IEEE Spectrum February, 2014 - 45

reneWables
Their premise was that equipment to harness the sun's rays could be made very cheaply.
If the manufacturing costs could be kept low,
they reasoned, the price would be proportional to the mass and cost per kilogram of
the constituent materials. So the key would be
to use, as much as possible, stuff that is both
lightweight and inexpensive. What stuff? The
answer struck them as obvious. Solar energy's
future, to borrow a line from The Graduate,
could be summed up in one word: plastics.
Madrone and Griffith eventually got funding
from the Advanced Research Projects Agency-
Energy (ARPA-E) to work on better ways to
steer the mirrors of a solar-thermal-energy
plant. These mirrors focus sunlight throughout the day on towers containing steam-driven
generators. Mechanisms that accomplish that
task-called heliostats-have been around for
decades, but they are not cheap.
Madrone and Griffith realized that they
could cut down on the heft required of the
heliostats by using a huge number of small
mirrors to replace what would normally be
a smaller number of big ones. Small mirrors
hug the ground and thus carry smaller wind
loads. And small, light-duty heliostats could be
built from plastic, following an approach that's
similar to the way certain flowering plants
track the sun's daily movements. "Originally,
we were origami inspired, and now we're bio
inspired," says Madrone.
Her latest prototype aims a mirror by
varying the pressures within pneumatically
inflated plastic chambers, which can be massproduced with the same tooling used to make
plastic bottles. "If we keep using heliostats that
have been around for half a century, there's
no way the price is going to go down," says
Madrone. "If we don't start taking advantage
of new technologies, we're just going to lose
the solar game."
A typical workday for Madrone as she tries
to win that game might entail consulting with
outside experts, modeling electronics in SPICE
(Simulation Program with Integrated Circuit
Emphasis), writing reports for ARPA-E, laying
out a printed-circuit board, preparing a patent
application, or any combination of such tasks.
And she gets to do those things in historic surroundings: a building in San Francisco's Mission District that once housed a pipe-organ
factory. With antique organ pipes adorning
the walls and aging hardwood everywhere,

LEILa
MadROnE
IEEE Member
age 37
What she Does
investigates ways to
produce solar energy
cheaply.
For Whom
otherlab
Where she Does
it San francisco
Fun Factors
Her office appears in
the national register
of Historic Places.

the building retains a turn-of-the- is the nature of the people she's
20th-century air. Other projects
laboring alongside. "There's
being pursued there include in- this cultural bias that if you
flatable robots, form-fitting fuel want a hard-core engineering
company, everyone's got to
tanks for natural-gas cars, and an
be intense and aggressive and
electric cargo tricycle that lets the
arrogant and all of that," she
rider lean into turns.
says. "Here people are confident
The engineers at Otherlab have
but not arrogant, and thoughttried to preserve their building's
Arts and Crafts aesthetic, fore- ful instead of aggressive."
going steel desks for oak ones
Best of all for her, though, is
and using old library card cata- knowing that her designs could
have a real impact. "I think a
logs in place of the usual plastic
dream job is getting to work on
parts bins. Casual visitors could
something that is really relevant
easily imagine they've wandered
that you're passionate about evinto the mad inventor's lair from
a steampunk novel.
ery day," she says. "For me, that
Even more pleasant than the
is what the dream is."
ambiance, Madrone explains, - dav id schneider

Deep-earth
Detective

SiGnaLS SPeCiaLiSt karin SiGLoCH
ProBeS tHe PLanet'S DarkeSt SeCretS

i X t y- f i v e m i l l i o n y e A r s A g o , i n t h e w A n i n g
days of the dinosaurs, when India was still floating alone near
Madagascar, an upwelling of hot rock from deep in the Earth's
mantle called a plume broke through the continent, depositing a
2-kilometer-thick blanket of volcanic material that can still be seen
today. Then India migrated northeastward, eventually slamming into Eurasia. But
the plume stayed put. And as the Indian and African plates passed over it, it spawned
a chain of volcanic islands that now decorate the floor of the Indian Ocean. Today,
that plume sits under Réunion, a French island located east of Madagascar.
That's the hypothesis anyway. And Karin Sigloch is determined to test whether
it's true. She's a geophysicist at the University of Oxford, in England, where she
uses vibrations from earthquakes to image the planet's interior. By observing
the waves' arrival at recording stations called seismometers, she is able to model,
using supercomputers, how the waves slow and scatter as they travel through the
Earth, revealing hidden subterranean structures.
Her career may seem an unusual choice for an engineering major. But Sigloch believes she couldn't have found a job more thrilling. After all, she is illuminating the very
rock beneath our feet-a place just as dynamic and yet less studied than outer space.
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Table of Contents for the Digital Edition of IEEE Spectrum February, 2014