The guilt-free air conditioning, called "cooling paper," is made from recyclable paper and doesn't use any electricity.
This article was originally published on our sister site, Freethink.
Air conditioning is something you barely notice — until the power goes out, and it no longer works. But what if keeping cool didn't require electricity at all?
A scientist has invented a material that reflects the sun's rays off rooftops, and even absorbs heat from homes and buildings and radiates it away. And — get this — it is made from recyclable paper.
The essential AC: Air conditioners are in 87% of homes in the United States, costing the homeowner $265 per year, on average. Some homes can easily spend twice that.
With global temperatures on the rise, no one is giving up their AC. More people are installing air conditioners than ever before, especially in developing countries where the middle class can finally afford them. 15 years ago, very few people in China's urban regions had air conditioners; now, there are more AC units in China than there are homes.
But AC has drawbacks: it's expensive, and it takes a ton of electricity, which usually comes from fossil fuels, causing air pollution and global warming.
No electricity required: Yi Zheng, an associate professor of mechanical and industrial engineering at Northeastern University, calls his material "cooling paper."
He hopes that people everywhere will wrap their houses in the cooling paper one day, reports Good News Network. In addition to the cooling benefits, the paper doesn't require any electricity, and it is 100% recyclable.
The paper can reduce a room's temperature by up to 10 degrees Fahrenheit, making it a radical but effective alternative to today's air conditioners, which consume a lot of power.
How to make "cooling paper": I remember making paper as a kid by soaking newsprint, shredding it in the blender, and rolling the slurry flat while pressing out the water. Zheng's technique isn't any more advanced than my 4th-grade science fair project. Except instead of pressing flower petals into his pulp, he mixed it with the material that makes up Teflon. The "porous microstructure of the natural fibers" inside the cooling paper absorbs heat and transfers it away from the house.
Zheng even tried recycling his cooling paper to remake a new sheet and found that it didn't lose any cooling power in the process.
"I was surprised when I obtained the same result," Zheng said. "We thought there would be maybe 10 percent, 20 percent of loss, but no."
Scientists created the mineral lonsdaleite in a lab and tested its strength using sound waves — before it was obliterated.
This article was originally published on our sister site, Freethink.
Diamonds may be a girl's best friend because of their shine and glam, but they are also helpful in practical ways. The superstrong mineral is used as an industrial abrasive, on the edges of cutting tools, or on ultra-powerful drill bits.
Whether they are used for adornment or tools, diamonds aren't cheap. Scientists have long hoped to find a way to create a material that is as strong as diamonds. Now they may have something better.
It is believed that lonsdaleite, also called hexagonal diamond, is even stronger than diamond. But the rare six-sided crystalline mineral has seldom been found in nature — generally only at meteorite impact sites — and only in sample sizes that are too small to be measured.
Its exact hardness remained unknown — until now.
Researchers from Washington State University's Institute for Shock Physics have developed hexagonal diamonds large enough to study in a lab and test their stiffness and hardness.
"Diamond is a very unique material," Yogendra Gupta, director of the Institute for Shock Physics and an author on the study, said in a statement. "It is not only the strongest — it has beautiful optical properties and a very high thermal conductivity. Now we have made the hexagonal form of diamond, produced under shock compression experiments, that is significantly stiffer and stronger than regular gem diamonds."
Using gunpowder and compressed gas, Gupta's team launched dime-sized graphite disks at a transparent material at 15,000 miles per hour.
Upon impact, shock waves coursed through the disks, transforming them into lonsdaleite.
Measuring Strength With Sound
Sound travels more quickly via stiffer materials. So the researchers generated a small sound wave shortly after impact and used lasers to track its progress through the diamond. The lonsdaleite proved to be more stiff than diamond.
Since more rigid materials are generally harder and more resistant to scratching, they concluded that lonsdaleite is stronger than diamond — by 58%, a new record. They published their findings in Physical Review Letters.
"If someday we can produce them and polish them, I think they'd be more in-demand than cubic diamonds."
We don't need to worry that lab-created super-diamonds will make our precious jewels seem dull. The lonsdaleite only lasted a few nanoseconds before the high-velocity impact obliterated the gem — just long enough for the team to get their measurements. Gupta says if they can manage to keep them around longer, the rare, fleeting nature of the lonsdaleite could make them more valuable than cubic diamonds.
"If someday we can produce them and polish them, I think they'd be more in-demand than cubic diamonds," said Gupta. "If somebody said to you, 'look, I'm going to give you the choice of two diamonds: one is lot rarer than the other one.' Which one would you pick?"
Metal-like materials have been discovered in a very strange place.
- Bristle worms are odd-looking, spiky, segmented worms with super-strong jaws.
- Researchers have discovered that the jaws contain metal.
- It appears that biological processes could one day be used to manufacture metals.
The bristle worm, also known as polychaetes, has been around for an estimated 500 million years. Scientists believe that the super-resilient species has survived five mass extinctions, and there are some 10,000 species of them.
Be glad if you haven't encountered a bristle worm. Getting stung by one is an extremely itchy affair, as people who own saltwater aquariums can tell you after they've accidentally touched a bristle worm that hitchhiked into a tank aboard a live rock.
Bristle worms are typically one to six inches long when found in a tank, but capable of growing up to 24 inches long. All polychaetes have a segmented body, with each segment possessing a pair of legs, or parapodia, with tiny bristles. ("Polychaeate" is Greek for "much hair.") The parapodia and its bristles can shoot outward to snag prey, which is then transferred to a bristle worm's eversible mouth.
The jaws of one bristle worm — Platynereis dumerilii — are super-tough, virtually unbreakable. It turns out, according to a new study from researchers at the Technical University of Vienna, this strength is due to metal atoms.
Metals, not minerals
Fireworm, a type of bristle wormCredit: prilfish / Flickr
This is pretty unusual. The study's senior author Christian Hellmich explains: "The materials that vertebrates are made of are well researched. Bones, for example, are very hierarchically structured: There are organic and mineral parts, tiny structures are combined to form larger structures, which in turn form even larger structures."
The bristle worm jaw, by contrast, replaces the minerals from which other creatures' bones are built with atoms of magnesium and zinc arranged in a super-strong structure. It's this structure that is key. "On its own," he says, "the fact that there are metal atoms in the bristle worm jaw does not explain its excellent material properties."
Just deformable enough
Credit: by-studio / Adobe Stock
What makes conventional metal so strong is not just its atoms but the interactions between the atoms and the ways in which they slide against each other. The sliding allows for a small amount of elastoplastic deformation when pressure is applied, endowing metals with just enough malleability not to break, crack, or shatter.
Co-author Florian Raible of Max Perutz Labs surmises, "The construction principle that has made bristle worm jaws so successful apparently originated about 500 million years ago."
Raible explains, "The metal ions are incorporated directly into the protein chains and then ensure that different protein chains are held together." This leads to the creation of three-dimensional shapes the bristle worm can pack together into a structure that's just malleable enough to withstand a significant amount of force.
"It is precisely this combination," says the study's lead author Luis Zelaya-Lainez, "of high strength and deformability that is normally characteristic of metals.
So the bristle worm jaw is both metal-like and yet not. As Zelaya-Lainez puts it, "Here we are dealing with a completely different material, but interestingly, the metal atoms still provide strength and deformability there, just like in a piece of metal."
Observing the creation of a metal-like material from biological processes is a bit of a surprise and may suggest new approaches to materials development. "Biology could serve as inspiration here," says Hellmich, "for completely new kinds of materials. Perhaps it is even possible to produce high-performance materials in a biological way — much more efficiently and environmentally friendly than we manage today."
In paint form, the world's "whitest white" reflects so much light that surfaces become cooler than the surrounding air.
- Scientists at Purdue University announce the whitest white ever developed. It will be available as paint and a nanofilm.
- The new paint can actually cool surfaces on which it's applied, potentially reducing the need for climate-unfriendly air conditioners.
- This is the second whitest white to come from these researchers, and they believe this is about as white as any material could ever be.
A few years ago, researchers announced the development of the blackest black ever, a place where colors go to die. It was called Vantablack®, and it was so absorptive of visible light that only the tiniest amount escaped its surface to reflect back to our eyes. (All of that light energy is dissipated into the surrounding substrate, so Vantablack doesn't become hot.)
In a new paper published in the journal ACS Applied Materials & Interfaces, scientists at Purdue University announced BaSO4 (barium sulfate), the whitest white ever. BaSO4 is practically impervious to the colors of the visible spectrum. Even better, while it's a very cool invention in the colloquial sense, it's also cool in the thermal sense.
The coolest white
The infrared image on the right shows how a square of the super-white paint and the board on which it's painted — shown in a normal image on the left — are cooler than the surrounding materials.Credit: Purdue University/Joseph Peoples
Most outside paints actually warm the surfaces to which they're applied. While there are already some reflective paints on the market, they only reflect 80 to 90 percent of sunlight, not enough for a cooling effect.
By contrast, BaSO4 results in 98.1 percent of sunlight bouncing off. According to senior investigator Xuilin Ruan, "If you were to use this paint to cover a roof area of about 1,000 square feet, we estimate that you could get a cooling power of 10 kilowatts. That's more powerful than the central air conditioners used by most houses."
Ruan and his colleagues tested BaSO4 using thermocouples, high-accuracy devices that measure voltage to determine temperature. They found that at night, BaSO4 surfaces are 19° F. cooler than surrounding air. Under strong sunlight the effect is not quite so extreme, but still dramatic: 8° of cooling.
The researchers even found the paint works in cold weather. Testing it on a 43° F. day, the surface on which BaSO4 was painted was a brisk 25° F. Their tests also indicate that BaSO4 is hardy enough for outdoor conditions.
How the new white was developed
Xuilin Ruan and a square of BaSO4Credit: Purdue University/Jared Pike
Research in the field of radiative paint for cooling goes back to the 1970s, though Ruan's team has been working toward BaSO4 for only six years. Along the way, they analyzed over 100 reflective materials, trying them out in about 50 experimental formulations.
Lead author, postdoc Xiangyu Li explains, "We looked at various commercial products, basically anything that's white. We found that using barium sulfate, you can theoretically make things really, really reflective, which means that they're really, really white."
The whitest white paint before — developed by the same team just last autumn — depended on calcium carbonate, a compound commonly found in seashells, rocks, and blackboard chalk.
The team crammed as many tiny BaSO4 particles into the paint as possible. Says Li: "Although a higher particle concentration is better for making something white, you can't increase the concentration too much. The higher the concentration, the easier it is for the paint to break or peel off."
Another factor that makes the team's BaSO4 formulation so reflective is that the researchers used barium sulfate particles of many different sizes. When it comes to reflecting light, size matters.
Co-author and PhD student Joseph Peoples said, "A high concentration of particles that are also different sizes gives the paint the broadest spectral scattering, which contributes to the highest reflectance."
The team's formulation method, they report, is compatible with commercial paint production.
Cool support for the planet
Purdue has applied for patents relating to BaSO4, though there are as yet no plans to make it commercially available.
However, the sooner they release it, the better. Air conditioning currently accounts for 12% of U.S. energy consumption. Also, many air conditioners use hydrofluorocarbons (HFCs). While HFCs constitute just a small percentage of greenhouse gases, they trap thousands of times the amount of heat as carbon dioxide.
Therefore, BaSO4 can play a role in combating global warming by reducing energy consumption and the emission of HFCs.
Measuring a person's movements and poses, smart clothes could be used for athletic training, rehabilitation, or health-monitoring.
In recent years there have been exciting breakthroughs in wearable technologies, like smartwatches that can monitor your breathing and blood oxygen levels.
But what about a wearable that can detect how you move as you do a physical activity or play a sport, and could potentially even offer feedback on how to improve your technique?
And, as a major bonus, what if the wearable were something you'd actually already be wearing, like a shirt of a pair of socks?
That's the idea behind a new set of MIT-designed clothing that use special fibers to sense a person's movement via touch. Among other things, the researchers showed that their clothes can actually determine things like if someone is sitting, walking, or doing particular poses.
The group from MIT's Computer Science and Artificial Intelligence Lab (CSAIL) says that their clothes could be used for athletic training and rehabilitation. With patients' permission, they could even help passively monitor the health of residents in assisted-care facilities and determine if, for example, someone has fallen or is unconscious.
The researchers have developed a range of prototypes, from socks and gloves to a full vest. The team's "tactile electronics" use a mix of more typical textile fibers alongside a small amount of custom-made functional fibers that sense pressure from the person wearing the garment.
According to CSAIL graduate student Yiyue Luo, a key advantage of the team's design is that, unlike many existing wearable electronics, theirs can be incorporated into traditional large-scale clothing production. The machine-knitted tactile textiles are soft, stretchable, breathable, and can take a wide range of forms.
"Traditionally it's been hard to develop a mass-production wearable that provides high-accuracy data across a large number of sensors," says Luo, lead author on a new paper about the project that is appearing in this month's edition of Nature Electronics. "When you manufacture lots of sensor arrays, some of them will not work and some of them will work worse than others, so we developed a self-correcting mechanism that uses a self-supervised machine learning algorithm to recognize and adjust when certain sensors in the design are off-base."
The team's clothes have a range of capabilities. Their socks predict motion by looking at how different sequences of tactile footprints correlate to different poses as the user transitions from one pose to another. The full-sized vest can also detect the wearers' pose, activity, and the texture of the contacted surfaces.
The authors imagine a coach using the sensor to analyze people's postures and give suggestions on improvement. It could also be used by an experienced athlete to record their posture so that beginners can learn from them. In the long term, they even imagine that robots could be trained to learn how to do different activities using data from the wearables.
"Imagine robots that are no longer tactilely blind, and that have 'skins' that can provide tactile sensing just like we have as humans," says corresponding author Wan Shou, a postdoc at CSAIL. "Clothing with high-resolution tactile sensing opens up a lot of exciting new application areas for researchers to explore in the years to come."
The paper was co-written by MIT professors Antonio Torralba, Wojciech Matusik, and Tomás Palacios, alongside PhD students Yunzhu Li, Pratyusha Sharma, and Beichen Li; postdoc Kui Wu; and research engineer Michael Foshey.
The work was partially funded by Toyota Research Institute.