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A D V A N C E D

M A T E R I A L S

&

P R O C E S S E S |

A P R I L

2 0 1 6

7

EARLIEST GOLD COIN

CHANGES HANDS

An extremely rare version of the

first gold coin ever struck in human his-

tory was purchased from Austin Rare

Coins and Bullion, Texas, by an Austin

collector for a six-figure sum. The ob-

verse, or “heads” side of the coin, de-

picts a lion and bull confronting each

other. Instead of a reverse design, the

“tails” side shows two overlapping

squares, the double-incuse mark left

by the punch that was struck to force

the gold into the obverse die. Issued

by King Croesus in Lydia (now Tur-

key), the coin dates to approximately

560 B.C. and is preserved in near-mint

condition. While the earliest coins were

made from electrum, a naturally occur-

ring alloy of gold and silver, Croesus

abandoned the alloy in favor of pure

gold and pure silver. Soon afterward,

nearly every mint in the Greek and Per-

sian world began issuing pure metal

coins.

austincoins.com

.

MICRO AIR VEHICLE WINGS

SHAPE SHIFT ON THE FLY

Researchers from the Universi-

ty of Southampton, UK, and Imperial

College London designed bat-inspired

Are you working with or have you

discovered a material or its properties

that exhibit OMG - Outrageous

Materials Goodness?

Send your submissions to

Julie Lucko at

julie.lucko@asminternational.org

.

OMG!

OUTRAGEOUS MATERIALS GOODNESS

First gold coin ever struck. Courtesy

of PRNewsFoto/Austin Rare Coins

and Bullion.

Model car with carbon fiber roof and bat-

tery electrodes made of wood. Courtesy

of KTH.

membrane wings that can adapt in-

flight to the forces they experience. The

wings have no mechanical parts, but

instead function like artificial muscles,

incorporating electroactive polymers

that allow them to stiffen and relax in

response to an applied voltage. The

development paves the way for a new

class of unmanned micro air vehicles

(MAVs) with improved aerodynamic

properties, longer flight ranges, and

an economic advantage over current

models. “This is a paradigm shift in the

approach to MAV design,” notes Dr. Ra-

fael Palacios of Imperial’s department

of aeronautics. “Instead of a tradition-

al approach of scaling down existing

aircraft design methods, we constant-

ly change the membrane shape under

varying wind conditions to optimize

aerodynamic performance.” Some-

times as small as 15 cm across, MAVs

are increasingly used in a wide variety

of civil and military applications, such

as surveying remote and dangerous

areas.

www.southampton.ac.uk

,

www. imperial.ac.uk

.

WOOD-BASED CAR BATTERY

LIGHTENS THE LOAD

The world’s first model car with a

roof and battery made of a wood-based

carbon fiber composite was produced

jointly by Swedish researchers from the

KTH Royal Institute of Technology and

research groups Innventia and Swerea.

Although built on a toy scale, the pro-

totype vehicle represents a significant

step toward reducing vehicle weight

using renewable materials. The key in-

gredient in the carbon fiber composite

is lignin, a constituent of plant cell walls

and the second most abundant natural

polymer in the world, surpassed only

by cellulose. Lignin batteries can be

produced from renewable raw mate-

rials, in this case the byproduct from

paper pulp production. “The lightness

of the material is especially important

for electric cars because then batteries

last longer,” explains Göran Lindber-

gh, professor of chemical engineering

at KTH. “Lignin-based carbon fiber is

cheaper than ordinary carbon fiber.

Otherwise batteries made with lignin

are indistinguishable from ordinary

batteries.” Lindbergh says carbon fi-

ber bodywork and batteries eventually

could be combined to simultaneously

manage mechanical loads and store

electrical energy.

www.kth.se

.

Southampton-Imperial MAV. Courtesy of

University of Southampton.