Researchers at the Massachusetts Institute of Technology are trying to establish if energy from trees could be used to power a network of sensors that would help prevent spreading forest fires.

What they learn could also raise the possibility of using trees as silent sentinels along the nation’s borders to detect potential threats such as smuggled radioactive materials.

The US Forest Service currently predicts and tracks fires using remote automated weather stations. But these stations are expensive and sparsely distributed. Additional sensors could save trees by providing better local climate data to be used in fire prediction models and earlier alerts. However, manually recharging or replacing batteries at often very hard-to-reach locations makes this impractical and costly.

The new sensor system seeks to avoid this problem by tapping into trees as a self-sustaining power supply. Each sensor is equipped with an off-the-shelf battery that can be slowly recharged using electricity generated by the tree.

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Scientists from the University of Tokyo have developed a stretchy, rubbery material which is able to conduct electricity.

When the material, which comprises single wall carbon nanotubes, elastic resin and an ionic liquid, is attached to a grid of tiny transistors, it cab be stretched up to 2.34 times its original size, without adverse effects to the conductivity. Later it reverts to its original form.

A similar material was developed in 2005, but was only able to stretch 1.25 longer than its original size, and its conductivity limited to 10S/cm. The newly developed material has a conductivity of 57S/cm.

According to a paper published by the scientists working on the project, the material could be used to create flexible electronics, and there have been suggestions it could be used on the joints of a robot’s arm.

Researchers at Ohio State University have invented a new material designed to make cars more efficient by converting heat wasted through engine exhausts into electricity.

Scientists rate the efficiency of thermoelectric (TE) materials based on how much heat they can convert into electricity at a given temperature. To maximise the amount of electricity produced by a TE material, engineers would normally try to limit the amount of heat that can pass through it without being captures and converted to electricity. So the typical strategy for making a good TE material is to lower its thermal conductivity.

Project leader, Joesph Heremans took a different approach, focussing on how to convert the maximum amount of heat that was naturally trapped in the TE material. To do this he took embraced some new ideas in quantum mechanics.

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