Although propeller engines have higher energy efficiency than jet engines, their noise levels make them a poor option for firms trying to make greener aircraft. In US patent application 2008/0105781, however, Airbus suggests an aircraft with twin propellers mounted in noise-absorbing ducts on either side of the vertical stabiliser – well away from passengers’ ears.
Hotheads who taste-test spicy foods may be out of a job. Carbon nanotubes can now measure levels of capsaicin, the molecule that gives chillies their heat. An extract of a hot food is added to a circuit containing the nanotubes, which the capsaicin molecules preferentially stick…
