Hackaday Links: December 18, 2022

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By now everyone has probably seen the devastation wrought by the structural failure of what was once the world’s largest free-standing cylindrical aquarium. The scale of the tank, which until about 5:50 AM Berlin time on Friday graced the lobby of the Raddison Blu hotel, was amazing — 16 meters tall, 12 meters in diameter, holding a million liters of saltwater and some 1,500 tropical fish. The tank sat atop a bar in the hotel lobby and was so big that it even had an elevator passing up through the middle of it.

But for some reason, the tank failed catastrophically, emptying its contents into the hotel lobby and spilling the hapless fish out into the freezing streets of Berlin. No humans were killed by the flood, which is miraculous when you consider the forces that were unleashed here. Given the level of destruction, the displaced hotel guests, and the fact that a €13 million structure just up and failed, we’re pretty sure there will be a thorough analysis of the incident. We’re pretty interested in why structures fail, so we’ll be looking forward to finding out the story here.

We’ve spent a lot of virtual ink here decrying the increase in “abandonware” products, where startups with a seemingly killer idea suddenly go belly-up and end up bricking their fancy connected devices. Users who bought into the ecosystem inevitably are the losers in these situations, having invested often considerable time and effort into the product or service, perhaps integrating it into their daily life and building a workflow around the offering, only to have the rug pulled out from them.

We’ve seen this a ton of times over the years — looking at you, Google — but we tend to see it as just an inconvenience for the abandoned users, and little more. But in a longish article, Cory Doctorow argues that it’s often more than an inconvenience, especially when you start talking about orphaned medical devices. The article cites several real-world examples, like implantable retinal implants that got bricked when the manufacturer went bust, but it clearly has eyes on as-yet experimental neurological implants like Neuralink. There’s also a lot of discussion on the failure modes of startups in general, and what it means for users when the most valuable asset of a defunct operation, which is usually the data it collected, hits the secondary market. It’s thought-provoking stuff, and honestly a little terrifying.

Say what you will about the US military — or pretty much any military in the world, for that matter — but they’re really good at teaching complex subjects to complete newbies as quickly and efficiently as possible. Boot camp transforms a civilian into a soldier in six to eight weeks, for example, and that’s no mean feat. But the military is also good at teaching more than marching around, including electronics, a fact that someone on r/amateurradio noticed and helpfully posted a link to the US Navy Electricity and Electronics Trains Series. NEETS trained a lot of utterly clueless young sailors to be electronics technicians who could support some of the world’s most advanced weapons systems. We’re not sure we fully agree with the OP’s out-of-hand dismissal of the quality of education received by EE students, but we do think that a self-paced NEETS run-through probably has a lot of value to anyone looking to level up their skills.

We got a great tip this week about Manhattan-style SMD breakout adapters. We love “Ugly” prototyping, but the methods generally favor through-hole components and DIP ICs. The adapters in this project turn that around, allowing SOIC and MSOP packages to be quickly added to projects and connected with a few flying leads. It’s a great way to avoid the parasitic capacitance of solderless breadboards while putting all those SMD components to work.

And finally, Editor-in-Chief Elliot Williams sent along a fascinating visualization of the human immune system in action. The short clip shows a neutrophil, one of the white blood cells which make up the bulk of the innate immune system, chasing down and gobbling up a hapless Staphylococcus aureus bacterium. This is a great example of chemotaxis, the process by which cells follow a chemical gradient; you can practically see the trail left by the tiny bacterium as the neutrophil surges along. Watching the hunter ignore the red blood cells and seek out the invader is like watching a nature film with a lion and a gazelle; you kind of root for the gazelle, but you pretty much know how it’s going to turn out in the end. The amazing thing here is that this isn’t an animation, but a real 16-mm film made through a microscope back in the 1950s — hats off to the late Dr. David Rogers for the effort on this one.

27 thoughts on “Hackaday Links: December 18, 2022

  1. The pressure is only one atmosphere at the bottom. And the center hollow has a pretty large radius. It is basically an annulus full of water and not as much as one might think. A wild guess is a problem with the base to which the two cylinders were sealed.

    1. The above specs on the tank state it to be 16 meters tall. Assuming the water is that deep, the pressure at the bottom of the tank would be approximately 2.75 atmospheres. You can generally add an atmosphere is pressure for each 33 feet of depth. One at the surface for the air column, then one at each 33 ft.

      1. Yes, I was wondering if that is an error. It looks more like 5 or 6 “diver lengths” to me. Maybe it includes the platform it is built on. One site calls it “25 meters high” and another “15.5 meters high”. Plus divers cleaning the inside at the bottom would have a 1 hour limit without a decompression stop, Berlin being basically sea level.

  2. I once had a job that gave me an inordinate amount of time for random thinking. At one point, I used it to design a tall aquarium for my angelfish. Before calculating how many gallons it held, I used the dimensions in a tropical fish handbook equation to calculate how big a heater I would need. I was shocked that the result was in kilowatts and went on to discover that my ‘modest’ design was 400 gallons. The scale of the Berlin aquarium is so far beyond that. I’m very interested in what the incident analysis will reveal.

  3. @ABC News said [1]: “The AquaDom, a 50-foot-tall cylindrical glass aquarium with a built-in elevator located inside the Radisson Collection Hotel, Berlin, collapsed shortly before 6 a.m. local time, officials said.”

    The AquaDom aquarium inside the Radisson Collection Hotel, Berlin is not made of glass as claimed by ABC News, it’s made by Reynolds Polymer Technology, Inc. [2] (Grand Junction, Colorado USA based, with offices in Thailand and The Netherlands) using “41 Higly (sic) Engineered Acrylic panels – 26 panels for the outside cylinder and 15 panels for the inside – and 16 on-site bonds”.[3]

    Also, the manufacturer Reynolds Polymer Technology claims “the aquarium is host to 56 species of fish (2,600 fish total)”, not 1,500 fish as stated by ABC News. But who actually knew how many fishies AquaDom hosted when it collapsed? Of course, ABC News did not cite a source.

    Look at the other projects shown on the Reynolds Polymer Technology web site (links below), amazing stuff.

    * References:

    1. Massive aquarium at Berlin hotel bursts, injuring 2 and causing loss of 1,500 fish


    2. Reynolds Polymer Technology, Inc.


    3. AquaDom Project (Opened December 2003)


  4. My understanding is that large aquariums like these are manufactured of sections of acrylic or polycarbonate that are glued together. Could it be that 20 years of the filtered sunlight in the atrium, or possibly UV from the tank’s internal lighting, caused it to get brittle enough to impact structural integrity? And do the glues have the same UV resistance as the polycarbonate?

    Polycarbonate is advertised as ideal for high strength applications, and is especially useful outdoors because it’s UV resistant. Acrylic doesn’t have the same strength, and even though it supposedly is also UV resistant, I keep seeing automotive headlight fixtures yellow or fog up after about 15 years or so. I seriously doubt the builders would have used acrylic instead of polycarbonate for such a high pressure tank, but then again I was shocked to learn they built the Millennium Tower by saving money on foundations that weren’t sunk to bedrock.

      1. Why would headlights need a coating if the plastic itself doesn’t require it? Asking as someone that polished the headlights every few years on my old beater car when they yellowed. If the coating was real then why did they yellow again after the first round of polishing?

  5. Speculation is that the freezing temperature (-10c, 14f) combined with heating system turned down to save gas led to water at the top of the tank freezing, with the resulting expansion causing a tank fracture that quickly made its way to the bottom.

    Again, just speculation. I’m wondering: how long it would take for enough ice to build up, and whether there was enough water circulation to prevent the ice buildup?

    1. I didn’t look if it was salt water tank but if so freezing would be pretty unlikely unless it was really, really cold. Also the filtration system for tanks really turns it over fast so freezing would be even less likely due to the mixing. All guessing on my part though.

    2. Very unlikely. Tropical fish have very narrow ranges of temperatures they can survive in. Usually +/- 10F around 80F. Aquariums are heated, even when the area around them are not heated and a reef aquarium has a lot of water movement. Typically you aim for 10x to 20x turnover.

      Oxygenation of the water is performed by protein skimmers and water movement at the surface of the water, to keep fish from suffocating, oxygenated water from the surface must be dispersed throughout the aquarium, meaning a fairly small gradient in temps.

  6. I think that the reddit poster assumes EEs are supposed to be able to build and repair things. Although these are admirable goals, that’s what technicians have historically been trained to do. The engineers are trained to design the things that get built and repaired. Of course, considering build and repair processes are very important when designing something, but they represent just one facet of the design considerations.

    I worked in a corporate research lab for about 9 years. We had some really amazing techs there who could build stuff far better than I ever could. They also were a critical sounding board when you got to the point where you were ready to go from theory to practice (assuming you were smart and humble enough to talk to them before you designed the whole thing and stuck them with building it). Unfortunately, companies seem to hire fewer and fewer techs, meaning fewer young people go into the field, and it’s getting harder to replace those who are retiring.

    But one universal thing I’ve noticed is that every profession thinks the next level up are idiots. I’ve never met a nurse who didn’t think the doctors were idiots, or a tech who doesn’t think the engineers are idiots. Or an engineer who thinks the management are idiots. It’s just sort of a time-honored way to get your gripes in.

    1. Commenting on self is the worst sorry. Anyway the linked article states
      “The neutrophil is “chasing” Staphylococcus aureus microorganisms, added to the film.”
      Sounds bogus. Small chance they meant liquid film rather than movie film.

    2. The film wss probably shot manually, one frame every few seconds, resulting in it appearing sped up. According to a paper (https://pubmed.ncbi.nlm.nih.gov/24809064/ ) neutrophils move about 19 ± 6 μm/min, and the scale bar puts the red blood cells at an average of 10μm diameter. If you want to work out the exact time compression, go for it.

      The page linked with the video also cites a previous paper written by Pollitt et al discussing how S. aureus might use dendrites to move itself. https://pubmed.ncbi.nlm.nih.gov/26680153/ Same guy you found, just earlier work.

      So, if the movie was filmed over the course of several or even tens of minutes, the movement wouldn’t rule out S. aureus being the bacteria involved. No flagella needed.

  7. I heard somewhere that the tank had been empty for cleaning and maintenance recently. My guess is thus chemical crazing/damage from improper cleaning or gluing agents used somewhere in the system. It doesn’t take much to weaken acrylic to the point of failure and one sub-sub-contractor somewhere not paying attention or not getting correct information.

  8. So named “startups” are smart-asses that targeting easy money fro.very stupid but rich (?!?) “investors” that (investors) believe in all kind of fairytales invented by the “startups”. And then :Waw, where my money goes”. In the luxury cars, luxury holidays across the world, buying of nonsense materials that clearly cannot contribute to the genial “idea” of so named “startups”. Western moronic “investors” must be tricked by false “startups” and left without money. This overall tend to left West without easy stolen money and at the end destroy completely shitty West.

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