Tag: allotrope

New laser-printed material is lighter than water, as strong as steel

Akshat RathiLeave a comment

Materials shape human progress – think stone age or bronze age. The 21st century has been referred to as the molecular age, a time when scientists are beginning to manipulate materials at the atomic level to create new substances with astounding properties.

Taking a step in that direction, Jens Bauer at the Karlsruhe Institute of Technology (KIT) and his colleagues have developed a bone-like material that is less dense than water, but as strong as some forms of steel. “This is the first experimental proof that such materials can exist,” Bauer said.

Material world

Since the Industrial Revolution our demand for new materials has outstripped supply. We want these materials to do many different things, from improving the speed of computers to withstanding the heat when entering Mars’ atmosphere. However, a key feature of most new materials still remains in their strength and stiffness – that is, how much load can they carry without bending or buckling.

All known materials can be represented quite neatly in one chart (where each line means the strength or density of the material goes up ten times):

Jens Bauer/PNAS

The line in the middle at 1000kg/m3 is the density of water – all materials to its left are lighter than water and those on the right are heavier. Few fully dense solid materials are lighter than water. Those that are tend to be porous, like wood or bone, and they exhibit exquisite structures when observed under a microscope, and they served as inspiration for Bauer’s work.

For many years, material scientists have thought that some empty areas on the compressive strength-density chart should be filled by materials that theory predicts. Computer simulations could be used to indicate an optimum microstructure that would give a material the right properties. However, nobody had tools to build materials with defined patterns at the scale of a human hair.

With recent developments in lasers and 3D printing, however, a German company called Nanoscribe started offering lasers that could do just what Bauer wanted. Nanoscribe’s system involves the use of a polymer that reacts when exposed to light and a laser that can be neatly focused on a tiny spot with the help of lenses.

A drop of a honey-like polymer is placed on a glass slide and the laser is turned on. A computer-aided design is fed into the system and the slide carefully moves such that the laser’s stationary focus touches only those points where the material is to be made solid. Once complete, the extra liquid is washed away, leaving behind materials with intricate internal structures.

However, these materials on their own are not as strong as Bauer wanted. So he coats them with a thin layer of alumina (aluminium oxide) before subjecting them to stress tests. Based on the tests, he was able to improve the theoretical models he used to design the internal structure of the materials. Their results were just published in the Proceedings of the National Academy of Sciences.

Even though alumina layers increase the density of these materials, all of them remain lighter than water. Bauer’s strongest material has a specific honeycomb internal structure and is coated with a 50 nanometre-thick (billionth of a metre) layer of alumina. It beats all natural and man-made materials that are lighter than 1000kg/m3, being able to withstand a load of 280MPa (mega pascals is a unit of measuring pressure), which makes it as strong as some forms of steel.

There are limitations. Nanoscribe’s system can only make objects that are tens of micrometres in size. “One of their newer machines can make materials in the milimetre-range, but that’s about it for now”, Bauer added. But that is not enough for any real-life application.

However, there have been rapid improvements in all the areas this work relies on: 3D printing, new polymers and laser technology. That means we may soon have a suite of new, super lightweight materials for everything from skis to aircraft parts. If nothing else, Bauer’s work shows that we are definitely in the molecular age.The Conversation

First published on The Conversation. Image credit: Jens Bauer.

We don’t value tinkering as much, but that’s what makes the world great

Akshat RathiLeave a comment

Review of The Tinkerers: The Amateurs, DIYers, and Inventors Who Make America Great by Alec Foege 

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The inventions of the late 19th and early 20th century that define our modern life were the result of America’s tinkering spirit, claims Alec Foege, an American journalist in his book “The Tinkerers”. That tinkering gave us airplanes, telephones, alternating current, light bulbs and air-conditioners.

America’s founding fathers like Benjamin Franklin and Thomas Jefferson, themselves inventors and scientists, infused this sense of tinkering right at the birth of the nation. But that can-do spirit has been replaced by hopelessness today. The stories of Alexander Bell and Thomas Edison made them heroes. But the mid-20th century needed more than one genius.

That pioneering need gave birth to innovative hubs like the Bell Labs, which invented semiconductor devices, or Xerox’s Palo Alto Research Centre, which built the first computer that used a mouse-based graphic interface. What made them special was that in these centres researchers were given a problem, plenty of resources and left alone to come up with a solution. Curiosity drove research rather than commercialisation. Karlheinz Bradenburg, the co-inventor of MP3 and a former Bell Labs employee, says: “It was like a university with famous professors, but no students”.

Foege argues that American culture is now focussed on efficiency and conformity rather than innovation. With the exception of Google and a handful of other firms, few companies embrace the spirit of tinkering.

But the tides are changing. The rise of the Internet has enabled these tinkerers to come together in larger numbers than ever before. The Do-It-Yourself (DIY) movement is America is larger than anywhere in the world, and it is growing rapidly. Make magazine, which started in 2005 with a focus on DIY projects, has over 125,000 subscribers today, and runs the hugely popular Maker Faire in many cities in America. Crowdfunding platforms like Kickstarter are enabling tinkerers to raise money from the public to support their innovative projects. There is even a Tinkering School that involves children to work on DIY projects over summer camps.

It will take time for new initiatives to show any change. In a 2012 survey of the most innovative countries of the world, America came tenth. And perhaps by limiting himself to America—and this is the only criticism of an otherwise well-written book—Foege has missed out on making an even stronger case for the spirit of tinkering. Nevertheless the stories of dabblers and hobbyists, of immigrants and natives, of dilettantes and experts, all living to pursue one dream makes for an engaging, entertaining and inspiring read.

Image credit: TODOIT

The 80-20 rule of scientific data loss

Akshat RathiLeave a comment

The Pareto principle, or more commonly known as the 80-20 rule, is quiet useful. It states that 80% of the effects come from 20% of the causes. It can be applied to all sorts of scenarios—80% of profits of a company come from 20% of its customers, 80% of sales come from 20% of the sales staff, and, also beyond business, 80% of healthcare resources are used by 20% of the patients.

There may now be a sort of 80-20 rule for scientific data loss, if this study in Current Biology can be replicated across different areas of science. In the study, the authors looked at 516 ecology papers between 1991 and 2011. They found that as the studies got older their failure rate of acquiring its raw data increased. In the end, nearly 80% of scientific raw data seems to have been lost after 20 years of a study being published.

Credit: Nature
Credit: Nature

We must remember, however, that this is the same period which saw the highest uptake of digital technologies by the scientific community. So it may mean that the 80-20 rule of scientific data loss may just apply to this period, or some period before and after it.

With better technology, more collaboration and cheaper storage, journals and scientists are both getting better at having access to data. While most data becomes useless after a while because of the nature of research, trying to keep all raw data accessible will mean that key data gets preserved.