A chemical field diffuses in a radial pattern. At the same time, this demo periodically creates .dat files to record the overall concentration of the field.

An initial concentration of the chemical is created from the included text file, and then DiffusionSolverFE controls the rest. 

Relevant documentation: 
- DiffusionSolverFE: https://compucell3dreferencemanual.readthedocs.io/en/latest/diffusion_solver.html
- List of all PDE solvers: https://compucell3dreferencemanual.readthedocs.io/en/latest/pde_solvers_section.html
- How to save simulation output: https://compucell3dreferencemanual.readthedocs.io/en/latest/writing_data_files_in_the_simulation_output_directory.html