How Green is Your Car

How Green

The three-year investigation by Oregon-based CNW Marketing Research measures the environmental impact of cars from the time they’re built until the moment they’re scrapped. The results have revealed the dilemma faced by buyers looking for cars that are kinder to the environment, with supposedly ‘green’ cars finishing well down its final league table.

The new analysis extends from the car’s fuel consumption and CO2 emissions to the energy used in its design and production, both in car assembly plants and by suppliers of parts and sub-assemblies. Researchers also looked at the energy consumed in transporting the cars to dealers, as well as in maintaining, servicing and scrapping them.

The total amount is called the car’s ‘dust to dust’ energy use.
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According to CNW’s table of 96 cars sold in the UK, the Honda Civic Hybrid finished 73rd and the Toyota Prius 74th, even though they have some of the lowest CO2 emissions of any car and are usually regarded as the most environmentally friendly. Top of the table was the Jeep Wrangler, closely followed by the Toyota Echo – the American version of the Yaris.

via bog-brush

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Insect Flight

Insect Flight

Traditionally, scientists assumed that the basic physics of insect flight resembled the basic physics of human aviation.

For example, there’s an urban legend that many decades ago, scientists analyzed the plump bodies and stubby wings of bumblebees and concluded they were too heavy to fly.
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To fly, every moment (the insect) has to be constantly figuring out: ‘Am I yawing? Am I pitching? Am I rolling? Am I drifting backward? Am I falling? Am I rising?’ And all that information is constantly streaming into a brain the size of about a poppy seed. Understanding insect flight requires understanding how that little ‘computer’ works — and that’s just as essential as understanding how the wings work.

In the 1990s, experimenters using sensitive observational equipment and high-speed cameras discovered that a beating insect wing forms a swirling funnel of air — technically known as the leading-edge vortex, a kind of micro-tornado — just above, and clinging to, the upper part of the wing. Air pressure inside the vortex is lower than surrounding air, just as air pressure inside a tornado is lower than in surrounding air. Thus higher-pressure air beneath the bug wing pushes it upward, providing lift to the insect.

A stable leading-edge vortex, Ellington thinks, is what keeps most insects aloft. True, it doesn’t explain their aerial acrobatics, but another phenomenon, recently discovered by Michael Dickinson at the University of California at Berkeley, might help. At the end of each downstroke and upstroke–as it enters the turns of the figure eight–an insect wing rotates, shedding the leading-edge vortex. For an instant, the rotation accelerates the airflow over the top of the wing, thus generating a burst of even greater lift. By controlling the timing of those wing flips, the insect can steer the direction of the lift.
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With military funding, Ellington and Dickinson are both now trying to build flying microvehicles.

True flight is shared only by insects, bats and birds. Examples of other animals that are capable of soaring are flying fish, flying squirrels, flying frogs, and flying snakes.

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