Month: April 2023

Enlarge / Archaeologists analyzed samples of Maya plasters collected from the Copan archaeological site in Honduras. (credit: Rodriguez-Navarro et al., 2023)

There is a rich body of scientific research investigating the secrets behind the remarkable durability of ancient Roman concrete. But ancient Maya masons had their own secrets when it came to making the lime plasters, mortars, and stuccos used to build their magnificent structures, many of which still stand today. A team of Spanish scientists has analyzed samples of Maya plasters from Honduras and confirmed that the Maya added plant extracts to improve the plasters' performance, 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.

Mayan lime plaster draws on similar ancient knowledge, according to Carlos Rodriguez-Navarro and his colleagues at the University of Granada. The use of lime plaster dates back to around 10,000 to 12,000 BCE, and the manufacturing process typically involved the calcination of carbonate rocks like limestone to produce quicklime, which was then slaked to create portlandite. It seems the Maya independently developed their own lime pyrotechnology around 1100 BCE, and the plasters, mortars, and stuccos they produced exhibit impressive resistance to granular disintegration, fracturing, or scaling, despite more than 1,200 years of exposure in a hot and humid tropical environment.

(credit: Instant Brands)

In this kitchen appliance edition of Dealmaster, we've gathered some of the best deals on some of our favorite tools for cooking. One of those favorites happens to be the Instant Pot, which our readers also love for its versatility and convenience (check this forum thread for proof!). We found both the six- and eight-quart sizes of the Instant Pot on sale, and regardless of the size you choose, we're confident that this humble tool will be worth the small investment.

In addition to the Instant Pot, we've also found some terrific deals on other kitchen tech. From coffeemakers to waffle makers, we've rounded up some of the best deals for you to host your next big family breakfast or brunch gathering.

The most versatile kitchen appliance you can buy is on sale

(credit: Instant Pot)

Whether you're slow-cooking or making yogurt or rice, or even stir-frying your dinner, the Instant Pot is an all-in-one tool that makes cooking easier. Use it to slow-cook a roast to perfection as a crockpot replacement, or if you're pressed for time, you can cut the cooking time on some foods with the pressure-cooking function. In my house, next to the oven, the Instant Pot is the most used appliance of all the countertop appliances that we own. The best part is that the Instant Pot is on sale for up to nearly 25 percent off.

Enlarge / OnLeaks' Pixel Fold render from December. The cluster of holes on the rear camera bar is interesting, as is the interior camera, which lives in a thick display bezel. (credit: OnLeaks x HowToiSolve)

Will the Pixel Fold ever exist? There is an increasing chorus from the rumor mill saying that Google's first foldable phone will launch at Google's I/O conference in May. The latest rumor is from CNBC's Jennifer Elias, who says the device will be announced at I/O and go on sale sometime in June, with a price that's "upward of $1,700." An earlier report from WinFuture also pegged the Pixel Fold with a June release date.

The report is based on internal photos and documents seen by CNBC and details many of the specs we've seen in previous rumors: There's a 7.6-inch inner display, a 5.8-inch outer display, and Google's Tensor G2 chip. The phone reportedly weighs 10 oz, or 283 g, which is heavier than a Galaxy Fold 4. One surprise spec is water resistance, which no foldable vendor other than Samsung ever attempts.

The report quotes an internal document saying that the phone has “the most durable hinge on a foldable." Durability is the primary problem with foldables, but most worries center on the display, so focusing on the hinge would be an interesting marketing strategy. Even Samsung, which is on its fourth generation of these devices, can't stop the display from dying right along the display crease. Complaints about the hinges do exist, though. At any given time, the front page of the Galaxy Fold subreddit is about 50 percent complaints about broken displays and 10 percent about broken hinges.

Enlarge (credit: Netflix)

For more than a decade, Netflix has been known primarily as a streaming video service. But the original version of Netflix was a much slower form of video-on-demand: red envelopes stuffed with physical DVDs, delivered via the postal service.

Netflix announced yesterday that it's finally ending the discs-in-the-mail version of Netflix on September 29th, 2023, just over 26 years after the company was founded. DVD returns will be accepted until October 27th.

"After an incredible 25 year run, we've made the difficult decision to wind down at the end of September," reads a Netflix FAQ page explaining the decision. "Our goal has always been to provide the best service for our members, but as the DVD business continues to shrink, that's going to become increasingly difficult. Making 2023 our Final Season allows us to maintain our quality of service through the last day and go out on a high note."