On Wed, 20 Sep 2006 21:10:03 -0500, Michael Leonhard wrote: > Please feel free to forward my replies to the mailing list. I suppose > I could have done this myself by replying to [EMAIL PROTECTED]
No, I need to reconfigure the mailing list to send replies to kragen-discuss, and reconfigure kragen-discuss to accept posts from kragen-tol (kragen-fw, kragen-hacks, kragen-journal) subscribers. > Perhaps flexibility in all directions is not required? I'm > imagining a closed cylinder, made of a stiff material with many > straight folds, allowing the cylinder to collapse and expand. Like > an accordion. Perhaps the machine could be manufactured in its > proper useful shape, and then collapsed via vacuum to a pocket size? > Then the user would release the vacuum and watch the machine > self-inflate and return to its rigid shape. It would be like a > flattened coke can where you crack open the lid to let the air in, > and watch as it returns to a proper coke-can shape. I guess this > would be a likely application of super-strong materials like carbon > nano-tube composites. That's an interesting idea. I wonder if it could work? I don't really know the math of how compressive strength (and in particular bending strength) changes as you increase the diameter of a tube while keeping its mass constant. > What material may be used for the hinges? It must be flexible at the > dimples/vertices. Well, the folds might be curves, like the surface of a saguaro or cholla cactus rather than creases, reducing the amount of flexibility needed from the material. > It would probably need extra internal pressure to be rigid enough. > Unless there was a very clever way to have the hard plates fit > together and lock in place. This sounds like a topic ripe for > research. But not by me; I'm no mathematician. :) I think that in order to interlock with one another like that, they would have to be thick enough at the interlock points that they would be quite heavy. Maybe I'm mistaken. > Powerisers look very cool! I wonder if one could use them every day > instead of a bicycle? I suppose they could cause health problems in > the legs over time. Bicycles sometimes cause health problems in the legs over time, too. If such a problem does arise, it might be possible to overcome it. > I wonder if they could improve the design to allow stability for > walking and standing? I definitely want to try Powerisers out once I > get a proper job and non-temporary health insurance. :) Heh, health-insurance moral hazard is real! :) The problem with stability is that you're standing on two points, rather than two whole feet, so without picking up one of them and moving it, there's no way to adjust your balance to keep from falling at right angles to the line between them. Walking is already stable, but standing is like treading water.
