After decades of improvements to hard disk drive (HDD) technology, manufacturers are now close to taking the next big leap that will boost storage density to new levels. Using laser-assisted writes, manufacturers like Seagate are projecting 50+ TB HDDs by 2026 and 120+ TB HDDs after 2030. One part of the secret recipe is heat-assisted magnetic recording (HAMR).
One of the hurdles with implementing HAMR is finding a protective coating for the magnetic media that can handle this frequent heating while also being thinner than current coatings, so that the head can move even closer to the surface. According to a recent paper by N. Dwivedi et al. published in Nature Communications, this new protective coating may have been found in the form of sheets of graphene.
Continue reading “How Graphene May Enable The Next Generations Of High-Density Hard Drives”
Water, high currents, blinding balls of plasma, and a highly flammable gas that’s toxic enough to kill you in three minutes if you breathe enough of it. What’s not to love about this plasma-powered water gas generator?
In all seriousness, [NightHawkInLight] is playing with some dangerous stuff here, and he’s quite adamant about this one being firmly in the “Don’t try this at home” category. But it’s also fascinating stuff, since it uses nothing but a tank of water and an electric arc to produce useful amounts of fuel very quickly. It’s easy to jump to the conclusion that he’s talking about the electrolytic splitting of water into the hydrogen-oxygen mix HHO, but this is something else entirely.
Using a carbon electrode torch connected to his arc welder, a setup that’s similar to the one he used to make synthetic rubies, [NightHawkInLight] is able to strike an underwater arc inside a vessel that looks for all the world like a double-barreled bong. The plasma creates a mixture of carbon monoxide and hydrogen which accumulates very rapidly in the gasometer he built to collect the flammable products produced by a wood gasifier.
The water gas burns remarkably cleanly, but probably has limited practical uses. Unless you live somewhere where electricity costs practically nothing, it’ll be hard to break even on this. Still, it’s an interesting look at what’s possible when plasma and water mix.
Continue reading “Fuel From Water Using Only An Arc Welder”
Anyone who was active in the phreaking scene or was even the least bit curious about the phone system back in the Ma Bell days no doubt remembers the carbon capsule microphone in the mouthpiece of many telephone handsets. With carbon granules sandwiched between a diaphragm and a metal plate, they were essentially sound-driven variable resistors, and they worked well enough to be the standard microphone for telephony for decades.
In an attempt to reduce complicated practices to their fundamentals, [Simplifier] has undertaken this surprisingly high-fidelity carbon microphone build that hearkens back to the early days of the telephone. It builds on previous work that was more proof of concept but still impressive. In both builds, the diaphragm of the microphone is a thin piece of wood, at first carved from a single block of softwood, then later improved by attaching a thin piece of pine to a red oak frame. The electrical side of the mic has four carbon rods running from the frame to the center of the diaphragm, where they articulate in a carbon block with small divots dug into it. As the diaphragm vibrates, the block exerts more or less pressure on the rods, varying the current across the mic and reproducing the sound. It works quite well, judging by the video after the break.
Congratulations to [Simplifier] for another great build and top-notch craftsmanship. We’ve seen homebrew vacuum tubes, conductive glass, and solar cells from him before, which sort of makes him the high-tech version of Primitive Technology. We’re looking forward to whatever comes next. Continue reading “Wood And Carbon Rods Used For This Handsome And Effective Microphone”
Of all the fictional cyborgs who turn against humanity to conquer the planet, this is as far from that possibility as you can get. These harmless mushrooms seem more interested in showing off their excellent fashion sense with a daring juxtaposition of hard grid lines with playful spirals. But the purpose of this bacteria-fungus-technology hybrid is to generate electricity. The mushrooms are there to play nurse to a layer of cyanobacteria, the green gel in the photo, while the straight black lines harvest electricity.
Cyanobacteria do not live very long under these kinds of conditions, so long-term use is out of the question, but by giving the cyanobacteria somewhere it can thrive, the usefulness grows. The interplay between bacterial and supportive organics could lead to advances in sensors and hydrogels as well. At some point, we may grow some of our hardware and a green thumb will be as useful as a degree in computer science.
Hydrogels could be the next medical revolution, and we’ve already made hydrogels into tattoos, used them as forms for artificial muscles, and hydrogels can be a part of soft tissue printing.
Props for your little RC airplane or drone are effectively consumables. They’re made of plastic, they’re cheap, and you’re going to break a lot of them. When you start swinging something larger than 12 inches or so, things start getting expensive. If you’re building gigantic octocopters or big RC planes, those props start adding up. You might not think you can build your own gigantic carbon fiber propellers, but [Tech Ingredients] is here to prove you wrong with an incredible video demonstration of the construction of large propellers
The key ideas behind the build are laid out in a video demonstration for building a single prop. The base begins with a CNC wire cut foam air foil. This foam airfoil is first modified for the attachment point by cutting a plug out of the root of the airfoil which is filled with epoxy.
With the skeleton of the airfoil complete, the build then moves on to laminating the foam core with carbon fiber. The epoxy itself is West Systems Pro-Set laminating epoxy, although we suspect the ubiquitous West Systems epoxy used for all those live-edge ‘river’ coffee tables will also work as well. This epoxy is spread out on a table, the carbon fiber laid over it, and a second layer of carbon fiber (check ‘yo biases!) laid over that. This is wrapped around the foam core, then cured with an electric heating pad.
Of course, this is only a demonstration of making a single blade for a prop. The next trick is turning that single blade into a propeller. This is done with a cleverly machined hub, attached through that epoxy plug placed in the foam core. The results are just as good as any large prop you could buy, and this has the added benefit of being something you made, not bought.
This is really a master class in composite construction, and well worth an hour’s of YouTube viewing. You can check out the intro video below.
Continue reading “The Carbon Fiber Construction Of Large Propellers”
Citizen scientist extraordinaire [Thought Emporium] put out a new video about colorful quantum dots which can be seen below the break. Quantum dots are a few nanometers wide and you can tell which size they are by which color they fluoresce. Their optical and electrical properties vary proportionally with size so red will behave differently than purple but we doubt they will taste like “cherry” and “grape.” Let’s not find out. This makes sense when you realize that a diamond will turn into black powder if you pulverize it. Carbon is funny like that.
[Thought Emporium] uses the video for two purposes. The first is to demonstrate the process he uses to make different size quantum dot in his home lab. The second purpose is to implore the scientific community, in general, to take better care when publishing scientific papers. A flimsy third reason is to show that the show must go on. Partway through, all the batteries for his light were dead so he hastily soldered a connection for his benchtop power supply.
We’ve mentioned [Thought Emporium] a few times before. Another of his carbon-based experiments involved graphene creation. How about magnetic DNA extraction? [Thought Emporium] did that too. If you can’t get enough magnets, how about implanting one?
Continue reading “Carbon Quantum Dots In Your Favorite Color”
When a rainforest is clearcut for agricultural use, we only see the surface problems: fewer trees, destruction of plant and animal habitats, and countless other negative effects on the environment. A lurking problem, however, is that the soil is often non-ideal for farming. When the soil is exhausted, the farmers move further into the rainforest and repeat the process.
In the Amazon, however, there are pockets of man-made soil that are incredibly nutrient-dense. Figuring out how to make this soil, known as Terra Preta, on a massive scale would limit the amount of forest destruction by providing farmers a soil with more longevity which will, in turn, limit the encroachment on the rainforest. That’s the goal of this Hackaday Prize entry by [Leonardo Zuniga]: a pyrolysis chemical reactor that can make this soil by turning organic matter into a type of charcoal that can be incorporated into the soil to make Terra Preta.
As a bonus to making this nutrient-dense soil on a massive scale, this reactor also generates usable energy as a byproduct of processing organic waste, which goes several steps beyond simple soil enrichment. If successful and scalable, this project could result in more efficient farming techniques, greater yields, and, best of all, less damage to the environment and less impact on the rainforests.