Hot idea: Christina Galitsky's energy-efficient cookstove makes life a little easier for Darfur's refugees.

NEARLY THREE YEARS AGO, Christina Galitsky joined a team of scientists who had been asked an urgent question. Was it possible for researchers at California's Lawrence Berkeley National Laboratory (LBNL), where she is an engineer, to devise an expedient method for the displaced of war-torn Darfur to cook their meals?

For the more than two million people uprooted by Sudan's genocidal civil war since 2003, it is a life-and-death question. "The refugee women," says Galitsky, "had long ago exhausted supplies of wood near the [refugee] camps. As a result, they were forced to move farther and farther into the surrounding country in a search for cooking fuel." When they did …