The bird demonstrates cutting-edge technology for devising self-folding nanoscale robots.
Cornell University has just announced what may be the smallest origami bird ever folded. While a typical origami animal is the product of an artist's dexterous hands, the Cornell bird was folded by the strategic application of small electrical voltages. It had to be: The material of which the bird is comprised is just 30 atoms thick.
Creative expression isn't the point of the university's little avian — its construction previews principles and techniques that will lead to new generations of moving, nano-scaled robots that "can enable smart material design and interaction with the molecular biological world," says Dean Culver of the U.S. Army Combat Capabilities Development Command's Army Research Laboratory, which supported the research.
According to Cornell's Paul McEuen, "We humans, our defining characteristic is we've learned how to build complex systems and machines at human scales, and at enormous scales as well. But what we haven't learned how to do is build machines at tiny scales. And this is a step in that basic, fundamental evolution in what humans can do, of learning how to construct machines that are as small as cells."
The lead author of the paper describing the tiny bird is postdoctoral researcher Qingkun Liu. The paper, "Micrometer-Sized Electrically Programmable Shape Memory Actuators for Low-Power Microrobotics," is the cover story of the March 17 issue of the journal Science Robotics.
A minuscule swarm of helpers
The project is the result of a collaboration between physical scientist McEeuen and physicist Itai Cohen, both of Cornell's College of Arts and Sciences. It's already resulted in a (very) small herd of nanoscale machines and devices.
Cohen explains, "We want to have robots that are microscopic but have brains on board. So that means you need to have appendages that are driven by complementary metal-oxide-semiconductor (CMOS) transistors, basically a computer chip on a robot that's 100 microns on a side."
The idea is that these minuscule workhorses—a metaphor, no nanoscale origami horses yet exist—are released from a wafer, fold themselves into the desired form factor, and then go on about their business. Additional folding would endow them with motion as they work, change shapes to move their limbs and manipulate microscopic objects. The researchers anticipate that these nanobots will eventually be able to achieve similar functionality to their larger brethren.
Credit: nobeastsofierce/Adobe Stock
How a tiny robot is made and works
The project combines materials science with chemistry, since the folding is achieved with the strategic deployment of electrochemical reactions. Liu explains, "At this small scale, it's not like traditional mechanical engineering, but rather chemistry, material science, and mechanical engineering all mixed together."
"The hard part," says Cohen, "is making the materials that respond to the CMOS circuits. And this is what Qingkun and his colleagues have done with this shape memory actuator that you can drive with voltage and make it hold a bent shape."
The bots are constructed from a nanometer-thick platinum layer that's coated with a titanium oxide film. Rigid panels of silicon oxide glass are affixed to the platinum. A positive voltage creates oxidation, forcing oxygen atoms into the platinum seams between the glass panels, and forcing platinum atoms out. This causes the platinum to expand, which bends the entire glass-platinum structure to a desired angle.
Because the oxygen atoms collect to form a barrier, a bend is retained even after the charge is switched off. To undo a fold, a negative charge can be applied that removes the oxygen atoms from the seam, allowing it to relax and unbend.
This all happens very quickly — a machine can fold itself within just 100 milliseconds. The process is also repeatable. The team reports that a bot can flatten and refold itself thousands of times, and all it takes is a single volt of electricity.
Artistry after all
None of this really removes what one might consider the artistry. Working out how and where to apply voltages to effect the desired shape is not a simple thing to do. McEuen says, "One thing that's quite remarkable is that these little tiny layers are only about 30 atoms thick, compared to a sheet of paper, which might be 100,000 atoms thick. So it's an enormous engineering challenge to figure out how to make something like that have the kind of functionalities we want."
Still, the group is getting quite good at microscopic robotics, and has already been awarded the Guinness World Record for assembling the smallest-ever walking robot. The little 4-legged dude is 40 microns wide and between 40 and 70 microns long. They're angling for a new record with their 60-micron-wide origami bird.
Says Cohen, "These are major advances over current state-of-the-art devices. We're really in a class of our own."
Researchers find a way to distort laser light to survive a trip through disordered obstacles.
- Lasers are great for measuring—if they can get a clear view of their target.
- In biomedical applications, there's often disordered stuff in the way of objects needing measurement.
- A new technique leverages that disorder to formulate a custom-made, optimal laser light beam.
Lasers can make amazingly precise measurements. Invaluable for precision construction and manufacturing, they also allow biomedical researchers and doctors to accurately detect the position and movement of microscopic objects, from cells to tissues to tiny biological structures. That is, when the laser can get a direct shot at the target, which is often not possible. In the human body, for example, these objects may be partially obscured by, situated in, or even behind complicated, obfuscating stuff.
Now scientists from Utrecht University (Netherlands) and TU Wien in Austria have devised a cool way to alter lasers so that they can bounce right through such distortion fields, arriving on the other side as an "optimal wave" intact enough to get to work.
Their new system is described in the journal Nature Physics.
Understanding the problem
Credit: gavran333/Adobe Stock
When working with lasers or any other measurement tool, "You always want to achieve the best possible measurement accuracy — that's a central element of all natural sciences," says paper co-author Stefan Rotter of TU Wien in a press release. A highly focused laser beam is an ideal tool for this. However, getting it through a disordered barrier without destroying the integrity of the beam is a challenge.
The researchers describe the problem using the example of the type of frosted glass one might encounter in a bathroom window. Explains Utrecht University's Allan Mosk, another co-author, "Let's imagine a panel of glass that is not perfectly transparent, but rough and unpolished like a bathroom window." To keep people from seeing into the bathroom, "Light can pass through, but not in a straight line. The light waves are altered and scattered, so we can't accurately see an object on the other side of the window with the naked eye."
This is not very different from what happens when a scientist tries to examine some tiny object inside biological tissue. The disordered stuff between the scientist and the object turns the concentrated laser beam into a complex wave pattern that scatters on its way through the visual barrier.
The new solution
Credit: TU Wien
The researchers have found that they can modify a laser's light in anticipation of the way it will travel through the disordered environment so that it hits its target on the other side with sufficient coherence for making accurate measurements.
While that optimal wave may not be a pure, pristine laser light, it's nonetheless just the light wave needed to successfully make its way through that particular barrier. The researchers were able to develop a mathematical procedure that gives them the distortion required to produce such a wave. Says first author Dorian Bouchet, also of Utrecht University, "You can show that for various measurements there are certain waves that deliver a maximum of information as, e.g., on the spatial coordinates at which a certain object is located."
Bouchet adds, "To achieve this, you don't even need to know exactly what the disturbances are. It's enough to first send a set of trial waves through the system to study how they are changed by [it]."
Returning to the glazed bathroom window example, the system would identify an optimal light wave that could travel through the disordered glass and still accurately measure movement of a person behind the glass.
Testing the system
The researchers confirmed that their formula worked in experiments at Utrecht in which they were able to make nano-scale measurements using a laser that successfully transited a turbid plate playing the role of a disordered medium. They also tried simpler and simpler laser beams—reducing the number of photons being used—to see how far they could push their system. They found that it even with the simplest laser possible, it still performed satisfactorily.
Says Mosk, "We see that the precision of our method is only limited by the so-called quantum noise. This noise results from the fact that light consists of photons—nothing can be done about that." Still, he says, "within the limits of what quantum physics allows us to do for a coherent laser beam, we can actually calculate the optimal waves to measure different things. Not only the position, but also the movement or the direction of rotation of objects."
Can computers do calculations in multiple universes? Scientists are working on it. Step into the world of quantum computing.
- While today's computers—referred to as classical computers—continue to become more and more powerful, there is a ceiling to their advancement due to the physical limits of the materials used to make them. Quantum computing allows physicists and researchers to exponentially increase computation power, harnessing potential parallel realities to do so.
- Quantum computer chips are astoundingly small, about the size of a fingernail. Scientists have to not only build the computer itself but also the ultra-protected environment in which they operate. Total isolation is required to eliminate vibrations and other external influences on synchronized atoms; if the atoms become 'decoherent' the quantum computer cannot function.
- "You need to create a very quiet, clean, cold environment for these chips to work in," says quantum computing expert Vern Brownell. The coldest temperature possible in physics is -273.15 degrees C. The rooms required for quantum computing are -273.14 degrees C, which is 150 times colder than outer space. It is complex and mind-boggling work, but the potential for computation that harnesses the power of parallel universes is worth the chase.
Fashion Week, 2050
- The clothing of the future will look nothing like what we wear today. Or maybe it will.
- A hunger for sustainability is leading researchers to new organic materials from which to design clothing.
- Other visionaries are working to make our future outfits as smart as we want to look.
One of the fun things about watching science fiction movies, especially old ones, is seeing filmmakers' sometimes daffy predictions of what future clothing will look like. A lot of these prognostications envision traditional fabrics such as cotton or contemporary synthetic fibers cut into "future-y" designs. Recent advances make the real future of clothing look much more imaginative: While some are busy discovering more sustainable materials from which to fashion our clothes, other are dreaming up new things for our outfits to do.
Nature knows best
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About 60 percent of the clothing we wear contains plastic microfibers. The best-known are polyester, nylon, and acrylic. Unfortunately, these fibers don't stay in our clothing. While some of them leach out as we go about our business, taking to the air and so on, doing laundry may be a significant contributor to the 8 million tons of microplastics dumped into our oceans annually. (Fun fact: Experts only know where about 1 percent of that plastic goes.) Nonetheless, research published in 2016 says that for an average wash load, over 700,000 fibers could be being released into the water supply.
In addition to ongoing efforts to find new ways of incorporating used materials in new clothing, textile-industry scientists are experimenting with a range of less environmentally damaging, more sustainable materials for us to wear. Much of it is derived from naturally occurring sources.
Piñatex is a leather substitute made from pineapple-leaf fiber. These leaves are discarded during harvesting of the fruit, and so they're readily available with no additional farming necessary, according to the Piñatex web site. The material, which is produced in sheets, is already being used for making shoes, handbags, and dresses.
There are a few mushroom-thread-based fabrics.
There's a synthetic leather called Mylo, from Bolt Threads, a vegan, eco-friendly material. The company's partnering with fashion brands Stella McCartney and Patagonia in making actual clothing from Mylo.
Then there's MycoTEX. The most startling thing about MycoTEX is that this living material can be grown into clothing. As producer Fungal Futures puts it, "the garment can be built three-dimensionally and shaped whilst being made, fitting the wearer's wishes," using clothing-shaped molds. Since MycoTEX grows into the desired shape without cutting, there's no waste material when a garment's complete.
One of the wildest ideas is another technology from Bolt Threads called "Microsilk." Based on the way in which spiders produce real silk, Microsilk is derived from yeast-based proteins, extracted, and then spun into fibers. The company released, and immediately sold out of, a Microsilk tie in 2017, and Stella McCartney showed a gold dress made from the fibers at NYC's MoMA that same year.
A company called Wool and the Gang (a pun better read than said) is selling a product, "Tina Tape Yarn," made from sustainably harvested eucalyptus trees. They call the material Tencel and claim it's "more absorbent than cotton, softer than silk and cooler than linen." It's also biodegradable, made with renewable energy and — heads up, sheep — totally vegan.
This company takes plant-based textiles beyond pineapples. We say that because pineapple leaves are just one of the castoff materials sourced to make their line of BioFibres. The others are oil-seed hemp, oil-seed flax, banana tree, cane bagasse, and rice straw. Agraloop notes that these six crops provide 250 million tons of textile fiber per year, 2.5 times the global demand.
Some of the rest
Other natural substances being reworked into clothing include chitin fiber from crustacean shells, seaweed, banana fiber, coconut fiber, and corn fiber.
Don’t forget to recharge your underwear
Popular future brands?
Image source: Boris Bobrov/Unsplash
Technology in textiles is not a new thing, but it's a booming field. Antimicrobial silver nanoparticles that prevent smelly bacteria — and therefore require less washing — have been embedded in fabrics since early in the new millennium. Researchers are working on water-repelling fabrics, and nanoparticles can also make clothing less flammable. Just this month, a nanoscale accelerometer was announced, perfect for incorporating into future motion-sensitive clothing.
What can clothes do? What can't they do? Get ready for smart textiles.
Google goes beyond Glass
Having been early into smart wearables with their Glass products, Google has has begun weaving its Jacquard platform into clothing, in particular a jacket co-developed with Levi's. The jacket is a wearable touch device you can use for controlling your devices.
Another smart-tech use being explored for fabrics are materials laced with sensors that can monitor the wearer's health, going far beyond fitness watches to clothes that keep an eye on a wide range of health indicators.
Clothes that change color
Scientists from the College of Optics and Photonics at The University of Central Florida have developed ChroMorphous, a color-changing fabric your can control using your smartphone. They cal it "eFabric." (What, does Apple own "iFabric?")
Some of the new materials are designed to be helpful. Wearable X specializes in materials that support haptic feedback, electrical signals that mimic a sense of being touched or of interaction with virtual objects. The company currently sells NADI X yoga garb with embedded haptic feedback that provides training cues. An earlier product put the "fun" in Fundawear by allowing touch to be transmitted from a smartphone to a partner anywhere in the world, "created with long-distance couples in mind."
Optical communicator hat
We'll let Yoel Fink of MIT pitch this one: "Think about pedestrian safety and self-driving cars. Tremendous investments are going into cars. How about the pedestrians? Do we as pedestrians or bikers get to know if the car has detected us? With fabric optical communications your baseball cap can not only alert a car to your presence but importantly let you know if the car detected you. Fabrics for the self-driving future." Alternately, those cars could just honk?
Look good, feel good
Obviously, any new materials designed for fashion need to be attractive, workable, and feel good to wearers in order to gain any traction, and these goals are very much elements in the development process. Will they be the comfy, loose-fitting fabrics of Star Wars, or will we be parading around in metallic armadillo-like facemasks? Who knows? Given our past track record, the odds are that we have no idea. We'll just have to wait to see what we'll look like when we control our personal universes from our intelligent pineapple jumpsuits.
Harvard engineers make a breakthrough polarization camera.
- Harvard researchers create a tiny camera that can see polarization.
- Seeing the invisible light can help in numerous applications, from self-driving cars to satellites.
- The scientists used nanotechnology to achieve this feat.
Scientists from Harvard University created a device that offers us a view into a normally unseen world. Their new compact polarization camera promises to achieve in one shot an imaging of the direction of vibrating light, invisible to our eyes. While some polarization cameras currently exist, they are very bulky, with expensive moving parts and limited uses.
The thumb-size Harvard camera's creators see it as a breakthrough, with wide usefulness, from self-driving vehicles to satellites, planes, facial recognition, security and chemistry applications.
The research was carried out by a team from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS).
Federico Capasso, professor of applied physics and senior researcher in electrical engineering at SEAS as well as senior author of the paper, called their study "game-changing for imaging."
"Most cameras can typically only detect the intensity and color of light but can't see polarization," he said. "This camera is a new eye on reality, allowing us to reveal how light is reflected and transmitted by the world around us."
Paul Chevalier, a postdoctoral fellow at SEAS and co-author of the study, explained that because polarization is a trait of light that changes when reflected from a surface, it can be helpful to reconstructing objects in 3D, allowing for better estimates of depth, texture and shape.
The team's accomplishment was in employing metasurfaces, nanoscale structures that have interaction with light at the scale of wavelengths, shared Harvard's press release.
Building upon new knowledge of how polarized light works, the team was able to create a metasurface that directed light and formed four images. Combined, these gave a full, pixel-deep snapshot of polarization.
Another advantage of the device – it's just 2 centimeters in length and can be worked into existing imaging systems like cell phone cameras.
Check out how the camera works here:
You can read the new study "Matrix Fourier optics enables a compact full-Stokes polarization camera" in Science.