Microscopic Metal 3D Printing With Gels

December 7, 2022 by Al Williams 3 Comments

Everyone wants to 3D print with metals, but it is a difficult task. You need high temperatures and metals with high thermal conductivity make the problem even worse. Researchers at Caltech have a way of printing tiny metal structures. The trick? They don’t print metals at all. Instead, they 3D print a hydrogel and then use it as a scaffold to form metallic structures. You can read the full paper, if you are interested in the details.

Hydrogels are insoluble in water and made from flexible polymer chains. If you’ve ever handled a soft contact lens, that’s a hydrogel. Like resin printing, UV light triggers chemical reactions in the hydrogels, causing them to harden in the desired pattern.

What about the metal? They infuse the hydrogel with a metallic salt dissolved in water. This saturates the hydrogel. Burning in a furnace causes the hydrogel to burn away but leaves the metal. The furnace also causes the structure to shrink, so this is a good method for very tiny pieces. The team has made prints with feature sizes around 40 microns.

By altering the metal salts, you can work with different metals or even mix different metals. The team has produced parts using copper, nickel, silver, and several alloys.

Printing small structures is a big research goal with many different approaches. We’ve even seen a tiny welder.

Hey Google, Is My Heart Still Beating?

March 23, 2021 by Tom Nardi 18 Comments

University of Washington researchers studying the potential medical use of smart speakers such as Amazon’s Echo and Google’s Nest have recently released a paper detailing their experiments with non-contact acoustic heartbeat detection. Thanks to their sensitive microphone arrays, normally used to help localize voice commands from the user, the team proposes these affordable and increasingly popular smart home gadgets could lead a double life as unobtrusive life sign monitors. The paper goes so far as to say that even with multiple people in the room, their technique can be used to monitor the heart and respiratory rate of a specific target individual.

Those are some bold claims, but they aren’t without precedent. Previous studies performed at UW in 2019 demonstrated how smart speaker technology could be used to detect cardiac arrest and monitor infant breathing. This latest paper could be seen as the culmination of those earlier experiments: a single piece of software that could not just monitor the vitals of nearby patients, but actually detect a medical emergency. The lifesaving potential of such a program, especially for the very young and elderly, would be incredible.

So when will you be able to install a heart monitor skill on the cheap Echo Dot you picked up on Prime Day? Well, as is often the case with this kind of research, putting the technique to work in the real-world isn’t nearly as easy as in the laboratory. While the concept is promising and is more than worthy of further research, it may be some time before our lowly smart speakers are capable of Star Trek style life-sign detection.

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Containing Conficker

March 30, 2009 by Eliot 50 Comments

conficker

With all the noise about Conficker turning your computer into liquid hot magma on April 1st, there’s actually some positive news. Researchers from the HoneyNet Project have been following the worm since infections started in late 2008. They recently discovered an easy way to identify infected systems remotely. Conficker attempts to patch the MS08-067 vulnerability during infection. A flaw in the patch causes the machine to respond differently than both an unpatched system and an officially patched system. Using this knowledge, the team developed a proof of concept network scanner in python to find infected machines. You can find it in [Rich Mogull]’s initial post. [Dan Kaminisky] has packaged it as an EXE and has instructions for how to build the SVN version of Nmap, which includes the new signature. Other network scanner vendors are adding the code as well.

In conjunction with this detection code, the team has also released the whitepaper Know Your Enemy: Containing Conficker. It discusses ways to detect, contain, and remove Conficker. They’ve combined this with a tool release that covers Conficker’s dynamic domain generation among other things.