The University of Leeds now has one of the largest teams in the world and the only group in the UK working on these 'nanofluids'.

The fluids could open the door to the next generation of computers, by overcoming one of the main limitations on developing smaller microchips: rapid heat dissipation.

During critical surgery, nanofluids could be used to cool the brain so it requires less oxygen and thereby enhance the patient's chance of survival and reduce the risk of brain damage. They could also be used to produce a higher temperature around tumours to kill cancerous cells without affecting nearby healthy cells.

Dr Ding said: "With the strong research team here at Leeds we have considerable expertise in developing nanofluids and already have a number of prototypes under investigation. We are looking to characterise these fluids so we fully understand their heat conductive properties under static and dynamic conditions in both large and micro channels."

The researchers are talking to industrial partners about moving towards large-scale production.

In Togo, authorities imported hundreds of thousands of pairs of special glasses that consumers cleared rapidly from shelves in the capital, Lome. Villagers in the interior will not have access to the eyewear and officials called on them to stay home.

"Please, do not go out and keep your children indoors on solar eclipse day," Togo's minister for health said in a message broadcast on state television.

Day will turn to night in the eclipse's route and a corona - the usually invisible extended atmosphere of the sun - will glow around the edges of the moon as it comes between the earth and the sun.

"Imagine if your hair was to stand up from static electricity, that's kind of what the corona looks like all around the sun," NASA's Young said. But the corona's light can burn eyes.

In Ghana, where the effect will be particularly visible, people were spending about $1 for "solar shades" - paper-rimmed glasses with dark plastic lenses that resemble eyewear used for viewing three-dimensional movies.

NASA said Turkey will be the best spot to view the eclipse, and tens of thousands of tourists were expected along the Turkish Mediterranean coast. Astronomers from NASA and Britain's Royal Institute of Astronomy were also going to an ancient Roman amphitheater in Turkey to view the phenomenon.

The moon is expected to first begin blocking out the sun in the morning in Brazil before the eclipse migrates to Africa, then on to Turkey and up into Mongolia, where it will fade out with the sunset.

Superstition will follow around the world, as it has for generations.

One Indian paper advised pregnant women not to go outside during the eclipse to avoid having a blind baby or one with a cleft lip. Food cooked before the eclipse should be thrown out afterward because it will be impure and those who are holding a knife or ax during the eclipse will cut themselves, the Hindustan Times added.

Total eclipses are rare because they require the tilted orbits of the sun, moon and earth to line up exactly so that the moon obscures the sun completely. The next total eclipse will occur in 2008.