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Ask a Scientist

Discussion in 'Permanent Threads' started by mekka, Oct 20, 2009.

  1. slippingaway

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    Here's a basic overview: <a class="postlink" href="http://www.csmonitor.com/USA/Society/2010/0222/Bloom-Box-What-is-it-and-how-does-it-work" onclick="window.open(this.href);return false;">http://www.csmonitor.com/USA/Society/20 ... es-it-work</a>

    The thing that's interesting, is look at the Ebay example they use. 5 boxes x $800,000 = $4,000,000.
    In 9 months, Ebay has saved $100,000 in electricity costs. This puts the break-even point at 9 mos. * $4M/$100K or....... 30 YEARS. And that's without considering things like interest they paid if they had to take out a loan to pay for them, interest they could have made if they'd invested elsewhere, changes in energy prices, or the possibility of other, cheaper energy alternatives being discovered. Or, of course, whether the unit will last 30 years and not require expensive maintenance.

    If the home model he's hoping to sell for $2,000 has the same savings to cost ratio, it will save you about $5.56 a month on your electric bill.
     
  2. jets22

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    If I'm reading the article correctly, Sirdhar's saying that he hopes to eventually bring the cost of the box down to $2,000 from the current level of $800,000. With a total investment of $10,000, eBay's reported savings of $100,000 over 9 months is an incredible return. Obviously the question is whether they can bring the costs down to anywhere near that level remains to be answered and the answer may be a number of years away, but just based on the potential, it certainly seems promising.
     
  3. slippingaway

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    He didn't say he'd bring the commercial version down to $2,000, he said that he wants to bring a residential model down to $2,000. People with inventions like this are very specific in what they say and how they say it, you have to be very careful when you're interpreting it. They will say anything they can to make themselves sound amazing, while stopping just short of lying.

    I'm not saying these things won't ever work, there's just a lot of work to be done to bring materials and manufacturing costs down to a level where they will make sense. There will also be a lot of work to be done on the power grid if people start pumping excess energy back in to the grid from their homes. Our power infrastructure is not set up to take any sizable amount of energy back from residences. I can get into more detail on that if you want in a PM, I have an Electrical Engineering degree, with a specialty in Power Transmission and Generation.
     
  4. PewPewPow

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    So this may seem more political than scientific but this seems to be the only relevant thread on the board. I'm wondering what peoples' opinions are of the "Zeitgeist" movies are. Is any of the research factual? I'm not interested in the 9/11 conspiracy crap more the religion and financial stuff.
     
  5. Solaris

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    Surely the 9/11 crap is a clue to the credibility of the rest of it.
     
  6. scotchcrotch

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    Why do farts in the shower always smell 10x worse?
     
  7. Maltob14

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    Assuming you take hot showers, it's basically like steamed vegetables. Regular broccoli smells bad and steamed broccoli smells like ass. Same applies for farts. Especially if you've eaten broccoli.
     
  8. Rush-O-Matic

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    Two unauthoritative sources:
    http://www.heptune.com/farts.html
    http://www.answerbag.com/q_view/18072

    It's curious that neither of these accounts for the lack of filtering effect normally created by wearing underwear and pants. Surely, someone has done a master's thesis on this.
     
  9. PewPewPow

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    i=I think it has something to do with the gases forming hydrogen bonds with the water molecules in the air. It just smells worse because it's not dissipating as quickly.
     
  10. The Dread Pirate

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    I'm doing a research paper for one of my classes on the British Medical Journal's retraction of the study that falsely linked the MMR vaccine with autism. Does anyone know where I can find some books that discuss the peer review process (exactly how it works, pitfalls, bias, etc)? From reading The Last Psychiatrist's blog it seems that the system sucks, but most of what I've found online is extremely basic and offers little commentary about any sort of internal politics or what happens behind closed doors.

    The one good source I've found so far is James Franklin's book What Science Knows: And How It Knows It.
     
  11. fourtytwo

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    I suspect you've found this article already, but if not I think it's probably pretty good. That site will also give you a lot of information about the whole MMR-Autism debacle as well -- probably too much information, actually.
     
  12. Stealth

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    Book :
    Peer review : a critical inquiry / David Shatz.
    Published Lanham, Md. : Rowman & Littlefield, c2004.

    You can find journal articles on the subject by doing a search in the Medline medical database or its equivalent, PubMeb (thats free for anyone to access online)
     
  13. Stealth

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    Why do farts in the shower always smell 10x worse?

    The increased humidity in the air "wets" the molecules, making it easier for you to smell them , the humidity becomes a medium with which the fart gasses can interact with your smell sensors.
     
  14. Rush-O-Matic

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    I didn't see this posted elsewhere.

    http://www.physorg.com/news189753348.html

    This dude is going to attempt to skydive from space. The attempt includes trying to be the first to break the sound barrier in a fall. From space. None of the articles explain how this will work -- not the suit, but the ability to go faster than terminal velocity.

    Can someone explain to me how he will be able to go faster than 125 mph? The speed of sound is around 750 mph, right? And, I believe, terminal velocity is reached when the pull of gravity on a person's mass can't overcome the drag of air friction against the surface area anymore. So, is he going to be so high, that the air is too thin to act as a brake? Meaning that once he gets closer to earth, he will start slowing down?
     
  15. Obviously5Believer

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    [​IMG]

    Your error is in thinking that terminal velocity is set in stone. Terminal velocity is a function of mass, gravity, the drag coefficient, density of the medium, and cross-sectional surface area. It can change with any one of these factors. Of course, the ones we are concerned with are drag, density, and surface area.

    You know in Point Break where Johnny Utah dives head first out of a plane and catches up with Bodhi by pointing his body straight down? Same principle. The terminal velocity of a ski-diver in the standard free fall position is indeed around 125 mph. In the upper atmosphere where the air is incredibly less dense, with a million dollar suit designed to decrease drag as much as possible, and by limiting the area of his body that is exposed to the oncoming air, he may very well be able to break the sound barrier. If I'm not mistaken the current record for unaided freefall was set a long time ago and is around 600 mph.
     
  16. Stealth

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    So I guess the free falling dude should produce a sonic boom when he breaks the sound barrier , but the boom will be directed into space due to the direction of his fall.
     
  17. Crazy Wolf

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    Would it be seen as cheating to carry a chunk of metal, shaped to be aerodynamically accommodating?
     
  18. fertuska

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    Fever is just one part of our body's effort to fight infection, and as has been said before, it's purpose isn't entirely clear. The most often quoted reason is slowing of viral/bacterial replication (a lot of bacteria have a narrow set of conditions they really love, such as a certain pH or temperature, so the body tries to change the temperature to basically screw the bacteria up), so that our immune system has more time to clear the infection. There are also thoughts on increased temperature making it easier for our immune cells to work, or making us tired and forcing us to rest (which gives the body more energy to spend on fighting the infection).

    The reason to decrease fever is to stop it from getting too high (maybe your doc was worried about that?), which can happen fairly rapidly with certain infections, and sometimes without you noticing. Another reason is to increase comfort, and I suspect that is why you have been told to take Advil. Advil (and all the other drugs), however, has many other effects on the immune response besides lowering temperature. It relieves pain and stops inflammation, both of which are also part of our immune response. But getting rid of them provides significant comfort. But remember, in order to completely suppress our body's efforts to fight infection, you'd have to be taking horse doses of Advil, and by then your main worry would be overdose, not a supressed immune response.

    In summary: yes, taking Advil (or any other NSAID) "harms" our body's natural immune response (which is way more complicated than a fever). However, it greatly increases comfort and prevents the fever from running too high and our own body damaging itself by an exaggerated immune response. We've all been taking NSAIDs for years now, and we're still here - our bodies can clearly fight infection very well even with a lower temperature, and with less inflammation and less pain. So basically you can suffer for 5 days, or you can take Advil for 6 days and be much happier.

    Credentials: I haven't failed out of med school yet.
     
  19. Backroom

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    Hey guys, I'm posting this in 2 different threads because I'm not sure where it goes but... One of my roommates works in a bar and for some reason, said bar had cases of beer from 9 months- 15 months ago (past the "sell-by" date. They range from hard cider to regular beers. Is there any harm in drinking them? I was told they were never cooled (and then warmed, thereby skunking them) I don't want to turn down beer, but I also don't want to wage a jihad on my colon. Thanks.
     
  20. Spoz

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    Edit: Preface: I am not a scientist.

    It supposedly isn't the cooling and warming of beer that does it any damage, but rather exposure to light. I first noticed this with some leftover beer I forgot about after a party. The cased beer was fine, but the few six-packs of the same batch I had sitting out, in the same place, were not. I've never experienced skunking from rechilling warm beers. A quick google tells me that kegged beer goes through a different pasteurisation process and warming/recooling can damage it. I hope this gives you something to go on until a real scientist can explain the beer skunking reaction.