used to create precipitate removal flux links from the current pathway to other pathways in the model. The Inflows tab is used to create precipitate removal flux links to the current pathway from other pathways in the model.

The two dialogs are almost identical in appearance. The Outflows tab (with a precipitate removal mass flux link A mass flux link in which precipitated species are removed from one pathway to another based on a user-specified transfer rate.) is shown below:

To create a new Outflow (a mass flux link from the current pathway to another pathway), do the following:

  1. Double-click on a pathway to display the pathway editing dialog.
  2. Click on the Outflow tab.
  3. Press the Add Outflow button. This will bring up a browser An alternative view of a GoldSim model, in which elements are displayed in a tree, and organized either hierarchically, or by type. showing all of the other pathways (or Containers with pathways) in the model.
  4. Select the pathway you wish to link to and press OK.
  5. GoldSim will then display a dialog for selecting the medium involved in the mass flux link:


    If you change your mind or have selected the wrong pathway, you can press the Select... button to change the pathway.

    The second field in this dialog is a drop list containing the Reference Fluid A special type of Fluid element that provides a basis for defining partition coefficients between media for the various species in the model (i.e., the ratio of the species’ concentration in the medium to its concentration in the Reference Fluid at equilibrium). in the Outflow ("from") pathway, as well any other media Materials (such as water, sand, clay, air) that constitute (are contained within) transport pathways. GoldSim provides two types of elements for defining media: Fluids and Solids. that the two pathways have in common. The Medium drop list will also include several other options, including "Precipitate transfer rate".

    The third field in this dialog specifies the Link Type. If you are connecting two Cells, this will default to Coupled. If the link involves any other type of pathway, it will default to Normal. In most cases, you will not need to change the field and can accept the default.

    Select "Precipitate transfer rate" for the Medium (and select a Link Type) and then press OK.
  6. You will then be returned to the Outflows tab. Move your cursor to the Properties of Selected Outflow section and enter the Transfer Rate for the link. In this case, this must be a vector A one-dimensional array. by species with dimensions An output attribute for an element that defines the dimensionality (in terms of Length, Time and other fundamental dimensions) of the output. of inverse time, representing the fractional transfer rates for all of the species.
  7. If you wish to save the mass flux Final Values or Time Histories for the link, select one or both of the checkboxes.
  8. Press OK to close the pathways dialog.
Note: The fractional transfer rates for all the species must be non-negative.

After an outflow is created, you can always change the properties of the outflow (i.e., the transfer rate and whether or not results are to be saved) by selecting the outflow in the top of the dialog (by clicking on the appropriate row in the List of Outflows) and editing the properties in the lower section of the dialog (Properties of Selected Outflow).

The Inflows and Outflows tab only displays the pathway name, and does not indicate where the pathway exists in the model. If, however, you hold your cursor over a pathway in the list, a tool-tip displays the full containment path for the pathway.

Note: A precipitate removal mass flux link can only be created as an Outflow of a Cell pathway. Any kind of pathway, however, can have a precipitate removal mass flux link as an Inflow (i.e., it can receive the mass flux). That is, you can transport mass via a precipitate removal mass flux link only from Cells but to any other kind of pathway.

An outflow is deleted by selecting the outflow in the top of the dialog (by clicking on the appropriate row in the List of Outflows) and pressing the Delete Outflow button.

The Inflows tab can be used to create precipitate removal mass flux links to the current Cell pathway from other Cell pathways in the model. The manner in which inflows are created, edited and deleted is identical to that for outflows, and the two tabs are essentially identical in appearance.

Note that when you create a mass flux link using the Outflows tab of one pathway, the link automatically appears in the Inflows tab of the linked pathway. The properties of the mass flux link can be edited from either location.

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