I found a first draft of this work but I am still looking for the final version. The student did some foaming tests according to the powder method without clear description of the foaming agent. He investigated the effect of the particle size distribution with fast and slow heating and obtained remarkable results.
He worked with fine and coarse powder but also with a mixture. He found that mixture gives a higher density for the green sample. But also that a much better foaming is present during fast heating of this mixture compared to the fine and coarse particle powder.
The last observation is remarkable and he used the following picture to explain the phenomenon. It suggests that working with a mixture of fine and coarse powder is giving a better cell structure. I think this really a new idea: working with a two peak particle size distribution to improve the cell structure.