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Thursday, July 6, 2017

A Concrete Idea: Roman Sea Walls--Ash Me No Questions

      Ancient Roman concrete is still standing strong after thousands of years and, not only does it resist damage, but the salt water actually makes it stronger. X-ray examinations may have found the key to the concrete's amazing longevity, which could help improve modern concrete recipes. Dissolving phillipsite in pumice, as seen in this Scanning Electron Microscope (SEM) image, is believed to be part of the secret:



      Note that modern sea walls last only a few years in salt water where these Roman sea walls have lasted thousands of years.



      Although the complete recipe has been lost over the years, studies of samples have shown that volcanic ash, lime, and seawater are the main ingredients. "But, according to an article published in American Mineralogist the real magic seems to happen when those ingredients interact with the environment – specifically the saltwater incessantly pounding on the surface."



     Al-tobermorite is part of the cementing matrix, key to its strength. Modern "Portland cement" relies more heavily on heating the elements, exacting an environmental toll.




Huzzah for the ancient Romans. . .and for seawater! Has this idea been cemented in your brain?
Steph

Pink Martini and Rufus Wainwright at Red Rocks, July 6, 2017:



69 comments:

  1. Now I have to dig up my photos of the Pantheon.

    I've long known about the binding and waterproof qualities of the pozzolonic fly ash - makes me wish we had more volcanoes around here, perhaps we can set something up at Mount St Helens. Interesting the reactive chemistry between the lime and salt water.

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  2. Bummer about your email, I hope you get it fixed soon. Amazing how quickly these systems have become indispensable.

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    1. Thanks, eco. Still working on it.

      To get away from this email issue for a bit, a friend and I went to Red Rocks last night to hear Rufus Wainwright and Pink Martini with the Colorado Symphony Orchestra. A magical evening was just the trick!

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    2. Pink Martini is perfect on a Friday afternoon, I'm popping in my old Sympathique CD now. Hard to believe it's almost 20 years.....

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    3. I know. A dear Portland friend turned me on to Pink Martini about then.

      Rufus and "Blue Moon" was wondrous with the moon rising. China Forbes can s i n g and have the audience spellbound as she moves all over the large Red Rocks stage. Ah! The stories, the languages, and Eugene!

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  3. OK, I don't care if it's mineralogically inaccurate, I still think this book design is cool.

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  4. Re: the last image above: What's the connection to the Swansea Bay Tidal Lagoon power plant project? Will that breakwater use Al-tobermorite? (Which sounded vaguely Arabic to me until I realized that it's a form of the mineral in which aluminum (aluminium, in Swansea?) substitutes for silicon.) I'm surprised that tidal hydro power isn't much of a thing yet; it's always seemed to me like it should be a cheap, reliable power source.

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    1. Tidal power is certainly rising as an idea (pun intended, even if it isn't funny). There's been talk about using it under the Golden Gate Bridge for over a decade, though we don't get 14' tides.

      My understanding is the biggest limitations are availability (not much in Ohio), limited scale (Golden Gate would only generate 15-17 MW), and environmental damage to marine environments.

      But I think it's one good piece in the puzzle, especially since it doesn't have the time limitations of solar, nor the inconsistency of wind.

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    2. "He's too far from the Bay of Funday
      From appaloosas and eagles and tides
      And the air conditioned cubicles
      And the carbon ribbon rides
      Are spelling it out so clear
      Either he's going to have to stand and fight
      Or take off out of here
      I tried to run away myself
      To run away and wrestle with my ego"


      She always said it best.

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    3. Tidal projects are intriguing. Good detective work on the photo, jan. I thought it would be a perfect place to use some concrete concrete.

      And, thanks for Joni, eco!

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    1. Except those cute tongues are surrounded by nasty teeth. I'll never forget a solo backpack trip many years ago: woke up at 2am to loud rasping noises. Looked out of my tent to see a couple of bears scratching on some pine trees, much like a cat does to sharpen its claws. They were maybe 30-40 feet away, and my first thought was "why are you sharpening your claws????" Fortunately my food and toothpaste were reasonably well treed about 100 feet away, and the bears never went after that. Or me.

      On one of the videos the narrator expressed surprise that bears are constantly eating even as they move from place to place. I think we should strap a camera on the all-American family in their mini-van on vacation, as they stop at McD's for lunch, then a big gulp and chips as they get gas, then gum and other snacks they bring along.

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    2. What an experience to outfit whales!

      Must be the smooth swimming. . .

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  6. I've read (and occasionally participated in) the RISKS Digest since its inception. It's a good place to keep up with the threats to the public from computers and stuff like that. A couple of items from the latest issue provide a good introduction. A piece in Wired tells how easily researchers were able to hack a wind farm. And a somewhat more esoteric blog post describes the risks presented by poor security of devices that are part of the Internet of Things (IoT).

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  7. jan, are there now increased risks to mobile devices? Interesting about the Wind Farm. . .

    IoT is news to me, though the Denver Public Library has a wonderful Library of Things .

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    1. Not just risks to devices, but also risks from them. Recent denial-of-service attacks have been caused by bots infecting, e.g., smart thermostats.

      Although I've known the term "Internet of Things", I was unfamiliar with the abbreviation "IoT" until I heard an ad on NPR from the company C3IoT. ("C3" is an old military term for "command, control and communication".) Their website is incomprehensible to non-techies.

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    2. Brings up the strange circumstances of Michael Hasting's death; Forbes has written about car hacking for several years.

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    3. Interesting, eco.

      I am glad my car is not hackable; I even have an actual metal key.

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    1. Yeah, I saw that, too, and ordered "Newtonian Physics for Babies" for my 6-month old granddaughter. Might as well start off with something more comprehensible. I like the Binky on the covers.

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    2. I may have noted this before, but speaking (or typing) of childhood education, did you know that decades before the "father of climate change" James Hanson gave his famous testimony, virtually every child born between roughly 1950 and 1965 was taught about the subject?

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    3. Every time I see a glacier calving, I do have a feeling of déjà vu.

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    4. I was always a big fan of all those old Bell Labs films.

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    5. They would show them in the multi-purpose rooms to several grades at once; we figured it was a chance for the teachers to be rid of us for a while and do "adult things", whatever they are.

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  9. Ah the ring of fire. I'm still trying to figure out the 1 comment to the article, but it's good to see Arthur C Clarke is still writing.

    Why is it we find volcanic regions to also be breathtakingly beautiful? Hawaii, Alaska, Cascades, Italian spine, Indonesia, Mexico, Iceland, Japan, New Zealand, etc.

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    1. For me? Because they have volcanoes!

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    2. Can you name the two places where you can see more of the earth's surface than anywhere else? Of course this is standing on land, being in an airplane or space station doesn't count.

      Hint: one is a well-known volcano. The second one is disputed, especially by people from LA. And no fair googling it until you get desperate.

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    3. I've seen some pretty good pictures of half the earth taken while standing on land on the moon.

      Jonathan Livingston Seagull said the gull sees the farthest who flies the highest, so Everest seems like a good bet.

      Do mirages count?

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    4. Remember that Everest is surrounded by mountains nearly as tall, so you can't see much of the earth's surface. That's besides the altitude sickness and snow blindness.

      I will hint that neither place requires remarkably specialized skills or training to get there. I've been to one of the places, and it was very easy to get there.

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    5. Seems like Mt. Kilimanjaro might be one.

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    6. Kiliminjaro is #1! It is the place where you can see more of the earth's surface.

      The #2 location is not very high, but some geographical anomalies make it possible to see over 150 miles away.

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    7. Much closer to home, very easy to get to, I've been there.

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    8. So much fun that you're having a devil of a time with this. The peak is known locally, but probably not nationally, and is much lower than you'd think. You can drive virtually to the top.

      I'll disclose after my morning meeting unless you want to keep thinking...

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    9. Did my devil hint give it away?

      Yes, folks at Mount Diablo, about 30 miles east of San Francisco, claim that its modest 3,849 foot peak is second only to Kilimanjaro in expanse of view. Geographers say this is due to the mountain's isolation, the relatively flat surrounding landscape, especially the Central Valley to the south and east, and most importantly the rise of the Sierra and Cascade Mountains to the east and north, which make up for the earth's curvature.

      3,849 feet would make it one of the lowest spots in Colorado.

      I drove by last Thursday on the way to a building department, but no time to stop - you can drive very close to the peak, the trail is ADA accessible. And you definitely can see Half Dome (120 miles away) and Lassen (160 miles) from there, but usually only in winter when the air is clear.

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    10. Yes, eco, the devil was in your details.

      What a cool view!

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    11. And Colorado does have the highest low point in the U.S., though it's not along the Arkansas River as thought for many years.

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    1. Pacifica radio did a piece on this last night, it is a grim future.

      Maybe Trump will defund that evil National Academy of Sciences (FAKE NEWS!) and replace it with kittens playing around Ivanka's shoes?

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    2. Ah, the wonderful Whole Earth Catalog ! Doomed now.

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  11. Not quite sure why Tardigrades are trending today as we here at Partial Ellipsis of the Sun have had them as our mascot for many years. . .

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    1. Silly piece, despite the cute tardigrade pic. There's no way that any organism that can't photosynthesize (or otherwise make its own food) could be the last surviving species, at least not for more than a few years after the cupboard is bare.

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    2. jan, I agree.

      I don't totally understand the whole trending thing either.

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    3. Trending thing is probably based on the hope to make an animated Disney movie, with concurrent profitable stuffed toy products.

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    4. eco, you are likely right. I forgot to follow the money.

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    5. Cynicism is one of my more positive attributes.

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    6. Indeed. At least there's a glass, right?

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    7. Plastic cup, spending years in the Pacific gyre before washing up on a once pristine island.

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    8. You do embody cynicism and I do enjoy the concept of gyres.

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    1. That is too bad, especially so young.

      Also reminds me how idiotic it is to make travel bans against countries, who might be excluded?

      Several years ago I met an Iranian cosmologist who was staying with one of my clients while he was attending an international conference. Brilliant guy, their research continued in spite of US sanctions at the time under Clinton/ Bush. And who knows how much he may have influenced my client's daughters, who pursued science degrees at top universities?

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    2. Yes, very sad. My son didn't know her when he was at Stanford, but they had friends in common.

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  13. New post on "Not Puzzling at All: Crossword Puzzlers Have Better Brain Function" is now up.

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