Hare and Turtle: The Tale

Hare and Turtle: The Tale

Dinosaur eel points to body armour of the future

An extraordinary fish that inhabits muddy pools in West Africa and whose lineage can be traced back 96 million years could be the model for light, bomb-proof body armour for the soldiers of the future.

So say Pentagon-backed scientists who have pored over the scales of Polypterus senegalus, also called the Senegal bichir or the dinosaur eel. Long and skinny and of ancient heritage, the 40-centimetre (16-inch) predator has multiple layers of scales that first dissipate the energy of a

strike, then protect against any penetration to the soft tissues below and finally limit any damage to the shield to the immediate area surrounding the assault.

Experts at the Massachusetts Institute of Technology (MIT) used nano-scale measurements to look at several scales that were harmlessly removed from a living fish. They found the scales — about 500 millionths of a metre thick — have four layers. The tiny shield was then put to the test, in a simulation of a biting attack.

The team believe the scales’ protection is remarkably effective because of the different composite materials, the geometry and thickness of each of these layers. The overlapping junctions between the layers themselves also play an important role.

The design is “fascinating, complex and multiscale,” say the scientists. “Such fundamental knowledge holds great potential for the development of improved biologically-inspired structural materials,” said Christine Ortiz, an MIT associate professor in materials science and engineering.

“Many of the design principles we describe — durable interfaces and energy-dissipating mechanisms, for instance — may be translatable to human armour systems.” The study appears on Sunday in a specialist journal, Nature Materials. afp

No hugs allowed at school

If you need a hug, you won’t get it at Percy Julian Middle School. Principal Victoria Sharts banned hugging among the suburban Chicago school’s 860 students anywhere inside the building. She said students were forming ‘hug lines’ that made them late for classes and crowded the hallways.

“Hugging is really more appropriate for airports or for family reunions than passing and seeing each other every few minutes in the halls,” Sharts said.

Another reason to institute the no-hugging policy was that some hugs could be too long and too close, she said. “There is another side to the issue when a hug is either unwanted or becomes inappropriate as judged by one of the students involved,” Sharts said. “On occasion, we do deal with those incidents. The goal is always to promote safe and orderly hallways where everybody can get by, be safe, and be on time.”