The Roller Ship Was Not An Effective Way To Cross The High Seas

Boats come in all shapes and sizes. We have container ships, oil tankers, old-timey wooden sailing ships, catamarans, trimarans, and all sorts besides. Most are designed with features that give them a certain advantage or utility that justifies their construction for a given application.

The roller ship, on the other hand, has not justified its own repeat construction. Just one example was ever built, which proved unseaworthy and impractical. Let’s explore this nautical oddity and learn about why it didn’t make waves as its inventor may have hoped.

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Sort Of Electromagnet Attracts Copper, Aluminum

It is a common grade school experiment to wind some wire around a screw, power it up, and watch it pick up paper clips or other ferrous materials. It is also grade school science to show that neither an electromagnet nor a permanent magnet will pick up nonferrous items like copper or aluminum. While technically not an electromagnet, it is possible to build a similar device that will weakly pull on copper and aluminum, and [Cylo] shows us how it works in a recent video you can see below.

The device sure looks like an electromagnet made with magnet wire and a steel core. But when he shows the ends of the core, you’ll see that the side that attracts aluminum has a copper ring embedded in it. The coil is fed with AC.

The magnetic field from the coil induces an opposite field in the copper ring that is out of phase with the exciting field. The two fields combine to produce a force on the metal it interacts with. This is often referred to as a shaded pole, and the same technique can help AC motors self-start as well as hold in relays driven by AC. If you want to see much more about aluminum floating on a magnetic field, check out the 1975 video from [Professor Laithwaite] in the second video below.

You probably have a shaded pole AC motor in your microwave oven. Or, maybe,your old 8-track player.

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Japan’s First Commercial Rocket Debuts With A Bang

Though it suffered through decades of naysayers, these days you’d be hard pressed to find anyone who would still argue that the commercialization of space has been anything but a resounding success for the United States. SpaceX has completely disrupted what was a stagnant industry — of the 108 US rocket launches in 2023, 98 of them were performed by the Falcon 9. Even the smaller players, such as Rocket Lab and Blue Origin, are innovating and bringing new technologies to market at a rate which the legacy aerospace companies haven’t been able to achieve since the Space Race.

So it’s no surprise that other countries are looking to replicate that success. Japan in particular has been following NASA’s playbook by offering lucrative space contracts to major domestic tech companies such as Mitsubishi, Honda, NEC, Toyota, Canon, Kyocera, and Sumitomo. Over the last several years this has resulted in the development of a number spacecraft and missions, such as the Hakuto-R Moon lander. It’s also laid the groundwork for exciting future projects, like the crewed lunar rover Toyota and Honda are jointly developing for the Artemis program.

But so far there’s been a crucial element missing from Japan’s commercial space aspirations, an orbital booster rocket. While the country has state-funded launch vehicles such as the H-IIA and H3 rockets, they come with the usual bureaucracy one would expect from a government program. In comparison, a privately developed and operated booster holds the promise of reduced costs and a higher launch cadence, especially if there are multiple competing vehicles on the market.

With the recent test flight of Space One’s KAIROS rocket, that final piece of the puzzle may finally be falling into place. While the launch unfortunately failed shortly after liftoff, the fact that the private rocket was able to get off the ground — literally and figuratively — is a promising sign of what’s to come.

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3D Printing Real Wood With Just Cellulose And Lignin

Although the components of wood – cellulose and lignin – are exceedingly cheap and plentiful, combining these into a wood-like structure is not straightforward, despite many attempts to make these components somehow self-assemble. A recent attempt by [MD Shajedul Hoque Thakur] and colleagues as published in Science Advances now may have come closest to 3D printing literal wood using cellulose and lignin ink, using direct ink writing (DIW) as additive manufacturing method.

Microstructures of 3D-printed wood after printing and post-printing operations. (Credit: Thakur et al., 2024)
Microstructures of 3D printed wood after printing and post-printing operations. (Credit: Thakur et al., 2024)

This water-based ink was created by mixing TOCN (tempo-oxidized cellulose nanofiber), a 10.6 wt % aqueous CNC (cellulose nanocrystals) and lignin in a 15:142:10 ratio, giving it roughly the viscosity of clay. The purpose of having both TOCNs and CNCs is to replicate the crystalline and amorphous cellulose elements of wood-based cellulose.

This ink was printed from a syringe head (SDS-60) installed in a Hyrel 3D Engine HR 3D printer. This printer is much like your average FDM printer, just targeting bioprinting and a wide range of heads to print and handle various attachments in a laboratory setting. The ink was extruded into specific shapes that were either freeze dried to get rid of the liquid component, or additionally also heated (at 180°C), with a third set of samples put into a hot press. These additional steps seem to promote the binding of the lignin and create a more durable result.

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Automatic Position Reporting Over HF Radio

While most of us carry cell phones that have GPS and other location services, they require a significant amount of infrastructure to be useful. Drive from Washington to Alaska like [Lonney] did a while back, where that infrastructure is essentially nonexistent, and you’ll need to come up with some other solutions to let friends and family know where you are.

A tool called the Automatic Packet Reporting System (APRS) is fairly robust in the very high frequency (VHF) part of the amateur radio spectrum, but this solution still relies on a not-insignificant amount of infrastructure for the limited distances involved with VHF. [Lonney] adapted a few other tools to get APRS up and running in the HF range, letting his friends keep tabs on him even from the most remote locations.

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Cosmic Ray Detection At Starbucks?

Want to see cosmic rays? You might need a lot of expensive exotic gear. Nah. [The ActionLab] shows how a cup of coffee or cocoa can show you cosmic rays — or something — with just the right lighting angle. Little bubbles on the surface of the hot liquid tend to vanish in a way that looks as though something external and fast is spreading across the surface.

To test the idea that this is from some external source, he takes a smoke detector with a radioactive sensor and places it near the coffee. That didn’t seem to have any effect. However, a Whimhurst machine in the neighborhood does create a big change in the liquid. If you don’t have a Whimhurst machine, you can rub a balloon on your neighbor’s cat.

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Grep By Example is also available as a PDF Minibook, and a Grep playground helps you learn quickly.

Galvanize Your Grip On Grep With This Great Grep Guide

These days, you can’t throw a USB stick without hitting something that’s running Linux. It might be a phone, an embedded device, or your TV. Either way, it’s running Linux, and somewhere along the line of the development of whatever your USB stick smacked into, somebody used the Global Regular Expression Print utility- better known as Grep. But what is Grep, and why do you need it? [Anton Zhiyanov] not only answers those questions but provides Grep by example: Interactive Guide to help you along.

Grep By Example is also available as a PDF Minibook, and a Grep playground helps you learn quickly.
Grep By Example is also available as a PDF Minibook, and a Grep playground helps you learn quickly.

To understand Linux, one must understand its commercial predecessor, Unix. One of the things that made Unix (and then Linux) unique was its philosophy: Write programs that work together, do one thing well, and handle text streams.  This philosophy describes a huge number of programs, and one of these programs is Grep. It’s installed everywhere there’s a *nix installed, and once one becomes familiar with it, their command-line-fu reaches an all new level.

At its core, Grep is simply a bloodhound. It’s scent? A magical incantation called Regular Expressions. Regular Expressions (aka Regex) are simply a way of describing what a stream of text should look like. So when you feed Grep a bit of Regular Expression, it Prints only the text that matches that expression. Neat, right?

The trouble is that Regex can be kind of hard, and Grep has various versions and capabilities that need to be learned. And this is where the article shines- it covers both in an excellent interactive tutorial that’ll help you become a Grep Guru in no time. And if you want to do a deeper dive, check out what it takes to make your own Regex Engine from scratch!