Thursday, September 09, 2010

Swarming Robots Autonomously Absorb Hard-to-Reach Oil

    Swarming Robots Autonomously Absorb Hard-to-Reach Oil
  • A team of scientists has developed autonomous robots that swarm to collect oil together. Armed with solar cells, GPS and nanowire filters, the robots could quickly clean oil spills.
  • A team of scientists has developed autonomous robots that swarm to collect oil together. Armed with solar cells, GPS and nanowire filters, the robots could quickly clean oil spills.Recently at Smarter Technology, we've brought you stories on several solutions about cleaning up the oil leftover from the Gulf of Mexico spill—everything from a military decontamination system to biotech solutions like natural fibers. A team of researchers at MIT is working on another promising oil-cleaning technology: an autonomous robot. Called the Seaswarm, the robot combines several promising technologies—including solar cells, GPS, WiFi and a nanowire filter—to become one of the most capable oil-fighting tools out there.

    The Seaswarm robot combines several technologies to efficiently collect oil (source: MIT). 
A 'Paper Towel' for Oil Spills
The basic technology behind the Seaswarm is a nanotech membrane developed by MIT engineers in 2008. Made of nano-sized wires, the material has the touch and feel of paper, but can absorb up to 20 times its weight of oil and other organic pollutants.
"What we found is that we can make 'paper' from an interwoven mesh of nanowires that is able to selectively absorb hydrophobic liquids—oil-like liquids—from water," said Francesco Stellacci, an associate professor in the Department of Materials Science and Engineering and leader of the work, according to a 2008 MIT press release.

Although it looks like paper, the material can absorb 20 times its weight of oil (source: MIT). 
The material consists of spaghettilike strands of nanowires, which have many tiny pores. Coated with a hydrophobic covering, the material does not soak up water, but will absorb all water-repellant substances. "Our material can be left in water a month or two, and when you take it out it's still dry," Stellacci said. "But at the same time, if that water contains some hydrophobic contaminants, they will get absorbed."
The nanowires are made from potassium manganese oxide, a heat-stable material. This property allows the material to be brought to high temperatures at which oil will boil away and condense elsewhere. Both the membrane and the oil can then be reused.

Porous nanowires absorb oil but repel water (source: MIT).
Joerg Lahann of the University of Michigan wrote a positive review of the research: "Stellacci and co-workers have provided an example of a nanomaterial that has been rationally designed to address a major environmental challenge."

The Water Tank
The scientists fashioned the nanowire material into conveyor belts, which are threaded into the Seaswarm robot. The belt, like that of a military tank, constantly rotates to propel the robot over the surface of the water. It soaks up oil as it moves. Because the material is hydrophobic, water is pushed away from the machine, allowing it to stay afloat.
Along with its conveyor belts, the Seaswarm robot also has a head that is covered with solar cells. The photovoltaic cells can power the machine for several weeks as it moves across water. The flexible conveyor belt easily adapts to changes in the water's surface, such as waves, to keep the head maximally exposed to the sun.

The Seaswarm was successfully tested in Boston's Charles River (source: MIT). 
A major advantage to the Seaswarm's design is its size. Current methods of oil collection—like fishing boats with skimmers attached—are large and unwieldy. The robot, however, is a svelte 7 by 16 feet. This small size allows it to clean hard-to-reach places where oil can collect, such as coastlines, marshes and estuaries.
An Oil-Soaking Swarm
The Seaswarm, aptly named, is intended to work as a fleet, or "swarm," of robots. Machines are outfitted with GPS and WiFi, tools that allow them to communicate with one another for cleanup organization. Unlike other cleaning methods, the robots are autonomous and do not require human involvement.
"Seaswarm works by detecting the edge of a spill and moving inward until it has removed the oil from a single site before joining other vehicles that are still cleaning," according to a statement on the project's Website.

The robots are equipped with communication tools like GPS and WiFi so they can coordinate for cleanup (source: MIT). 
Because its nanomaterial is highly absorbent and its power source is unlimited, the robot does not need to make repeated trips to the shore. Time, money and the environment are all saved by the highly efficient machine.
In August 2010, the first Seaswarm prototype completed a test run on the Charles River in Boston. The project's Website reports successful outcomes from the conveyor belt and solar cells.

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