Anti Depression Guide

Tunnelling through soft ground is relatively easy. Set a drilling machine to work in hard rock such as granite or basalt, though, and the rate of progress drops dramatically because of slow cutting speed and the increased rate at which drill bits wear out.

One way to speed up drilling would be to heat up the rock ahead, causing it to crack. Engineers have attempted to do this using gas jets, lasers and even electric heaters, but with little success, says Jacques Ouelett, a mining engineer at McGill University in Montreal, Quebec, Canada.

Instead, he suggests fitting a drilling head with a low energy microwave generator to heat rock just ahead of the drill bit. This fractures the rock efficiently making it much easier to cut.

Read the full microwave rock drill patent application.

Justin Mullins, New Scientist consultant

The quest for quieter aircraft has spurred the development of quieter engines. But one of the primary sources of noise during take off and landing is the airflow around the landing gear.

Airflow is quietest when it flows smoothly around an object and sticks closely to its shape. But landing gear prevents this and causes the flow to separate from the surface of the aircraft, causing turbulence and noise.

Now Thomas Flint at the University of Notre Dame in Indiana says it may be possible to encourage smoother flow by creating a plasma around the landing gear while it is down.

This is done generating a powerful electric field to ionise the air nearby. The plasma acts as a kind of buffer for the airflow, encouraging it to move around the gear more smoothly, thereby reducing noise, says Flint.

Read the fullplasma noise reduction patent application.

Justin Mullins, New Scientist contributor