Abstract: A device for isothermal expansion and compression of a gas, ensuring the compression of the gas by consuming mechanical energy and the restitution of the mechanical energy by the expansion of the gas. The device includes at least two liquid pistons movable in at least two chambers each including a gas that is able to be compressed or expanded by movement of the liquid pistons. A mechanical actuator, including at least one solid piston, ensures the movement of the liquid pistons in the chambers. Each chamber includes an insert, through which the liquid and the gas can circulate, the insert including through-cells, which extend in a direction parallel to the direction of movement of the liquid piston in the insert. The device includes at least one first phase separator connected to an outlet of each of the chambers, and to a tank for storing pressurized gas.

Abstract: A method for producing a 3D-printed tissue substitute is disclosed, utilizing a 3D printing device including a tank including a yield stress fluid in which the material is printed, the printing material delivered by the cartridge includes polyvinyl alcohol and gelatin, the method including a step following which, after printing the material in the yield stress fluid, a printed intermediate device is solidified in the yield stress fluid by lowering the temperature of the tank. The intermediate device is removed from the tank, rinsed and dried in order to obtain the tissue substitute.