Reviewing Nuclear Accidents: Separating Fact From Fiction

July 22, 2024 by Maya Posch 94 Comments

Few types of accidents speak as much to the imagination as those involving nuclear fission. From the unimaginable horrors of the nuclear bombs on Nagasaki and Hiroshima, to the fever-pitch reporting about the accidents at Three Mile Island, Chernobyl and Fukushima, all of these have resulted in many descriptions and visualizations which are merely imaginative flights of fancy, with no connection to physical reality. Due to radiation being invisible with the naked eye and the interpretation of radiation measurements in popular media generally restricted to the harrowing noise from a Geiger counter, the reality of nuclear power accidents in said media has become diluted and often replaced with half-truths and outright lies that feed strongly into fear, uncertainty, and doubt.

Why is it that people are drawn more to nuclear accidents than a disaster like that at Bhopal? What is it that makes the one nuclear bomb on Hiroshima so much more interesting than the firebombing of Tokyo or the flattening of Dresden? Why do we fear nuclear power more than dam failures and the heavy toll of air pollution? If we honestly look at nuclear accidents, it’s clear that invariably the panic afterwards did more damage than the event itself. One might postulate that this is partially due to the sensationalist vibe created around these events, and largely due to a poorly informed public when it comes to topics like nuclear fission and radiation. A situation which is worsened by harmful government policies pertaining to things like disaster response, often inspired by scientifically discredited theories like the Linear No-Threshold (LNT) model which killed so many in the USSR and Japan.

In light of a likely restart of Unit 1 of the Three Mile Island nuclear plant in the near future, it might behoove us to wonder what we might learn from the world’s worst commercial nuclear power disasters. All from the difficult perspective of a world where ideology and hidden agendas do not play a role, as we ask ourselves whether we really should fear the atom.

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Carbon–Cement Supercapacitors Proposed As An Energy Storage Solution

July 19, 2024 by Maya Posch 29 Comments

Although most energy storage solutions on a grid-level focus on batteries, a group of researchers at MIT and Harvard University have proposed using supercapacitors instead, with their 2023 research article by [Nicolas Chanut] and colleagues published in Proceedings of the National Academy of Sciences (PNAS). The twist here is that rather than any existing supercapacitors, their proposal involves conductive concrete (courtesy of carbon black) on both sides of the electrolyte-infused insulating membrane. They foresee this technology being used alongside green concrete to become part of a renewable energy transition, as per a presentation given at the American Concrete Institute (ACI).

Functional carbon-cement supercapacitors (connected in series) (Credit: Damian Stefaniuk et al.)

Putting aside the hairy issue of a massive expansion of grid-level storage, could a carbon-cement supercapacitor perhaps provide a way to turn the concrete foundation of a house into a whole-house energy storage cell for use with roof-based PV solar? While their current prototype isn’t quite building-sized yet, in the research article they provide some educated guesstimates to arrive at a very rough 20 – 220 Wh/m³, which would make this solution either not very great or somewhat interesting.

The primary benefit of this technology would be that it could be very cheap, with cement and concrete being already extremely prevalent in construction due to its affordability. As the researchers note, however, adding carbon black does compromise the concrete somewhat, and there are many questions regarding longevity. For example, a short within the carbon-cement capacitor due to moisture intrusion and rust jacking around rebar would surely make short work of these capacitors.

Swapping out the concrete foundation of a building to fix a short is no small feat, but maybe some lessons could be learned from self-healing Roman concrete.

Secrets Of The Old Digital Design Titans

July 18, 2024 by Al Williams 46 Comments

Designing combinatorial digital circuits seems like it should be easy. After all, you can do everything you want with just AND, OR, and NOT gates. Bonus points if you have an XOR gate, but you can build everything you need for combinatorial logic with just those three components. If all you want to do is design something to turn on the light when the ignition is on AND door 1 is open OR door 2 is open, you won’t have any problems. However, for more complex scenarios, how we do things has changed several times.

In the old days, you’d just design the tubes or transistor circuits you needed to develop your logic. If you were wiring up everything by hand anyway, you might as well. But then came modules like printed circuit boards. There was a certain economy to having cards that had, say, two NOR gates on a card. Then, you needed to convert all your logic to use NOR gates (or NAND gates, if that’s what you had).

Small-scale ICs changed that. It was easy to put a mix of gates on a card, although there was still some slight advantage to having cards full of the same kind of gate. Then came logic devices, which would eventually become FPGAs. They tend to have many of one kind of “cell” with plenty of logic gates on board, but not necessarily the ones you need. However, by that time, you could just tell a computer program what you wanted, and it would do the heavy lifting. That was a luxury early designers didn’t have. Continue reading “Secrets Of The Old Digital Design Titans” →

FDM Filament Troubles: Keeping Hygroscopic Materials From Degrading

July 17, 2024 by Maya Posch 18 Comments

Despite the reputation of polymers used with FDM 3D printing like nylon, ABS, and PLA as being generally indestructible, they do come with a whole range of moisture-related issues that can affect both the printing process as well as the final result. While the concept of ‘baking’ such 3D printing filaments prior to printing to remove absorbed moisture is well-established and with many commercial solutions available, the exact extent to which these different polymers are affected, and what these changes look like on a molecular level are generally less well-known.

Another question with such hygroscopic materials is whether the same issues of embrittlement, swelling, and long-term damage inflicted by moisture exposure that affects filaments prior to printing affects these materials post-printing, and how this affects the lifespan of FDM-printed items. In a 2022 paper by Adedotun D. Banjo and colleagues much of what we know today is summarized in addition to an examination of the molecular effects of moisture exposure on polylactic acid (PLA) and nylon 6.

The scientific literature on FDM filaments makes clear that beyond the glossy marketing there is a wonderful world of materials science to explore, one which can teach us a lot about how to get good FDM prints and how durable they will be long-term.

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Smart Ball Technology Has Reached Football, But The Euros Show Us It’s Not Necessarily For The Better

July 16, 2024 by Lewin Day 56 Comments

*Adidas brought smart balls to Euro 2024, for better or worse. Credit: Adidas*

The good old fashioned game of football used to be a simple affair. Two teams of eleven, plus a few subs, who were all wrangled by a referee and a couple of helpful linesmen. Long ago, these disparate groups lived together in harmony. Then, everything changed when VAR attacked.

Suddenly, technology was being used to adjudicate all kinds of decisions, and fans were cheering or in uproar depending on how the hammer fell. That’s only become more prevalent in recent times, with smart balls the latest controversial addition to the world game. With their starring role in the Euro 2024 championship more than evident, let’s take a look at what’s going on with this new generation of intelligent footballs.

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The Mysterious Roman Dodecahedron Was Possibly Just For Knitting

July 14, 2024 by Maya Posch 40 Comments

Over the years archaeological digs of Roman sites have uncovered many of these strange dodecahedrons, usually made out of metal and with various holes in their faces. With no surviving records that describe how they were used, speculation has ranged from jewelry to a knitting aid. In a 2023 video by [Amy Gaines] it is this latter use which is explored, using a 3D printed dodecahedron and some wooden dowels to knit both gold wire and yarn into rather intricate patterns that are also referred to as ‘Viking Knitting’.

As we mentioned previously when yet another one of these dodecahedrons was uncovered, their use was unlikely to be of supreme relevance in military or scientific circles on account of a lack of evidence. What is quite possible is that these were both attractive shapes for jewelry (beads), and useful knitting aids for both jewelry makers (for e.g. gold wire braiding) and quite possibly yarn-related uses. The results which [Amy] demonstrates in the video for the gold wire in particular bear a striking resemblance to ancient braided gold chains on display at the Met and other museums, which leads credence to this theory.

If these items were effectively just common knitting tools, that would explain why the historical record is mum on them, as they would have been as notable as a hammer or a precision lathe used by the ancient Greeks.

Thanks to [john] for the tip.

Continue reading “The Mysterious Roman Dodecahedron Was Possibly Just For Knitting” →

The NSA Is Defeated By A 1950s Tape Recorder. Can You Help Them?

July 13, 2024 by Jenny List 59 Comments

One of the towering figures in the evolution of computer science was Grace Hopper, an American mathematician, academic, and Naval reservist, whose work gave us the first programming languages, compilers, and much more. Sadly she passed away in 1992, so her wisdom hasn’t directly informed the Internet Age in the manner of some of her surviving contemporaries.

During her life she gave many lectures though, and as [Michael Ravnitzky] discovered, one of them was recorded on video tape and resides in the archives of America’s National Security Agency. With the title “Future Possibilities: Data, Hardware, Software, and People”, it was the subject of a Freedom Of Information request. This in turn was denied, on the grounds that “Without being able to view the tapes, NSA has no way to verify their responsiveness”. In short, the recording lies on Ampex 1″ reel-to-reel video tape, which the NSA claims no longer to be able to read.

It’s fairly obvious from that response that the agency has no desire to oblige, and we’d be very surprised to find that they keep a working Ampex video system to hand on the off-chance that a passing researcher might ask for an archive tape. But at the same time it’s also obvious that a lecture from Rear Admiral Hopper is an artifact of international importance that should be preserved and available for study. It’s an interesting thought exercise to guess how many phone calls Hackaday would have to make to secure access to a working Ampex video recorder, and since we think for us that number would be surprisingly low it’s likely the NSA know exactly who to call if they needed that tape viewed in a hurry. We don’t have influence over secretive government agencies, but if we did we’d be calling shame on them at this point.

If you’re curious about Grace Hopper, we’ve talked about her work here in the past.

Thanks [F4GRX] for the tip.

Ampex image: Telecineguy., Public domain.