He then tested how much friction there was when a ceramic ball and a polyethylene socket were immersed in a liquid with the same properties as synovial fluid.

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The concept is not that fanciful: after all, fluid-coupling flywheel devices, where a confined liquid does the job normally done by two abrasive discs as in a conventional clutch, have been used in many vehicles, including traditional London buses.

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Italian Environment Minister Corrado Clini said there was evidence that liquid was leaking from the ship, but he could not confirm whether the fluid was fuel.

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And at 1.8 fluid ounces, the whole thing comes in well under the TSA's carry-on liquid restrictions.

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