Month: March 2020

This kind of perspective? Yeah, it's ideal but not available to the admirals of WWI and WWII. (credit: Samuel Axon)

"Network-centric warfare" is the hot concept in modern military thinking—soldiers fighting not just with weapons but within a web of sensors and computation, giving them and their commanders superior awareness of the battlefield. But the problems this approach was conceived to solve are timeless. I’m here, the enemy is out there somewhere. How do I find them? How do I keep track of them? Once the battle has started, how do I know where to move? Heck, how do I even keep track of my own people?

Long before IoT concepts littered the world, the navies of the early 20th century were among the first to take a systematic approach to answering these questions. Sail had given way to steam and European colonies had metastasized around the world. Warships were moving faster and required coordination across greater distances than ever. Meanwhile, telegraphs and radio allowed instant communications at previously unheard-of distances. All of this combined to create a revolution in how navies used information.

If you’ve played strategy games like StarCraft or Civilization or watched Cold War techno-thrillers, you’ve seen the ideal display for a commander: a map where the positions and status of friends and enemies alike are displayed and tracked in real time. This single, unified picture gave those in leadership a god’s-eye view of the battlefield that could be used for accurate decision-making. But how did commanders create this picture without computers, GPS, and communications satellites? How did they keep their maps accurate and up to date?

Enlarge (credit: Lawrence Glass / Getty)

A week after the first Amazon warehouse worker tested positive for COVID-19 at a facility in Queens, New York, a total of nine Amazon warehouses have seen employees contract the virus, according to local news reports.

Workers have tested positive for the virus at Amazon distribution facilities near Oklahoma City, Louisville, Houston, Jacksonville, and Detroit. There have also been coronavirus cases at Amazon facilities on Staten Island, New York; Wallingford, Connecticut, and most recently Moreno Valley, California, east of Los Angeles.

“We are supporting the individuals, following guidelines from local officials, and are taking extreme measures to ensure the safety of all the employees at our sites,” an Amazon spokesman told Ars.

Enlarge / Whiskey web patterns are unique to each sample of tested American whiskey. (l-r) Four Roses, Heaven Hill, Maker's Mark Cask Strength, Jack Daniel's Single Barrel Proof, Pappy Van Winkle's Family Reserve 23 Year, and Woodford Reserve Double Oak. (credit: Stuart J. Williams et al./PRF)

American whiskeys are distinctive from their Scottish counterparts in one very distinctive way: they leave behind an unusual web-like pattern as droplets dry up, and those webs are different for different brands—making them a kind of "fingerprint." That's a property that can be used not only to tell the difference between brands of American whiskeys but could one day lead to an effective method for the identification of counterfeits, according to a new paper published in ACS Nano.

As we reported last year, Stuart Williams, a professor of mechanical engineering at the University of Louisville in Kentucky, noticed one day that if he diluted a drop of bourbon and let it evaporate under carefully controlled conditions, it formed what he terms a "whiskey web": thin strands that form various lattice-like patterns, akin to networks of blood vessels. Intrigued, he decided to investigate further with different types of whiskey—plus a bottle of Glenlivet Scotch whisky for comparison. It was the perfect project for his sabbatical leave to study colloids (suspended particles in a medium, like Jell-O, whipped cream, wine, and whiskey) at North Carolina State University.

Fundamentally, it's the same underlying mechanism as the "coffee ring effect," when a single liquid evaporates and the solids that had been dissolved in the liquid (like coffee grounds) form a telltale ring. It happens because the evaporation occurs faster at the edge than at the center. Any remaining liquid flows outward to the edge to fill in the gaps, dragging those solids with it. Mixing in solvents (water or alcohol) reduces the effect, as long as the drops are very small. Large drops produce more uniform stains.