Inputs and Outputs Associated with Diffusive Mass Flux Links

When a diffusive mass flux link A mass flux link in which species diffuse between pathways according to a concentration gradient. is created, GoldSim creates several new inputs and outputs on the two linked pathways which subsequently appear in the browser An alternative view of a GoldSim model, in which elements are displayed in a tree, and organized either hierarchically, or by type. view and interfaces for these pathways.

For the Outflux Pathway in the link:

• GoldSim creates a new output named Medium1_to_Medium2_in_Path2, where Medium1 is the name of the fluid on the Outflux side of the link, Medium2 is the name of the fluid on the Influx side of the link, and Path2 is the name of the linked pathway (the Influx Pathway). For example, if Cell1 was linked to Cell2 via a diffusive link in which Water was the fluid on the Outflux side and Air was the fluid on the Influx side, GoldSim would create a new output on the Cell1 pathway called Water_to_Air_in_Cell2. Like all GoldSim outputs, when the output appears in an expression, the name of the element is included prior to the output name (Cell1.Water_to_Air_in_Cell2). This output represents the mass flux itself, and is a vector A one-dimensional array. by species The chemical (or non-chemical, such as bacterial or viral) constituents that are stored and transported through an environmental system in a contaminant transport model. In GoldSim, the Species element defines all of the contaminant species being simulated (and their properties). with dimension of mass/time.

Note: Although this output is referred to as a "flux", it technically is a mass rate, not a flux (since fluxes have dimensions An output attribute for an element that defines the dimensionality (in terms of Length, Time and other fundamental dimensions) of the output. of mass/time/area). The term "flux" is used here for convenience.

• GoldSim creates two new inputs named Length in Path1 and Length in Path2, where Path1 is the Outflux pathway, and Path2 is the Influx pathway. These are the thicknesses of the diffusive layer on either side of the link.
• GoldSim creates an additional new input named Area. This is the diffusive area for the link.

These new items are organized under a "folder" within the browser view of the element called Diffusive Outfluxes:

For the Influx Pathway in the link:

• GoldSim creates a new input named Medium2_from_Medium1_in_Path1, where Medium1 is the name of the fluid on the Outflux side of the link, Medium2 is the name of the fluid on the Influx side of the link, and Path1 is the name of the linked pathway (the Outflux Pathway). For example, if Cell1 was linked to Cell2 via a diffusive link in which Water was the fluid on the Outflux side and Air was the fluid on the Influx side, GoldSim would create a new input on the Cell2 pathway (the Influx Pathway) called Air_from_Water_in_Cell1.

This item is placed in a Diffusive Influxes "folder" within the browser view of the element:

These new items in the browser views of the pathways are useful because they can be used in conjunction with the Link Cursor A special cursor for creating links invoked by double-clicking on an input or output object in a browser. to create links. For example, rather than editing the diffusive area in the link using the editing dialog, you could create a link to Area using the Link Cursor. Similarly, you could link the mass flux output itself into an Expression element A function element that produces a single output by calculating user-specified mathematical expressions., a Sum element A simple function element that sums values. or an Extrema element A function element that computes the maximum value (peak) or minimum value (valley) achieved by its input during a simulation..

Note: If you create multiple diffusive fluxes between the same two Cells, GoldSim will append the letter "c" and a number to the end of the input and output names. For example, if a second diffusive flux was added from Cell1 to Cell2, the output on Cell1 would be named "Water_to_Air_in Cell2c2" and the input on the Cell2 would be "Air_from_Water_in_Cell1c2".