Abstract: Inside a tight sealed chamber defined between a rim and a tire of a pneumatic tire wheel for vehicles, there is provided a predetermined amount of a two-phase system in a substantially balanced state at the tire temperature and inflation pressure. The two-phase system comprises a liquid in a balanced state with its own vapor contained within a sealed, elastically deformable toric bladder which is mounted to the rim. By changing the amount of heat in the two-phase system so as to change its balance condition, a variation is obtained in the inflation pressure of the tire.

Abstract: A padding element for protection against shocks, particularly useful with a crash helmet, which confers on the helmet unusual adaptability to the user's head, comprises at least one deformable vesicle containing a fluid which, in use of the padding element, is a saturated vapor state, a Peltier-effect thermoelectronic component having a face in contact with a surface section of said at least one vesicle, and a power supply for supplying an electric current in either directions to said component, so as to either develop or absorb heat from said face and adjust the vesicle internal pressure.