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The London Underground Is Too Hot, But It’s Not An Easy Fix

December 4, 2024 by 89 Comments

The London Underground is an iconic piece of Victorian era engineering. What started in 1863 quickly became a core piece of infrastructure that would define the modern character of the British capital. It’s grown and changed immensely in the many years that have passed. Sadly, increasing patronage and more trains have created problems that the original designers never envisaged.

Deep in those London tunnels lies an engineering challenge. The Tube is literally cooking itself. Every day, millions of commuters descend into a network of tunnels that have been absorbing heat since the reign of Queen Victoria. Those clay-lined tubes have been soaking up excess thermal energy like a giant underground radiator, and now they’re giving it back with interest. The tunnels are simply too hot, and cooling them down is inordinately difficult.

The Perfect Storm of Thermal Chaos

The Tube’s heat problem isn’t just about one thing gone wrong – it’s about everything gone wrong at once. When Victorian engineers designed these tunnels, cooling wasn’t a major consideration. The tight, compact tunnels were built deep, nestled in the clay beneath London. In the early days, temperatures in the Underground were considered comfortably low.

“The Underground’s the only spot for comfort when the days are hot; it is cooler below.” – London Underground poster, 1926

Originally, the clay surrounding the tunnels sat at around 14°C, acting as a heat sink for the network. However, over the years, with more trains coming and going and more heat pouring in, the temperature has risen. It now typically sits anywhere from 19° to 26 °C. That’s just the earth around the tunnels, though. Air temperatures are worse—hitting as high as 47°C during a 2006 heatwave. The problem has been a continual bugbear of the beloved Tube, with concerns that future heatwaves could see temperatures rise ever higher. Continue reading “The London Underground Is Too Hot, But It’s Not An Easy Fix” →

Scratch And Sniff Stickers And The Gas Panic Of ’87

December 3, 2024 by 41 Comments

Ever wonder how those scratch and sniff stickers manage to pack a punch of aroma into what looks like ordinary paper? The technology behind it is deceptively clever, and has been used everywhere from children’s books to compact discs.

Most Scratch and Sniff stickers are simple nose-based novelties, though they’ve seen other uses as diagnostic tools, too. As Baltimore Gas and Electric discovered in 1987, though, these stickers can also cause a whole lot of hullabaloo. Let’s explore how this nifty technology works, and how it can go—somewhat amusingly—wrong.

The Science

3M developed the scratch and sniff technology in the 1960s. It quickly gained iconic status in the decades that followed. via eBay

At its heart, scratch and sniff technology involves the microencapsulation of tiny smellable particles, which are then impregnated into stickers or other paper products. Microscopic amounts of aromatic materiale are trapped inside gelatin or plastic capsules, and then stuck to paper. When you scratch the surface, these capsules rupture, releasing their aromatic cargo into the air. It’s an elegant feat of materials engineering, originally developed by Gale W. Matson. Working at 3M in the 1960s, he’d been intending to create a new kind of carbonless copy paper.

Scratch and Sniff stickers soon became a popular novelty in the 1970s. The catchy name was perfect—it told you everything you need to know. A children’s book named Little Bunny Follows His Nose was one of the first widespread applications. Released in 1971, it  was entirely based around the whole scratch and sniff concept. Children could read along and scratch various illustrations of peaches, roses and pine needles to see what they smelled like. The book was reprinted multiple times, remaining in publication for over three decades.

Other popular media soon followed. Pop rock band The Raspberries put a scratch and sniff sticker on their album cover in 1972. Director John Waters would go on to release his 1981 film Polyester with an accompanying “Odorama” card, which featured multiple smells for viewers to sniff during the movie. The concept still resurfaces occasionally, though the gimmick is now well-worn. In 2010, Katy Perry’s Teenage Dream album smelled like cotton candy thanks to a scratch-and-sniff treatment on the Deluxe Edition, and King Gizzard & The Lizard Wizard put a similar touch on 2017’s Flying Microtonal Banana. Continue reading “Scratch And Sniff Stickers And The Gas Panic Of ’87” →

Boss Byproducts: Corium Is Man-Made Lava

November 27, 2024 by 19 Comments

So now we’ve talked about all kinds of byproducts, including man-made (Fordite), nature-made (fulgurites), and one that’s a little of both (calthemites). Each of these is beautiful in its own way, but I’m not sure about the beauty and merit of corium — that which is created in a nuclear reactor core during a meltdown.

A necklace made to look like corium.
A necklace made to look like corium. Image via OSS-OSS

Corium has the consistency of lava and is made up of many things, including nuclear fuel, the products of fission, control rods, any structural parts of the reactor that were affected, and products of those parts’ reaction with the surrounding air, water, and steam.

If the reactor vessel itself is breached, corium can include molten concrete from the floor underneath. That said, if corium is hot enough, it can melt any concrete it comes in contact with.

So, I had to ask, is there corium jewelry? Not quite. Corium is dangerous and hard to come by. But that doesn’t stop artisans from imitating the substance with other materials.

Continue reading “Boss Byproducts: Corium Is Man-Made Lava” →

Rendering of a JetZero blended wing body aircraft with US Air Force markings. (Credit: US Air Force)

Blended Wing Body Passenger Airplanes And The End Of Winged Tubes

November 21, 2024 by 69 Comments
The SR-71 with its blended wing body design. (Photo by Tech. Sgt. Michael Haggerty, US Air Force, 1988)
The SR-71 with its blended wing body design. (Photo by Tech. Sgt. Michael Haggerty, US Air Force, 1988)

Ask someone to picture an airplane and they’re likely to think of what is essentially a tube with wings and a stabilizing tail tacked onto one end of said tube. Yet it is also no secret that the lift produced by such a tube is rather poor, even if they’re straightforward for loading cargo (static and self-loading) into them and for deciding where to put in windows. Over the decades a number of alternative airplane designs have been developed, with some of them also ending up being produced. Here most people are probably quite familiar with the US Air Force’s B-2 Spirit bomber and its characteristic flying wing design, while blended wing body (BWB) maintains a somewhat distinctive fuselage, as with for example the B-1 Lancer.

Outside of military airplanes BWBs are a pretty rare sight. Within the world of passenger airplanes the tube-with-wings pattern that the first ever passenger airplanes adopted has persisted with the newest designs, making it often tricky to distinguish one airplane from another. This could soon change, however, with a strong interest within the industry for passenger-oriented BWBs. The reason for this are the significant boosts in efficiency, quieter performance and more internal (useful) volume, which makes airline operators very happy, but which may also benefit passengers.

With that said, how close are we truly to the first BWB passenger airplane delivery to an airline?

Continue reading “Blended Wing Body Passenger Airplanes And The End Of Winged Tubes” →

Do You Dream In Color?

November 18, 2024 by 86 Comments

According to the Sapir–Whorf hypothesis, our language influences how we think and experience the world. That’s easy to imagine. Certainly our symbolism of mathematics influences how we calculate. Can you imagine doing moderately complex math with Roman numerals or without zero or negative numbers? But recently I was reminded that technological media also influences our perception of reality, and I have a Hackaday post to thank for it.

The post in question was about color TV. When I was a kid, most people had black and white TVs, although there were color sets. Even if you had a color set, many shows and movies were in black and white. Back then, many people still shot black and white film in their cameras, too, for many reasons. To make matters worse, I grew up in a small town, reading books from the local library that were ten or twenty years behind the times.

At some point, I read a statistic that said that most people dream in black and white. You may find this surprising, as I’ll bet you dream in color. It turns out, how people dream may have changed over the years and still and motion photography may be the reason.

The Post

In the post, I posed a question I’ve thought about many times: Did people dream in black and white before the advent of photography? It was kind of an off-hand remark to open the post, but many people reacted to it in the comments. They seemed surprised that I would ask that because, of course, everyone dreams in color.

I asked a few people I knew who also seemed very surprised that I would assume anyone ever dreams in color. But I was sure I had been told that sometime in the past. Time to hit the Internet and find out if that was incorrect or a false memory or something else. Turns out, it was indeed something else.

The Science

Charlie Chaplin’s “Modern Times“

A scientific paper from 2008 held the answer. It turns out that science started asking questions like this in the early 1900s. Up through the 1940s, people overwhelmingly reported dreaming in black and white, at least most of the time. Color dreams were in the minority, although not unheard of.

Then something changed. Studies that occurred in the 1960s and later, show exactly the opposite. People almost always dream in color and rarely in black and white. Of course, that correlates well with the rise of color photos, movies, and television. What’s more is, while there is no scientific evidence gathering about earlier times, there is a suspicious lack of, for example, a Shakespeare quote about “The gray world of slumber…” or anything else that would hint that the writer was dreaming in black and white.

Interpretation

Judging from the paper, it seems clear that most people agree that color media played a role in this surprising finding. What they can’t agree on is why. It does seem unlikely that your dreams really change based on your media consumption. But it is possible that your recollection changes. This is particularly true since the way researchers acquired data changed over that time period, too. But even if the data doesn’t show that you dreamed in black and white, it did show that you remembered dreaming in black and white.

For that matter, it isn’t clear that anyone understands how you experience dreams visually, anyway. It isn’t like the back of your eyelids are little movie screens. You don’t actually see anything in a dream, you only remember seeing it.

The Question

If something as simple as black-and-white movies and TV can change how we perceive dreams, you have to wonder how much tech is changing our reality experience in other ways. Do we live differently because we have cell phones? Or the Internet? Will virtual reality alter our dream lives? It would be interesting to fast-forward a century and see what historians say about our time and how strangely we perceive reality today.

I Want To Believe: How To Make Technology Value Judgements

November 15, 2024 by 70 Comments

In the iconic 1990s TV series The X Files, David Duchovny’s FBI agent-paranormal investigator Fox Mulder has a poster on his office wall. It shows a flying saucer in flight, with the slogan “I Want To Believe”. It perfectly sums up the dilemma the character faces. And while I’m guessing that only a few Hackaday readers have gone down the full lizard-people rabbit hole, wanting to believe is probably something that a lot of us who love sci-fi understand. It would be a fascinating event for science if a real extraterrestrial craft would show up, so of course we want to believe to some extent, even if we’re not seriously expecting it to appear in a Midwestern cornfield and break out the probes any time soon.

By All Means Believe. But Don’t Wreck Your Career

The first page of a scientific paper: "Electrochemically induced nuclear fusion of deuterium".
The infamous Fleischmann and Pons paper from 1989 on cold fusion.

Outside the realm of TV drama and science fiction it’s a sentiment that also applies in more credible situations. Back at the end of the 1980s for example when so-called cold fusion became a global story it seemed as though we might be on the verge of the Holy Grail of clean energy breakthroughs. Sadly we never got our Mr. Fusion to power our DeLorean, and the scientific proof was revealed to be on very weak foundations. The careers of the two researchers involved were irreparably damaged, and the entire field became a byword for junk science. A more recently story in a similar vein is the EM drive, a theoretical reactionless force generator that was promising enough at one point that even NASA performed some research on it. Sadly there were no magic engines forthcoming, so while it was worth reporting on the initial excitement, we’re guessing the story won’t come back.

When evaluating a scientific or technical breakthrough that seems as miraculous as it is unexpected then, of course we all want to believe. We evaluate based on the information we have in front of us though, and we all have a credibility pyramid. There’s nothing wrong with having an interest in fields that are more hope than delivery, indeed almost every technology that powers our world will at some time have to overcome skepticism in its gestation period. Perhaps it’s best to say that it’s okay to have hope, but hope shouldn’t override our scrutiny of the proof. Of course I want a perpetual motion machine, who wouldn’t, but as a fictional engineer once allegedly said, “Ye cannae change the laws of physics”. Continue reading “I Want To Believe: How To Make Technology Value Judgements” →

Ask Hackaday: How Much Would You Stake On An Online Retailer

November 8, 2024 by 69 Comments

On the bench where this is being written, there’s a Mitutoyo vernier caliper. It’s the base model with a proper vernier scale, but it’s beautifully made, and it’s enjoyable to see younger hardware hackers puzzle over how to use it. It cost about thirty British pounds a few years ago, but when it comes to quality metrology instruments that’s really cheap. The sky really is the limit for those in search of ultimate accuracy and precision. We can see then why this Redditor was upset when the $400 Mitutoyo they ordered from Amazon turned out to be nothing of the sort. We can’t even call it a fake, it’s just a very cheap instrument stuffed oddly, into a genuine Mitutoyo box.

Naturally we hope they received a refund, but it does raise the question when buying from large online retailers; how much are we prepared to risk? We buy plenty of stuff from AliExpress in out community, but in that case the slight element of chance which comes with random Chinese manufacture is offset by the low prices. Meanwhile the likes of Amazon have worked hard to establish themselves as trusted brands, but is that misplaced? They are after all simply clearing houses for third party products, and evidently have little care for what’s in the box. The £30 base model caliper mentioned above is an acceptable punt, but at what point should we go to a specialist and pay more for some confidence in the product?

It’s a question worth pondering as we hit the “Buy now” button without thinking. What’s your view? Let us know in the comments. Meanwhile, we can all be caught with our online purchases.

Thanks [JohnU] for the tip.