Science Daily January 30, 2019 Water molecules change the electrical resistance of this carbon material, which introduces a false signal into the sensor. An international team of researchers (Sweden, Germany) discovered that when this two-dimensional material is integrated with the metal of a circuit, contact resistance is not impaired by humidity. They used graphene together with gold metallization and silica substrates in transmission line model test structures, as well as computer simulations to demonstrate their discovery. As part of the European CO2-DETECT project, they are applying this new approach to create the first prototypes of graphene-based sensors to measure carbon […]
Category Archives: Materials science
Turning Round Drops Square
American Physical Society Synopsis December 13, 2018 An international team of researchers (Canada, France) found that for a drop sandwiched between two thin, stretchable films can develop a noncircular outline, such as a square, with its exact shape depending on the amount of tension in the two films. They found that the partial wetting of droplets capped by taut elastic films is highly tunable. Adjusting the tension allows the contact angle and droplet morphology to be controlled. By exploiting these elastic boundaries, droplets can be made elliptical, with an adjustable aspect ratio, and can even be transformed into a nearly […]
Study reveals mechanisms that promote icing responsible for power disruptions
Eurekalert November 26, 2018 Researchers in China monitored the icing process (at 10 meters and 1.5 meters) of agglomerate fog, an event where massive amounts of fog come together during a cold surge which lasted for 102 hours. They found that agglomerate fogs, snow and rain, contributed to the icing process. They observed significant differences in the thickness and density of the accumulated ice, as well as the mechanism that contributed to icing growth and the duration of the icing at the two different heights. The sticking efficiency of snow particles has a significant impact on icing growth rate…read more. […]
Uncovering secret structure to explosives
Lawrence Livermore National Laboratory October 17, 2018 In most high explosives, detonation is initiated through a process where pores get compressed by a shockwave. Researchers at the Lawrence Livermore National Laboratory found that in an explosive compound called HMX when pores are at the surface, they speed up the reaction, if a shockwave hits a number of surface pores at once, they bootstrap each other. While they showed that many small pores can work together to accelerate one another’s burning, they also were able to identify a threshold where pores become so small that the reaction is extinguished. This examination […]
Metal that withstands ultra-high temperature and pressure identified
Science Daily September 27, 2018 Researchers in Japan analyzed the ultrahigh-temperature tensile creep behaviour of a TiC-reinforced Mo-Si-B-based alloy in the range of 1400–1600 °C at constant true stress range in vacuum. It displayed excellent creep strength with relatively reasonable creep parameters and moderate strain-rate oscillations. The findings have applications in aircraft jet engines and gas turbines for electric power generation…read more. Open Access TECHNICAL ARTICLE
Scientists squeeze nanocrystals in a liquid droplet into a solid-like state and back again
Science Daily August 8, 2018 An international team of researchers (USA – Lawrence Berkeley National Laboratory, UC Berkeley, UMass Amherst, Japan) put a droplet of a liquid containing iron oxide nanocrystals into an oily liquid containing tiny polymer strands and cause the nanoparticles assembled here to jam, making it act like a solid, and then to unjam and return to a liquid-like state by the competitive push-pull action of the polymer and the additive. They can control the rate at which this happens through the use of a ligand at a defined concentration and manipulate the properties of the liquid […]
Close-ups of grain boundaries reveal how sulfur impurities make nickel brittle
Eurekalert July 17, 2018 It is known that sulfur embrittlement is related to the grain boundary segregation of sulfur, but the underlying atomic mechanisms have remained elusive. Researchers at UC San Diego examined the general grain boundaries in nickel polycrystals doped with sulfur. They found that competition between interfacial ordering and disordering leads to the alternating formation of amorphous-like and bilayer-like facets at general grain boundaries. They also found that bipolar interfacial structures cause brittle intergranular fractures between polar sulfur-nickel structures that are disorderly aligned in two opposite directions. The discovery enriches fundamental understanding of general grain boundaries that often […]
Slippery when dry
Phys.org July 13, 2018 Researchers at Argonne National Laboratory have developed a process based on graphene which shows that a few layers of graphene not only reduce friction in steel rubbing against steel by seven times and the wear by 10,000 times but also significantly reduces the tribo-corrosion problem. Graphene can be applied by spraying a solution in the air and can coat any complicated shape or size—and over a large surface area. According to the researchers it could help wind turbines move with greater ease, allowing them to produce more energy. It can better seal off machinery as it […]
Solutions to water challenges reside at the interface
Phys.org July 17, 2018 Interfaces between components of water systems and the water-based fluids themselves govern the performance of the vast majority of water treatment and conveyance processes. A team of researchers in the US (Argonne National Laboratory, University of Chicago) examines many of these interfaces, ranging from those in sorbents and sensors to membranes and catalysts, and surveys opportunities for scientists and engineers to reveal new insights into their function and, thereby, to design novel technologies for next-generation solutions to our collective energy-water challenges… read more. Open Access TECHNICAL ARTICLE
Electrons slowing down at critical moments
Nanowerk July 7, 2018 An international team of researchers (USA – Argonne National Laboratory, Northwestern University, University of Illinois, Ireland) has shown an unusual slowing down of the recovery of an electronic phase across a first-order phase transition. Following optical excitation, the recovery time of both transient optical reflectivity and X-ray diffraction intensity from the charge-ordered superstructure in a La1/3Sr2/3FeO3 thin film increases by orders of magnitude as the sample temperature approaches the phase transition temperature. In this regime, the recovery time becomes much longer than the lattice cooling time. According to the researchers the abnormal behavior of electrons is […]