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Will McGough

This is Where Tar Comes From

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Will McGough

Pitch Lake is located on the southwest side of Trinidad (see above photo), but a visitor will probably feel like they’re on the moon at times. Called Tierra de Brea, it is a natural deposit of asphalt, and sometimes referred to as a "tar pit." It's true—you can literally stick a stick into the ground, pull it up, and with it will come what looks like tar. Stand in one place too long, and you’ll feel your shoes begin to sink in and create an imprint.

According to most histories, Sir Walter Raleigh was shown the lake by locals when he arrived in Trinidad in search of El Dorado, the fabled city of gold. He found the tar to be great for caulking for his ships, and was credited with its discovery when he returned home with several barrels.

Trinidad's Pitch Lake is one of five of its kind. There are three others in California and one more in Venezuela. (Although there are smaller deposits of asphalt found in various locations around the world, these are the only lakes.) Pitch Lake is the biggest, measuring 246 feet deep and about 99 acres in size.

The second-largest lake, Lake Bermudez in Venezula, halted its commercial mining operations back in the 1930s, and the pit in Los Angeles is dedicated to archaeological research and the preservation of fossils. The area in Carpinteria is just south of where I used to live in Santa Barbara, and its presence is felt along the coast. I can tell you firsthand that there were many days when I walked out of the ocean near Santa Barbara and had tar on the bottom of my feet and bathing suit. And I still have the stained suits to prove it.

Ironically enough, despite having such a supply of asphalt on hand, Trinidad has some of the worst roads in the Caribbean—the country is an aggressive exporter of its product for road and runway construction in Europe and the United States. According to our guide, scientists predict that there's about a 400-year supply left underground—which really isn't that long, although I suppose it gives Trinidad plenty of time to patch up a few potholes if they so choose. Another interesting piece of trivia is that the "pitch"—another name for the tar—is where the phrase "pitch black" comes from, similar to the descriptions “red rose,” “sky blue,” and “snow white.”

There’s a picture under a hut outside of the visitor’s center that shows a man who had been in up to his waist—the pitch sucking him in like quicksand—but unfortunately they weren’t willing to let me become the second person to go that deep. (I’m weird like that.) Instead, I settled for a walking tour and a quick dip in one of the sulfur pools, making sure to leave hand and footprints in my wake. The pools are obviously bigger during the rainy summer months, but I found one deep enough to swim in during my dry-season visit in March.

Will McGough

More nerdy stuff: The pitch drop experiment in Australia is one of the longest running scientific experiments in which a “solid” piece of pitch is placed in a funnel and flows over a very long timescale. Because the viscosity of pitch is 230-billion times that of water, a droplet falls from the funnel only once every eight to 12 years. Only eight drops have fallen since the experiment was set up in 1927. In a case of very good timing, the 9th drop is expected to fall sometime this year.

Pretty cool, yeah? Now every time you turn out the lights or get in your car, you can think of Trinidad.

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iStock // Ekaterina Minaeva
technology
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Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
May 21, 2017
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iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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Stephen Missal
crime
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New Evidence Emerges in Norway’s Most Famous Unsolved Murder Case
May 22, 2017
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A 2016 sketch by a forensic artist of the Isdal Woman
Stephen Missal

For almost 50 years, Norwegian investigators have been baffled by the case of the “Isdal Woman,” whose burned corpse was found in a valley outside the city of Bergen in 1970. Most of her face and hair had been burned off and the labels in her clothes had been removed. The police investigation eventually led to a pair of suitcases stuffed with wigs and the discovery that the woman had stayed at numerous hotels around Norway under different aliases. Still, the police eventually ruled it a suicide.

Almost five decades later, the Norwegian public broadcaster NRK has launched a new investigation into the case, working with police to help track down her identity. And it is already yielding results. The BBC reports that forensic analysis of the woman’s teeth show that she was from a region along the French-German border.

In 1970, hikers discovered the Isdal Woman’s body, burned and lying on a remote slope surrounded by an umbrella, melted plastic bottles, what may have been a passport cover, and more. Her clothes and possessions were scraped clean of any kind of identifying marks or labels. Later, the police found that she left two suitcases at the Bergen train station, containing sunglasses with her fingerprints on the lenses, a hairbrush, a prescription bottle of eczema cream, several wigs, and glasses with clear lenses. Again, all labels and other identifying marks had been removed, even from the prescription cream. A notepad found inside was filled with handwritten letters that looked like a code. A shopping bag led police to a shoe store, where, finally, an employee remembered selling rubber boots just like the ones found on the woman’s body.

Eventually, the police discovered that she had stayed in different hotels all over the country under different names, which would have required passports under several different aliases. This strongly suggests that she was a spy. Though she was both burned alive and had a stomach full of undigested sleeping pills, the police eventually ruled the death a suicide, unable to track down any evidence that they could tie to her murder.

But some of the forensic data that can help solve her case still exists. The Isdal Woman’s jaw was preserved in a forensic archive, allowing researchers from the University of Canberra in Australia to use isotopic analysis to figure out where she came from, based on the chemical traces left on her teeth while she was growing up. It’s the first time this technique has been used in a Norwegian criminal investigation.

The isotopic analysis was so effective that the researchers can tell that she probably grew up in eastern or central Europe, then moved west toward France during her adolescence, possibly just before or during World War II. Previous studies of her handwriting have indicated that she learned to write in France or in another French-speaking country.

Narrowing down the woman’s origins to such a specific region could help find someone who knew her, or reports of missing women who matched her description. The case is still a long way from solved, but the search is now much narrower than it had been in the mystery's long history.

[h/t BBC]

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