Engineering

Engine treatment can slash jet noise

There's a song anyone who lives near an airport or directly under the flight path of incoming and departing jets daily wishes they could play: Simon and Garfunkel's "The Sound of Silence."

Electronics & Semiconductors

Radiative cooler that cools down even under sunlight

Now that autumn is upon us, there is a large temperature gap between day and night. This is due to the temperature inversion caused by radiative cooling on the Earth's surface. Heat from the sun during the day causes its ...

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Pollutant

A pollutant is a waste material that pollutes air, water or soil, and is the cause of pollution.

Three factors determine the severity of a pollutant: its chemical nature, its concentration and its persistence. Some pollutants are biodegradable and therefore will not persist in the environment in the long term. However the degradation products of some pollutants are themselves polluting such as the products DDE and DDD produced from degradation of DDT

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