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Blue whirl. Photo: Sriram Bharath Hariharan/University of Maryland

A fire phenomenon known as the blue whirl can emerge from fire tornadoes. This week scientists reported new details of the structure of the mysterious clean-burning flame.

Why it matters: Researchers hope to one day harness the blue whirl as a source of energy and to clean up fuel spills. To do that, they need to understand the flame's form — and how it might be controlled.

Background: A team at the University of Maryland discovered the blue whirl in 2016 when testing the idea of using fire whirls, products of intense heat and wind, to clean up oil spilled on water.

  • Fire whirls generate soot (though not as much as typical fires) — small particles of carbon produced when fuel isn't completely burned and that give a flame its yellow color.
  • In a lab, the whirls can transition to become blue whirls, in which the fuel is completely combusted and no soot is produced.

What they did: Joseph Chung, Xiao Zhang and their colleagues at the University of Maryland created a computer simulation of the blue whirl and compared it with video of the flame forming in the lab.

  • They found the whirl is made up of "a diffusion flame and premixed rich and lean flames — all of which meet in a fourth structure, a triple flame that appears as a whirling blue ring," they write in Science Advances.
  • Blue whirls haven't been seen in nature. Why and under what conditions they may occur in nature are still open questions, says Chung.

What's next: "This is a first step to applying the blue whirl to a more practical application," says Zhang. There are more questions, she adds, for example: whether a larger blue whirl can be created so it can burn more effectively (it is currently just a few inches in size) and whether it can burn faster.

Go deeper

Buffett eyes slow U.S. progress, but says "never bet against America"

Warren Buffett in New York City in 2017. Photo: Daniel Zuchnik/WireImage

Warren Buffett called progress in America "slow, uneven and often discouraging," but retained his long-term optimism in the country, in his closely watched annual shareholder letter released Saturday morning.

Why it matters: It breaks months of uncharacteristic silence from the 90-year-old billionaire Berkshire Hathaway CEO — as the fragile economy coped with the pandemic and the U.S. saw a contentious presidential election.

Restaurant software meets the pandemic moment

Illustration: Annelise Capossela/Axios

Food delivery companies have predictably done well during the pandemic. But restaurant software providers are also having a moment as eateries race to handle the avalanche of online orders resulting from severe in-person dining restrictions.

Driving the news: Olo filed last week for an IPO and Toast is rumored to be preparing to do the same very soon.

Bryan Walsh, author of Future
5 hours ago - Technology

How the automation economy can turn human workers into robots

Illustration: Sarah Grillo/Axios

More than outright destroying jobs, automation is changing employment in ways that will weigh on workers.

The big picture: Right now, we should be less worried about robots taking human jobs than people in low-skilled positions being forced to work like robots.