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Synthesis of Goldene: Single-Atom Layer Gold With Interesting Properties

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The synthesis of single-atom layer versions of a range of atoms is currently all the hype, with graphene probably the most well-known example of this. These monolayers are found to have a range of mechanical (e.g. hardness), electrical (conduction) and thermal properties that are very different from the other forms of these materials. The major difficulty in creating monolayers is finding a way that works reliably and which can scale. Now researchers have found a way to make monolayers of gold – called goldene – which allows for the synthesis of relatively large sheets of this two-dimensional structure. In the research paper by [Shun Kashiwaya] and colleagues (with accompanying press release ) as published in Nature Synthesis, the synthesis method is described. Unlike graphene synthesis, this does not involve Scotch tape and a stack of graphite, but rather the wet-etching of Ti 3 Cu 2 away from Ti 3 AuC 2 , after initially substituting the Si in Ti 3 SiC 2 with Au. At the end of t
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Combadge Project Wants to Bring Trek Tech to Life

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While there’s still something undeniably cool about the flip-open communicators used in the original Star Trek , the fact is, they don’t really look all that futuristic compared to modern mobile phones. But the upgraded “combadges” used in Star Trek: The Next Generation and its various large and small screen spin-offs — now that’s a tech we’re still trying to catch up to. As it turns out, it might not be as far away as we thought. A company called Vocera actually put out a few models of WiFi “Communication Badges” in the early 2000s that were intended for hospital use, which these days can be had on eBay for as little as $25 USD. Unfortunately, they’re basically worthless without a proprietary back-end system. Or at least, that was the case before the Combadge project got involved . Designed for folks who really want to start each conversation with a brisk tap on the chest, the primary project of Combadge is the Spin Doctor server , which is a drop-in replacement for the original
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A Smart Power Distribution Unit for Home Automation

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Power distribution units, as the name implies, are indispensable tools to have available in a server rack. They can handle a huge amount of power for demands of intensive computing and do it in a way that the wiring is managed fairly well. Plenty of off-the-shelf solutions have remote control or automation capabilities as well, but finding none that fit [fmarzocca]’s needs or price range, he ended up building his own essentially from scratch that powers his home automation system . Because it is the power supply for a home automation system, each of the twelve outlets in this unit needed to be individually controllable. For that, three four-channel relay boards were used, each driven by an output on an ESP32. The ESP32 is running the Tasmota firmware to keep from having to reinvent the wheel, while MQTT was chosen as a protocol for controlling these outlets to allow for easy integration with the existing Node-RED-based home automation system. Not only is control built in to each chan
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The Myth of Propellantless Space Propulsion Refuses to Die

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In a Universe ruled by the harsh and unyielding laws of Physics, it’s often tempting to dream of mechanisms which defy these rigid restrictions. Although over the past hundred years we have made astounding progress in uncovering ways to work within these restrictions — including splitting and fusing atoms to liberate immense amounts of energy — there are those who dream of making reality a bit more magical. The concept of asymmetrical electrostatic propulsion is a major player here, with the EmDrive the infamous example. More recently [Dr. Charles Buhler] proposed trying it again , as part of his company Exodus Propulsion Technologies. This slide from Dr. Buhler’s APEC presentation shows the custom-made vacuum chamber built to test their propellantless Propulsion drive in a simulated space environment. Image Credit: Exodus Propulsion Technologies, Buhler, et al. The problem with such propellantless space propulsion proposals is that they violate the core what we know about the phy
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The Performance Impact of C++’s `final` Keyword for Optimization

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In the world of software development the term ‘optimization’ is generally reason for experienced developers to start feeling decidedly nervous, especially when a feature is marked as an ‘easy and free optimization’. The final keyword introduced in C++11 is one of such features. It promises a way to speed up object-oriented code by omitting the vtable call indirection by marking a class or member function as – unsurprisingly – final, meaning that it cannot be inherited from or overridden. Inspired by this promise, [Benjamin Summerton] figured that he’d run a range of benchmarks to see what performance uplift he’d get on his ray tracing project . To be as thorough as possible, the tests were run on three different systems, including 64-bit Intel and AMD systems, as well as on Apple Silicon (M1). For the compilers various versions of GCC (12.x, 13.x), as well as Clang  (15, 17) and MSVC (17) were employed, with rather interesting results for final versus no final tests. Clang was pr
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Downloading Satellite Imagery With a Wi-Fi Antenna

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Over the past century or so we’ve come up with some clever ways of manipulating photons to do all kinds of interesting things. From lighting to televisions and computer screens to communication, including radio and fiber-optics, there’s a lot that can be done with these wave-particles and a lot of overlap in their uses as well. That’s why you can take something like a fairly standard Wi-Fi antenna meant for fairly short-range communication and use it for some other interesting tasks like downloading satellite data . Weather satellites specifically use about the same frequency range as Wi-Fi, but need a bit of help to span the enormous distance. Normally Wi-Fi only has a range in the tens of meters, but attaching a parabolic dish to an antenna can increase the range by several orders of magnitude. The dish [dereksgc] found is meant for long-range Wi-Fi networking but got these parabolic reflectors specifically to track satellites and download the information they send back to earth. W
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More Mirrors (and a Little Audio) Mean More Laser Power

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Lasers are pretty much magic — it’s all done with mirrors. Not every laser, of course, but in the 1980s, the most common lasers in commercial applications were probably the helium-neon laser, which used a couple of mirrors on the end of a chamber filled with gas and a high-voltage discharge to produce a wonderful red-orange beam. The trouble is, most of the optical power gets left in the tube, with only about 1% breaking free. Luckily, there are ways around this, as [Les Wright] demonstrates with this external passive cavity laser . The guts of the demo below come from [Les]’ earlier teardown of an 80s-era laser particle counter , a well-made instrument powered by a He-Ne laser that was still in fine fettle if a bit anemic in terms of optical power. [Les] dives into the physics of the problem as well as the original patents from the particle counter manufacturer, which describe a “stabilized external passive cavity.” That’s a pretty fancy name for something remarkably simple: a thir
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