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Solar energy is becoming more and more popular as prices drop, yet a home powered by the Sun isn’t free from the grid because solar panels don’t store energy for later. Now, researchers have refined a device that can both harvest and store solar energy, and they hope it will one day bring electricity to rural and underdeveloped areas.

The problem of energy storage has led to many creative solutions, like giant batteries. For a paper published today in the journal Chem, scientists trying to improve the solar cells themselves developed an integrated battery that works in three different ways. It can work like a normal solar cell by converting sunlight to electricity immediately, explains study author Song Jin, a chemist at the University of Wisconsin at Madison. It can store the solar energy, or it can simply be charged like a normal battery.

It’s a combination of two existing technologies: solar cells that harvest light, and a so-called flow battery. The most commonly used batteries, lithium-ion, store energy in solid materials, like various metals. Flow batteries, on the other hand, store energy in external liquid tanks. This means they are very easy to scale for large projects. Scaling up all the components of a lithium-ion battery might throw off the engineering, but for flow batteries, “you just make the tank bigger,” says Timothy Cook, a University at Buffalo chemist and flow battery expert not involved in the study. “You really simplify how to make the battery grow in capacity,” he adds. “We’re not making flow batteries to power a cell phone, we’re thinking about buildings or industrial sites.

Jin and his team were the first to combine the two features. They have been working on the battery for years, and have now reached 14.1 percent efficiency. Jin calls this “round-trip efficiency” — as in, the efficiency from taking that energy, storing it, and discharging it. “We can probably get to 20 percent efficiency in the next few years, and I think 25 percent round-trip is not out of the question,” Jin says.

Apart from improving efficiency, Jin and his team want to develop a better design that can use cheaper materials. The invention is still at proof-of-concept stage, but he thinks it could have a large impact in less-developed areas without power grids and proper infrastructure. “There, you could have a medium-scale device like this operate by itself,” he says. “It could harvest in the daytime, provide electricity in the evening.” In many areas, Jin adds, having electricity is a game changer, because it can help people be more connected or enable more clinics to be open and therefore improve health care.

And Cook notes that if the solar flow battery can be scaled, it can still be helpful in the US. The United States might have plenty of power infrastructure, but with such a device, “you can disconnect and have personalized energy where you’re storing and using what you need locally,” he says. And that could help us be less dependent on forms of energy that harm the environment.

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As it nears the launch of its first commercial service, Waymo is celebrating a new milestone: 10 million miles driven on public roads. In recognition of this threshold, the Alphabet company released a video that features a lot of new footage of its cars operating without a human driver behind the wheel. In addition, Waymo’s top executive is setting realistic expectations about some of the limitations of its advanced technology.

Last November, Waymo announced it had driven 4 million miles on public roads. Then, in July, the company said it had crossed 8 million miles. At the end of August, it hit 9 million miles, so today’s announcement is clearly another sign of Waymo’s aggressive scaling as it prepares to kick off its first ride-hailing service in Phoenix, Arizona, before the end of the year.

The news comes at a time of skepticism around the technology. In March, a self-driving Uber vehicle struck and killed a pedestrian while the backup safety driver was streaming a video on her phone, police said. Uber suspended testing in the aftermath, and some safety advocates said the crash showed the system was not yet safe enough to be tested on public roads.

Waymo is clearly the leader in this space, but there is also growing skepticism about its technology. In August, The Information reported that Waymo has been trying to remove human safety drivers from its self-driving cars, but that process has been slower and more challenging than anticipated. The vehicles have trouble making unprotected left turns, for example, and some of the cars have difficulty merging with highway traffic, the site reported, citing unnamed sources. Last week, The Information also reported that a previously disclosed crash was actually caused by a safety driver falling asleep at the wheel and accidentally disengaging the self-driving system. (No injuries were reported.)


In a blog post on Wednesday, Waymo CEO John Krafcik acknowledged that there were still some technical challenges to solve.

“Our driving should feel natural to our riders and others on the road. Today, our cars are programmed to be cautious and courteous above all, because that’s the safest thing to do. We’re working on striking the balance between this and being assertive as we master maneuvers that are tough for everyone on the road. For example, merging lanes in fast-moving traffic requires a driver to be both assertive enough to complete the maneuver without causing others to brake and smooth enough to feel pleasant to our passengers.

The experience of using one of Waymo’s self-driving cars to run errands, for example, is likely to be less convenient than driving yourself or using a human-driven ride-hailing service, Krafcik said. But only at first.

“Today, our cars are designed to take the safest route, even if that means adding a few minutes to your trip,” he said. “They won’t block your neighbor’s driveway and will choose the safest place to pull over, even if it means having to walk a few extra steps to a destination.”

Waymo also posted a video of an upbeat interview with Nathaniel Fairfield, principal software engineer at the company. The video features plenty of shots of Waymo’s self-driving Chrysler Pacifica minivans operating on public roads without a driver behind the wheel, which seems like an effort to rebuff reports that it is still using safety drivers in the majority of its testing. Also, see Waymo’s driverless cars navigate tricky situations, like snowy roads, dust storms, and that time a ball went into the street!

“Today, our vehicles are fully self-driving, around the clock, in a territory within the Metro Phoenix area,” Krafcik writes. Previously, Waymo said its robot taxi service will be “fully driverless” at launch, which the company promises will take place before the end of the year. The clock is ticking.

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The answer, if you’re familiar with Wi-Fi standards coming from the Institute of Electrical and Electronics Engineers, is 802.11ac — and by the way, the upcoming 802.11ax is better than both.

But in an effort to make the wireless networking terms more useful and less like alphanumeric gibberish, the Wi-Fi Alliance trade group has some new names it wants for those technologies: Wi-Fi 4, Wi-Fi 5 and Wi-Fi 6.

The idea is to be clearer about what’s better and what your phone or home router can handle without sounding as much like an electronic engineer. Not that there’s anything wrong with electronic engineers, but even techies can have a hard time remembering that IEEE 802.11 means wireless networks, IEEE 1394 governs FireWire data connections, and IEEE 802.3 is about Ethernet network connections.

The underlying Wi-Fi specifications will keep their IEEE technical names, of course. The Wi-Fi Alliance comes later in the development process, just before the point when consumers get involved, smoothing the way with compatibility tests that let device manufacturers put reassuring certification logos on their product boxes.

Even though there were older versions of the Wi-Fi specs — 802.11a, 802.11b, 802.11g — the Wi-Fi Alliance isn’t going to try to reach back that far in time and attach any 1, 2 or 3 version numbers to them.

Changing brands can be rough as people try to reconcile the old and new labels. But if it all works out as planned, we can chalk it up as a victory for the ordinary person.

And cross your fingers that the marketing people don’t get carried away and stick us with Wi-Fi 2020, Wi-Fi XS Max or Wi-Fi Creators Edition.





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Ever fancied on-ear headphones that you could swap for over-ear pads? Master & Dynamic has made that possible with the MW50+ headphones that retail for $399 — these are premium cans with 40mm beryllium drivers, after all. For the high price, M&D includes a predictably wide range of accessories: a USB-C charging cable, 3.5mm audio cable, carrying pouch, and a case for the ear pads.

Headphones that offer both on-ear and over-ear experiences aren’t all that common, but it has been done before, in fact more than once, in efforts to cater to both portability and audio quality. The idea is that you’ll want the smaller cans for while you’re out on the move and the bigger version for when you want higher-quality listening at home.




  • Solid audio performance when using on-ears
  • Charming aesthetics
  • Good battery life


  • Over-ear pads degrade audio quality
  • Weak magnets on over-ear pads
  • Can’t fold inward
  • On-ears can become uncomfortable

Before I get to how the MW50+ headphones sound, it’s important to talk about how they fit and look. They have a charming design with modern and retro touches, like the faux open-back mesh. Strangely, they only fold flat and can’t fold inward, making them less portable than they arguably could be.

Every pair of MW50+ headphones comes with on-ear and over-ear pads, held in place by two small pegs and magnets. When using the on-ear pads, the experience is vastly different compared to the over-ears: they sit comfortably due to how soft they are, but are prone to listening fatigue after an hour of usage. They’re plush to the touch, wrapped in lambskin, and filled with memory foam.

The over-ear pads are made from the same materials as the on-ears, but are less plush and eventually feel like they’re clamping onto your skull due to the small size of the headband. They also have small cut-outs on the outside to ensure the headband and wires are unobstructed. Whether I was using them on my commute, at work, or in my home office, the MW50+’s over-ear pads were more comfortable than the on-ears.

Basically, the on-ears are most comfortable for a short listening session while the over-ears are best for longer sessions.

The on-ears deliver decent noise isolation when I’m commuting — M&D currently doesn’t offer noise-canceling headphones — but of course the over-ear pads offer encapsulation, so they do a much better job of keeping environmental sounds out.

Unfortunately, the over-ear pads are the weakest part of the MW50+’s kit because they fall off too easily. They will separate from the headphones’ headband while they’re in your bag, or if you shake them, or even if you just hold them by the ear pads. You can even mistakenly separate them while taking the MW50+ off your head, if you’re not careful. It’s a horrible oversight to have the main feature — interchangeable ear pads — be unreliable on a new pair of otherwise great-sounding headphones, especially for an audio company that frequently markets its attention to detail.

I have a diverse listening style — K-pop, hip-hop, EDM, classical, jazz, and lo-fi, to name a few — so it was to my surprise when I found out that the larger pads made the MW50+ sound worse. It took several listens of the same tracks (switching between pads) to come to the conclusion that bass is almost completely snuffed out when using the bigger pads.

On the flip side, audio quality is much better when using the MW50+ with the on-ear pads. I’d describe the sound profile as having punchy bass when it’s needed, with clear mids, and acute highs that can catch your attention when you’re listening. Without a doubt, the MW50+ was designed to be used with on-ear cups; use anything else and it doesn’t sound nearly as good.

Master & Dynamic also sells the MW60 over-ear wireless headphones, which were designed to use over-ear pads with larger speaker drivers, whereas the MW50+ are on-ear headphones with over-ear pads, tacked on as an afterthought. In this scenario, there’s less speaker for the same size ear cup, explaining why they don’t sound similar or better than using the smaller on-ear pads.

For on-ear headphones, the MW50+ have decent battery life around 15-16 hours, making them suitable for coast-to-coast flights. You can charge them via the supplied USB-C cable and port, but unfortunately you can’t transmit audio with them over Type-C.

Overall, the MW50+ headphones are tough to recommend because of their numerous flaws, including how different (read: worse) music sounds when using the over-ear pads instead of the on-ear variants. For the $399 asking price, you can find similar or better audio quality in both on-ear or over-ear headphones, like Bowers & Wilkins’ $399 PX wireless over-ears or Beyerdynamic’s Aventho Wireless, or if you’re on a more frugal budget get the Status Audio CB1 for over-ear headphones with great sound quality.





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