A strong and silent hydrogen-powered artificial muscle that is equivalent in size and power to human muscle has been created by scientists.
"People are trying to use metal hydrides as hydrogen storage devices. What we did was use metal hydrides to create a new artificial muscles," Discovery News quoted Kwamg Kim, a professor at the University of Nevada in Reno, as saying.
Metal hydrides are extremely porous metals that lock onto and hold hydrogen gas at lower pressures and temperatures than is possible with cold and highly compressed pure hydrogen gas.
Kim and colleagues used a metal hydride made from nickel, copper, calcium and manganese to hold the hydrogen.
Once the metal hydride is full of the gas, it has to be released - providing the muscle's power source.
"Heat it up and hydrogen comes out, cool it down and the hydrogen goes back into the metal hydride," said Kim.
Kim used a thermoelectric device, which takes electrical energy and converts it into heat, to control the release of the gas.
As the device heats up and more hydrogen is released, the gas expands, pushing outwards and moving whatever object is attached to the muscle.
During recent lab tests the two-ounce artificial muscle, about six inches long and less than half an inch thick, lifted over 60 pounds in less than two minutes.
The artificial muscle also contracted between 15 and 30 percent of its total length, which is about the same as most human skeletal muscle, which contracts between 15 and 20 percent of its length.
The new research has been published in the journal Smart Materials and Structures.