Bluesky

Second law of thermodynamics: Spontaneous cold-to-hot heat transfer in a nonchaotic medium

It has long been known that, fundamentally different from a large body of rarefied gas, when a Knudsen gas is immersed in a thermal bath, it may never reach thermal equilibrium. The root cause is nonchaoticity: as the particle-particle collisions are sparse, the particle trajectories tend to be independent of each other. Usually, this counterintuitive phenomenon is studied through kinetic theory and is not considered a thermodynamic problem. In current research, we show that if incorporated in a compound setup, such an intrinsically nonequilibrium behavior has nontrivial consequences and cannot circumvent thermodynamics: cold-to-hot heat transfer may happen spontaneously, either continuously (with an energy barrier) or cyclically (with time-dependent entropy barriers). It allows for production of useful work by absorbing heat from a single thermal reservoir without any other effect. As the system obeys the first law of thermodynamics, it breaks the boundaries of the second law of thermodynamics.

Cuál es la mejor manera de columpiarse según la física - La Ciencia de la Mula Francis

Aprender a columpiarse solo, sin ayuda, es todo un reto en los parques infantiles. Tras prueba y error acaban aprendiendo a ascender cada vez más alto. El columpio se comporta […]