They are lethal weapons that stags crash together when duelling. John Currey, from The University of York, UK, has been intrigued by the mechanical properties of bone for over half a century and has become fascinated by the mechanical properties of antler through a long-standing collaboration with Tomas Landete-Castillejos at the Universidad de Castilla-La Mancha.
'Antlers look as if they are dry,' says Currey, 'but no one knew if they really are dry when used in contests'. Curious to find out whether red deer antlers are used wet or dry when duelling, and how this affects the antlers' mechanical properties, Currey headed south to La Mancha to test the mechanical properties of red deer antlers and publishes the discovery that dry antler is stiff and tough on 27 November 2009 in the Journal of Experimental Biology at http://jeb.biologists.org.
But before the team could begin testing the antler's strength, they needed to find out how dry the bones were. Collecting freshly cut antlers from the university farm and a local game estate just after stags had shed the antler's protective velvet, Currey, Landete-Castillejos, José Estevez and their colleagues weighed the antlers each week to find out how much they dried. Amazingly, over the first 2 weeks, the antlers lost a colossal 8% of their weight, compared with 1% weight loss if they were cut at other times of the year. Eventually the weight loss stabilised and the antler's humidity was in balance with that of the surrounding air. It was clear that the antlers were dry when the stags began duelling.
But how did this water loss affect the bone's material properties in comparison with those of normal bones, which function internally and are always wet? Would the dry antler make a better weapon than wet bone?
The team prepared 40 mm long blocks of dry antler and wet deer femur and measured the amount of force needed to bend the blocks to find out how flexible the materials were. Even though most bones are relatively brittle and inflexible when dry, the team found that the dry antlers are almost as stiff as wet bone: which is ideal for weapons that have to survive a lengthy pushing contest after the initial clash.
But how 'tough' was the antler? How much energy could it absorb in the initial crash? Applying a force to the middle of the blocks of bone and gently increasing it until the bone broke, the team plotted a curve of the bending force against the amount that the bone bent. Calculating the amount of energy that the antler could absorb before shattering, Currey found that the tissue was incredibly tough: 2.4 times tougher than normal wet bone. And when Currey measured the amount of energy that the dry antler could absorb in an impact, he was surprised and pleased to see that it could survive impacts 6 times greater than the impacts that shattered wet femur. The dry antler was tougher than wet bone and ideally suited to survive the stags' initial clash.
So dry deer antlers are simultaneously stiff, yet tough, making them perfectly suited to their role as a weapon. And the deer seem to have solved a problem that has puzzled engineers for decades. 'It is very difficult to make anything that is both stiff and tough,' says Currey, but it seems that duelling deer solved the problem eons ago.
Scientists uncover the role of a protein in production & survival of myelin-forming cells
19.07.2018 | Advanced Science Research Center, GC/CUNY
NYSCF researchers develop novel bioengineering technique for personalized bone grafts
18.07.2018 | New York Stem Cell Foundation
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
19.07.2018 | Earth Sciences
19.07.2018 | Power and Electrical Engineering
19.07.2018 | Materials Sciences