News from the NNI Community - Research Advances Funded by Agencies Participating in the NNI

By using simulations on a supercomputer at the University of Texas at Austin (UT Austin) and a small transformer powered by UT Austin's one megawatt micro grid, researchers from UT Austin, the University of Maryland, Rensselaer Polytechnic Institute in Troy, NY, and the U.S. Department of Agriculture’s Forest Products Laboratory in Madison, WI, have developed a solution to address the overheating of grid transformers. The researchers created a high thermal conductivity paper using nanoparticles of boron nitride and tested it on the small transformer. "Our results indicate that if the thermal conductivity is increased by a few times using the engineered paper, the hotspot temperature inside a transformer can be reduced by between 5 to 10 °C," said Robert Hebner, one of the scientists involved in this study. "In most conditions, that should be enough to double or triple the life of the transformer."

Using a pair of sensors made from carbon nanotubes, researchers from the Massachusetts Institute of Technology (MIT), the Singapore-MIT Alliance for Research and Technology, and the National University of Singapore have discovered signals that reveal when plants are experiencing stresses, such as heat, light, or attack from insects or bacteria. The researchers found that plants produce hydrogen peroxide and salicylic acid (a molecule similar to aspirin) at different timepoints for each type of stress, creating distinctive patterns that could serve as an early warning system. Farmers could use these sensors to monitor potential threats to their crops, allowing them to intervene before the crops are lost, the researchers said.

Researchers from the Massachusetts Institute of Technology, Universitat de Girona in Spain, and Universidade do Porto in Portugal have shown that they can prevent cracks from spreading between layers in a composite material by depositing chemically grown forests of carbon nanotubes between the composite layers. The tiny, densely packed fibers grip and hold the layers together, like ultrastrong Velcro, preventing the layers from peeling or shearing apart. In experiments with an advanced composite, known as a thin-ply carbon fiber laminate, the team showed that layers bonded that way improved the material's resistance to cracks by up to 60% compared with composites with conventional polymers.

Duke University researchers have captured close-ups of corrosion in action. They zapped nanocrystals of a catalyst called ruthenium dioxide with high-energy radiation and then watched the changes that occurred. To take pictures of such tiny objects, they used a transmission electron microscope, which shoots a beam of electrons through the nanocrystals (suspended inside a thin pocket of liquid) to create time-lapse images of the chemistry taking place at 10 frames per second. The result: close-ups of virus-sized crystals, more than a thousand times finer than a human hair, as they get oxidized and dissolve into the acidic liquid around them.

Scientists at Princeton University have, for the first time, successfully visualized the elusive Wigner crystal – a strange form of matter made only of electrons that assemble into a crystal-like formation of their own (without the need to coalesce around atoms). The scientists cooled the sample down to extremely low temperatures—just a fraction of a degree above absolute zero—and applied a magnetic field perpendicular to the sample, which created a two-dimensional electron gas system between two thin layers of graphene – a two-dimensional material made of carbon atoms. “Our work provides the first direct images of this crystal,” said Yen-Chen Tsui, one of the scientists involved in this study. “We proved the crystal is really there and we can see it.”

Researchers from the University of California, Berkeley, the U.S. Department of Energy’s Berkeley Lab, and the National Institute for Materials Science in Tsukuba, Japan, have taken the first atomic-resolution images and demonstrated electrical control of a chiral interface state – an exotic quantum phenomenon that could help researchers advance quantum computing and energy-efficient electronics. To prepare chiral interface states, the researchers worked at the Molecular Foundry, a user facility at Berkeley Lab, to fabricate a device called twisted monolayer-bilayer graphene, which is a stack of two atomically thin layers of graphene rotated precisely relative to one another.

Silver nanoparticles are highly sought-after products in the nanotechnology industry because of their antibacterial, antifungal, antiviral, electrical, and optical properties. Now, researchers from the U.S. Department of Agriculture (USDA)'s Agricultural Research Service and Oklahoma State University have revealed the ability of cotton gin waste – a byproduct from the process that separates fibers from the seeds of cotton – to synthesize and generate silver nanoparticles in the presence of silver ions. The researchers used a simple heat treatment of cotton gin waste materials in water containing silver ions that produced silver nanoparticles without the need for additional chemical agents.

Researchers from the University of California Santa Cruz have created a lab-on-a-chip diagnostic system that combines optofluidics and nanopore technology. To run the test, a sample of biofluid is mixed in a container with magnetic microbeads. The microbeads are designed with a matching RNA sequence of the disease for which the test is designed to detect. The microbeads are put into a silicon microfluidics chip, where they are caught in a light beam that pushes them against a wall that contains a nanopore. The researchers apply heat to the chip, which makes the RNA sequences come off the microbeads and get sucked into the nanopore, which detects that the virus RNA is present.

Researchers at the Massachusetts Institute of Technology have found that neutrons can be made to cling to nanoparticles called quantum dots, which are made up of tens of thousands of atomic nuclei, held there by the strong force. Until this new work, nobody thought that neutrons might actually stick to the materials they were probing. “The fact that [the neutrons] can be trapped by the materials, nobody seems to know about that,” said Ju Li, one of the scientists involved in this study. “We were surprised that this exists.”

Engineers from the University of Massachusetts Amherst, Florida Institute of Technology, and the U.S. Naval Research Laboratory have created ultraviolet (UV) rays-emitting glass that can reduce 98% of biofilm from growing on surfaces in underwater environments. Says lead study author Leila Alidokht, "As UV enters the glass, we scatter the UV from inside of the glass to the outside," using a coating made of light-scattering silica nanoparticles. "Contrary to an external UV irradiation technique, UV-emitting glass inhibits biofilm formation directly at the surface of interest – the surface itself serves as a UVC source," Alidokht adds.