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6
Will a new ecological coating based on sharkskin
help the U.S. Navy increase the speed of its ships?
The new cover protects the hull (
scafo
) of ships
below the waterline, where algae, crustaceans
and other tiny ocean creatures attach themselves,
slowing ships and reducing their manoeuvrability.
“Algae really build up on ships in ports, where
ships spend most of their time,” says Anthony
Brennan, a University of Florida professor of
materials science and engineering and the inventor
of the new coating. Powerful paints such as
tributyltin (TBT) kill algae and other parasites,
but TBT is banned (
vietato
) by the International
Maritime Organisation (IMO) of the United Nations
because it is toxic. According to Susan Sang, a
Canadian toxicologist, TBT can cause mutations in
some insects and crustaceans.
The chemical also damages
the reproductive and immune
systems of fish, sea birds and
marine mammals.
The U.S. Navy used to
spray its ships with TBT, but it
no longer does. Although
military ships are exempt from
the IMO ban, the Navy stopped using
TBT many years ago and switched to copper-based
protective paints. “These paints are less harmful
than TBT, but they are still toxic,” says Sang.
To remove rather than kill algae, Brennan and
his colleagues have turned to nature. Sharks live
in the water all their lives but don’t have algae
problems because their skin is made up of tiny
rectangular scales covered with even smaller spines.
This irregular surface prevents algae spores from
attaching themselves to sharks.
With a combination of plastic and rubber,
Brennan has reproduced a version of shark skin
that is made up of billions of tiny diamond-shaped
patterns, visible under a microscope. The new
coating, called Gator Sharkote, is the safest and most
environmentally friendly anti-parasite paint in use.
It is also more effective than the old copper paints,
because it reduces by 85 percent the settlement of
spores from Ulva, one of the most common and
damaging types of algae.
Shark skin inspires new material
Reading
18
Leggi l’articolo. Poi abbina le due parti di ogni frase.
19
Leggi le frasi. Ascolterai una conversazione fra una persona che fa compere,
Liam, e un commesso, Nigel, su differenti tipi di scarpe. Decidi se ogni frase è corretta
o errata. Se è corretta, metti un tick (
3
) nel quadratino sotto la A per dire SÌ.
Se è errata, metti un tick (
3
) nel quadratino sotto la B per dire NO.
A
B
0
Liam is looking for heavy winter shoes.
1
He isn’t interested in coloured fabrics.
2
He doesn’t like the boots because they’re green.
3
The wellies are 100% rainproof.
4
Liam thinks the blue shoes are warmer than the boots.
5
According to Nigel, Gore-Tex is the most resistant material.
6
Sports shoes are sold at a reduced price.
0
The TBT paint
a
billions of diamond-shaped patterns.
1
The Gator Sharkote
b
a combination of plastic and rubber.
2
The U.S. Navy is currently using
c
a science professor.
3
The IMO banned
d
kills algae and other sea creatures.
4
Susan Sang is
e
copper-based paints.
5
Anthony Brennan is
f
TBT.
6
Shark skin is made up of
g
a toxologist.
7
The new coating is made from
h
is the most effective coating against Ulva.
8
The new coating is made of
i
tiny scales.
d
BACK TO SKILLS
20
PET
Listening
Part 4
ENGLISH TOOLS-Sec2-U4.indd 63
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