Engineering

585 Articles

Radio Apocalypse: Hardening AM Radio Against Disasters

June 6, 2023 by 64 Comments

If you’ve been car shopping lately, or even if you’ve just been paying attention to the news, you’ll probably be at least somewhat familiar with the kerfuffle over AM radio. The idea is that in these days of podcasts and streaming music, plain-old amplitude modulated radio is becoming increasingly irrelevant as a medium of mass communication, to the point that automakers are dropping support for it from their infotainment systems.

The threat of federal legislation seems to have tapped the brakes on the anti-AM bandwagon, at least for now. One can debate the pros and cons, but the most interesting tidbit to fall out of this whole thing is one of the strongest arguments for keeping the ability to receive AM in cars: emergency communications. It turns out that about 75 stations, most of them in the AM band, cover about 90% of the US population. This makes AM such a vital tool during times of emergency that the federal government has embarked on a serious program to ensure its survivability in the face of disaster.

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Learning 3D Printing Best Practices From A Pro

May 26, 2023 by 13 Comments

It might seem like 3D printing is a thoroughly modern technology, but the fact is, it’s been used in the industry for decades. The only thing that’s really new is that the printers have become cheap and small enough for folks like us to buy one and plop it on our workbench. So why not take advantage of all that knowledge accumulated by those who’ve been working in the 3D printing field, more accurately referred to as additive manufacturing, since before MakerBot stopped making wooden printers?

That’s why we asked Eric Utley, an applications engineer with Protolabs, to stop by the Hack Chat this week. With over 15 years of experience in additive manufacturing, it’s fair to say he’s seen the technology go through some pretty big changes. Hes worked on everything from the classic stereolithography (SLA) to the newer Multi Jet Fusion (MJF) printers, with a recent focus on printing in metals such as Inconel and aluminum. Compared to the sort of 3D printers he’s worked with, we’re basically playing with hot, semi-melted, LEGOs — but that doesn’t mean some of the lessons he’s learned can’t be applied at the hobbyist level. Continue reading “Learning 3D Printing Best Practices From A Pro” →

Smoke Some Weeds: Lasers Could Make Herbicide Obsolete

April 26, 2023 by 53 Comments

We’ve all tangled with unwelcome plant life at one point or another. Whether crabgrass infested your lawn, or you were put on weeding duty in your grandfather’s rose patch, you’ll know they’re a pain to remove, and a pain to prevent. For farmers, just imagine the same problem, but scaled up to cover thousands of acres.

Dealing with weeds typically involves harsh chemicals or excessive manual labor. Lasers could prove to be a new tool in the fight against this scourge, however, as covered by the BBC.

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The UK’s ST40 Spherical Tokamak Achieves Crucial Plasma Temperatures

April 11, 2023 by 23 Comments

As the race towards the first commercially viable nuclear fusion reactor heats up, the UK-based Tokamak Energy has published a paper on its recent achievements with its ST40 spherical tokamak. Most notable is the achieving of plasma temperatures of over 100 million Kelvin, which would put this fusion reactor firmly within the range for deuterium-tritium fusion at a rate that would lead credence to the projection made by Tokamak Energy about building its first commercial fusion plants in the 2030s.

The ST40 is intended to provide the necessary data to construct the ST80-HTS by 2026, which itself would be a testing ground for the first commercial reactor, called the ST-E1, which would be rated at 200 MWe. Although this may seem ambitious, Tokamak Energy didn’t come out of nowhere, but is a spin-of of Culham Centre for Fusion Energy (CCFE), the UK’s national laboratory for fusion research, which was grounded in 1965, and has been for decades been involved in spherical tokamak research projects like MAST and MAST-Upgrade, with STEP as its own design for a commercial fusion reactor.

The advantage offered by spherical tokamaks compared to regular tokamaks is that they favor a very compact construction style which puts the magnets very close to the plasma, effectively making them more efficient in retaining the plasma, with less power required to maintain stable plasma. Although this makes the use of super-conducting electromagnets not necessary, it does mean that wear and tear on these magnets is significantly higher. What this does mean is that this type of tokamak can be much cheaper than alternative reactor types, even if they do not scale as well.

Whether or not Tokamak Energy will be the first to achieve commercial nuclear fusion remains to be seen. So far Commonwealth Fusion’s SPARC and a whole host of Western and Asian fusion projects are vying for that gold medal.

The Real John Wick-Style Bullet Proof Suit

April 10, 2023 by 55 Comments

If you’ve seen the John Wick movies, you’ve probably had to suspend your disbelief about many things, but the bulletproof suits are perhaps the hardest thing to swallow. They look like stylish suits but are impervious to just about anything at any range. What’s more is when you are hit, they seem to absorb all impact with no effect on the wearer at all.

You can keep running, firing, or karate kicking while the suit takes all of the bullets. You can even pull your jacket up over your face if you want to protect that million-dollar smile. Physics, of course, tells us that a suit like this is pretty much impossible. Except that they actually exist. Granted, the real-life suits don’t have the magic physics-defying powers of Mr. Wick’s suit, but if you have the cash, you can get a smart-looking suit that protects you from getting killed by a bullet.

Real Life, Part I

In the movies, the suits supposedly have Kevlar in them just like a real piece of ballistic body armor. The problem is, Kevlar is bulky. However, most of the real body armor you see — like a vest on a SWAT team operative — is made from Kevlar or similar ballistic fibers like Twaron, Goldflex, or Dyneema. They also have plates made of metal or ceramic. Continue reading “The Real John Wick-Style Bullet Proof Suit” →

Self-Healing Concrete: What Ancient Roman Concrete Can Teach Us

April 3, 2023 by 30 Comments

Concrete is an incredibly useful and versatile building material on which not only today’s societies, but also the ancient Roman Empire was built. To this day Roman concrete structures can be found in mundane locations such as harbors, but also the Pantheon in Rome, which to this day forms the largest unreinforced concrete dome in existence at 43.3 meters diameter, and is in excellent condition despite being being nearly 1,900 years old.

Even as the Roman Empire fell and receded into what became the Byzantine – also known as the Eastern Roman – Empire and the world around these last remnants of Roman architecture changed and changed again, all of these concrete structures remained despite knowledge of how to construct structures like them being lost to the ages. Perhaps the most astounding thing is that even today our concrete isn’t nearly as durable, despite modern inventions such as reinforcing with rebar.

Reverse-engineering ancient Roman concrete has for decades now been the source of intense study and debate, with a recent paper by Linda M. Seymour and colleagues adding an important clue to the puzzle. Could so-called ‘hot mixing’, with pockets of reactive lime clasts inside the cured concrete provide self-healing properties?

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Tour A PCB Assembly Line From Your Armchair

April 2, 2023 by 15 Comments

Those of us who build our own electronics should have some idea of the process used to assemble modern surface-mount printed circuit boards. Whether we hand-solder, apply paste with a syringe, use a hotplate, or go the whole hog with stencil and oven, the process of putting components on boards and soldering them is fairly straightforward. It’s the same in an industrial setting, though perhaps fewer of us will have seen an industrial pick-and-place line in action. [Martina] looks at just such a line for us, giving a very accessible introduction to the machines and how they are used. Have a look, in the video below the break.

It’s particularly interesting as someone used to the home-made versions of these machines, to see the optical self-alignment and the multiple pick-and-place tools which are beyond the simpler pick-and-place machines you’ll find in a hackerspace. Multiple machines in a line are also beyond hackerspaces, so the revelation that the first machine is deliberately run slowly to avoid the line backing up is a valuable one.

At the end of the line is the reflow oven itself, through which the boards pass on a belt through carefully graded hot air zones. Certainly a step up from a toaster oven with an Arduino controller!

Sadly not all of us will be lucky enough to have such a line at our disposal, but pick-and-place projects come up here quite often. We did a teardown on the feeders from a Siemens machine a couple of years ago.

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