Tech Radar | What caught our attention outside of the world of oil and gas this month
October 13, 2017
Down the tubes
Researchers from Northeastern University in Boston have successfully used carbon nanotubes to desalinate water molecules.
In a paper published in Science, the group describes how nanotubes of a certain size – 0.8 nm – will only allows one water molecule to pass through at a time. This single-file line-up disrupts the hydrogen bonds within the water, so it can be pushed through the tubes at an accelerated pace.
In addition to being the right size, carbon nanotubes also have a negative electric charge, meaning they will repel the negative ions in salt, as well as other unwanted particles.
Co-author Meni Wanunu, associate professor of physics at Northeastern, and post-doctoral student Robert Henley collaborated with Aleksandr Noy at the Lawrence Livermore National Laboratory in California to conduct the research.
“While salt has a hard time passing through because of the charge, water is a neutral molecule and passes through easily,” Wanunu said. Noy’s lab had previously suggested that nanotubes could be designed for ion selectivity, but it did not have a reliable system of measurement – this is where Meni’s team could step in. The result is a novel system that could have major implications for the future of water security. Their study has shown that nanotubes are better at desalination than any other existing method, natural or man-made. The two labs have now partnered with a water purification organisation based in Israel. And the group was recently awarded a National Science Foundation/Binational Science Foundation grant to conduct further studies and develop water filtration platforms based on their new method.
Scientists at Imperial College London have tuned nanoparticle arrangements to create a filter that can change between a mirror and a window. The material could enable new kinds of optical filters and possibly miniaturised sensors. The layers of precisely arranged gold nanoparticles were made by applying a small voltage across the interface between two liquids that do not mix. This layer can be dense or sparse, enabling it to switch between being a reflective mirror and a transparent surface. Study co-author Professor Joshua Edel, from the Department of Chemistry at Imperial, said: “It’s a really fine balance – for a long time we could only get the nanoparticles to clump together when they assembled, rather than being accurately spaced out. But many models and experiments have brought us to the point where we can create a truly tuneable layer.”
The distance between the nanoparticles determines how different wavelengths of light are reflected or pass through. But unlike previous systems that used chemical means, this process is reversible. Co-author Professor Anthony Kucernak, from the Department of Chemistry, commented: “Putting theory into practice can be difficult, as one always has to be aware of material stability limits, so finding the correct electrochemical conditions under which the effect could occur was challenging.”
Your biggest fan
Rolls-Royce has set a new record for the world’s most powerful aerospace gearbox. Speaking at the International Society for Air Breathing Engines (ISABE) conference, the company’s CTO, Paul Stein, confirmed that the Power Gearbox had successfully reached 70,000 horsepower while on test at Rolls-Royce’s dedicated facility in Dahlewitz, Germany. The Power Gearbox will play a central role in the company’s next-generation UltraFan® engine, helping to deliver improved efficiency over a wide range of thrusts.
The Power Gearbox is designed to run to 100,000 HP and future demonstrators are expected to achieve these levels. When running at maximum power, each pair of teeth on the gearbox will transmit more power than an entire grid of Formula 1 cars between them. The associated improvement in efficiency and reduction in weight will allow the UltraFan engine to offer a 25% fuel efficiency improvement over the first generation of Rolls-Royce Trent engines.
Defence and technology conglomerate Lockheed Martin has unveiled a new unmanned drone system that can be deployed from a canister.
Dubbed “OUTRIDER”, the drone is a mere four inches (101 mm) wide and weighs just 1.7 kg. It is designed to be used in environments where conventional, larger unmanned air systems would not be practical. It was developed at Lockheed Martin UK's Havant facility in partnership with Wirth Research.
Launched via canister at the press of a button, the UAV can be operated remotely or has the ability to be autonomous. Although small, OUTRIDER can travel at up to 50 knots (93 kph) and carries several visual payloads, including an HD image feed TV and infrared camera. Lockheed says this enables potential military, civil or commercial applications.
Lockheed Martin UK plans to offer it to market both in the UK and to export customers.
"We're excited and very proud of our collaboration with Lockheed Martin UK on the OUTRIDER project," said Nick Wirth, CEO and Wirth Research founder. "Performance enhancement and innovation are fundamental to our motor sport heritage at Wirth Research. Transferring this approach from racing, combined with our rapid concept development and aero expertise, has been key to successfully meeting the technical challenges set by the Lockheed Martin team. OUTRIDER is the leading edge result."
Candied carbon supercaps
Drexel University researchers have created a “fabric-like material electrode” that could enable the manufacturer of safer, faster batteries and supercapacitors.
The group has designed a new supercapacitor, which looks “like a furry sponge infused with gelatin”, and offers an alternative to the flammable electrolyte solutions that can cause battery malfunction.
Designed by College of Engineering Professor Vibha Kalra and her team, the device uses a thick ion-rich gel electrolyte absorbed in a mat of porous carbon nanofibre to produce a solid device. The design was published in a paper in the American Chemical Society journal Applied Materials and Interfaces.
In addition to being non-flammable, the group claims that the design is more durable and offers greater energy storage capacity and charge-discharge lifespan than current, comparable devices. It can also operate at temperatures as high as 300°C, making it suitable for use in hotter or more hazardous environments. The key to the device is the fibre-like electrode framework. This was created using a process called electrospinning, where a fibrous mat is created by being extruded through a rotating electric field — a process that apparently resembles making candy floss. The ionogel is then absorbed in the carbon fibre.
The next step for Kalra’s group, Drexel says, will be to apply this technique to the production of solid-state batteries, as well as exploring its application for smart fabrics.