Have you ever watched a mile-long freight train rumble by and wondered how one locomotive can pull more than a hundred fully loaded cars? The locomotive weighs maybe 150 metric tons, and each car is about 100 metric tons, which means it's hauling 10,000 tons. I mean, if you weigh 170 pounds, this would be like pulling three SUVs totaling 12,000 pounds.
Tuning frictional behavior on the fly has been a long-standing engineering dream. This new insight into how surface geometry governs slip pulses paves the way for tunable frictional metamaterials that can transition from low-friction to high-grip states on demand.
We were not expecting to find so much richness and depth from a physics point of view underneath the sole of a shoe, says Adel Djellouli, a scientist at Harvard University and co-lead of the study. In a new study, scientists explore the physics that give rise to the familiar squeak of basketball shoes sliding on a hard surface.
Squeaking occurs across various contexts including shoes, bike brakes, rubber tires, and biomedical implants when soft and hard surfaces contact each other. Researchers used high-speed photography to study a rubber block sliding across hard acrylic to identify the source of these sounds. The investigation revealed that pulses similar to earthquake dynamics drive the squeaking phenomenon.
the automation of heavy machinery enabled plants to operate continuously, increasing productivity and revenue. The downside was that any small hiccup was acutely felt, cascading through the production line. At first, it was assumed that inadequate lubrication of factory equipment was causing parts to seize up or break apart. And so, the Lubrication and Wear Group of the Institution of Mechanical Engineers, along with the Iron
The reason we can gracefully glide on an ice-skating rink or clumsily slip on an icy sidewalk is that the surface of ice is coated by a thin watery layer. Scientists generally agree that this lubricating, liquidlike layer is what makes ice slippery. They disagree, though, about why the layer forms. Three main theories about the phenomenon have been debated over the past two centuries. Last year, researchers in Germany put forward a fourth hypothesis that they say solves the puzzle.
The vascular system and the brain are examples of physical networks that differ from the networks typically studied in network science owing to the tangible nature of their nodes and links, which are made of material resources and constrain their layout. The importance of these material factors has been noted in many disciplines: as early as 1899, Ramón y Cajal suggested that we must consider the laws conserving the 'wire' volume to explain neuronal design8
