High Voltage Ion Engines Take Trip On The High Seas

June 12, 2023 by Tom Nardi 21 Comments

Over the last several months, we’ve been enjoying a front-row seat as [Jay Bowles] of Plasma Channel has been developing and perfecting his design for a high voltage multi-stage ionic thruster. With each installment, the unit has become smaller, lighter, and more powerful. Which is important, as the ultimate goal is to power an RC aircraft with them.

There’s still plenty of work to be done before [Jay] will be able to take his creation skyward, but he’s making all the right moves. As a step towards his goal, he recently teamed up with [RcTestFlight] to attach a pair of his thrusters — which have again been further tweaked and refined since we last saw them — to a custom catamaran hull. The result is a futuristic craft that skims across the water with no moving parts and no noise…if you don’t count the occasional stray arc from the 40,000 volts screaming through its experimental thrusters, anyway. Continue reading “High Voltage Ion Engines Take Trip On The High Seas” →

Spy Tech: Unshredding Documents

June 12, 2023 by Al Williams 38 Comments

Bureaucracies generate paper, usually lots of paper. Anything you consider private — especially anything that could get you in trouble — should go in a “burn box” which is usually a locked trash can that is periodically emptied into an incinerator. However, what about a paper shredder? Who hasn’t seen a movie or TV show where the office furiously shreds papers as the FBI, SEC, or some other three-letter-agency is trying to crash the door down?

That might have been the scene in the late 1980s when Germany reunified. The East German Ministry of State Security — known as the Stasi — had records of unlawful activity and, probably, information about people of interest. The staff made a best effort to destroy these records, but they did not quite complete their task.

The collapsing East German government ordered documents destroyed, and many were pulped or burned. However, many of the documents were shredded by hand, stuffed into bags, and were awaiting final destruction. There were also some documents destroyed by the interim government in 1990. Today there are about 16,000 of these bags remaining, each with 2,500 to 3,000 pieces of pages in them.

Machine-shredded documents were too small to recover, but the hand-shredded documents should be possible to reconstruct. After all, they do it all the time in spy movies, right? With modern computers and vision systems, it should be a snap.

You’d think so, anyway.

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Spaying Cats In One Shot

June 12, 2023 by Navarre Bartz 61 Comments

Feral cats live a rough life, and programs like Trap, Neuter, Release (TNR) attempt to keep their populations from exploding in a humane way. Researchers in Massachusetts have found a non-surgical way to spay cats that will help these efforts.

A single dose of anti-Müllerian hormone (AMH) gene therapy suppresses ovarian follicle formation, essentially turning off the ovulation cycle. After following the test cats for two years, none had kittens, unlike the cats in the control group. Other major hormones like estrogen were unaffected in the cats and they didn’t exhibit any negative side effects. The researchers said it will be some time before the treatment can be widely deployed, but it offers hope for helping our internet overlords and the environs they ~~terrorize~~ inhabit.

For those of you doing TNR work, you might want to try this trap alert system to let you know you’ve caught a cat for spaying or neutering. If you’d rather use a cat treat dispenser to motivate your code monkeys, then check out this hack.

A Modular Analogue Computer

June 12, 2023 by Jenny List 20 Comments

We are all used to modular construction in the analogue synth world, to the extent that there’s an accepted standard for it in EuroRack. But the same techniques are just as useful wherever else analogue circuits need to be configured on the fly, such as in an analogue computer. It’s something [Rainer Glaschick] has pursued, with his Flexible Analog Computer, an analogue computer made from a set of modules mounted on breadboard strips.

Standard modules are an adder and an integrator, with the adder also having inverter, comparator, and precision rectifier functions. The various functions can be easily configured by means of jumpers, and there are digital switches on board to enable or disable outputs and inputs. he’s set up a moon landing example to demonstrate the machine in practice.

We’re not going to pretend to be analogue computer experts here at Hackaday,but we naturally welcome any foray into analogue circuitry lest it become a lost art. If you’d like to experiment with analogue computing there are other projects out there to whet your appetite, and of course they don’t even need to be electronic.

Characterizing Singular Atoms Using X-Ray Spectroscopy And Scanning Tunneling Microscopy

June 11, 2023 by Maya Posch No comments

Scanning Tunneling Microscopes (STMs) are amazing tools which can manipulate singular atoms, but they cannot characterize these atoms as they act only on the outer electron shell. Meanwhile X-ray spectroscopy is a great tool for characterizing materials, but has so far been unable to scale down to singular atoms. This is where a recent study (paywalled, see summary article) by Tolulope M. Ajayi and colleagues demonstrates how both STM and X-rays can be combined in order to characterize singular atoms.

Structure of a part of the supramolecular complex used to measure the x-ray absorption spectrum of a single iron atom. The iron atom (red) is held within several ring-shaped structures. (Credit: Ajayi et al., 2023)

This research builds on previous research on synchrotron X-ray STM (SX-STM) which has been used for nanoscale imaging since 2009, but not down to the scale of a singular atom yet. Key to this achievement was to synthesize supramolecular complexes that could act as ‘tweezers’ to hold the atom under investigation in place and away from atoms of the same species. This not only allowed the atom to be identified using SX-STM, it also demonstrated that more subtle chemical properties of the atom can be analyzed in this manner, such as the way it interacts with other atoms.

The information gleaned this way matches up with what we know about the two atoms used in the study: iron and the rare earth terbium, with the latter’s lack of hybridization of its f orbitals (ℓ = 3) observable. For less well-studied atoms this method could provide a very efficient way to get a detailed overview of its properties. What is more, in future studies the researchers hope to use polarized X-rays to also obtain information about an atom’s spin state, opening interesting possibilities in areas such as spintronics and memory technologies.

Heading image: As the tip was scanned across ten positions in a sample containing two terbium atoms, it picked a signal only from the positions (2 and 9) where terbium was located (left: STM image; right: sketch of the corresponding molecular structure). (Credit: Ajayi et al, 2023)

The First Search Engines, Built By Librarians

June 11, 2023 by Bryan Cockfield 14 Comments

Before the Internet became the advertisement generator we know and love today, interspersed with interesting information here and there, it was originally a network of computers largely among various universities. This was even before the world-wide web and HTML which means that the people using these proto-networks, mostly researchers and other academics, had to build things we might take for granted from the ground up. One of those was one of the first search engines, built by the librarians who were cataloging all of the research in their universities, and using their relatively primitive computer networks to store and retrieve all of this information.

This search engine was called SUPARS, the Syracuse University Psychological Abstracts Retrieval Service. It was originally built for psychology research papers, and perhaps unsurprisingly the psychologists at the university also used this new system as the basis for understanding how humans would interact with computers. This was the 1970s after all, and most people had never used a computer, so documenting how they used search engine led to some important breakthroughs in the way we think about the best ways of designing systems like these.

The search engine was technically revolutionary for the time as well. It was among the first to allow text to be searched within documents and saved previous searches for users and researchers to access and learn from. The experiment was driven by the need to support researchers in a future where reference librarians would need assistance dealing with more and more information in their libraries, and it highlighted the challenges of vocabulary control in free-text searching.

The visionaries behind SUPARS recognized the changing landscape of research and designed for the future that would rely on networked computer systems. Their contributions expanded the understanding of how technology could shape human communication and effectiveness, and while they might not have imagined the world we are currently in, they certainly paved the way for the advances that led to its widespread adoption even outside a university setting. There were some false starts along that path, though.

Hackaday Links: June 11, 2023

June 11, 2023 by Dan Maloney 20 Comments

As Tom Nardi mentioned in this week’s podcast, the Northeast US is pretty apocalyptically socked in with smoke from wildfires in Canada. It’s what we here in Idaho call “August,” so we have plenty of sympathy for what they’re going through out there. People are turning to technology to ease their breathing burden, with reports that Tesla drivers are activating the “Bioweapon Defense Mode” of their car’s HVAC system. We had no idea this mode existed, honestly, and it sounds pretty cool — the cabin air system apparently shuts off outside air intake and runs the fan at full speed to keep the cabin under positive pressure, forcing particulates — or, you know, anthrax — to stay outside. We understand there’s a HEPA filter in the mix too, which probably does a nice job of cleaning up the air in the cabin. It’s a clever idea, and hats off to Tesla for including this mode, although perhaps the name is a little silly. Here’s hoping it’s not one of those subscription services that can get turned off at a moment’s notice, though.

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