Tech Tuesday 06/18/19 – “Is Plastic-Man Biodegradable?” Edition

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Oscar Gordon

A Navy Turbine Tech who learned to spin wrenches on old cars, Oscar has since been trained as an Engineer & Software Developer & now writes tools for other engineers. When not in his shop or at work, he can be found spending time with his family, gardening, hiking, kayaking, gaming, or whatever strikes his fancy & fits in the budget.

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29 Responses

  1. Avatar Oscar Gordon
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    says:

    One last link: We’ve figured out how to turn Type A Blood into Type O- (Universal Donor).

    This is actually pretty damn big news.Report

    • Avatar Jaybird in reply to Oscar Gordon
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      says:

      Holy crap. That’s huge. How long does it take? How expensive is it?

      (Do people who are type A+ get special benefits from A+ blood that they don’t get from O-?)Report

      • Avatar Oscar Gordon in reply to Jaybird
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        says:

        From what I recall, it’s pretty simple. Add a couple drops of enzyme to the blood, give it a shake and leave it alone for a bit.Report

        • Avatar Michael Cain in reply to Oscar Gordon
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          says:

          Right. And the paper clearly states that the standard centrifuge treatment applied to donated blood separates the enzymes from the red blood cells. Nothing about any impacts on platelets or plasma.

          If (just hypothetically) the process messes up platelets in particular, it will be used sparingly. Our local blood bank nags donors mercilessly to donate platelets rather than whole blood. I am not eligible to donate platelets by apheresis — none of my veins have any straight segments long enough to use safely.Report

    • Avatar Michael Cain in reply to Oscar Gordon
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      says:

      I pulled the paper and the article has a large error, or at least exaggeration, in it. The abstract says clearly that the Rh factor is not changed. Further, all of the testing was done on Rh-positive blood. No Rh-negative blood of any type was produced. It’s plausible that the process would convert A-negative to O-negative, but it hasn’t been demonstrated.Report

      • Avatar Oscar Gordon in reply to Michael Cain
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        says:

        Yes, from what I can tell, it only affects the type, not the Rh factor. This detail seems left out of all 3 media reports I’ve read so far.

        That said, if we can add an enzyme to strip the type, we can probably find one to strip the Rh as well.Report

    • Avatar George Turner in reply to Oscar Gordon
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      says:

      But how does it affect the flavor?

      Asking for a friend.Report

      • Avatar Oscar Gordon in reply to George Turner
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        says:

        It’s like going from good salsa to one of those healthy organic ketchups with no sugar or salt and some weird-ass spices that only the super crunchy granola vegans claim to like.

        Or so I heard, from a friend…Report

  2. Avatar DensityDuck
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    says:

    [TT09] looks cool but the idea of “stopped rotor becomes wing” has been a thing since disco was on the charts. It’s also not something you really *need* to do, you can get the same effect from having a pusher-prop and letting the rotor windmill to act as a lifting surface (which was done on the Lockheed AH-56, and is sort-of done on the current Sikorsky S-97 and developments of that).Report

  3. Avatar DensityDuck
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    says:

    [TT10] mmm-hmm, this won’t be used just for the last mile, it’ll be used for all the miles, because this is what autonomous vehicles will look like; minibuses sized for four adults (or one adult and one wheelchair/powered-mobility-device). Boxy for volume efficiency, high profile so it’s easy to see coming, wheels at the corners for good maneuverability in tight spaces and low speeds. You won’t be cruising at 120 mph on the freeway but you weren’t going to be doing that anyway given California traffic, and this thing is basically an office on wheels so you don’t really care if the trip takes longer, because once you get in this you’re pretty much at work.

    Got a meeting? Call a Deluxe EZ and ride around in circles for an hour. Got a piece of stuff and want to avoid awkward partner questions or just too drunk to remember your address? Call a Couch EZ and crash while telling it to take you from Castro to Pleasanton (and then take BART back into town.)Report

  4. Avatar Jaybird
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    says:

    Consumer goods edition: I was given reason to remember something I wrote a million years ago. In 2012, I wrote this:

    To use a silly example that I brought up in another thread, a handful of years back, I read about a 100″ HDTV that had the pricetag of $100,000. Today, Costco has an 80″ television for less than $5,000.

    In another 5 years, I’m sure we’ll finally see that 100″ television at Costco for under 10 thousand.

    That’s, what? 10 years from only being available to the Bill Gateses to being something that you could get instead of a 2nd car? (And you wouldn’t believe how much the price of the 65″, 52″, and 40″ televisions have gone down in that same period.)

    Well, I got this wrong. Costco (I went there last night) does not sell 100″ televisions. I walked around and the biggest television that I saw was 75″. (Sadly, no 100″ televisions.on the website either.)

    When I was a kid, my dad had to get the 27″ television set. It was furniture. We kept a lamp on it. It held our cable box and the VCR.

    The smallest televisions that Costco had were larger than that (well, diagonally). They were about an inch thin, though. They sold for less money, without any inflation adjustment, than the 27″ television cost in the late 70’s. A 32″ television for $164.

    The cheapest 75″ television is $1,279.99.Report

  5. Avatar George Turner
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    says:

    TT03: Artemis itself is probably not going to perform within the schedule and budget because it relies on Orion and SLS. Although Bridenstein was open to Pence’s statement that if SLS can’t get it done by 2024, NASA would use other launchers, there’s just no way for NASA to commit to such a move.

    Given the speed at which they need to get the lander contracts rolling, they’ll probably commit to a warmed-over Altair/Apollo style lander. Altair was going to have a crew of four, and is basically an Apollo LM do-over, with one descent engine in a descent stage with splayed legs, and one ascent engine in a stage that sits on top of the descent stage. The descent stage has a top hatch for docking and a side-door and longer ladder for lunar access.

    It’s a simple design that uses a vertically stacked pair of stages because that configuration packed easily into the launch vehicle, and “up” in the launch configuration in Florida is the same as “up” for lunar operations because up is up. That puts the docking hatch on the vehicle’s roof, puts the lunar access door on the side, and puts the ascent module on top of the lander so the astronauts have to climb up and down a tall ladder to get to the surface, much like using a third-floor apartment’s fire escape to go back and forth. There are dozens of better layouts that don’t resemble Apollo and which would work much better, but those probably won’t be explored.

    And Musk and Bezos may make the whole thing moot. The other day I was crunching numbers on a Starship launched by three Super Heavy boosters into GTO (three boosters gives a tremendous payload gain, without which a Starship can barely even get to GTO) then refueled by two similar Starhip refueling flights to GTO to top it up. Fully fueled in GTO, and reserving enough fuel for the final landing burn on Earth return, it should be able to deliver about 255,000 tonnes of payload to the lunar surface, or about 17 times more payload mass than the uncrewed cargo version of Altair. The Artemis lander won’t even deliver as much payload as Altair because it will be designed for the SLS, which is not as capable as the Constellation program’s Ares V.

    Between that and Blue Origin’s program, what NASA does with SLS and Orion may be irrelevant except as a program driver/tech developer/support resource.Report

    • Avatar DensityDuck in reply to George Turner
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      says:

      “The other day I was crunching numbers”

      hey the other day i was crunching numbers and if you put a semi-truck engine into a sports car it would go really, really fast because semi-truck engines have, like, lots of horsepowerReport

      • Avatar George Turner in reply to DensityDuck
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        says:

        The analysis stemmed from a post about the likely early configuration of Starship/Superheavy, which will likely only have about 150% of the payload capability of Falcon 9 Heavy. Musk could get a bigger increase (163%, by his calculation) by just adding two more side boosters to F9H.

        So that brought up a discussion that the Superheavy architecture was designed for in-orbit refueling. Well, given the early guesses as to the design, the early architecture is supposed to have a LEO payload capacity of 100,000 kg, and the ship has a dry weight of 87,000 kg. Landing fuel requirements probably set the minimum orbit mass at 103,000 kg.

        So the assumption was that a Starship, fully fueled in LEO, could fly a lunar mission. I ran the numbers and found it could deliver -7,400 kg to the lunar surface, which is slightly less than nothing. But someone pointed out that Musk said it might have to be refueled in a high elliptical orbit for such a mission. That made sense, so I ran the numbers for a common elliptical orbit, a GTO (which is the insertion half of putting a geostationary satellite in position, before the satellite does a circularization burn).

        The Starship’s Raptor engines have a specific impulse is 380 seconds, and that means the required mass ratio to insert into a geosynchronus transfer orbit is about two, which is nearly the same as the attainable mass ratio of Starship in the simple, straight-from-launch, low-earth orbit configuration. Oddly enough, despite its truly massive size, its high dry mass and return and landing requirements gives the Starship less GTO payload capacity than a Falcon 9. It would be almost useless for launching geostationary satellites.

        That also means that Starship/Superheavy can’t refuel a Starship in GTO because they can’t deliver any useful amount of fuel (50 to 100 refueling flights just to top up one ship).

        The only way around that fundamental problem (caused by hitting LEO with a high dry weight and low mass ratio), is to use a much bigger booster. The simplest way to do that is to use three instead of one, which is something SpaceX already does with Falcon Heavy.

        This leads me to believe that the early configuration of Starship is basically a bigger LEO Space Shuttle (Four times more payload capacity), and the deep space capability will be added to the booster (Super Heavy), not to Starship.

        Strangely enough, although landing Starship on the moon on its tail is pretty daft, the surface payload capability is almost exactly the same as if it parked in low lunar orbit and discharged a huge, one-way hypergolic lander with an ISP of 310 seconds and a cargo to landed-weight ratio of 75%.

        There are of course some serious stumbling blocks to refueling in GTO. For one, nobody has really ever refueled anything in space yet, much less multiple times. For another, sending the crewed Starship to GTO first would mean the astronauts would be zipping all the way through the Van Allen Belt every five hours while waiting for multiple refueling rendezvous that might be days or weeks apart. Flying through the Van Allen belt twice exposed Apollo crews to a pretty big dose of radiation, so much that they saw spots as their optic nerves fired off. So it’s certainly not a mission plan, just a potential capability.

        But what it points out is how obsolete NASA Artemis architecture is. It would take nine to twelve Superheavies (three boosters in each launch) to launch three or four Starships to execute one lunar mission that delivers 255,000 kg of cargo to the lunar surface. That mission would deliver more payload than about twenty SLS Orion missions, so each Superheavy booster is accomplishing about twice the useful work (useful pounds to the moon) as the SLS. More importantly, none of those boosters, nor a Starship, nor anything else gets thrown away. They can all be used over and over again, so the only thing being expended is fuel.

        In contrast, each SLS mission throws away the incredibly expensive core booster that takes 4.5 years to build, two solid rocket boosters, an upper stage that isn’t even flying yet, but which will likely use four expensive RL10 engines, and of course an Orion (which isn’t reusable) and at least a lander descent stage. The cost estimate for launching just a basic SLS Orion mission is somewhere between $1.5 and $2.5 billion dollars. A lunar landing mission might hit $3 to $6 billion, and those are recurring costs for each mission.

        The Starship approach might have a 50 or 100 to 1 cost advantage per pound delivered.

        One approach might conceivably lead to commercial lunar development, and even permanent settlement. The other might put twelve more people on the moon before being abandoned due to high cost and low returns.

        But Bridenstein is boxed in by all the existing bureaucratic and technical structures of NASA human space flight program, including the Congressional mandates, and there’s really no good way to break out of it. If Starship or Bezo’s New Glenn and New Armstrong start flying, we’d be much better off with NASA attaching themselves to those two programs, providing massive expertise, personnel, and mission support than trying to run a program that by its nature can’t really get past an exploration phase.Report

        • Avatar DensityDuck in reply to George Turner
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          says:

          This whole post reminds me of the guys talking about how if you got so-and-so and such-and-such on the same baseball team it would be absolutely awesome, because look at how the stats line up.

          I mean, sure, based on Powerpoint engineering, this works, but I remember how Crew Dragon was advertised to have a capability of eight people to ISS, and also not explode, and so far neither of those capabilities has actually been demonstrated.Report

  6. Avatar DensityDuck
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    says:

    Also, if you’re talking about costs, it’s important to remember that the Apollo Program cost seven hundred billion dollars to get where they got.Report

    • Avatar George Turner in reply to DensityDuck
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      says:

      It was about $25 billion in period dollars. The initial estimate was $10 billion, but just on a hunch James Webb doubled that number when he presented the program idea to the White House. As NASA flight director Wayne Hale (now on NASA’s supervisory committee) said this morning,

      “Norman Augustine captured this in his book “Laws” about aerospace projects: (Law XXIV) “The most unsuccessful three years in the education of cost estimators appears to be fifth-grade arithmetic.

      The Apollo program used a horribly inefficient approach left over from WW-II, which is to solve a problem by throwing a nearly infinite amount of money and people at it. Nothing about it was supposed to be sustainable.

      And there’s the rub. Projects that are really expensive, difficult, and producing little if any benefit will not be maintained. If it costs two billion dollars to put one guy on the moon for a week, there won’t be many guys ever setting foot on the moon.

      About 400,000 people worked on Apollo, whereas SpaceX employs 7,000, about 2% as many, and that includes all the folks who are working on creating a massive constellation of Internet satellites.

      What Apollo showed was than an American top-down big-government socialist rocket program was superior to a Soviet top-down big-government socialist rocket program. Both became dead ends.Report

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