Sunday 24 September 2023

Cheese science

As mentioned yesterday, I'm keeping the large block of cheese in a weightless environment. Indeed, it could be in danger of collapsing under its own weight, at standard gravity. 

In fact, it was not clear to the structural engineers at the LUMEN labs whether this would happen, as the elastic moduli of cheese varies a lot across different types. With their help I have performed some structural tests, using small samples taken from the block:

From the turnover at "D" in the graph it is clear that at that point, the rate of collapse of the cheese matrix overtakes the build-up of force within the cheese sample through further compression, and a peak force is
reached. From this peak force, the critical stress and fracture strain can be calculated. It turns out that at room temperature, the block will become unstable at one standard gravity. The properties are however very temperature dependent, and the block is expected to remain stable when cooled to below 7 degrees centigrade.

Nevertheless, no risks were taken, and the block is now stored under conditions of weightlessness.

It is also kept sealed in a protective atmosphere and in a cooled environment, as it is not clear how the elastic moduli change with age.

Finally, this cheese has a specific heat of about 3.3 kJ/(kg.K), so that it requires 100 Terajoules of energy to be extracted in order to cool it down from room temperature to storage conditions. Taking into account the rather low efficiency of large volume cooling devices, this thing will need a cooler of about a gigawatt power (a nuclear power station) in order to cool it down in a single day. Probably it will take longer anyway, as one needs to model the heat conductivity through the block in more detail to compute the time evolution of the temperature field in the block. Simulations are underway.

I am facing a huge electricity bill from Mehatoor station.

((ooc attribution: graphs and measurements from Fox, P.F., Guinee, T.P., Cogan, T.M., McSweeney, P.L.H. (2017). Cheese: Structure, Rheology and Texture. In: Fundamentals of Cheese Science. Springer, Boston, MA.))