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  1. #1546

    Re: Let's Discuss Science

    I really enjoyed her logarhithmic discussion. While some of that was stuff I had learned a long time ago, it was still a really good explanation that brought to mind many other places where that is useful.

    I know that Ponchi's post just above was totally tongue-in-cheek, but since I am still hearing people around here all the time who don't understand what the 19 in COVID-19 is from, I'm going to clarify: The 19 refers to the year (2019) when the disease first appeared. So if another unique Coronavirus causes disease in 2020, it would be COVID-20.

    Unless there are some major breakthroughs in treatment of the aging process, I definitely agree that "we will not feel the difference between COVID-119 and COVID-120." None of us will likely be around to feel that.

    GH

  2. #1547

    Re: Let's Discuss Science

    Quote Originally Posted by mmmm8 View Post
    Thanks for posting that, suliso. Another type of unconscious bias.
    Indeed. Humans are not mathematically logical beings (evolutionary would have been bad) so none of us can be fully free of unconscious bias, but I believe we can lessen it if we are aware of it.
    Roger forever

  3. #1548

    Re: Let's Discuss Science

    Serious question: how many people do you/we know that apply correction to these biases? How many people apply corrections to basic solipsism? How many people do you know that work under the operative directive that they, too, can be wrong?
    I have known three, maybe four at most. I try to do it myself but of course, I cannot judge how I work because of, well bias.
    How many people work under the operative of "what if I am wrong?"
    Face it. It's the apocalypse.

  4. #1549
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    Re: Let's Discuss Science

    Quote Originally Posted by ponchi101 View Post
    Serious question: how many people do you/we know that apply correction to these biases? How many people apply corrections to basic solipsism? How many people do you know that work under the operative directive that they, too, can be wrong?
    I have known three, maybe four at most. I try to do it myself but of course, I cannot judge how I work because of, well bias.
    How many people work under the operative of "what if I am wrong?"
    No one does it 100% or even 50% of the time, but I do know a lot of people who try.

    I don't think it's exactly a "what if I am wrong?" but more "Is there a perspective I'm not seeing" or "Why do I think that?" because just because a bias influences an action, doesn't make the action wrong, necessarily. There is a lot of scientific evidence that just slowing down your decision weakens unconscious biases, even without any other interventions.


  5. #1550

    Re: Let's Discuss Science

    "How many people work under the operative of 'what if I am wrong?'"

    One thing I would say is this: That percentage differs a lot depending on your profession. As an oncologist, I was always having to keep that concept in mind. I made decisions and recommendations based on the best medical evidence available, but given the vagaries of cancer and the human body, I had to still think about the unanticipated things that could go wrong. I'm sure most professions wouldn't have as high a percentage of that as I did.

    GH

  6. #1551

    Re: Let's Discuss Science

    This one is more technology than science, but still.

    A breakthrough approaches for solar power


    One of the few parts of the UK economy to have a good April was solar power.

    The Met Office says it has probably been the sunniest April on record and the solar power industry reported its highest ever production of electricity (9.68GW) in the UK at 12:30 on Monday 20 April.

    With 16 solar panels on his roof Brian McCallion, from Northern Ireland, has been one of those benefitting from the good weather.

    "We have had them for about five years, and we save about £1,000 per year," says Mr McCallion, who lives in Strabane, just by the border.

    "If they were more efficient we could save more," he says, "and maybe invest in batteries to store it."

    That efficiency might be coming. There is a worldwide race, from San Francisco to Shenzhen, to make a more efficient solar cell.

    Today's average commercial solar panel converts 17-19% of the light energy hitting it to electricity. This is up from 12% just 10 years ago. But what if we could boost this to 30%?

    More efficient solar cells mean we could get much more than today's 2.4% of global electricity supply from the sun.

    Solar is already the world's fastest growing energy technology. Ten years ago, there were only 20 gigawatts of installed solar capacity globally - one gigawatt being roughly the output of a single large power station.

    By the end of last year, the world's installed solar power had jumped to about 600 gigawatts.

    Even with the disruption caused by Covid-19, we will probably add 105 gigawatts of solar capacity worldwide this year, forecasts London-based research company, IHS Markit.

    Most solar cells are made from wafer-thin slices of silicon crystals, 70% of which are made in China and Taiwan.

    But wafer-based crystalline silicon is bumping pretty close to its theoretical maximum efficiency.

    The Shockley-Queisser limit marks the maximum efficiency for a solar cell made from just one material, and for silicon this is about 30%.

    However, combining six different materials into what is called a multi-junction cell can push efficiency as high as 47%, under concentrated light.

    Another way to break through this limit, is to use lenses to focus the sunlight falling on the solar cell.

    But this is an expensive way to produce electricity, and is mainly useful on satellites.

    "Not anything you would see on anybody's roof in the next decade," laughs Dr Nancy Haegel, director of materials science at the National Renewable Energy Laboratory in Boulder, Colorado.

    The fastest improving solar technology is called perovskites - named after Count Lev Alekseevich von Perovski, a 19th Century Russian mineralogist.

    These have a particular crystal structure that is good for solar absorption. Thin films, around 300 nanometres (much thinner than a human hair) can be made inexpensively from solutions - allowing them to be easily applied as a coating to buildings, cars or even clothing.

    Perovskites also work better than silicon at lower lighting intensities, on cloudy days or for indoors.

    You can print them using an inkjet printer, says Dr Konrad Wojciechowski, scientific director at Saule Technologies, based in Wroclaw and Warsaw. "Paint on a substrate, and you have a photovoltaic device," he says.

    With such a cheap, flexible, and efficient material, you could apply it to street furniture to power free smartphone charging, public wifi, and air quality sensors, he explains.

    He's been working with the Swedish construction firm Skanska to apply perovskite layers in building panels.

    According to Max Hoerantner, co-founder of Swift Solar, a San Francisco start-up, there are only about 10 start-up firms in the world working on perovskite technology.

    Oxford PV, a university spin-off, says it reached 28% efficiency with a commercial perovskite-based solar cell in late 2018, and will have an annual 250-megawatt production line running this year.

    Both Oxford PV and Swift Solar make tandem solar cells - these are silicon panels which also have a thin perovskite film layer.

    Since they're made from two materials, they get to break through the Shockley-Queisser limit.

    The silicon absorbs the red band of the visible light spectrum, and the perovskite the blue bit, giving the tandem bigger efficiency than either material alone.

    One challenge is when "you work with a material that's only been around since 2012, it's very hard to show it will last for 25 years," says Dr Hoerantner.

    Insolight, a Swiss startup, has taken a different tack - embedding a grid of hexagonal lenses in a solar panel's protective glass, thus concentrating light 200 times.

    To follow the sun's motion, the cell array shifts horizontally by a few millimetres throughout the day. It is a bid to make concentrated solar cheap.

    "The architecture of these conventional concentrated photovoltaics is very costly. What we've done is miniaturise the sun tracking mechanism and integrate it within the module," says Insolight's chief business officer David Schuppisser.

    "We've done it in a cheaper way [that] you can deploy anywhere you can deploy a conventional solar panel," he says.

    The Universidad Politécnica de Madrid's solar energy institute measured Insolight's current model as having an efficiency of 29%. It is now working on a module that is hoped to reach 32% efficiency.

    Current silicon technology is not quite dead, though, and there are approaches to make tiny, quick wins in efficiency. One is to add an extra layer to a cell's back to reflect unabsorbed light back through it a second time. This improves efficiency by 1-2%.

    Another is to add an outside layer, which lessens losses that occur where silicon touches the metal contacts. It's only a "small tweak", says Xiaojing Sun, a solar analyst Wood Mackenzie research - adding 0.5-1% in efficiency - but she says these changes mean manufacturers only need to make small alterations to their production lines.

    From such small gains - to the use of concentrated solar and perovskites - solar tech is in a race to raise efficiency and push down costs.

    "Spanning this magical number 30%, this is where the solar cell industry could really make a very big difference," says Swift Solar's Max Hoerantner.

    https://www.bbc.com/news/business-51799503
    Roger forever

  7. #1552

    Re: Let's Discuss Science

    Few comments from me regaring the article above and the emerging non fossil and non nuclear energy options in general.

    As I see it there are three major alternatives - good old hydro, wind and solar. Everything else (geothermal, waves, biomass etc) is likely to be forever a niche. Hydropower has been around for a long time and is well understood, however everything what can reasonably be damed has already been and environmental cost of any new projects is high. I don't see any serious expansion in the developed world. So the fight really is between solar and wind. Both will have it's share, but in my opinion solar is more versatile and likely with lower long term environmental cost if the efficiency can be raised further as described in that BBC article. Batery technology allowing storage for 24 h operations will be crucial as well. I've noticed a lot of scientific papers about those perovskites for some years already, nice to see that commerical applications are not that far off now.

    Finally no doubt someone will bullshit that oh all those solar cells need mining and fossil fuels to build them. Of course they do, but in oil industry too some percentage of oil is spent to extract and refine more oil. One would expect that if the conversion works well eventually all those mines and factories will work indirectly on solar/wind power making a closed supply circuit with an energy surplus for all other needs. It's easier to start with end consumers instead of heavy industry in this case.
    Roger forever

  8. #1553

    Re: Let's Discuss Science

    A bit more about those "mysterious" perovskites. Note that this is from 2017 so some downsides have been overcome already.




    P.S. I love youtube - can be used equally well for music, comedy, travel shows, science etc.
    Last edited by suliso; 05-26-2020 at 09:57 AM.
    Roger forever

  9. #1554

    Re: Let's Discuss Science

    Agree mostly. I would only add that even if we switch on a very large percentage to solar and wind, we do need storage capacity. That will have to come. Wind is very variable and it does die down at night in most places.
    And, we need to re-forest large patches of land and clean our oceans, for them to be able to absorb the CO2 already in the atmosphere. These two are my pet projects or peeves, depending how you see it.
    Face it. It's the apocalypse.

  10. #1555

    Re: Let's Discuss Science

    Quote Originally Posted by suliso View Post
    A bit more about those "mysterious" perovskites. Note that this is from 2017 so some downsides have been overcome already.




    P.S. I love youtube - can be used equally well for music, comedy, travel shows, science etc.
    Nice simple explanation of perovskites. Thanks.
    “No matter how cynical I get, I just can't keep up.” – Lily Tomlin.




  11. #1556

    Re: Let's Discuss Science

    Just a heads up.
    Today at 16:33 EDT USA NASA and SpaceX will launch the Falcon 9 with a Dragon Capsule and 2 astronauts into orbit.
    NASA TV has a free APP (viewable through ROKU or other platforms) that will of course cover the launch for hours.
    Lots of expectations. Another Elon Musk project, so if he succeeds the man must be given his dues.
    If something does not go according to plan (I don't want to jinx this thing) it would be a major setback.
    Face it. It's the apocalypse.

  12. #1557

    Re: Let's Discuss Science

    Quote Originally Posted by ponchi101 View Post
    Just a heads up.
    Today at 16:33 EDT USA NASA and SpaceX will launch the Falcon 9 with a Dragon Capsule and 2 astronauts into orbit.
    NASA TV has a free APP (viewable through ROKU or other platforms) that will of course cover the launch for hours.
    Lots of expectations. Another Elon Musk project, so if he succeeds the man must be given his dues.
    If something does not go according to plan (I don't want to jinx this thing) it would be a major setback.
    Here is NASA live youtube channel covering the event (translation started already)

    Roger forever

  13. #1558

    Re: Let's Discuss Science

    No launch today for weather reasons...
    Roger forever

  14. #1559

    Re: Let's Discuss Science

    But good. It shows how delicate it is to launch a rocket. After Challenger so long ago, no way they were going to go all heroic on a first launch.
    Same emoji as Suliso.
    Face it. It's the apocalypse.

  15. #1560

    Re: Let's Discuss Science

    I just saw Tiny was there. I guess his photo-op will have to wait.
    “No matter how cynical I get, I just can't keep up.” – Lily Tomlin.




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