|BERKELEY, CA Researchers at the U.S. Department of Energy's
Lawrence Berkeley National Laboratory have demonstrated that
liquids known as ferrofluids, in response to magnetic fields,
can flow in any direction through soils of different
permeability to assume predetermined, uniformly distributed
Ferrofluids are colloidal suspensions of nanoscale magnetic
particles in a carrier fluid; the particles form magnetic
domains separated by coats of dispersant only a molecule thick.
These magnetic fluids have been used in many waysto form
airtight seals around rapidly moving parts, to move drugs in the
bloodstream and rocket propellants in spacecraft, even to cool
and dampen powerful audio speakers. Now steerable ferrofluids
may give rise to new tools for subsurface environmental
engineering and laboratory safety. "This is a way of controlling
the movement of fluids underground without direct physical
contact," says George Moridis of Berkeley Lab's Earth Sciences
Division, who has investigated ferrofluids with his col