Super-cooling nanofibre inspired by ants

‘PhysicsWorld: Cool’ Saharan ants’ silver hairs cause total internal reflection

From BusinessWire

The summer of 2023 was by far the hottest in history. People were seeking solace in air-conditioned spaces or donning cooling attire. Here’s some food for thought: Can buildings also be outfitted with similar cooling solutions?

Led by Professor Dehui Wan from the Institute of Biomedical Engineering at National Tsing Hua University (NTHU) in Taiwan, a research team drew inspiration from the silver ants inhabiting the Sahara Desert and created a biomimetic material called "super-cooling nanofiber."

Covering roofs with this thin, pliable, and durable fiber membrane, which is resistant to UV rays and acid rain, is like adorning buildings with cooling attire. This innovation can lead to a reduction of over 12˚C in indoor temperatures, resulting in significant savings in electricity costs. Furthermore, it aligns with the broader goals of energy efficiency, carbon reduction, and ultimately, the protection of our planet.

Professor Wan pointed out that Saharan silver ants manage to thrive in scorching temperatures of up to 70˚C primarily because of their triangular prism-like hairs. These hairs reflect a significant portion of the sunlight that hits them. Most of the absorbed energy from visible light is converted to longer wavelength infrared light, which is then emitted through the hairs, leading to an efficient cooling effect.

Taking cues from the hairs of these desert-dwelling ants, the research team embarked on a comprehensive exploration of diverse materials, configurations, dimensions, and hues. Using advanced optical engineering techniques, they employed ceramic materials to create white fibers measuring just a few hundred nanometers in diameter. These fibers possess the ability to reflect 97% of sunlight, resulting in a substantial cooling effect.

In the blistering sun, Professor Wan led his students as they conducted experiments on the roofs of campus buildings. They applied the super-cooling nanofiber membrane to the roofs of small-scale houses and used an infrared thermal camera to measure the temperature. This resulted in a notable decrease from 50˚C to 29˚C. Likewise, temperatures often rose to 60˚C inside a model car during the hot summer days. Yet, after applying the super-cooling nanofiber membrane, the temperature decreased by 17˚C.

The research team found that this innovative ceramic nanofiber doesn't just reflect sunlight; it also converts absorbed heat into infrared radiation, which passes through the atmospheric layer known as the "atmospheric window" and dissipates into the cold vastness of outer space, rather than being retained at the Earth's surface or in the atmosphere. This development holds promise for mitigating the greenhouse effect, providing a ray of hope in the battle against global warming.

The research project, led by NTHU in collaboration with National Taiwan University and National Yang Ming Chiao Tung University, achieved international recognition when it was published in the prestigious journal Nano Today in February 2023. The team is currently in the process of applying for twelve domestic and international patents for the super-cooling materials.

If we can cool houses using a nano-fibre cover, we'll be able to use less electricity for air conditioning.  Makes sense. 

The telephone of the future

 

First successful flight of Starship

 

SpaceX has successfully launched and landed Starship, without it blowing up.  It wasn't perfect: there was a methane fire after landing (soon extinguished); the rocket appears to have skipped a metre or so when it landed; and one of the Raptor engines appeared not to ignite.   

All the same, it was a magnificent achievement.  Remember, everything about this rocket is new technology: the methane Raptor engine; the use of steel as a construction material; and the "belly-flop" landing manoeuvre.  And they all worked.  In development, SpaceX started with the Starship upper stage first, because this was the hardest  part of the two-stage Super Heavy booster + Starship combo. The success of Starship brings the colonisation of Mars much closer, because SpaceX knows all about making re-usable boosters.  That's what the Falcon 9 rocket is.  

There is much further to go.  To make Starship truly re-usable, the ceramic tiles used as a heat shield must be easily replaceable.  Starship must demonstrate that it can return to Earth at orbital velocity without burning or breaking up.   But all the -out-there concepts that SpaceX pushed have been shown to work, at a cost 1 thousandth of current rockets, even before they are re-used.

Starship will change everything about space and a great deal about Earth.  Technology responds to need.  As Musk says, the colonisation of Mars will drive a forcing function in technologies, like genetic engineering, air and water purification, construction techniques, AI, to name just a few.  The most obvious right now is high speed internet access round the world via SpaceX's Starlink.  Here's an interesting article about that from The Economist.  Starlink is being used to fund Starship, but it's also being advanced by Starship because Starship will cut launch costs so much.

Here's The Guardian's take on the launch:

Success came on the 60th anniversary of the flight of first American in space, Alan Shepard. And it capped a stunning two weeks of achievements for SpaceX: the launch of four more astronauts to the space station for Nasa, the nation’s first night-time crew splashdown since the Apollo moonshots, and a pair of launches for its mini internet satellites.

Less than a month ago, Nasa chose SpaceX’s Starship to deliver astronauts to the lunar surface in the next few years. The $3bn contract was halted last week, however, after the losing companies – Jeff Bezos’s Blue Origin and Dynetics – protested against the selection.

And here's a video of the whole sequence from launch to landing, with however the sections where signal from the rocket was lost omitted:

Mobile phones

 

Today  in 1973  Martin Cooper of Motorola makes the first handheld mobile phone call to Joel S. Engel of Bell Labs.

On October 13, 1983, Ameritech Mobile Communications became the first company to launch a 1G phone network in the US, starting with Chicago. On March 13, 1984, the Motorola DynaTAC 8000x of Cooper’s call finally went on sale—for $3,995.

The 8000x wasn’t very mobile—it weighed almost two pounds and took ten hours to charge for thirty minutes of talk time.

(From A Brief History of the Smartphone)

Compare smartphones--a computer in your pocket--with the earliest mobile phone to remind yourself just how rapid technological advance can be.   Then think of how rapidly battery-pack prices have fallen; how EVs have moved from very expensive to price parity; how the cost of lifting a tonne of payload into low earth orbit has fallen 90% and will fall another 90%; how precision fermentation will slash the price of food, while drastically reducing food's environmental impact.