articles

Designers of solar cells may soon be setting their sights higher, as a discovery by a team of researchers has revealed a class of materials that could be better at converting sunlight into energy than those currently being used in solar arrays. Their research shows how a material can be used to extract power from a small portion of the sunlight spectrum with a conversion efficiency that is above its theoretical maximum -- a value called the Shockley-Queisser limit. This finding, which could lead to more power-efficient solar cells, was seeded in a near-half-century old discovery by Russian physicist Vladimir M. Fridkin, a visiting professor of physics at Drexel, who is also known as one of the innovators behind the photocopier.

A new analysis suggests that massive earthquakes on northern sections of the Cascadia Subduction Zone, affecting areas of the Pacific Northwest that are more heavily populated, are somewhat more frequent than has been believed in the past.

The chance of one occurring within the next 50 years is also slightly higher than previously estimated.

The findings, published this week in the journal Marine Geology, are based on data that is far more detailed and comprehensive than anything prior to this. It used measurements from 195 core samples containing submarine landslide deposits caused by subduction zone earthquakes, instead of only about a dozen such samples in past research.

Manatee advocates are raising concerns about the number of these gentle giants who have been killed in Florida this year. They hope that increased vigilance and other measures will help keep this from being the worst year on record.

The Florida Fish and Wildlife Conservation Commission (FWC) has already counted 71 manatees killed by boats as of July 22. The numbers are already higher than they were for the same period in 2009, which was the deadliest year on record with a total of 97 deaths.

What connects Earth's largest, hottest desert to its largest tropical rain forest?

The Sahara Desert is a near-uninterrupted brown band of sand and scrub across the northern third of Africa. The Amazon rain forest is a dense green mass of humid jungle that covers northeast South America. But after strong winds sweep across the Sahara, a tan cloud rises in the air, stretches between the continents, and ties together the desert and the jungle. It’s dust. And lots of it.

For the first time, a NASA satellite has quantified in three dimensions how much dust makes this trans-Atlantic journey. Scientists have not only measured the volume of dust, they have also calculated how much phosphorus – remnant in Saharan sands from part of the desert’s past as a lake bed – gets carried across the ocean from one of the planet’s most desolate places to one of its most fertile.

Los investigadores en Abu Dabi están probando un dispositivo experimental que puede almacenar la energía solar en la arena para mejorar la eficiencia de las plantas de energía y proporcionar energía por la noche. La tecnología, desarrollada en el Instituto Masdar de Ciencia y Tecnología, utiliza la gravedad para drenar la arena de una cuenca más alta a una más baja y calentar los granos de arena con energía solar durante la transición