[MCTG] Fwd: 3D Printer: Tan Oak Logging Helicopter Balloon: MIT Discovery Strength Structure of Materials: Graphene, Polymers, Metals, Concrete.

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Date: 	Sun, 8 Jan 2017 15:36:33 -0800
From: 	Eric Sunswheat <eric.sunswheat at gmail.com>
Reply-To: 	eric.sunswheat at gmail.com

	


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Science Advances 06 Jan 2017:
Vol. 3, no. 1, e1601536
DOI: 10.1126/sciadv.1601536

http://advances.sciencemag.org/content/3/1/e1601536.full

Although the porous graphene assembly can likely (but not directly) 
substitute helium, its material features, including its ultralight 
nature, outstanding mechanical properties, high surface area, and stable 
chemical and thermal properties, remain promising for many engineering 
applications, making products lighter and stronger, which can thereby 
play a profound game-changing role in broad industrial areas. Using the 
knowledge learned from the current study that the natural curved 2D 
surface of graphene is disadvantageous to the mechanics of the 3D 
assembly, we are working toward further designing and optimizing the 
structure of these porous materials by tuning the surface chemistry of 
graphene and combining the 2D material with other polymers for a more 
efficient use of the material and to derive improved mechanical scaling 
laws. The combination of a theoretical model and computational 
simulations provides a powerful tool to explore these opportunities for 
carbon material designs.

http://www.upi.com/Science_News/2017/01/06/MIT-scientists-create-super-strong-lightweight-3D-graphene/9871483738388/

"One of our samples has 5 percent the density of steel, but 10 times the 
strength," research scientist Zhao Qin told MIT News.

Computer models allowed scientists to study each material's structural 
form and simulate its response to loading. The findings suggest a 3D 
material's tensile and compressive properties are dependent on the 
geometry of its structure, not the strength of the 2D material from 
which it is derived.

"You could either use the real graphene material or use the geometry we 
discovered with other materials, like polymers or metals," explained 
Markus Buehler, the head of MIT's Department of Civil and Environmental 
Engineering. "You can replace the material itself with anything. The 
geometry is the dominant factor. It's something that has the potential 
to transfer to many things."

http://www.techtimes.com/articles/191674/20170107/mit-researchers-develop-porous-3d-graphene-10-times-stronger-than-steel-but-lighter.htm

For the current study, the researchers decided to analyze graphene down 
to individual atoms in its structure and they were able to come up with 
a mathematical framework that closely matched observations in their 
experiments.

Combining heat and pressure, the researchers were able to compress 
graphene flakes, creating a strong, stable structure similar in form to 
microscopic creatures known as diatoms and certain corals. With a 
surface area enormous compared to its volume, the structure was proven 
to be remarkably strong.

"Once we created these 3D structures, we wanted to see what's the limit 
- what's the strongest possible material we can produce," said Zhao Qin, 
one of the study authors. <snip>

The researchers produced different 3D models in the process, which they 
all subjected to tests. In computational simulations, it was the 
graphene sample that resulted in a material that had 10 times steel's 
strength but had just 5 percent of its density.


      Applications

Graphene is just an atom thick but the geometry that gave its new form 
strength without added heft can also be used on large-scale structural 
materials, according to the researchers. For instance, concrete for 
structures like bridges can take on porous geometry to give it a boost 
in strength at just a fraction of added weight. As the form features 
airspaces within, it may also be used to improve insulative properties 
or as part of a filtration system for either chemical or water processing.

Recently, graphene also made news after researchers from Trinity College 
Dublin combined the material with Silly Putty to create a sensor that is 
sensitive enough to measure footsteps from spiders.

Called G-putty, the new material dramatically changes in electrical 
resistance with the slightest deformation or pressure. Specifically, 
just compressing or stretching it by 1 percent of its usual size will 
result in a shift in electrical resistance by a factor of five.

If other materials that can detect deformations were compressed or 
stretched at the same rate, just a 1-percent change in electrical 
resistance will be observed. This means G-putty has a sensitivity level 
500 times better than these materials.


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