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I'm far too dumb to select an appropriate category: Feynman

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    Scary, sounds like something from Nova or Joshs!
    http://www.steorn.com/forum/comments.php?DiscussionID=62105&page=5#Item_2
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      CommentAuthorGrimer
    • CommentTimeOct 26th 2009
     
    Waynegage is obviously someone who has been banned and is now reverting to his original handle. At a guess I would say it was nova. He is certainly ignorant enough.
    • CommentAuthornova
    • CommentTimeOct 26th 2009 edited
     
    Posted By: GrimerWaynegage is obviously someone who has been banned and is now reverting to his original handle. At a guess I would say it was nova. He is certainly ignorant enough.

    This is funny coming from a guy who thinks pre stressed concrete holds energy. There might be enough stored energy in the stressed rebars to light an led (momemtarily) but it would be very costly energy wise to extract that energy.
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      CommentAuthorGrimer
    • CommentTimeOct 26th 2009
     
    No one's proposing to extract it, you moron. There is enough energy to punch a very big hole right through you if you stood in front of one end and I released the wedges at the other. And the term "rebar" applies to reinforced concrete not prestressed concrete.
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    Posted By: nova
    This is funny coming from a guy who thinks pre stressed concrete holds energy. There might be enough stored energy in the stressed rebars to light an led (momemtarily) but it would be very costly energy wise to extract that energy.


    Hang on, I don't normally agree with Frank, but there can be an enormous amount of energy stored in the tendons used to provide the stress in pre stressed concrete. It's a big bundle of steel cables (i.e. a spring) stretched by some enormous hydraulic jacks and then wedged in place. Why would you think that this system doesn't contain energy?
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      CommentAuthorAngus
    • CommentTimeOct 26th 2009
     
    Posted By: hairykrishna
    Posted By: nova
    This is funny coming from a guy who thinks pre stressed concrete holds energy. There might be enough stored energy in the stressed rebars to light an led (momemtarily) but it would be very costly energy wise to extract that energy.


    Hang on, I don't normally agree with Frank, but there can be an enormous amount of energy stored in the tendons used to provide the stress in pre stressed concrete. It's a big bundle of steel cables (i.e. a spring) stretched by some enormous hydraulic jacks and then wedged in place. Why would you think that this system doesn't contain energy?


    I third that.
    • CommentAuthornova
    • CommentTimeOct 26th 2009
     
    Posted By: Angus
    Posted By: hairykrishna
    Posted By: nova
    This is funny coming from a guy who thinks pre stressed concrete holds energy. There might be enough stored energy in the stressed rebars to light an led (momemtarily) but it would be very costly energy wise to extract that energy.


    Hang on, I don't normally agree with Frank, but there can be an enormous amount of energy stored in the tendons used to provide the stress in pre stressed concrete. It's a big bundle of steel cables (i.e. a spring) stretched by some enormous hydraulic jacks and then wedged in place. Why would you think that this system doesn't contain energy?


    I third that.

    Why not harvest that energy?
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    Posted By: nova
    Posted By: Angus
    Posted By: hairykrishna
    Posted By: nova
    This is funny coming from a guy who thinks pre stressed concrete holds energy. There might be enough stored energy in the stressed rebars to light an led (momemtarily) but it would be very costly energy wise to extract that energy.


    Hang on, I don't normally agree with Frank, but there can be an enormous amount of energy stored in the tendons used to provide the stress in pre stressed concrete. It's a big bundle of steel cables (i.e. a spring) stretched by some enormous hydraulic jacks and then wedged in place. Why would you think that this system doesn't contain energy?


    I third that.

    Why not harvest that energy?


    Because you'd be better off using the energy you used to to tension the cables in the first place?
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    That energy can be and is harvested. Have you ever watched a controlled demolition of a prestressed concrete structure? Careful charge placement can cause disproportionate effects, due to the release of that stored stress energy.
    I think a lot of the dust produced when the WTC buildings came down was a result of such energy release. Not to mention the tremendous stored gravitational energy released (which was put in when all that stuff was hoisted up there in the first place.)
    • CommentAuthornova
    • CommentTimeOct 26th 2009 edited
     
    .
    • CommentAuthornova
    • CommentTimeOct 26th 2009
     
    Posted By: hairykrishna
    Posted By: nova
    This is funny coming from a guy who thinks pre stressed concrete holds energy. There might be enough stored energy in the stressed rebars to light an led (momemtarily) but it would be very costly energy wise to extract that energy.


    Hang on, I don't normally agree with Frank, but there can be an enormous amount of energy stored in the tendons used to provide the stress in pre stressed concrete. It's a big bundle of steel cables (i.e. a spring) stretched by some enormous hydraulic jacks and then wedged in place. Why would you think that this system doesn't contain energy?

    This is not the stored energy that Frank was alluding to in his previous claims. It had something to do with some kind of atmosphere or something Gamma or something.
    I know what stored energy is. When cutting into pipes there is a possibility of releasing stored energy and it could be a dangerous thing to do.
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    Posted By: nova
    This is not the stored energy that Frank was alluding to in his previous claims. It had something to do with some kind of atmosphere or something Gamma or something.
    I know what stored energy is. When cutting into pipes there is a possibility of releasing stored energy and it could be a dangerous thing to do.


    Franks gamma atmosphere stuff is normally his alternative 'explanation' of some physical phenomenon. It's important to distinguish between this and the phenomenon itself (or the accepted theory). I just had issues with your assertion that there was no, or very little, energy stored in a pre-stressed concrete system. I thought that Frank was referring to energy stored in the tendons; hence his references to releasing the wedges etc.
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      CommentAuthoralsetalokin
    • CommentTimeOct 26th 2009 edited
     
    The energy stored in those tendons is matched by a corresponding energy stored in the concrete itself. After all, the finished structure is static, therefore the tension in those steel members is balanced by compression zones in the concrete. I suppose.

    (Edit to add: I am just going on general principles here; I really don't know wtf I'm talking about wrt concrete. I'm sure Frank will be chortling in his beard if I make an error.)
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    Posted By: alsetalokinThe energy stored in those tendons is matched by a corresponding energy stored in the concrete itself. After all, the finished structure is static, therefore the tension in those steel members is balanced by compression zones in the concrete. I suppose.

    (Edit to add: I am just going on general principles here; I really don't know wtf I'm talking about wrt concrete. I'm sure Frank will be chortling in his beard if I make an error.)


    I think so. The idea is to put the concrete into compression after all. As you say, despite his wacky FE ideas, I have no doubt that Frank knows a lot more about concrete than us...
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    What I know about concrete was that it set before Frank just as it does today.
    IIRC Frank admits he was a paper pusher not a scientist from age 21 on.
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      CommentAuthorAngus
    • CommentTimeOct 26th 2009 edited
     
    Posted By: hairykrishna
    Posted By: alsetalokinThe energy stored in those tendons is matched by a corresponding energy stored in the concrete itself. After all, the finished structure is static, therefore the tension in those steel members is balanced by compression zones in the concrete. I suppose.

    (Edit to add: I am just going on general principles here; I really don't know wtf I'm talking about wrt concrete. I'm sure Frank will be chortling in his beard if I make an error.)


    I think so. The idea is to put the concrete into compression after all. As you say, despite his wacky FE ideas, I have no doubt that Frank knows a lot more about concrete than us...


    I think not. The forces balance but the energy is stored primarily in the elastic member, viz. the tendon. It is for the same reason that you pressure test scuba tanks with water (incompressible -if the tank fails the floor gets wet) not air (compressible-that is to say, elastic. If the tank fails there is an explosion).

    Torpedoes run on compressed air motors. There is a new car concept that works the same.
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    Posted By: Angus
    I think not. The forces balance but the energy is stored primarily in the elastic member, viz. the tendon. It is for the same reason that you pressure test scuba tanks with water (incompressible -if the tank fails the floor gets wet) not air (compressible-that is to say, elastic. If the tank fails there is an explosion).

    Torpedoes run on compressed air motors. There is a new car concept that works the same.


    Doh. Yes, that makes more sense, it's just like a stretched spring - the forces balance with the supports holding it but the majority of the stored energy is in the spring.

    Historic torps used compressed air but modern ones have all kinds of crazy systems and are pretty much rocket fuel burning!
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    Makes sense to me, too. Thanks.
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      CommentAuthorAngus
    • CommentTimeOct 27th 2009
     
    Posted By: hairykrishnaHistoric torps used compressed air but modern ones have all kinds of crazy systems and are pretty much rocket fuel burning!


    In the sense that the fuel and oxidiser are both present. The Russians got a little carried away with the Squall thing.

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