Phys.org September 16, 2021 Existing technologies lack accuracy and ability to scale to effectively aid disaster relief and recovery. Even today, most wildfire event inspectors visit sites and manually classify building damage using before and after images of the buildings. A team of researchers in the US (Stanford University, California Polytechnic State University) has developed DamageMap, an artificial intelligence-powered post-wildfire building damage classifier. It is a binary classifier. Unlike existing solutions DamageMap relies on post-wildfire images alone by separating the segmentation and classification tasks. The model has an overall accuracy of 98% on the validation set (five wildfire events all […]
Creating cotton that is fireproof and comfortable
Phys.org September 15, 2021 Researchers in Switzerland utilized a tri-functional phosphorous compound (trivinylphosphine oxide), which has the capability of reacting only with specifically added molecules (nitrogen compounds like piperazin) to form its own network inside cotton. This makes the cotton permanently fire-resistant without blocking the favorable -OH groups. This flame retardant treatment does not include carcinogenic formaldehyde. The phosphine oxide networks do not wash out. After 50 launderings, 95 percent of the flame retardant network was still present in the fabric. To fix the phosphine oxide networks inside the cellulose they treated the cotton with an aqueous solution of phosphorus […]
Engineering a polymer network to act as active camouflage on demand
Phys.org September 16, 2021 Despite extensive efforts to create colour-changing materials and devices, it is challenging to achieve pixelated structural coloration with broadband spectral shifts in a compact space. An international team of researchers (USA – University of Pennsylvania, South Korea) describes pneumatically inflating thin membranes of main-chain chiral nematic liquid crystalline elastomers that have such properties. By taking advantage of the large elasticity anisotropy and Poisson’s ratio (>0.5) of these materials, they geometrically programed the size and the layout of the encapsulated air channels to achieve colour shifting from near-infrared to ultraviolet wavelengths with less than 20% equi-biaxial transverse […]
Jet stream changes could amplify weather extremes by 2060s
Phys.org September 13, 2021 A team of researchers in the US (MIT, Woods Hole Oceanographic Institution, University of Arizona, University of Hawaii, Desert Research Institute) collected glacial ice core samples from nearly 50 sites spanning the Greenland ice sheet to reconstruct changes in windiness across the North Atlantic dating back to the eighth century. Model projections forecast a northward migration of the North Atlantic jet stream which could render the jet stream significantly different within a matter of decades. The ice core layers tell us about how much precipitation fell each year and about the temperatures that airmasses were exposed […]
Just by changing its shape, scientists show they can alter material properties
Nanowerk September 13, 2021 An international team of researchers (USA – Argonne National Laboratory, University of Chicago, Israel) explored confined transport using a patterned structure in titania films, with feature sizes of 11–20 nm. They described how confinement changes the competing charge transport mechanisms, the patterned antidot array leads to displacement fields and confines the charge density that results in modified and emergent electron transport with an increase in conductivity. This emergent behavior can be described by considering electron interference effects. Characterization of the charge transport with electron holography and impedance spectroscopy, and through comparison with modeling, showed that nanoscale […]
Laser loops create ultrafast electric currents in solid materials
Nanowerk September 15, 2021 An international team of researchers (Germany, Spain, USA – the Flatiron Institute) predicted that a unique laser source could produce highly controllable electric currents in any bulk material. They focused on an intense laser beam comprised of only low-energy photons, which incorporates two circularly-polarized carrier frequencies. The polarization of the electromagnetic field of this beam plots a distinct shape in space and time. The combination of the two colors leads to a double-loop motion that pushes electrons in the solid in various directions. Together with the intense beam, the double-loop laser light produces many photons which […]
Magnetic field turns handed superconductor into liquid crystal-like nematic state
Nanowerk September 15, 2021 Recent measurements of the resistivity in magic-angle twisted bilayer graphene near the superconducting transition temperature show twofold anisotropy, or nematicity, when changing the direction of an in-plane magnetic field. This was interpreted as strong evidence for exotic nematic superconductivity instead of the widely proposed chiral superconductivity. An international team of researchers (Germany, USA – the Flatiron Institute, Spain) has suggested a surprising connection between the nematic behavior of a superconductor in a magnetic field and its spiral-like ground state in the absence of the field. Their theory could not only explain recent experiments on twisted bilayer […]
New DNA-based chip can be programmed to solve complex math problems
Science Daily September 14, 2021 The reactions in DNA-based combinational logic computing are mostly achieved through a manual process. For DNA-based Boolean logic, researchers in South Korea have fabricated a DNA-based microfluidic processing unit (MPU). They cast polydimethylsiloxane using double-sided molding techniques for alignment between the microfluidics and valve switch. For a uniform surface, molds fabricated using a three-dimensional printer were spin-coated by a polymer. For programming control, the valve switch arms were operated by servo motors. In the MPU controlled via a personal computer or smartphone application, the molecules with two input DNAs and a logic template DNA were […]
Researchers create nanoparticle paste to make perovskite solar cells more efficient
Nanowerk September 10, 2021 Large-scale and low-cost approaches for creating functional nanostructures are still not developed. An international team of researchers (Russia, Italy) has developed a method to create mesoporous electron transport layer based on optically resonant silicon nanoparticles incorporated into TiO paste to be applied for perovskite (MAPbI) solar cell. The inclusion of Mie-resonant silicon nanoparticles helps to improve light absorption by a perovskite layer without reduction of the active material. The management of Si nanoantennas concentration provides a power conversion efficiency higher than 21% by increasing all main device parameters. The new silicon nanoparticles provide physical understanding on […]
Scientists Built a New Kind of Invisibility Cloak, But It’s Not For Your Eyes
Science Alert September 4, 2021 An international team of researchers (Switzerland, UK) has achieved active acoustic cloaking and holography without prior knowledge of the wavefield so that objects remain invisible and illusions remain intact even for broadband moving sources. In the new approach, there’s a lot more versatility in making objects disappear – and it can even work the other way around to make it sound as if a non-existent object is taking up space in the room. FPGAs can respond to the audio speaker outputs with virtually no delay at all. So far, the researchers have managed to get […]