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Normally, the user will apply Menu Selection 7 to automatically distribute all four phases amongst the initial cement particles. However, in those cases where special control over the distribution process is needed, the user may control each step in the distribution process using Menu Selections 8, 9, and 10. Specifically, Menu Selection 8 is used to filter a 3-D image using a specific correlation file for a specific cement. Basically, an image of random noise is superposed on the random particle microstructure image and filtered by (convolved with) the correlation function for one or more phases determined from the 2-D SEM images. Then, the correlated noise image is thresholded to separate one phase of the microstructure into two phases, with the user specifying the desired volume fraction of each phase. For example, initially, the cement particles are separated into silicates and aluminates using a cemXXX.sil correlation file [1]. In subsequent passes of this algorithm, the silicates are separated into C3 S and C2S, while the aluminates are separated into C3 A and C4AF. When the user executes Menu Selection 7, all three passes are conducted in one execution of the program.
To execute the filtering (rand3d) program, the user must supply a random number seed, the names of the input and output microstructures, the correlation file to be used, the volumetric phase fraction of the first phase to be retained after the filtering, and their e-mail address. As with many of the other menu selections, the user will be notified by an e-mail message once execution of the filtering is complete. The VCCTL is set up to perform only one microstructure filtering at any specific time. Therefore, if the system is busy filtering one microstructure when another request is submitted, the user will be notified to resubmit their job at a later time.
Figure 10: Form to specify inputs to be used in filtering a 3-D microstructure.