The Size Distribution subtab contains a table with the particles size distribution.

For the default settings of Finite Size as Particle Diameter, Constant as Particle Density, Caught on first touch as Collision Model, and Brownian Motion as Particle Diffusivity (chosen under the Interaction Model tab) only two columns are available.

The first column lists the different particle Diameters (m) of the particle size distribution.

The second column contains the particle Percentages of each particle size in relation to the entire size distribution. The percentage of the entire particle size distribution can be defined in percentage of mass (Mass %), volume (Volume %) or total number of particles (Count %), that can be selected to the right of the table.

Additional columns appear under the Size Distribution tab, depending on the user choices under the Interaction Model tab.

If Molecules (Limit d=0) is selected as Particle Diameter, the column Diameter disappears, and the percentages of the particle distribution can be defined only in percentage of the total number of particles (Count %).

Selecting Individual per particle type for the Particle Density causes the Particle Density (kg/m3) column to appear.

Dependent on the choice for the solid and porous material IDs collision models, an individual column for each material ID may appear. After choosing Caught on first touch, no additional columns appear. When choosing the Hamaker collision model for a material, the columns Restitution and Adhesion appear. In the case of Sieving and particles of finite size, only the Restitution column appears.

The values in the Restitution column(s) determine the amount of energy not absorbed by a collision with the solid material. The restitution value ranges from 0 to 1. If the restitution value is set to 1, no energy is lost, and the particle is reflected with the same speed it had before the collision. For restitution values smaller than one, energy is absorbed by the collision and the particle slows down. For example, a restitution value of 0.7 means that a particle loses 30% of its velocity in the collision and gets 30% slower.

The Adhesion column defines the Hamaker constant (Adhesion / (J)). The values generally lie in the range of 10−19 to 10−20 Joule.

When choosing Random as collision model, a column for the Deposition Probability appears.

The Deposition Probability defines the probability that a particle is trapped if it hits a solid or porous material.

Choosing Molecules for the Particle Diameter or Individual per particle type for the Particle Diffusivity of a particle with Finite size, adds column(s) for the diffusivity in the pore space and for each porous material with Pass Through Models All particles pass or Bounce Probability.

Choosing Individual per particle type for the Particle Charge in the Electrostatic Effects subtab adds a column for the Particle Charge.

Below the size distribution table, a graphical presentation of the particle size distribution is displayed, if particles with Finite Size are selected. The graph is automatically updated after changes in the table. The x-axis shows the Particle Diameter, and the y-axis the Mass, Count, or Volume percentage. Right-click the plot to store the graph as a *.txt file, to save the graph as image, to copy the values to the clipboard, or to edit the plot settings.

To the right of the size distribution table multiple buttons are available:

• Clicking Delete Row deletes the currently selected row.
• Clicking Insert Row inserts a row below the currently selected one. The inserted row is a copy of the currently selected row and contains the same data.
• Clicking Import allows to import data from ASCII text files that contain two columns, for diameter (in [m]) and count percentage. Percentages in the *.txt file are always considered as count percentages. You can save your current settings in the size distribution table by changing the displayed values to Count % and saving the graph as text file. It is possible to load the text file into the dialog for other simulations.

After editing a distribution table and clicking OK, a warning message appears if the new percentages do not sum up to 100%. The values can be automatically normalized by clicking Yes, or manually by clicking Cancel and returning to the particle distribution table.