Transparent Metal (Hydroxide) Without Mr. Scott

There’s a famous scene in one of the Star Trek movies where Scotty, who has traveled to the past, teaches a metal company to create the transparent aluminum he needs to bring some whales back to the future. But [The Action Lab] shows that we already have see-through metal, just not aluminum. You can see a video about why metals are normally opaque.

The metal in question is sodium. Normally, it isn’t transparent, but molten sodium hydroxide does turn transparent after it — well, sort of explodes. Of course, sodium hydroxide isn’t really a metal, but then neither is the aluminum oxide that’s been touted as real transparent aluminum. Aluminum oxide also makes transparent gemstones like rubies. However, there is some — kind of — transparent aluminum at the end of the video.

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In My Neighborhood, We Played Asteroids…with Real Asteroids

There was a comedian in the 1980s who always said he grew up in a tough neighborhood. He claimed they played cops and robbers with real cops. They played gin rummy with real gin. Well, maybe if he knew about [Neal Agarwal]’s asteroid launcher simulation website, he would have said they played asteroids with real asteroids.

If you ever wondered what would happen if a 1,500-foot stone or iron asteroid hit your hometown going at 38,000 mph, now you can find out.  Apparently, I live far enough in the suburbs that even a 1 mile-wide iron asteroid hitting the center of Houston wouldn’t put a crater under my house. The 17-mile-wide and 2,608-foot-deep crater would release the equivalent of 399 Gigatons of TNT, but it wouldn’t reach me.

The 29-mile-wide fireball would be a different story. Oh, and the 244 dB shockwave would almost certainly reach me. So if the clothes catching on fire resulting in second- and third-degree burns didn’t get me, perhaps the shockwave would. The simulation says that zone will have 99% fatalities, and even further out, people will get severe lung damage. Eardrums burst even further away. Homes would collapse almost to the Mexican border.

The 1,000-mile-per-hour wind might present problems, too. While we are well-situated for hurricanes in this area, that’s about five times more wind than even a big hurricane generates. And we are not well prepared for earthquakes, much less the magnitude 70 quake that would occur.

Pretty bleak. On the plus side, a strike like that happens about once every 2.6 million years. If you try it yourself, be sure to scroll down the right panel to see the graphical representation of the different effects.

Maybe NASA is on to something when they tell us they want to learn to deflect asteroids. Even private foundations are getting into the business of finding them.

Asbestos: The Miracle Mineral Of Our Worst Nightmares

For much of the 19th and 20th century, the mining and use of asbestos saw near-constant growth, with virtually every material used in the construction of homes, offices, ships, road networks and industries featuring this miraculous mineral in some fashion. Some of these materials would contain only a few percent asbestos mineral as a binder, while others would be mostly or entirely composed out of asbestos.

What had begun as mostly a curiosity thousands of years prior was now turning into the material that was helping propel humanity into an era of hitherto unknown levels of prosperity and technological progress. It seemed as if the addition of even just a bit of asbestos would make houses weather- and fireproof, make concrete and asphalt nearly indestructible and add just that little bit of zing to tiling and interior decorations, as well as rigidity to the predecessor to today’s plastics: bakelite. Continue reading “Asbestos: The Miracle Mineral Of Our Worst Nightmares”

A wafer being loaded into an electron microscope

Using Electron Beams To Draw Tiny Shapes Onto Silicon

Over the past few years we’ve seen several impressive projects where people try to manufacture integrated circuits using hobbyist tools. One of the most complex parts of this process is lithography: the step in which shapes are drawn onto a silicon wafer. There are several ways to do this, all of them rather complicated, but [Zachary Tong] over at Breaking Taps has managed to make one of them work quite well. He shares the results of his electron-beam lithography experiments in his latest video (embedded below).

In e-beam lithography, or EBL, shapes are drawn onto a wafer using an electron beam in a vacuum chamber. This is a slow process compared to optical lithography, as used in mass production, but it is reasonably simple and very flexible. [Zach] decided to use his electron microscope as an e-beam litho machine; although not designed for lithography, it has the same basic components as a real EBL machine and can act as a substitute with a bit of software tweaking.

An AFM image of Rick Astley
[Zach] also has an atomic force microscope, which he used to make these beautiful images.
The first step is to coat a wafer with a layer of e-beam resist. [Zach] used PMMA, commonly known as acrylic plastic, and applied it using spin coating after dissolving it in anisole. He then placed the wafer into the electron microscope and used it to scan an image. The image was then developed by rinsing the wafer in cold isopropyl alcohol.

[Zach] explains the whole process in detail in his video, including how he tuned all the parameters like resist thickness, beam strength, exposure time and development time, as well as the software tricks needed to persuade the microscope to function as a litho machine. In his best runs he managed to draw lines with a width of about 100 nanometers, which is seriously impressive for such a relatively simple setup.

These e-beam lithography experiments follow on from [Zach]’s earlier research using lasers. Homebrew IC expert Sam Zeloof has also used electron beams in his work. Thanks for the tip, [smellsofbikes]!

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Miracle Of Science: Scotch Tape Improves Generator

We were always amused that one of the biggest scientific discoveries of the recent past — graphene — was started with pencil lead and Scotch tape. Now, researchers at the University of Alabama in Huntsville have determined that double-sided Scotch tape can improve triboelectric power generators. Triboelectric generation, of course, is nothing new. These energy harvesters take mechanical and thermal energy and turn them into tiny amounts of electricity. What’s new here is that PET plastic, aluminum, and double-sided tape can make an inexpensive generator that works well.

Keep in mind we are talking about little bits of power. In the best scenario with the device stimulated at 20 Hz, the generator peaked at 21.2 mW. That was better than some designs that only got to 7.6 mW in the same configuration.

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App Detects Parkinsons Disease And COVID-19 Via Audio

One of the challenges of diagnosing diseases is identifying them early. At this stage, signs may be vague or confusing, or difficult to identify. Early diagnosis is often tied to the best possible treatment outcomes, so there’s plenty of incentives to improve methods in this way.

A new voice-based method of diagnosing disease could prove fruitful in this regard. It relies on machine learning techniques to detect when patients may be suffering from certain conditions.

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Tesla Coil Makes Sodium Plasma

Looking for a neat trick to do with your Tesla coil? [The Action Lab] uses his coil to make a metal plasma — in particular, sodium. You can see the results in the video below.

To create a metal plasma, you need a metal vapor and sodium can create a vapor at a relatively low temperature, especially in a vacuum. The resulting glow is pretty to look at, but you will need a bit of lab gear to pull it off.

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