Exploring The Downsides Of Cooling Roof Paint

The idea of painting a roof or wall white in order to reflect sunshine and keep the building’s insides cool is hardly a new one, and even in the loosest interpretation of the word ‘white’ it generally works pretty well. This is also what [NightHawkInLight] found after using an off-the-shelf silicone-based coating for his shed’s tin roof, though with a few caveats.

One might say that this is mostly a problem for people who live in non-desert climates — like Michigan in this case — yet it’s undeniable that having a cooler indoors in a high-humidity climate will inevitably lead to a higher indoor humidity level. This was the first issue that was encountered, though it mostly meant that instead of running an air conditioner eight hours a day, a weekly dehumidifier session was required, which was at least less expensive in terms of kWh.

While the current silicone-based paint on the roof stays above ambient, in a subsequent test both [NightHawkInLight]’s DIY sub-ambient cooling paint and a commercial option get a sample panel down to around ambient temperature, which could cool down the roof even more. Of course, in this case the humidity issues would get worse, with likely condensation forming that would have to be dealt with.

Overall, a cooling paint on the roof is a pretty thing even if you’re not living in the desert, but you have to be able to tame the resulting humidity and condensation issues.

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Doubling Thermal Printer Resolution By Wiggling

Insides of the Sears 12 calculator. (Credit: Danalog, YouTube)
Insides of the Sears 12 calculator. (Credit: Danalog, YouTube)

Thermal printers are still extremely common today, using small heating elements in combination with temperature-sensitive paper to create a dot matrix-like effect without messing with ink ribbons and complex mechanisms. Of course, even with just a line of elements you still needed one of these per pixel, which at least in the 1970s when the Sears 12 calculator was released added significantly to the cost. The solution here was to wiggle the elements, doubling the resolution of the print head, as detailed in this video by [Danalog].

Using a contemporary Texas Instruments TI-5015 calculator as comparison with its non-wiggling print head, it’s easy to see the advantages here. In an era where electronic calculators didn’t have displays but a thermal printer, this print quality was the selling point, yet adding more thermal elements added to the price tag of the final device and more complexity to the design in terms of driving circuitry.

In this regard adding a way to make the print head move side-to-side at a set rate and tying this fact into the printing would save about half of that circuitry. Inside the Sears 12 is a fairly standard Mitsubishi M58671 calculator IC, but also the whole printer mechanism. When operating, as demonstrated in the video with the cover removed, you can see the whole print head moving rapidly.

With this mechanism this much cheaper Sears 12 definitely gives the TI-5015 a run for its money, even if as noted by [Danalog] the timing would go off a bit after a longer session, resulting slightly wavy printing. Presumably with the massive cost savings of buying a Sears calculator over a TI one, this was deemed an acceptable trade-off.

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Harvesting Namib Desert Fog With High Voltage

As fun as mucking about with simulated environments in a laboratory is, at some point you have to do those field tests to demonstrate that your prototype actually works in the real world, under real conditions. This is what the [Plasma Channel] recently did for their fog harvesting system by setting it up in the Namib desert.

We previously covered the atmospheric water harvesting attempts, using electrostatic precipitation to draw the moisture in the air onto the collectors where it can then be harvested. This is rather different from existing approaches with e.g. fine meshes and hoping that enough water molecules bump into your mesh, so theoretically it should be much more efficient. In the lab it worked well, but reality always has the last word.

The Namib desert is at the top of the world’s most arid regions, competing with the Atacama desert. What it does have going for it is regular fog rolling in that lasts until sunrise, providing a good target for water harvesting. Interestingly, this field test was performed together with the University of Namibia.

Of course, moving the prototype in check-in luggage for the flight to Namibia took some redesigning and testing. Fortunately everything, including the solar panel, arrived intact, allowing trials to commence. This initially took place at the campus of the University of Namibia, joining a number of other atmospheric water harvesting projects that had been previously installed there.

Unfortunately the fog proved to be rather elusive, leading to a few fruitless attempts. It also proved that the salt in the air from the ocean spray, even a few kilometers inland, was highly corrosive, especially to high-voltage electronics. Although the system basically worked, happily harvesting water under the right conditions, it does need some redesign before it’ll be tested next in the Atacama desert.

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Creating The Greenest Possible Clothing With Living Fungi

Despite the wide variety of fabrics used for our clothing, they all share the property of not being living tissues. This could be due to them never having been part of an organism, or having been removed from said organism. Another approach here entails so-called engineered living materials (ELMs), with a recent research article by [Ke Li] et al. in Science Advances providing a good example of a fungal platform for such living textiles.

Although it may seem frivolous to create something like this, the direct benefits would be to have a fabric that can self-heal and respond to its environment, including blocking UV radiation and changing its coloring through pigmentation.

The research demonstrated in this paper covers essentially a platform for creating a living textile that can be adapted to a wide variety of applications and colorizations. Of note is that the researchers have not yet tested aspects like washability, abrasion resistance, breathability and wearer comfort, so this should definitely be regarded as setting the stage for more research.

For the basic material the fungi Cordyceps militaris was chosen, which were subsequently placed between films. To this additional microbial cultures were added, including the pigment-producing S. cerevisiae and melanized A. niger for UV blocking.

As for what it can look like with clothing, this article at De Zeen gives somewhat of an idea, as well as how the living textile is prepared.

Haiku OS Releases Beta 6

After just a little over 25 years of the Haiku project trying to keep the BeOS spirit alive, the team has now released Beta 6. The spicy details of what is now all better can naturally be found in the detailed release notes. Part of the size of these release notes is due to the previous beta release being two years ago, though nightly builds have kept Haiku users appeased in the meantime.

The headline features that are new compared to the previous release include the ability to run the Firefox browser and derivatives, QEMU hardware virtualization using the NetBSD Virtual Machine Monitor (NVMM), improved POSIX and hardware compatibility, as well as many bug fixes. Unfortunately 64-bit ARM support still has to wait a bit longer.

Naturally, such a joyful new release wouldn’t go unnoticed by [Action Retro], who decided to celebrate by installing this new release on a stack of old laptops that he bought for a dollar each. With system requirements starting at a Pentium II with 256 MB of RAM, it’s very zippy to install and boot on. As [Action Retro] noticed, a fresh install on a random 2000s Asus laptop both WiFi and audio worked out of the box.

Wrestling through his e-waste pile of laptops, the functional laptops provided a pretty good experience, making these at least an excellent target for a fresh Haiku install as a daily driver.

We looked at Beta 5 and the nightlies back in 2024, with recently attempts being made to port Nvidia GPU drivers to Haiku, with good results.

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How Gold Plastic Syndrome Is Killing Toys And Game Consoles

In a recent video [Sqwerks] does a deep-dive into the problem of disintegrating plastic enclosures of Nintendo DS consoles. These original NDS handheld consoles have a metallic-like coating that appears to interact with the ABS plastic, causing yellowing as well as extreme brittleness and correspondingly broken hinges. Unsurprisingly, this causes the shell to essentially disintegrate the moment you try to disassemble them for something like a screen replacement.

While somewhat the opposite of plasticizer migration into ABS from PVC insulation that we covered before, the underlying cause is probably similar, with the Transformers toy community having come to call it Gold Plastic Syndrome (GPS) based on the fact that it were mostly gold-colored parts on these plastic toys that seemed to be affected. Over time the additives used to add a cool metal sheen and swirls to the plastic appear to interact in a way that makes the ABS plastic very brittle.

Although the underlying cause of GPS doesn’t appear to be known yet, the Transformers community has documented this happening since the late 1980s and into the early 2000s, with even reports that some toys from the mid-2010s suffer from this. Whatever the underlying cause of GPS is, the result is always the same, with disintegrating brittle plastic and often a powdery residue.

In the case of NDS consoles, replacing the affected shell with a third-party replacement is still a viable option today, with [Sqwerks] recommending this solution. For other enclosures and toys where the plastic effectively is the toy, it might be that all we can do is watch them slowly disintegrate until we figure out how to revert GPS.

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PETG: The PLA Filament Alternative That Just Works

A typical response to the previous article on why PLA filament is so darn brittle. This has led some people to not use PLA filament at all, while others promote using PLA only for prototyping and throw-away parts, especially in light of PLA being compostable under the right conditions. For many mechanical parts, people turn to PETG.

Much like the PET polymer used for everything from food containers to drink bottles, PETG is durable, more resistant to degradation through mechanisms like hydrolysis and its filament form doesn’t need to be coddled like PLA does. PETG, on the other hand, tends to come from crude oil and shrugs at industrial composting conditions.

In terms of durability, degradation mechanisms and recyclability, is PETG the basic FDM filament which we should all just be using?

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