En­gines de­vel­oped that run on spores and wa­ter

The China Post - - LIFE -

U.S. re­searchers said Tues­day they have de­vel­oped a way to har­ness wa­ter eva­po­ra­tion as a cheap and plan­et­friendly way of pow­er­ing en­gines.

A team from Columbia Univer­sity in New York and Loy­ola Univer­sity Chicago built tiny ex­per­i­men­tal gad­gets that op­er­ate au­tonomously in the pres­ence of mois­ture in the air.

The key, the team re­ported in the jour­nal Na­ture Com­mu­ni­ca­tions, is the use of another per­va­sive nat­u­ral re­source — bac­te­rial spores.

The harm­less spores puff up when ex­posed to wa­ter mol­e­cules and shrink when they are dry.

Like flex­ing and con­tract­ing bi­ceps, the move­ment can be ex­ploited to power ma­chines.

“Wa­ter in na­ture is in con­stant trans­for­ma­tion — that process has enor­mous power, enor­mous energy in it,” said lead au­thor Ozgur Sahin, an as­so­ciate pro­fes­sor of bi­o­log­i­cal sciences at Columbia.

“So far, we’ve been able to cap­ture energy as wa­ter comes down from the clouds, but we would like to cap­ture energy from eva­po­ra­tion, which makes wa­ter go into the air, into the at­mos­phere,” he ex­plained in a video dis­trib­uted by Na­ture.

“That process is very pow­er­ful, (but) we haven’t been able to cap­ture energy from that ef­fec­tively. Un­til now.”

The team built tiny en­gines made of thin plas­tic tape strips treated with spores, which they used to power a 100-gram (3.5-ounce) car and lightemit­ting diodes (LEDs).

Ex­posed to mois­ture, the spores ex­pand and the tape stretches.

But it con­tracts very quickly when the source of mois­ture is re­moved — an upand-down mo­tion that can drive wheels and pis­tons.

“When you com­bine many, many tapes to­gether, then you can in­crease the force they are pro­duc­ing,” said Sahin.

The team’s two cre­ations so far are an “eva­po­ra­tion en­gine” and a “mois­ture mill.”

The first is a type of bio-en­gi­neered “mus­cle” com­prised of a par­cel of spore­treated tape rib­bons en­cased by plas­tic walls and an open bot­tom over a con­tainer of wa­ter.

The tape “mus­cle” is con­nected to shut­ters at the top of the de­vice which open and close as the strips re­lax and con­tract.

The mois­ture mill, in turn, con­sists of a wheel with small wings of spore­treated tape all around it.

The wheel runs on an axle at­tached to a wa­ter-treated plas­tic cover over half the wheel, the other half is out­side in drier air.

With the spores in­side ex­pand­ing and those out­side con­tract­ing, a tiny mass im­bal­ance on the wheel causes it to turn for as long as the in­side is kept moist through eva­po­ra­tion.

The tech­nol­ogy is the lab.

But it may one day be used to power pros­thet­ics or ro­bot limbs, bat­ter­ies and gen­er­a­tors or in sports­wear that re­sponds to sweat — the more you per­spire, the more energy you pro­duce.

still very much in

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