CLOSE
Original image

TNT vs. Dynamite: What's the Difference?

Original image

dynamite.jpgThe Dilemma: Either you're a rabid AC/DC fan in search of lyrical meaning or you've got some pressing need to blow something up. Either way, we've got your answer.


People You Can Impress: demolition experts, mustachioed villains from silent movies, and Wile E. Coyote


The Quick Trick: If it's a white powder found in sticks, it's dynamite. If it's a yellow crystal, it's TNT. Use this little mnemonic to remember dynamite's inventor: "Winning a Nobel Prize would be dynamite!" The alternative, that winning would be TNT, just doesn't make any sense.

The Explanation: A lot of people use these two terms interchangeably, and the common misperception is that TNT is the chemical name and dynamite is the colloquial term. But like any good misperception, that's just plain wrong.

nobel.jpgWe'll start with dynamite. Patented in 1867 by the Swedish chemist Alfred Nobel (as in Nobel Prize), dynamite was discovered when old Alfie was looking for a way to make nitroglycerin more stable and less prone to, well, exploding in your face. By combining nitroglycerine with diatomaceous earth (the ground-up shells of microscopic diatoms, today used as a filtering agent in swimming pools) and sodium carbonate (found in baking soda and soaps), Nobel took explosives in a whole new direction. And because it was stable and wouldn't explode from jiggling, like nitroglycerin, dynamite was initially marketed as Nobel's Safety Blasting Powder. (Well, it wasn't that safe; an explosion at the family factory killed Alfred's brother Emil.) Nobel used the huge profits from his dynamite patent to endow the Nobel prizes—one of which is for peace. He may have been inspired to create the Nobel Prize after a premature obituary in a French newspaper called him a "merchant of death."

As for TNT, it's also a high explosive, but it ain't dynamite. TNT is a yellowish compound with the chemical name trinitrotoluene(try-night-row-TALL-you-een), which is somewhat easier to remember than its chemical formula, CH 3C6H2(NO2)3. TNT was discovered in Germany in 1863 by Joseph Wilbrand. Although not quite as powerful as dynamite (and harder to detonate), the main benefit of TNT is that it's even more stable than dynamite (Wilbrand, for instance, never lost a single brother to an explosion). Also, TNT can be melted down and poured into shell casings. On the downside, however, TNT is extremely toxic.

While TNT packs plenty of bang by itself, it's often mixed with other things. A TNT and ammonium nitrate cocktail will get you amatol, a military explosive. Remix those two and add some powdered aluminum, and you'll get ammonal, a common industrial explosive.

AC/DC
The confusion between TNT and dynamite isn't helped by popular culture. The two are routinely used interchangeably in movies. And in the song "TNT" by AC/DC, deceased lead singer Bonn Scott declares "I'm TNT, I'm dynamite." So which one is it, Bonn?

This post was excerpted from the mental_floss book What's the Difference? For more columns like this, click here.

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

Original image
Opening Ceremony
fun
arrow
These $425 Jeans Can Turn Into Jorts
May 19, 2017
Original image
Opening Ceremony

Modular clothing used to consist of something simple, like a reversible jacket. Today, it’s a $425 pair of detachable jeans.

Apparel retailer Opening Ceremony recently debuted a pair of “2 in 1 Y/Project” trousers that look fairly peculiar. The legs are held to the crotch by a pair of loops, creating a disjointed C-3PO effect. Undo the loops and you can now remove the legs entirely, leaving a pair of jean shorts in their wake. The result goes from this:

501069-OpeningCeremony2.jpg

Opening Ceremony

To this:

501069-OpeningCeremony3.jpg

Opening Ceremony

The company also offers a slightly different cut with button tabs in black for $460. If these aren’t audacious enough for you, the Y/Project line includes jumpsuits with removable legs and garter-equipped jeans.

[h/t Mashable]

SECTIONS
BIG QUESTIONS
BIG QUESTIONS
JOB SECRETS
QUIZZES
WORLD WAR 1
SMART SHOPPING
STONES, BONES, & WRECKS
#TBT
THE PRESIDENTS
WORDS
RETROBITUARIES