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  Fuel cell - Wikipedia 

  http://en.wikipedia.org/wiki/Fuel_cell

  [ edit ] Efficiency [ edit ] Fuel cell efficiency The efficiency of a fuel is dependent on the amount of power drawn from it. Drawing more power means drawing more current, which increases the losses ... in the fuel cell. As a general rule, the more power (current) drawn, the lower the efficiency. Most losses manifest themselves as a voltage drop in the cell, so the efficiency of a cell is almost proportional to its voltage. For this reason, it is common to show graphs of voltage versus current (so-called polarization curves) for fuel cells. A typical cell running at 0.7 V has an efficiency of about 50%, meaning that 50% of the energy content of the hydrogen is converted into electrical energy; the remaining 50% will be converted into heat. (Depending on the fuel cell system design, some fuel might leave the system unreacted, constituting an additional loss.) For a hydrogen cell operating at standard conditions with no reactant leaks, the efficiency is equal to the cell voltage divided b   [More...] [Less...]

  First added: 20 September 2007, by: David Wiblin  [Report as spam]

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  Artificial intelligence - Wikipedia, the free encyclopedia 

  http://en.wikipedia.org/wiki/Artificial_intelligence

  The 800 million-Euro EUREKA Prometheus Project on driverless cars (1987-1995) showed that fast autonomous vehicles, notably those of Ernst Dickmanns and his team, can drive long distances (over 100 miles) ... in traffic, automatically recognizing and tracking other cars through computer vision , passing slower cars in the left lane. But the challenge of safe door-to-door autonomous driving in arbitrary environments will require additional research. The DARPA Grand Challenge was a race for a $2 million prize where cars had to drive themselves over a hundred miles of challenging desert terrain without any communication with humans, using GPS , computers and a sophisticated array of sensors. In 2005, the winning vehicles completed all 132 miles (212 km) of the course in just under seven hours. This was the first in a series of challenges aimed at a congressional mandate stating that by 2015 one-third of the operational ground combat vehicles of the US Armed Forces should be unmanned. [30] For   [More...] [Less...]

  First added: 16 November 2007, by: David Wiblin  [Report as spam]

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