Cornell University researchers have solved a kitchen mystery by demonstrating that sharp knives produce fewer and slower-moving droplets when cutting onions compared to dull blades. The findings used high-speed cameras and particle tracking to analyze droplet formation during onion cutting at speeds up to 20,000 frames per second. The team discovered that onion droplets form through a two-stage process: an initial violent ejection driven by internal pressure, followed by slower fragmentation of liquid streams in air. Blunter blades create up to 40 times more droplets because the onion's tough outer skin acts as a barrier, allowing the softer interior tissue to compress significantly before rupturing and releasing pressurized liquid. The research reveals that droplets are ejected at speeds between 1 and 40 meters per second, with the fastest ones posing the greatest risk of reaching a cook's eyes. Beyond tear reduction, the study suggests sharp knives may also limit the spread of foodborne pathogens, since atomized droplets can carry bacteria like Salmonella from contaminated cutting boards.

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An interesting piece on Construction Physics that examines how Japan transformed discarded American wartime shipbuilding techniques into a revolutionary manufacturing system that captured nearly half the global market by 1970. The story reveals the essential ingredients for industrial dominance: government backing, organizational alignment, relentless will to improve, and the systematic coordination needed to turn existing technologies into something entirely new. A few excerpts: During WWII, the US constructed an unprecedented shipbuilding machine. By assembling ships from welded, prefabricated blocks, the US built a huge number of cargo ships incredibly quickly, overwhelming Germany's u-boats and helping to win the war. But when the war was over, this shipbuilding machine was dismantled. Industrialists like Henry Kaiser and Stephen Bechtel, who operated some of the US's most efficient wartime shipyards, left the shipbuilding business. Prior to the war, the US had been an uncompetitive commercial shipbuilder producing a small fraction of commercial oceangoing ships, and that's what it became again. At the height of the war the US was producing nearly 90% of the world's ships. By the 1950s, it produced just over 2%. But the lessons from the US's shipbuilding machine weren't forgotten. After the war, practitioners brought them to Japan, where they would continue to evolve, eventually allowing Japan to build ships faster and cheaper than almost anyone else in the world. [...] The third strategy that formed the core of modern shipbuilding methods was statistical process control. The basic idea behind process control is that it's impossible to make an industrial process perfectly reliable. There will always be some variation in what it produces: differences in part dimensions, material strength, chemical composition, and so on. But while some variation is inherent to the process (and must be accepted), much of the variation is from specific causes that can be hunted down and eliminated. By analyzing the variation in a process, undesirable sources of variation can be removed. This makes a process work more reliably and predictably, reducing waste and rework from parts that are outside acceptable tolerances.

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An anonymous reader shares a report: Vietnam's technology ministry has instructed telecommunication service providers to block the messaging app Telegram for not cooperating in combating alleged crimes committed by its users, according to a government document reviewed by Reuters. The document, dated May 21 and signed by the deputy head of the telecom department at the technology ministry, ordered telecommunication companies to take measures to block Telegram and report on them to the ministry by June 2.

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