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TTK Ciar

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  1. Fun conversation, sorry to have missed it. As others have already said, DU doesn't get you that much more penetration over WHA. According to ye olde Lakowski lore, DU (99.25% U + 0.75% Ti) penetrates about 20% more than WHA (90% W + 7% Ni + 3% Fe). Going by density, 70% Pt + 30% Ir should penetrate about 35% more than WHA, but that's completely theoretical and the material cost would be prohibitive. E5M has the right idea. If you ditch HEDP and design a nice modern high-precision HEAT-only warhead for 40mm, with a long enough nose for 80mm standoff, you should get somewhere in the realm of 160-180mm of penetration. Then any Tom, Dick or Harry with an under-barrel grenade launcher could realistically take a pot-shot at a tank's rear, top or rear flank. A dedicated grenade launching platform chambered for a new 45mm or 50mm design could work, but recoil gets fierce fast. All other factors being equal (which of course they won't be) scaling up from 40mm to 45mm comes to about 40% more volume per munition, and going to 50mm that's 95% more, almost double the volume and presumably weight. IMO you're better off sticking with 40mm.
  2. Some clever gents gently broke buckyballs "to form a disordered nano-clustered graphene-based hard phase with more than 90% elastic recovery after deformation", a novel amorphous material with extraordinarily high hardness and compressive strength: https://academic.oup.com/nsr/advance-article-pdf/doi/10.1093/nsr/nwab140/39584180/nwab140.pdf From what I can tell this creates layers of graphene-like platelets with enmeshed edges. Now that we know what it looks like, maybe it can be synthesized from graphene rather than buckyballs, for slightly more economical mass production.
  3. I don't think that team has done anything but realized that the goalposts have moved in favor of hybrid solutions. The fusion physics community has been making advances towards making fusion break-even. They're not there yet, but have succeeded in reducing the power requirements of fusion quite a bit (orders of magnitude). Since the power requirements for fusion have decreased, more of the hybrid reactor's output is available for external use.
  4. Yes :-( the Polywell seemed very promising, but they over-promised and the Navy cut its funding when those promises failed to materialize. In the meantime, the Russians did a clever thing: https://phys.org/news/2020-01-scientists-concept-hybrid-thorium-reactor.html There are inexpensive, highly available fission fuels which haven't been deemed practical because they require an external neutron source to keep fission going (specifically, lithium-6 and common thorium-232). Refined plutonium and uranium of appropriate isotope can provide that neutron source, but if you have those, why bother with the Lithium-6 or Thortium-232? This Russian team observed that even though fusion technology has not advanced to the point where it can break even on energy, it has advanced to the point where it is a relatively inexpensive source of neutron radiation. They are using D-T ICF to generate neutrons to drive thorium fission, which does net energy. On a similar note, scientists have been using the Coulomb Effect to implode lithium deuteride wires and demonstrate D-D fusion since the 1990s. The advantages of lithium deuteride are that it is a dense, stable way to store and hold deuterium fusion fuel, and it is highly conductive (the Coulomb Effect requires high electrical currents, on the order of hundreds of thousands of amps). Perhaps a lithium-6 deuteride wire, enclosed in a tungsten carbide neutron reflector, could use the neutron by-products of D-D fusion to split the lithium-6 and net energy thereby?
  5. In that era, "complex target" usually (but not always) referred to NATO Triple Heavy.
  6. I have read claims on other forums that the US Army has had the manufacturer adjust the propellant used in M855A1 so that its chamber pressure is 57,500 psi, down from 62,000 psi. Some quick Googling failed to bring up a reputable source confirming this, but my Google-fu is known to be deficient. Does anyone know if it's true?
  7. What I found interesting (and a bit depressing) is that Orion is a Windows-only application. That didn't make any difference at all for this exploit (inserting trojan code at the repo is completely OS-agnostic), but it does signify that all of these companies and government agencies are using Windows in mission-critical roles. That bodes ill for future security.
  8. Just found this thread, and it sparked a couple of thoughts.. I've been working in telecom off and on for twenty-four years, and one of the more interesting quirks of the industry is how laying "just enough" fiber in the 1990's turned out to be overkill as the switching fabric evolved to push more and more data through the same buried strands. Strands that used to carry 44.7Mbit/s are now carrying six independent channels at 1Tbit/s per channel. My current employer is a CLEC, and we have been laying new fiber to escape dependence on AT&T's copper infrastructure. The most expensive part is paying people who are digging the trenches and hanging things on utility poles (and often repairing/replacing utility poles), so it doesn't make sense to skimp on the fiber itself. The total cost of running 1-strand cable and 192-strand cable is nearly identical, so of course we run the 192-strand cable. This has resulted in the bandwidth itself being very, very cheap -- not quite free, but next to it. We charge our customers for ancillary services, and throw them all the bandwidth they can eat, because why not. In the meantime the tech pushing more and more data down the same old fiber continues to improve, and upgrading the hardware isn't particularly expensive. Again, the main cost is paying trained techies to plan, provision, configure, monitor and maintain the infrastructure. If the author is aware of this trend, that could be where the "free communication" idea comes from -- eventually fiber will be everywhere and pushing ungodly data throughput. But they're ignoring the ancillary services which are labor-intensive and thus cost customers money. Switching subtopics .. Someone commented about hard boiled eggs, and it's totally true. When communities got hit with pandemic lockdowns, the local grocers couldn't keep the overly-packaged, pre-peeled hard-boiled eggs on the shelves. The damn things cost nearly twice what you'd pay for a dozen eggs, but people either don't know how to cook or can't be arsed and are willing to pay for the convenience. If that trend continues, we'll end up with something like individually-wrapped cheerios, at $1.25 per unit. Fortunately, from what I've seen, Gen-Z'ers are learning basic life skills (like cooking) which Millennials somehow missed, so perhaps there's hope for that trend to reverse itself. Marketers will have to figure out some other way to make food more profitable. As for home manufacturing, this is so far the domain of "Makers" -- hobbyist-geeks with money to burn, building useless gee-gaws for the gee-whiz of it. At my previous employer, when one of the office kitchen microwave ovens' door latch broke, one of the engineers whipped up a replacement with one of the lab 3D printers. It worked great, but TPTB threw a shit-fit because of potential liability issues. They tossed the (perfectly functional) microwave oven and bought a new one to replace it. Bureaucratic and legal obstacles will likely stand in the way of innovation for a while, impairing adoption of entirely useful technologies. One of the ways I see 3D printing potentially changing our lives is by tailoring shoes and clothing to our bodies. Right now centralized textile industry is far more efficient, but at the cost of only offering a few sizes (multiplied by other dimensions not documented -- a size 10 shoe might be wider or narrower, for instance, or provide too much arch support or not enough). I'm 6'4" with a narrow waist but a runner's butt and thighs. Finding pants that fit is nearly impossible. When I do find something that works, I buy twelve pairs because it will be years before I get the chance again. I'm not the only one; anyone with a body shape that doesn't fit the textile industry's standard set of parameters knows exactly what I'm talking about. Similarly, children grow so fast that parents have little choice but buy clothes that are too big, let their kids "grow into" them, and hunt frantically for replacements before the tykes outgrow them once again. If parents could get clothes that fit their children "on tap", it would make their lives easier and give their children clothes that fit every day, not just as a transient state. My parents' generation would use simple sewing skills to let seams and hems in/out to accommodate growth, but this seems to have fallen into the gap between generations. Not that anyone has the time to do it anyway, with both parents necessarily working full-time. If 3D printing tech gets to the point where it can crank out tailor-made shoes and garments on demand, there will be a market for it. That market will grow as the technology becomes more affordable and more versatile. To get there it will need to evolve beyond the current one-trick glue-gun print head, and turn into more of a multi-tool, capable of applying, moving, and welding/stitching a variety of materials. Maybe my expectations are too high, but I think there's every reason to expect this to come about, maybe even in my own lifetime. We will see.
  9. My wife and I keep a list of "surprisingly good" movies. I already posted most of it, but it has some new additions, and I don't remember which ones already got posted, so 'scuze if there's a repeat or two: Hellmington -- 2/5 stars, about 25% horror, 75% whodunnit. I See You -- 4/5 stars, Ellen Hunt, the twists keep surprising .. poltergeist? Well, no, but maybe yes? Almost Mercy -- 3/5 stars, childhood is hell. "Wristcutters"-style dark comedy, does blood well. The Voices -- 1/5 stars, two schizophrenics sharing a cabin in the woods with a closet full of guns. What could possibly go wrong? Ashes -- 3/5 stars, OMG what is wrong with these people? Never quite gels into a horror movie, more like a dark comedy with a tragedy tacked onto the end. It's a riot. Note that the "stars" rankings are entirely my own assessment, and are only meaningful relative to each other. These are all good movies, IMO, and "1/5 stars" just means that it's a good movie that isn't quite as good as the "2/5 stars" movie.
  10. The infected population hasn't stopped growing. The number of Americans who will know someone who died of covid19 will depend on how long it takes to arrest its spread. The first crop of vaccines is still about eight months away (give or take) from widespread availability, making this pandemic only halfway over. Don't count your chickens just yet :-)
  11. To be fair, we thought taking social media mainstream would be like USENET writ large, not realizing that the relatively few people participating in USENET in the 1980's were unusually considerate, reasonable and well-educated, and the infrastructure was run by relatively disinterested admins without a political agenda. The last 20'ish years in particular have been an eye-opener. Not only does social media need to accommodate joe-sixpack and grandma, it also needs to resist corporate exploitation, government regulation, and mass surveillance by alphabet agencies. The next generation of social media is coming, if slowly. Bits and pieces have been implemented separately (Tor, DHT, bittorrent, IPFS, TPB, etc) and the "decentralized web" movement is scraping them together into a new kind of platform -- https://blog.archive.org/2018/07/21/decentralized-web-faq/ We'll see how it goes.
  12. For what it's worth, I'm interested in the size of the infected population because it's one of the terms needed to calculate the risk accrued when exposed to random strangers. Also, because it's where we'll see the inflection start when the infected population approaches its saturation point. Dunno how common that is, though.
  13. That sucks! But I'm glad it wasn't worse, and hope you mend quickly.
  14. Yeah, the mask issue isn't simple. Everything rmgill and Ssnake said, and also the CDC was trying to discourage ordinary-joe citizens from using the more effective masks so that health care workers could have enough of them. Wearing two masks actually makes sense sometimes. There are N95 masks with a valve for exhalations, which means they protect you from droplets but spew your droplets everywhere, which isn't good for other people. Wearing a cheap surgical-style masks over one of those helps. Also, when not using N95 was considered the socially aware thing to do, people would catch shit from others if seen shopping in an N95 mask, so wearing a cloth mask over it was effective camouflage. I wonder if Biden is wearing a mask over his mask to hide that he's using one of those controversial Chinese KN95? There are "layers upon layers" in both senses of the term, here.
  15. When you put it that way, it seems like a pretty raw deal for Ukraine.
  16. Perhaps the shipyard is being operated by BAE? Or is BAE otherwise building these ships with UK employees? If this loan just goes into BAE coffers in Switzerland, the hypotheses offered here seem invalid (except for the one about Ukrainian stimulus).
  17. That's what I meant. The UK is giving them money and Ukraine is giving it (the principle) back, so all the Ukrainians are paying out of their own pocket is the interest. If the UK loans them 1.25 billion UKP, and Ukraine ends up paying back 2.0 billion UKP, it's as though they bought eight boats for 750 million UKP of their own money (or however much the interest works out to be).
  18. 0.003% is about right if you take the total number of SARS-CoV-2 deaths which did not involve comorbidities and divide it by the entire population, rather than the population of infected people. Other methods of calculation will yield much higher mortality rates. It is arguably more useful to base the calculation on outcomes (deaths from infection divided by infected population), because then you get a predictor of how many people will die as the infection count increases. Using the other method, the mortality rate will seem to increase as the number of infected increase.
  19. Since the hub-motors are capable of delivering more power than the diesel engine can generate, the battery pack would allow for both, regenerative braking (as sunday already mentioned) and temporarily increased drive power -- the sum of battery output + engine output, the batteries to be recharged later when drive power drops below the engine's output limit. It's clever. They're taking advantage of heterogeneous demands over time, so that excess energy from the engine can be stored in the batteries to use later when extra power is needed.
  20. https://uk.reuters.com/article/uk-britain-ukraine-navy-idUKKBN26S1SM If I understand this correctly, the UK is loaning money to Ukraine for Ukraine to buy eight Barzan FAC from the UK. This more or less works out to the UK giving money to itself, with Ukraine on the hook for the interest. Is this a financial structuring play on the UK's part? Taking a lump sum from this year's foreign aid budget to secure a ten-year revenue stream for Vosper Thornycroft? It would make the actual cost of the eight Barzan FAC (from the Ukrainians' perspective) equal to the interest on the loan. Is there perhaps an additional consideration, that indebting Ukraine to the UK like this gives the UK a credible claim of national interest? This could perhaps be used to justify additional investments and/or defense interventions.
  21. Yes, you can. Or you can do it better (more retained velocity, more retained energy, flatter trajectory, less wind drift -- see attached graphs) with the 6mm ARC, or something like it, using a lighter rifle and carrying more ammunition (lighter case, lighter bullet). There's doesn't need to "be only one", and you're right that soldiers need good marksmanship skills to use a rifle at long range. These are all factors that other people are going to weigh, and they're not asking my opinion 😉 I'm just pointing out some advantages and making light speculation. Maybe this will just be another tool in the toolbox and nothing much will change. Time will tell.
  22. Well, yes and no. The main advantage of these long, heavy, narrow intermediate calibers is their ability to retain energy downrange, due to extremely high ballistic coefficients. At long range the 6mm ARC retains somewhat more energy than the .308 (see first chart attached) and the wider cartridge with larger bore will burn propellant more efficiently (slightly more muzzle energy per grain). Note that this is vs the old M80, not the new M80A1, mainly because this ballistic calculator doesn't accommodate that easily 😉 The M80A1 does retain more energy longer, but that just pushes out the crossover distance, and does not prevent it. Shortening the barrel does indeed reduce muzzle velocity. According to the Powley calculator the ELD-X should only get 2503 feet per second out of a 14" barrel. Even so, it handily outperforms 5.56x45mm at all ranges (see second chart attached). Same caveat as before, the M855A1 will do better. I really should do something to make such comparisons easier. Another caveat: I'm dubious of kinetic energy as a measure of performance. Terminal effect is more a function of shot placement (which is a function of velocity and drift) and permanent wound cavity volume (which is a function of velocity and degree of fragmentation). But since you brought up energy, we can talk about energy. IMO a 5.56x45mm replacement really should use an 87gr bullet, but of course its long range performance would suffer, even with a very long, narrow ogive. As for recoil, I can't say from experience. It has been said that bracing the stock against body armor gentles recoil, but I don't know if that's the whole story (muzzle climb?) Perhaps someone on this Grate Sight who does have personal experience can speak to that point. I hope the charts show up okay. If the new site lets me embed an image mid-text, I'm not finding it. It seems to only let me attach files. In short, I'm unconvinced that 6mm ARC is a slam-dunk. It does fall a bit short as a GPC. It gets close, though, and IMO has good potential to replace 5.56mm (but not so much 7.62mm).
  23. 6mm AR only requires a barrel swap, and 6mm ARC is about 2% smaller than 6mm AR, so I wouldn't expect the lower receiver to be a limiting factor.
  24. Yeah, it seems pretty clear that 6mm ARC is a niche cartridge. Still waiting to hear who exactly will be using it. It's definitely not a 5.56x45mm replacement (though fitting it with lighter bullets might make it more appropriate for such use). I haven't heard anything lately about the .264 USA or the mysterious new 6.8mm cartridge. I can't help but wonder if we're going to see different military branches try various mid-caliber weapons for a few years to see how they work, then standardize on one. Perhaps the LCAAP would tool up for manufacturing the emergent winner en masse?
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