Physics at its best brings the world together. Its power is that a single simple framework can describe wildly different systems. But even the greatest descriptive equations reach their limits ...

When a fluid is in motion, it must move in such a way that mass is conserved. To see how mass conservation places restrictions on the velocity field, consider the steady flow of fluid through a duct ...

The Nature Index 2024 Research Leaders — previously known as Annual Tables — reveal the leading institutions and countries/territories in the natural and health sciences, according to their output in ...

The Lagrangian description of absolutely continnous curves of probability measures on the real line is analyzed. Whereas each such curve admits a Lagrangian description as a well-defined flow of its ...

A new equation for accurate approximation of the Moody friction factor in the general gas-flow equation better approximates a wide range of Reynolds numbers than previously published equations. Other, ...