New Drug Has Potential As Dirty Bomb Antidote

May 25, 2023 by 39 Comments

It perhaps goes without saying that one nuclear bomb can really ruin your day. The same is true for non-nuclear dirty bombs, which just use conventional explosives to disperse radioactive material over a wide area. Either way, the debris scattered by any type of radiation weapon has the potential to result in thousands or perhaps millions of injuries, for which modern medicine offers little in the way of relief.

HOPO 14-1, aka 3,4,3-Li(1,2-HOPO). The four hydroxypyridinone groups do the work of coordinating radioactive ions and making them soluble so they can be eliminated in urine.

But maybe not for long. A Phase 1 clinical trial is currently underway to see if an oral drug is able to scour radioactive elements from the human body. The investigational compound is called HOPO 14-1, a chelating agent that has a high affinity for metals in the actinide series, which includes plutonium, uranium, thorium, and cerium curium. Chelating agents, which are molecules that contain a multitude of electron donor sites, are able to bind to positively charged metal ions and make the soluble in aqueous solutions. Chelators are important in food and pharmaceutical processing — read the ingredients list on just about anything from a can of soda to a bottle of shampoo and you’re likely to see EDTA, or ethylenediaminetetraacetic acid, which binds to any metal ions that make it into the product, particularly iron ions that come from the stainless steel plumbing used in processing equipment.

The compound under evaluation, HOPO 14-1, is a powerful chelator of metal ions. Its structure is inspired by natural chelators produced by bacteria and fungi, called siderophores, which help the microorganisms accumulate iron. Its mechanism of action is to sequester the radioactive ions and make them soluble enough to be passed out of the body in the urine, rather than to have the radioactive elements carried around the body and incorporated into the bones and other tissues where they can cause radiation damage for years.

HOPO 14-1 has a number of potential benefits over the current frontline chelator for plutonium and uranium toxicity, DTPA or diethylenetriaminepentaacetic acid. Where DTPA needs to be injected intravenously to be effective, HOPO 14-1 can be made into a pill, making stockpiling and administering the drug easier. If, of course, it passes Phase 1 safety trials and survives later trials to determine efficacy.

The Thousand Year (Radioactive) Diamond Battery

May 22, 2023 by 44 Comments

The Holy Grail of battery technology is a cell which lasts forever, a fit-and-forget device that never needs replacing. It may seem a pipe-dream, but University of Bristol researchers have come pretty close. The catch? Their battery lasts a very long time, but it generates micropower, and it’s radioactive.

They’re using a thin layer of vapour-deposited carbon-14 diamond both as a source of beta radiation, and as a semiconductor material which harvests those electrons. They’re expected to be used for applications such as intermittent sensors, where they would slowly charge a supercapacitor which could release useful amounts of power in short bursts.

It’s being touted as an environmental win because the carbon-14 is sourced from radioactive waste, but against that it’s not unreasonable to have a concern about the things being radioactive. The company commercializing the tech leads with the bold question: “What would you do with a power-cell that outlasts the device it powers?“, to which we would hope the answer won’t be “Throw it away to be a piece of orphaned radioactive waste in the environment when the device it powers is outlasted”. We’ll have to wait and see whether devices containing these things turn up on the surplus market in a couple of decades.

Fortunately the carbon-14 lives not in cartoonish vats of radioactive green slime but safely locked away in diamond, about the safest medium for it to be in. The prototype devices are also tiny, so we’re guessing that the quantity of carbon-14 involved is also small enough to not be a problem. We’re curious though whether they could become a valuable enough commodity to be reused and recycled in themselves, after all something that supplies energy for decades could power several different devices over its lifetime. Either way, it’s a major improvement over a tritium cell.

Passively Generating Power Day And Night Takes The Right Parts

May 13, 2023 by 18 Comments

A thermoelectric generator (TEG) can turn a temperature difference into electricity, and while temperature differentials abound in our environment, it’s been difficult to harness them into practical and stable sources of power. But researchers in China have succeeded in creating a TEG that can passively and continuously generate power, even across shifting environmental conditions. It’s not a lot of power, but that it’s continuous is significant, and it could be enough for remote sensors or similar devices.

Historically, passive TEGs have used ambient air as the “hot” side and some form of high-emissivity heat sink — usually involving exotic materials and processes — as the “cold” side. These devices work, but fail to reliably produce uninterrupted voltage because shifting environmental conditions have too great of an effect on how well the radiative cooling emitter (RCE) can function.

The black disk (UBSA) heats the bottom while the grey square (RCE) radiates heat away, ensuring a workable temperature differential across a variety of conditions.

Here is what has changed: since a TEG works on temperature difference between the hot and cold sides, researchers improved performance by attaching an ultra-broadband solar absorber (UBSA) to the hot side, and an RCE to the cold side. The UBSA is very good at absorbing radiation (like sunlight) and turning it into heat, and the RCE is very good at radiating heat away. Together, this ensures enough of temperature difference for the TEG to function in bright sunlight, cloudy sunlight, clear nighttime, and everything in between.

As mentioned, it’s not a lot of power (we’re talking millivolts) but the ability to passively and constantly produce across shifting environmental conditions is something new. And as a bonus, the researchers even found a novel way to create both UBSA and RCE using non-exotic materials and processes. The research paper with additional details is available here.

The ability to deliver uninterrupted power — even in tiny amounts — is a compelling goal. A few years ago we encountered a (much larger) device from a team at MIT that also aimed to turn environmental temperature fluctuations into a trickle of constant power. Their “Thermal Resonator” worked by storing heat in phase-change materials that would slowly move heat across a TEG, effectively generating continuously by stretching temperature changes out over time.

What Is A Schumann Resonance And Why Am I Being Offered A 7.83Hz Oscillator?

May 12, 2023 by 110 Comments

Something that probably unites many Hackaday readers is an idle pursuit of browsing AliExpress for new pieces of tech. Perhaps it’s something akin to social media doomscrolling without the induced anger, and it’s certainly entertaining to see some of the weird and wonderful products that can be had for a few dollars and a couple of weeks wait. Every now and then something pops up that deserves a second look, and it’s one of those that has caught my attention today. Why am I being offered planar PCB coils with some electronics, described as “Schumann resonators”? What on earth is Schumann resonance, anyway? Continue reading “What Is A Schumann Resonance And Why Am I Being Offered A 7.83Hz Oscillator?” →

Op Amp Contest: Magnetic Core Memory The Dr Cockroach Way

May 10, 2023 by 24 Comments

No matter how memory technology marches on, magnetic core memory is still cool. Radiation-hard, nonvolatile, and so pretty. What’s there not to love? [Mark Nesselhaus] is no stranger to fun in-your-face electronics builds — judging from his hackaday.io projects — and this entry to the Hackaday Op-Amp contest is no outlier. This is a sixteen-bit magnetic core RAM demonstrator built upon glass using copper tape and solder, which always looks great and is actually not all that hard to do yourself provided you grab a new scalpel blade from the pack before starting.

Transformer-coupled differential front-end amplifier driving an SR latch.

For the uninitiated, the crossed X and Y wires each host a hard magnetic toroid which can only be magnetised by a field beyond a certain threshold due to the shape of the B-H curve of ferrite materials. The idea is for a required threshold current, drive the selected X line and Y line each with a current half of this value, so that only the selected core bit ‘sees’ the full field value, and flips state. This means that only a single bit can be written for each core plane, so to form longer words these layers are stacked, producing some wonderful cubic structures. These magnetic circuits are responsible for putting a human on the moon.

Reading the bit state is basically the opposite. A third sense wire is passed sequentially through each bit in the array. By driving a current the opposite way through the selected core bit, if the core was previously magnetised then the sense wire will read a short pulse that can be amplified and registered. The eagle-eyed will realise that reading is a destructive process, so this needs to be followed up by a write-back process to refresh the bit, although the core state will persist without power, giving the memory nonvolatile behaviour.

[Mark] utilises a simple discrete transistor differential transformed-coupled front end which senses the tiny current pulse and passes it along to a Set-Reset latch for visualisation. This simple concept could easily be extended to make this a practical memory, but for now, addressing is courtesy of a pair of crocodile clips and a discrete write/read pulse switch. We will watch with interest how far this goes.

DIY core memory builds are not a regular occurrence around these parts, but we see them from time to time, like this polished 64-bit setup. Core arrays are not the only magnetic memory in town, we’ve also seen DIY core rope memories as well.

Continue reading “Op Amp Contest: Magnetic Core Memory The Dr Cockroach Way” →

NASA’s Voyager Space Probe’s Reserve Power, And The Intricacies Of RTG-Based Power Systems

May 3, 2023 by 45 Comments

Launched in 1977, the Voyager 1 and 2 space probes have been operating non-stop for over 45 years, making their way from Earth to our solar system’s outer planets and beyond. Courtesy of the radioisotope thermoelectric generators (RTGs) which provided 470 W at launch, they are able to function in the darkness of Deep Space as well as they did within the confines of our Sun-lit solar system. Yet as nothing in the Universe is really infinite, so too do these RTGs wear out over time, both from natural decay of their radioactive source and from the degradation of the thermocouples.

Despite this gradual drop in power, NASA recently announced that Voyager 2 has a hitherto seemingly unknown source of reserve power that will postpone the shutdown of more science instruments for a few more years. The change essentially bypasses a voltage regulator circuit and associated backup power system, freeing up the power consumed by this for the scientific instruments which would otherwise have begun to shut down years sooner.

While this is good news in itself, it’s also noteworthy because the Voyager’s 45+ year old Multi-Hundred Watt (MHW) RTGs are the predecessor to the RTGs that are still powering the New Horizons probe after 17 years, and the Mars Science Laboratory (Curiosity) for over 10 years, showing the value of RTGs in long-term exploration missions.

Although the basic principle behind an RTG is quite simple, their design has changed significantly since the US put a SNAP-3 RTG on the Transit 4B satellite in 1961.

Continue reading “NASA’s Voyager Space Probe’s Reserve Power, And The Intricacies Of RTG-Based Power Systems” →

Don’t Let The Baluns Float Over Your Head

April 29, 2023 by 5 Comments

Most ham radio operators will build an antenna of some sort when they first start listening or transmitting, whether it’s a simple dipole, a beam antenna like a Yagi, or even just a random wire vertical antenna. All of these will need to be connected feedline of some sort, and in the likely event you reach for some 50-ohm coax cable you’ll also need a balun to reduce noise or unwanted radiation. Don’t be afraid of extra expenses when getting into this hobby, though, as [W6NBC] demonstrates how to construct an “ugly balun” out of the coax wire itself (PDF).

The main purpose of a balun, a contraction of “balanced-unbalanced” is to convert an unbalanced transmission line to a balanced one. However, as [W6NBC] explains, this explanation obscures much of what baluns are actually doing. In reality, they take a three-wire system (the coax) and convert it to a two-wire system (the antenna), which keeps all of the electrical noise and current on the shield wire of the coax from interfering with the desirable RF on the interior of the coax.

This might seem somewhat confusing on the surface, as coax wires only have a center conductor and a shield wire, but thanks to the skin effect which drives currents to the outside of the conductor, the shield wire effectively becomes two conductors when taking into account its inner and outer surfaces. At these high frequencies the balun is acting as a choke which keeps these two high-frequency conductors separate from one another, and keeps all the noise on the outside of the shield wire and out of the transmitter or receiver.

Granted, the world of high-frequency radio circuits can get quite complex and counter-intuitive and, as we’ve shown before, can behave quite unexpectedly when compared to DC or even mains-frequency AC. But a proper understanding of baluns and other types of transformers and the ways they interact with RF can be a powerful tool to have. We’eve even seen other hams use specialty transformers like these to make antennas out of random lengths and shapes of wire.

Continue reading “Don’t Let The Baluns Float Over Your Head” →