On July 18th, 2018 we learned about

Engineers’ brief attempts to speed up trains with airplane engines

When I first read my kids the story of “Thomas and the Jet Engine,” I treated it as nothing more than fan service for kids. Sure, the idea of their favorite train being temporarily boosted across the tracks by a jet engine was fun, but clearly ridiculous. And of course, I was wrong. Not only have there been real attempts to build trains powered like aircraft, but working prototypes powered by jet aircraft have been built in multiple countries. These experimental trains were designed to join the speed of air travel with the hauling capacity of trains, although none of them ever went into regular, if speedy, service.

Pushed and pulled by propellers

The very first attempt at a plane/train hybrid was the railplane. George Bennie created a vertically oriented track that was intended to be built above existing railways, saving space and simplifying logistics. At the front and back of the pill-shaped vehicle, electric motors drove large propellers so that the railplane could ‘fly’ down the track without worrying about actual flight. The test track was too short to confirm it, but Bennie estimated that the railplane could have traveled as fast as 120 miles-per-hour, beating even today’s travel times. Unfortunately, Bennie couldn’t get enough funding to continue developing his prop-propelled train, leaving us only with advertisements and some footage of the prototype.

Jet-powered propulsion

With airplanes shifting to jet engines in the 1950s, trains in the 1960s had some catching up to do. By 1966, multiple parties were looking to either retrofit or design jet-powered trains from scratch. In France, Jean Bertin started work on the Aérotrain, which was designed to hover on an air-cushion atop an elevated track. The hovering was intended to reduce friction, making it easier for the Aérotrain’s single jet engine to propel the train down the track. Multiple rounds of prototypes were developed, including an 80-passenger train that could reach 155 miles-per-hour under the power of two jet-engines. Like the railplane before it, the Aérotrain was eventually abandoned in 1977 due to funding problems, although you can still find sections of test track France and near Pueblo, Colorado.

In the United States, turbojet train development looked a bit more like a retrofit. Don Wetzel led an effort to make trains faster and cheaper, which translated to front-mounted jet engines on an otherwise traditional-looking commuter train. Early iterations used recycled General Electric jet engines, purchased from the Air Force. Like the Aérotrain, Wetzel’s jet-powered trains never progressed past test tracks and prototypes, although they did manage to hit an impressive 183 miles-per-hour before the project was shut down.

Even if commuters never got to enjoy jet-engine speeds on the rails, these efforts caught the attention of engineers in the Soviet Union. With long-distance travel served by rail, plus a Cold War competitive spirit, the Speed Wagon Laboratory started work on their own jet-train in the late 60s as well. Target speeds ranged from 155 to a theoretical 223 miles-per-hour, but the project was dropped in the 1970s, partially thanks to the expenses associated with all the jet fuel those speeds would require.

Rounding things out, Japan had their own attempt at jet-powered trains, starting around 1968. Engineer Hisanojo Ozawa offered a few twists on the “common” jet-train design, aiming for a train with three jet engines that ran on rollers instead of traditional, flanged train tracks. The project didn’t seem to progress past a working scale-model, although that model predicted speeds up to 733 miles-per-hour.

Floating but not based on flight

Like Thomas the Tank Engine’s accidental sprint across the Island of Sodor, the age of jet-powered trains was short-lived. Fuel and other expenses made this form of propulsion less attractive, and so high-speed train designs have moved on to other design concepts, mostly. While not explicitly modeled after air travel, maglev trains do hover over the ground to reduce friction, allowing them to reach speeds of up to 249 miles-per-hour. The form of propulsion is different, but the basic premise of track-based transportation still appears to be one of our most practical ways to cross long distances.

Source: Turbojet train, Wikipedia

On July 17th, 2018 we learned about

Making sense the inconsistencies of cars’ mud flaps

Kids are supposed to ask why the sky is blue, what happened to the dinosaurs, and maybe where babies come from. My five-year-old, apparently content in his knowledge of such things, has instead been wanting to know more about mud flaps on cars. What are they for? Do they help a car drive faster somehow? The thing that was really bothering him though, was if mudflaps are useful, why aren’t they part of every car and truck on the road?

Mudflaps have probably been conceived a number of different times throughout automotive history, but Oscar Glenn March of Jones, Oklahoma is generally credited with inventing the products we know today. Unlike the side-mounted “anti-splashers” patented by William Rothman in 1922, March’s flaps were built and put into immediate use. March worked in the motor pool on Tinker Air Force Base during World War II, and realized that they needed a way to protect sensitive radar equipment from mud and rocks when it was hauled on flatbed trucks. The flaps were originally made of canvas which has since been replaced by rubbers and plastics, although March’s original bracket-mounting design is still in use today.

How functional are rubber flaps?

In addition to keeping your radar equipment clean, mud flaps can also protect the vehicle they’re mounted on. In areas with lots of rain, snow, salted roads and of course, dirt and mud, the right mud flaps can help prevent dirt and rocks from damaging the paint on fenders right behind a car’s wheel well. Beyond one’s own car, mud flaps can also help cut down on how much dust and water your vehicle will spray on anyone around you, which is part of the reason they’re legally required on trucks in many states. These vehicles’ higher frames and larger wheels makes them prime candidates to launch more rocks and water at other drivers, and so properly-sized mudflaps trap those materials before they cause trouble.

Of course, not every car today has mudflaps, which raises the raises questions about how valuable they really are. A piece of heavy rubber can’t be that expensive, so why don’t all cars come equipped with mud flaps by default? Many modern cars do have some extra plastic molded behind their wheels, but why not use the flexible flaps trucks are required to use? This is a trickier question to answer, as there’s no single authority declaring that mud flaps be excluded from modern car designs. Sometimes there are concerns over improperly mounted mud flaps, which require holes be drilled in a car’s body that can end up leading to rust damage. Other people argue that the flaps cause a small amount of aerodynamic drag, making them slightly less efficient to drive with. Finally, there’s the issue of aesthetics— some people think they look great on their cars, while others think they’re simply eyesores that will get bent up against speed bumps. There may not be a single “right” answer to this, although that won’t stop some people from asking questions.

Source: Who Invented the Mud Flap?, Fruehauf Trailer Historical Society

On June 24th, 2018 we learned about

3D-printed watercraft propel themselves without fuel, engines or sails

Swimming requires a lot of effort, easily consuming hundreds of calories in an hour’s worth of work. Muscles throughout your body have to contract and extend to push your body through dense water, easily leaving even the most seasoned swimmers hungry for more fuel. Even whales and submarines burn a lot of fuel to travel through the water, even with their hydrodynamic specializations. However, engineers may have figured out a way around all of this, creating small watercraft that can move themselves around without motors, sails or batteries. All that’s really needed are some very specially designed snap bracelets.

Snap bracelets never propelled anyone through the ocean, but the way they could release potential energy when their geometry changed is similar to what engineers are developing. When a snap bracelet is straightened, it holds some energy imparted from the fingers the pressed it into that rigid shape. Flexing the bracelet back into a curve then releases that energy, causing the bracelet to curl itself back up with a satisfying snap. So while a coiling fashion-accessory isn’t great for paddling through the water, collecting and releasing energy thanks to changes in geometry does allow for a paddle to function with requiring a motor to move it.

Pushing with paddles

Instead of a motor or set of fingers, these specialized paddles are 3D printed with multiple layers of material that expand and contract at different rates from each other. As one face of the paddle expands, it forces the paddle essentially stiffen up, like a rigid snap bracelet. At a certain threshold, that geometry pops into a more relaxed position, pushing the paddle back, propelling the small watercraft forward. By varying the materials in each paddle, researchers are able to build structures that allow for relatively complex movement. For example, one small, motorless drone could paddle forward, flex smaller “paddles” to release a coin it carried as a payload, then eventually flex its paddles in the opposite direction. It’s not a speedy way to get through the water, but it does allow for more autonomy than simply riding in the ocean’s currents.

At this point, these tiny robots aren’t about to replace the more robust robots that are exploring the oceans. However, because they can be 3d printed at small sizes, they could be a cost-effective way to send sensors or delivery devices into the ocean en masse. Alternatively, the basic paddle design could be used in conjunction with a more traditional motor as a low-power method of locomotion, allowing a craft to remain active for extremely long duration of time without needing to recharge or refuel.

Source: Swimming without an engine by ETH Zurich, Science Daily

On June 5th, 2018 we learned about

Sorting out how microbes survive on supposedly sterilized spacecraft

As much as humans want to discover life on other planets, we also want to make sure we didn’t accidentally send it there. Humans have a bad track record with introducing invasive species on to environments on our own planet, and we would really like to avoid doing so as we explore other planets. Allowing for crewed missions to Mars at some point in the future, a lot of effort goes into decontaminating any spacecraft that will be sent to potential ecosystems, like the Curiosity rover on Mars. Since there’s a good chance that some bacteria may be able to survive a trip through space, these spacecraft are assembled so called “clean rooms,” minimizing contact with the multitude of microbes that live in every other environment on Earth. Bunny suits and sterilization procedures have been fairly successful, but it seems that life has found an opportunity in these otherwise unoccupied environments. Not only have some microbes specialized to live in clean rooms around the world, but they’ve done so by evolving to eat our cleaning products.

Scientists have found traces of a variety of microbes on our spacecraft, including bacteria, fungi and single-celled archaea. To investigate the ecology of these unwanted microbiomes, students from Cal Poly Pomona focused on Acinetobacter, the most common genus of would-be astro-bacteria. Samples were collected from the rooms where the Odyssey and Phoenix spacecrafts were built, then analyzed to see how they could survive in supposedly sterile environments. Even if the bacteria were somehow hearty enough to survive contact with a cleaning agent, it wasn’t clear what these microbes could all be eating in these spaces in order to grow and multiply.

Consuming the cleansers

Normally, a cleaning agent like isopropyl alcohol sterilizes a surface by ripping bacterial cells apart. The lipids in the cell membrane basically dissolve in the presence of alcohol, rupturing the organism entirely. Acinetobacter aren’t necessarily immune to this chemistry, but if they aren’t wiped out completely they do use the alcohol to their advantage. As the alcohol biodegrades, the bacteria actually eat its carbon as their primary source of food. They were also able to take on Kleenol 30, another common cleaning agent. If that wasn’t resilient enough, Acinetobacter turned out to be able to survive a fair amount of oxidative stress. This means that they could possibly handle the higher radiation levels of space, as well as the dry conditions on a planet like Mars.

This doesn’t mean that every spacecraft we build will necessarily lead to a bacterial invasion on other planets. Missions that might involve contact with habitable environments, like the surface of Mars or a wet moon like Enceladus, will simply need to be cleaned more rigorously than before. Knowing how bacteria like Acinetobacter live off of our usual cleaning supplies will spur the development of new strategies, keeping spacecraft clean until the next round of bacterial evolution catches up with us.

Source: Team discover how microbes survive clean rooms and contaminate spacecraft by California State Polytechnic University, Phys.org

On May 21st, 2018 we learned about

Autonomous vessels promise to sail and soar for ubiquitous ocean observations

Armadas of robotic boats may soon sail the seven seas, although there won’t be a single sailor among them. While there’s obviously value is moving humans across the oceans, doing so requires a lot of space and supplies, requiring much bigger, costlier vessels. Instead of making fully-stocked, mobile bases of operation, designers have been looking at sailboats and soaring birds for inspiration, coming up with extremely lightweight and efficient vehicles. The resulting drones can then be sent on extended missions around the planet, gathering data that would be impractical for humans to pick up in person.

Mechanical mariner

The Saildrone was actually inspired by a car. Designer Richard Jenkins took what he learned about sail design when breaking a world record for “land sailing” and applied it to an autonomous sailboat. Resembling a hard-shelled catamaran with a vertical surfboard, the solar-powered craft can be deployed for weeks of reconnaissance work without worrying about supplies or sailors’ safety.

Saildrones have already embarked on a number of missions, from long-distance travel to watching clusters of sharks in a patch of the Pacific Ocean called the White Shark Cafe. With cameras and a battery of sensors, the drones can basically mill about for as long as necessary, beaming data in real time back to shore.

Soaring or sailing

If a Saildrone is too slow for your observational needs, engineers from MIT may soon have a solution that combines elements of sailboats with albatrosses. The boat-glider mash-up is actually meant to function primarily as a glider, with a narrow, nine-foot wing mounted over a keel and below a sail. The unusual form-factor allows the six-pound craft to fly over the surface of the water much faster than the average sailboat, then drop into the water and continue on its journey if the winds grow too weak.

Albatrosses can soar enormous distances, relying on their long wings to harvest energy from varying airflows over the ocean. They’ll spend some time in a faster air current, then get a forward boost when dropping down to slower air. The glider then copies this strategy, and as a result can move up to 23 miles-per-hour when the prevailing wind is moving closer to six miles-per-hour. When this kind of super-efficient gliding isn’t sufficient, the drone can then dip its keel into the water and push on, waiting for the wind to pick it up again.

Saturating the seas

Both of these designs are designed to be part of larger fleets. With 1000 Saildrones or gliders patrolling at once, researchers could gain a much more holistic picture of what’s happening in the ocean. Temperatures, wind speed, salinity and more could allow us to better understand larger patterns in the weather or ocean currents, pick up signs of a tsunami, or track migrating animals in a way that’s never been practical before.

Source: Autonomous glider can fly like an albatross, cruise like a sailboat by Massachusetts Institute of Technology, Science Daily

On May 13th, 2018 we learned about

The Mars 2020 rover will have help scouting its surroundings from a tiny robotic helicopter

When the next rover to arrives on Mars in early 2021, it will have a sidekick along for the ride. For the first time ever, NASA will be sending a small aircraft to Mars to help scout the terrain for potential points of interest on behalf of the slower-moving rover. Consisting of a small cube, four flexible landing feet and two high-speed rotors, the device looks a bit like a remote controlled helicopter you might find at a toy store. Of course, since it will have to fly in an environment with hardly any air, there’s a bit more to this particular aircraft than anything you’d find flying around this planet.

For a helicopter to take flight, it needs a sufficient amount of air to push against in order to create lift. On Earth, those conditions exist until you reach an altitude of around 40,000 feet, at which point the atmosphere is too thin to support a helicopter’s weight. The Martian atmosphere is even thinner, approximating flying on Earth at about 100,000 feet. To get off the surface of Mars, a number of engineering feats had to be achieved, from reducing the weight of the Mars helicopter to four pounds to designing dual rotors that can spin at around 3,000 rpm. Fortunately, tests in vacuum chambers suggest that this helicopter should manage to be the first robot to lift off the surface of the Red Planet.

Sight-seeing for science

As satisfying a milestone as that represents, scientists are hoping that the Mars Helicopter will make some important contributions to the rover’s work, starting planning routes. The Curiosity rover has been working for close to six years, but has yet to travel a full 12 miles across Mars. We have spacecraft orbiting Mars, but researchers are hoping that the Helicopter can give us a more practical bird’s-eye-view of the rover’s surroundings. Even flying a few hundred feet will help mission controllers pick where to send the rover, making it’s time more efficient. This work won’t be strictly necessary, but even 30 days of modest flights would likely add to the impact of the rover’s investigations.

Since the Mars Helicopter is solar powered, there’s a chance it will be able to do more than its five scheduled test flights. Each trip will help prove that this kind of reconnaissance is viable for future missions, documenting details that may be hard to pick up from orbiting instruments like the ExoMars Orbiter or ground-based rovers and landers.

Source: Mars Helicopter to Fly on NASA's Next Red Planet Rover Mission, Jet Propulsion Laboratory News

On May 9th, 2018 we learned about

Eavesdropping on elephants with equipment designed to detect earthquakes

From three feet away, an elephant’s trumpeting can sound as loud as a construction site. At 110 dB, these calls are loud and distinctive, but they only make up a small portion of how elephants can communicate with sound. Their vocal range is enormous, stretching from a rumbling 27 Hz to a piercing 470 Hz, much of which is easily missed by a human listener. To really tune into what elephants may be communicating, researchers are now proposing that we do more of our listening through the ground, even if it means employing seismic sensors meant for earthquakes to do so.

This investigation started with the idea that elephants already make use of the ground to communicate with each other. Like the low-pitched song of a blue whale that carries across the ocean, elephants seem to use the ground like a giant microphone to send low-pitched sounds across long distances. While many of their complex calls sound impressive in the air, low-pitched vibrations are transmitted much further in dense earth and rock. So while it may be annoying when the bass notes from your neighbor’s stereo rattle your walls so easily, elephants make use of the ground as a transmission line for long-distance communication.

Listening in with seismic sensors

Researchers are hoping that humans will soon be listening in to these calls as well. Using sensors developed for monitoring seismic activity associated with earthquakes, they’re now investigating how to remotely monitor elephant activity. Starting with cataloging vibrations and directly observed behaviors, researchers aim to keep track of what a herd is doing from miles away. This won’t only let us observe elephants in a less obtrusive manner, but may also help with conservation, as herd panicking about threats like a poacher should be detectable, triggering the immediate deployment of local law enforcement to that location.

There are some complications to be worked out before we start eavesdropping on the world’s pachyderms. Certain types of terrain seem to limit the effective range of our underground listening stations. This work is has also drawn attention to sources of noise pollution, such as heavy vehicles. This kind of human activity makes listening in on elephant calls much more difficult for our sensors, which means that its probably disruptive to the elephants as well, similar to the way large ships’ engines interfere with whale call and navigation in the ocean.

Source: Could seismology equipment help to protect elephants from poachers?, EurekAlert!

On May 6th, 2018 we learned about

NASA launches the InSight mission to figure out how Mars was made

On the morning of May 5, 2018, cheers of excitement went up over the prospect of landing a robot on the most boring part of Mars imaginable. The target location wasn’t picked because we’re running out of interesting features to look at on Mars of course, but because we wanted a relatively “quiet” place for the Interior exploration using Seismic Investigations, Geodesy, and Heat Transport (InSight) lander to learn about what’s under Mars. To do that, the lander will essentially listen to the planet’s seismic activity for a year just north of the equator, trying to weed out other disruptions from the activity happening deep in the planet’s core.

Digging in the dirt

For this extended listening session, InSight will land in one spot, then set up shop. In a first, a robotic arm will lower its two primary instruments to the ground where they can then go to work for at least a year of data collection. The Heat Flow and Physical Properties Probe (HP3) will be inserted over 10 feet underground, where it will both heat the surrounding dirt and then measure how quickly that heat travels through the surrounding material. These measurements will then give researchers a good idea about the geological composition of Mars’ surface.

Super-sensitive seismic sensor

The second instrument will sit on the ground in a vacuum chamber further protected by a small dome. This will help block out wind, dust, and other possible sources of “noise.” This is important, because the Seismic Experiment for Interior Structure (SEIS) is so sensitive to vibrations it pick up the movement of ocean waves from as far away as Colorado. Even the movement of a single hydrogen atom is said to be detectable, which is why a tiny leak in the protective vacuum chamber required the entire InSight mission be delayed by two years— to truly be effective, the SEIS data must be as free of unexpected disruptions as possible.

On Mars, those vibrations will tell us a lot about the planet. Unlike the Earth’s moving, crunching and melting geology, Mars stopped churning 20 to 50 million years after it was formed. The quakes the Red Planet does experience are tied to the gradual cooling and contraction of the planet as a whole, and measuring the frequency and intensity of those quakes will tell us more about how the planet was formed in the first place. Naturally, a device as sensitive as SEIS will pick up other activity as well, meaning we can look forward to a log of asteroid impacts around the planet as they happen.

If this weren’t enough, we’ll also be tracking how our stationary lander’s position shifts throughout the year. Nobody is expecting a marsquake to start moving InSight around, but Mars’ axis of rotation is known to be gradually changing. So as we track signals from the lander, we’ll be able to detect how that telemetry shifts over time.

Mini-mission

Some of that will be made easier by the two other bots sent to space with InSight. Two mini-satellites in a class often referred to as “cubesats,” will be going into orbit around Mars to help track and report on InSight’s landing process. They’re not strictly necessary for InSight’s success, which is great since they’re actually an experiment themselves. While many cubesats now orbit the Earth,  MarCO-A and MarCO-B (aka Wall-E and Eva, thanks to their gas propulsion thrusters’ resemblance to a certain fire-extinguisher) will be the first such devices to visit another planet. If they prove up to the task, they could herald a new way for us to explore our solar system in a more modular, inexpensive manner.


My five-year-old asked: What kind of spaceship did they send the lander on?

InSight and the two cubesats were sent on an Atlas V rocket. The relatively lightweight payload and powerful rocket enabled the mission to launch from Vanderberg Air Force Base in California, rather than Cape Canaveral in Florida. While an east coast launch is generally beneficial to help push interplanetary missions out of Earth’s orbit, InSight planners wanted to avoid crowded schedule in Florida, opting for a bigger rocket from California instead. As such, this was the first time an interplanetary mission launched from the west coast.

Source: Meet InSight: The Mission To Measure Marsquakes and Unlock the Red Planet by Emily Lakdawalla, Popular Mechanics

On April 29th, 2018 we learned about

Details and developments in how plastics get can be efficiently recycled

My five-year-old is quite confident that it’s better to when waste goes in the blue bin, instead of the black. Even though it gets hauled away in an identical garbage truck each week, he knows the blue bin items will be recycled, turned into something useful enough to avoid sitting in a landfill. Those last few steps probably get pretty fuzzy, because they’re basically invisible from our perspective. We don’t see the work that goes into sorting recyclables, how they get shipped, and the difficulties in actually making these materials into something new. It’s not quite the magical process many of us may imagine it to be, but researchers are helping us get closer to the promise of recycling everything that goes in those special blue bins.

Sorting recyclables from other refuse

Once a truck hauls away recyclables, the first step at the local waste processing center is to sort what we’ve dumped in our bin. Items that are too dirty, oily or saturated with contaminants may need to be removed, alongside all the materials that shouldn’t have been placed in the recycling bin in the first place. Some items, like Tetra Paks, may technically being made of recyclable materials but are constructed in a way that preclude them from being cost effective to properly disassemble. The overall impact of all these special cases add up- a processing center in New York estimated that around 50 percent of what’s put in a recycling bin has to be sent to a landfill, despite people’s good intentions for their reuse.

That still leaves a considerable amount of goods that can be reused though, although the cost effectiveness of each material can vary greatly. Pulling out items like glass and metal are fairly straightforward, and they can generally be sold as completely reusable materials in manufacturing. Conversely, plastics are a bit harder to manage, as some types can be repeatedly reprocessed, while others aren’t worth working with after one or two manufacturing cycles.

Squashing, scrubbing and shredding

One of the more reusable types of plastic is polyethylene terephthalate (PET). It’s highly compressible, which means that it can be crushed into bales for efficient shipping to facilities that will actually be able to reprocess it into an useful material. Until recently, this may have included shipping those bales to places like China, although those arrangements have now been terminated leaving many cities without a clear destination for their recyclable goods. Within the United States, some companies are equipped to take the next steps in reusing PET plastics, with one facility in California processing over two billion bottles a year.

To reuse a single bottle, it must first be sorted according to color. This sorting is automated, with lasers quickly assessing what types of plastic are running down the conveyor belt at any given moment. Once sorted, the mashed bottles are washed and heated to cleanse them of residual labels, bottle caps and any other organic materials that may be left behind. After that, the bottles are shredded in small flakes, then washed and heated again before they get packaged for manufacturers. If those flakes might be used in food packaging, they require further cleaning testing before being reused. All this preparation obviously requires a fair amount of energy, but the resulting PET flakes can be used in everything from carpet fibers to new bottles.

Making polymers perfectly mutable

Not every piece of plastic is as recyclable as PET, although researchers are working on some very promising alternatives. While PET can be chopped into relatively small bits, the core structure of plastics make them frustratingly durable— even when reduced to pellets, the chains of molecules that plastics are made of, called polymers, don’t break down in most environments, which is part of why a cheap bottle can sit in a landfill for 500 years. Of course, weakening those polymers too much leaves us with unstable products that would become unusable if heated as much as a warm beverage.

One solution may be to add new, reinforcing molecules to softer polymers. Researchers from Colorado State University have found that adding ringed molecules to polymer chains can make them less sensitive to higher temperatures, without making them too difficult to break down by other means. Ideally, these new plastics could be broken down to their original plasticity in a bath of specific chemicals, making them into a highly versatile and cost effective material for manufacturing. The one catch is that the reinforcement has left these plastics a little too stiff, making them brittle. With any luck, they’ll find a happy medium soon enough making recycling a wider range of products more practical in the near future.


My third-grader said: It’s too bad we can’t just stop using plastic.

Plastic is really useful though. It can be incredibly strong, light, and formed into all kinds of products. It’s unlikely to fall out of use any time soon. However, that doesn’t mean we can’t be thoughtful about when we use it, and when we might re-use it. Specifically, single-use products, like a drinking straw, or water bottle, can probably be skipped or replaced by other, more durable items. Avoiding tossing items into either the trash or recycle bin after using it once is one of the easiest ways to avoid contributing to the world’s piles of plastic.

Source: The Violent Afterlife of a Recycled Plastic Bottle by Debra Winter, The Atlantic

On April 5th, 2018 we learned about

Kirigami-inspired folds and cuts enables flexible, stretchable circuits

If we ever hope to wear truly smart clothing, we’ll need to really work on how fabrics are made. It’s not that there’s anything wrong with cotton or wool, but a smart, as in computerized, jacket or shirt will need to somehow incorporate electric circuits and sensors in a way that won’t inhibit movement. Since current wiring can generally only flex by six percent before inhibiting electrical currents and efficiency, engineers are looking into techniques pioneered by Japanese papercraft known as kirigami to boost the flexibility of otherwise stiff substances.

Structures and circuits

Kirigami is a method of sculpting with both careful folds and strategic slices in each sheet of paper. While origami can create amazing shapes with just folds, making small slices in the paper can often simplify what folds are needed to achieve a similar shape. Those properties make it attractive for making 3D structures out of materials normally printed or shipped as flat sheets, almost like a pop-up book.

For electronics designers, the interest in kirigami is focused more on how cuts and folds can add flexibility to a material without losing tensile strength. Making wiring in a kirigami-inspired lattice shape allows polymers like PthTFB to be stretched and bent by 2,000 percent, without sacrificing any performance in the circuit.

A fit for electrified fabrics

Since these folds and slices are still beneficial on small scales, there are a lot of possible applications for flexible, stretchy circuits. Sensors in artificial skin could connect to nerves, displays could be build onto soft surfaces, or we could all start dressing ourselves in wearable computers. While not as inspiring as artificial skin for humans or robots, the smart clothing market is expected to be huge once these technologies mature, which is why kirigami isn’t the only kind of flexible circuit being developed these days. If you’re not into powering your shirt with papercraft, carbon-based spider silk may be the “it” textile you’ll be looking for next season.

Source: Ancient paper art, kirigami, poised to improve smart clothing, Science Daily