<%-- Page Title--%> Sci-Tech <%-- End Page Title--%>

<%-- Volume Number --%> Vol 1 Num 146 <%-- End Volume Number --%>

March 19, 2004

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Artificial ExoskeletonTakes The Strain

A human exoskeleton, which could help soldiers and fire-fighters carry heavy loads, is about to take its first public steps. Called the Berkeley Lower Extremity Exoskeleton (BLEEX), it is part of a Defense Advanced Research Projects Agency venture designed to help foot soldiers carry heavier loads over even longer distances, by connecting robotic supports to their legs to reduce the load. Besides helping soldiers, it could also assist medical personnel carrying wounded people from disaster areas or fire fighters in hauling heavy equipment up countless flights of stairs. A human 'pilot' straps the exoskeleton's legs to their own and dons a large rucksack, containing the engine, control system and space for the payload. Although the device itself weighs a hefty 50-kg, the pilot should not notice this because the machine takes its own weight. In addition, it will carry a 32-kg payload within the backpack, which, to the pilot, would feel as if carrying just 2 kilograms. The key element is that the pilot needs no joystick, keyboard or buttons to operate it, leaving your hands free for other tasks. This is because the entire control system is designed to ensure it moves in concert with the person wearing the exoskeleton. One simply pushes ones leg and it moves. To drive the powerful hydraulics necessary for heavy lifting BLEEX has a small purpose built combustion engine built into it. On a full tank the system should be able to run for as long as two hours.

Fighting Fire
With A Steam Machine

When used for boats, the engine works by injecting steam through a rear-facing, ring-shaped nozzle into a cylindrical chamber. As the steam emerges at three times the speed of sound, it rapidly condenses, generating a shock-wave that pulls in water through an intake and expels it from the rear, generating thrust. During the tests, a technician squirted water into it with a garden hose purely out of curiosity and to everyone's surprise, the water emerged as a jet of fine droplets that drenched anyone standing within 20 metres of it. The engineers later found that shock waves, generated as steam emerges from the nozzle, were breaking the water down into a fine spray, which was projected at high speed. The droplets in the spray are about 10 times the size of droplets in clouds, and this turns out to be within the optimum range for extinguishing fires. Moreover, chemicals injected into the unit mix rapidly with the water in the mist, and hence, the device will be useful for neutralising chemical spills or even disinfecting buildings or people after a biological or chemical attack.


Source: NewScientist.com


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