Month: January 2023

Enlarge / A new analysis of ancient Roman concrete samples from the Privernum site yields fresh insights into manufacturing process. (credit: MIT)

The famous Pantheon in Rome boasts the world's largest unreinforced concrete dome—an architectural marvel that has endured for millennia, thanks to the incredible durability of ancient Roman concrete. For decades, scientists have been trying to determine precisely what makes the material so durable. A new analysis of samples taken from the concrete walls of the Privernum archaeological site near Rome has yielded insights into those elusive manufacturing secrets. It seems the Romans employed "hot mixing" with quicklime, among other strategies, that gave the material self-healing functionality, according to a new paper published in the journal Science Advances.

As we've reported previously, like today's Portland cement (a basic ingredient of modern concrete), ancient Roman concrete was basically a mix of a semi-liquid mortar and aggregate. Portland cement is typically made by heating limestone and clay (as well as sandstone, ash, chalk, and iron) in a kiln. The resulting clinker is then ground into a fine powder, with just a touch of added gypsum—the better to achieve a smooth, flat surface. But the aggregate used to make Roman concrete was made up of fist-sized pieces of stone or bricks.

In his treatise De architectura (circa 30 CE), the Roman architect and engineer Vitruvius wrote about how to build concrete walls for funerary structures that could endure for a long time without falling into ruins. He recommended the walls be at least two feet thick, made of either "squared red stone or of brick or lava laid in courses." The brick or volcanic rock aggregate should be bound with mortar composed of hydrated lime and porous fragments of glass and crystals from volcanic eruptions (known as volcanic tephra).

• 

  The Apple Books icon on a Mac. [credit: Samuel Axon ]

Apple's digital storefronts now offer audiobooks recorded by artificial narrators instead of humans in a sound booth. The audiobooks are listed in the Books app as "Narrated by Apple Books."

Clicking on the information icon next to that line brings up a text box that clarifies the book is narrated by "a digital voice based on a human narrator." There are multiple digital voices across the Apple Books library, with names like "Madison" or "Jackson"—but each book is offered with just one of them.

We listened to an hour each of two digitally narrated titles. The calm tones were clear and mostly benign, and they could be mistaken for real human voices with a short listen. We did hear some anomalies, though—for example, an odd pronunciation of the city "San Antonio." And obviously, the neutral and emotionless voices are not replacements for styles of human audiobook narration that can be passionate performances.

• 

  The new Android Auto is super flexible. Here's a big-screen mode. [credit: Google ]

After a big delay, Google's big revamp of Android Auto is finally here. This new version of Android Auto puts a big focus on a new split-screen interface, which is a lot more flexible than the old, rigid Android Auto display. This update was first shown off at Google I/O and promised in the summer of 2022, but somehow that got pushed back to CES 2023. Car apps have a lot of safety regulations to go through.

Android Auto is an app that lives on your phone and sends a custom interface (wirelessly or wired) to a compatible car's dashboard. Unlike regular Android, which can scale to any size or shape display, Android Auto was originally designed rigidly around a horizontal 16:9 display. It's been updated over the years to be slightly more flexible, but it has always wanted to live in this horizontal, widescreen configuration. Not all car screens are widescreen, though, and for cars like the Volvo XC90, which has a big 4:3 iPad-style screen in the center console, Android Auto was just in a tiny window in the middle of the display. Some manufacturers gave it a letter or pillar box. Apple's CarPlay received a similar flexibility update in iOS 13.

Unlike the old version, the split-screen interface should be able to adapt to any rectangular screen.  There are three components: a navigation bar, the main app interface, and a smaller sidebar section that can show one or two additional widgets. These can all be configured in a way that makes sense for the screen's shape. The navigation bar can be on the right side or the bottom. The main app interface can be next to the sidebar section or stacked on top. The sidebar can be a tall vertical strip or a skinny horizontal strip. Some configuration is going to work!