Swiss scientists created fiber-reinforced concrete that’s more eco-friendly than the stuff on the market today, Los Angeles is putting charging stations into streetlights to make it easier for electric-vehicle owners, and a new catalyst developed by researchers in the Netherlands could enable ambitious sustainable-energy storage projects. In this week’s coolest scientific advances, researchers all over this big blue planet are thinking green.
Amir Hajiesmaeili developed a material that’s strong enough to reinforce bridges — but much more eco-friendly than typical concrete. Image credit: Alain Herzog/2019 EPFL.
What is it? Engineers at the Structural Maintenance and Safety Laboratory at Switzerland’s Ecole Polytechnique Fédérale de Lausanne have created the “next generation” of eco-friendly concrete.
Why does it matter? According to EPFL, the construction industry accounts for about 40% of the world’s carbon emissions — and a large part of that comes from the manufacturing of concrete. Researchers have been working to create what’s called ultra-high-performance fiber-reinforced concrete — a material strong enough to reinforce bridges, for instance, but which produces less CO2 during manufacturing than traditional concrete. This is particularly important in countries like Switzerland, EPFL notes, where many concrete structures have been built since the 1960s that need upkeep. Making them last longer is also more environmentally friendly than razing them and building them fresh.
How does it work? The new material is the brainchild of PhD candidate Amir Hajiesmaeili, who sought to develop “a material that retains the mechanical properties found in today’s concrete, but without the steel fibers.” He did it by replacing the steel fiber with stiff synthetic polyethylene fiber and replacing half of the cement — which acts as a binder in concrete — with commonly available limestone. The resultant material is 10% lighter than other reinforced concrete, with a 60% to 70% lower environmental impact.
A new shoebox-sized laser produces terahertz waves (green squiggles) by using a special infrared laser (red) to rotate molecules of nitrous oxide, or laughing gas, packed in a pen-sized cavity (grey). Image courtesy of Chad Scales, US Army Futures Command.
What is it? X-ray vision? That’s so 20th-century. Now researchers are interested in T-ray vision— using terahertz waves to see through thin materials such as clothing and book covers. It could enable high-res imaging that’s safer than X-ray.
Why does it matter? T-ray vision figures into a new machine designed by a team from MIT, Harvard and the U.S. Army. The concept has been around for decades, but it’s been hampered by some problems. The basic setup of the device involves a laser shot through a gas-filled tube, but researchers have struggled to perfect the technology; other iterations are large and bulky, required supercold temperatures to operate, and work only at a single frequency. The new device is the size of a shoebox and, working at a range of frequencies, can penetrate a variety of materials. Terahertz waves could also be used for long-distance wireless communication.
How does it work? After sorting through some of the more theoretical problems associated with terahertz imaging, the team tackled the hardware element, landing on a compact and tunable quantum cascade laser and, to fill the tube, nitrous oxide — yep, laughing gas. “These gas lasers were for a long time seen as old technology, and people assumed these were huge, low-power, nontunable things, so they looked to other terahertz sources,” said MIT mathematics professor Steven Johnson. “Now we’re saying they can be small, tunable, and much more efficient. You could fit this in your backpack, or in your vehicle for wireless communication or high-resolution imaging.” Johnson is a co-author of a new paper on the subject in Science.
Listen up: This holographic brain’s got something to say. Top and above images credit: Getty Images.
What is it? Researchers at the University of Sussex have gotten “the closest yet to re-creating one of the most iconic of Star Wars technology,” according to a university press release: They’ve developed a device that produces holograms that are auditory and tactile — heard and felt, in addition to seen. Its name isn’t Princess Leia, though. It’s called the Multimodal Acoustic Trap Display, or MATD for short.
Why does it matter? The team that developed MATD sees it as “an incredibly useful visualisation tool for a huge range of professions including anyone working in biomedicine, design or architecture.” Sussex informatics professor Sri Subramanian, who led the project, said, “It is not just that the content is visible to the naked eye and in all ways perceptually similar to a real object while still allowing the viewer to reach inside and interact with the display. It is also the fact that it relies on a principle that can also stimulate other senses.”
How does it work? That stimulating principle is ultrasound, which the MATD machine uses to trap a particle and illuminate it with different-colored lights, controlling its color “as it quickly scans through an open space to reveal the illusion of volumetric content.” The ultrasound also allows for a sense of hearing and touch, explains Sussex professor Diego Martinez Plasencia, who co-created the machine: “Even if not audible to us, ultrasound is still a mechanical wave and it carries energy through the air. Our prototype directs and focuses this energy, which can then stimulate your ears for audio, or stimulate your skin to feel content.” The paper is available in Nature.
A Charging Station On Every Corner?
With charging stations attached to streetlights, electric-vehicle owners could have plenty of places to recharge. Image credit: Getty Images.
What is it? The city of Los Angeles has begun installing electric-vehicle charging stations in a ubiquitous and highly convenient place: on more than 100 streetlights, with hundreds more in the works.
Why does it matter? Los Angeles Mayor Eric Garcetti wants to have at least 100,000 new EVs on the road by 2025 as part of his Green New Deal, announced in May; the plan sets the further goal of 100% electric vehicles in LA by 2050. One hitch, though, is that two-thirds of LA households are renters who don’t necessarily have the ability to charge their cars at home. According to the sustainable-energy news site Electrek, “Access to EV charging for apartment-dwellers is perhaps the single biggest remaining challenge to solve regarding electric cars.”
How does it work? The city operates more than 220,000 streetlights, so they’re a natural place to install EV chargers that anyone can use. Attaching the charging stations to the light posts, moreover, eliminates the need to place a separate piece of infrastructure on the city’s busy sidewalks. Drivers will be able to charge their vehicles for $1 to $2 per hour, and parking will be free.
A new catalyst could make it easier to get the most out of solar power. Image credit: Getty Images.
What is it? Researchers at the Netherlands’ Eindhoven University of Technology, together with colleagues from China, Singapore and Japan, developed a catalyst for storing energy in hydrogen, described in Science.
Why does it matter? Storing energy in chemical bonds, a press release from the university explains, is better than keeping it in batteries, which can’t store large amounts. An electrolyzer converts electrical energy into hydrogen for storage; later, a fuel cell converts it back into electrical energy. The process requires a catalyst, which today is typically platinum — a rare and expensive material that will hamper this technology’s adoption on a wide scale. The researchers came up with a catalyst of “hollow nanocages of an alloy of nickel and platinum” that has 20 times higher activity than a catalyst of platinum alone.
How does it work? The hollow nanocages, explains study co-author Emiel Hensen, create surface area, “allowing more material to react at the same time.” Hensen thinks the technology could someday be used in ambitious sustainable energy projects: “I hope that we will soon be able to install an electrolyzer in every neighborhood. This refrigerator-sized device stores all the energy from the solar panels on the roofs in the neighborhood during the daytime as hydrogen. The underground gas pipelines will transport hydrogen in the future, and the domestic central heating boiler will be replaced by a fuel cell, the latter converting the stored hydrogen back into electricity. That’s how we can make the most of the sun.”