What caught our attention outside the world of oil and gas this month
Boiling or exposure to UV rays in daylight are the most common ways of disinfecting water in which there is a risk of harmful microbes. However, both processes are time-consuming and require fuel input.
A new innovation from the US Department of Energy’s SLAC National Accelerator Laboratory and Stanford University could change this. Researchers have devised a nanostructured device, about half the size of a postage stamp, which can disinfect water faster than the UV method and using the visible part of the solar spectrum.
In a paper published in Nature Nanotechnology, sunlight falling on the little device triggered the formation of hydrogen peroxide and other disinfecting chemicals which killed more than 99.999% of bacteria in just 20 minutes. When this was complete, the chemicals dissipated, leaving pure water. The device uses “nanoflakes” of molybdenum disulphide that are stacked on edge on top of glass, and topped with a thin layer of copper. The compound is usually used as a lubricant, but in this nano-application it works as a photocatalyst, alongside the copper, to produce reactive oxygen species such as hydrogen peroxide – killing bacteria in the water.
It will not work with chemical pollutants, but in tests has managed to kill three strains of bacteria. More experiments will be required to evaluate eventual real-world applications.
Researchers at Massachusetts’ Tufts University have succeeded in creating nano-scale sensors, electronics and microfluidics which can be woven into natural and synthetic fibres. The resulting “smart threads” have been used in medical sutures to gather tissue and diagnostic information.
The threads can then transmit the data wirelessly to a smartphone or computer, all in real time.
The hope is that such a system could enable further developments in wearable technology and medical diagnostic devices.
Conductive threads are a number of chemical and physical sensing materials which could collect data such as pressure, stress, tissue strain, temperature, pH and glucose levels, all of which can be used to determine such things as how a wound is healing, whether infection is emerging, or whether the body’s chemistry is out of balance.
Sameer Sonsukale, director of the interdisciplinary Nano Lab in the Department of Electrical and Computer Engineering at Tufts School of Engineering One, and one of the paper’s co-authors, stated: “We think thread-based devices could potentially be used as smart sutures for surgical implants, smart bandages to monitor wound healing, or integrated with textile or fabric as personalised health monitors and point-of-care diagnostics.”
Quest for tribofilm
A new paper in Nature, authored by a team from the US’ Argonne National Laboratory, has described the discovery of a self-healing, diamond-like carbon (DLC) nanofilm.
Generated using the heat and pressure of an internal combustion engine, the new tribofilm – a film that forms between moving surfaces – could enable the design of more efficient and durable engines.
Argonne Distinguished Fellow Ali Erdemir, who led the team, stated: "We have developed many types of diamond-like carbon coatings of our own, but we've never found one that generates itself by breaking down the molecules of the lubricating oil and can actually regenerate the tribofilm as it is worn away.”
The discovery was made when Erdemir and Osman Levent Eryilmaz investigated the effects of coating a steel ring with a catalytically active nanocoating, which then underwent high pressure and heat using a base oil without the additives of normal lubricants. Following the experiment, the ring was intact, but with an odd blackish deposit on the contact area.
Further experiments, led by postdoctoral researcher Giovanni Ramirez, revealed that multiple types of catalytic coatings can yield DLC tribofilms. The experiments showed that the coatings interact with the oil molecules to create the DLC film, which adheres to the metal surfaces. When the tribofilm is worn away, the catalyst in the coating is re-exposed to the oil, causing the catalysis to restart and develop new layers of tribofilm.
The process is self-regulating, keeping the film at consistent thickness. Tests suggested that the DLC tribofilm reduced friction by 25 to 40%, and reduced wear to “unmeasurable” values.
Further investigation revealed the mechanics by which this worked: the nanocomposite coatings were stripping hydrogen atoms from the hydrocarbon chains of the lubricating oil, then breaking the chains down into smaller segments. The smaller chains then joined together under pressure to create the DLC tribofilm.
The hope is that the team’s innovation could reduce the need for expensive coatings, and the need to replace them once they are depleted. They also believe that this could reduce the need for anti-friction and anti-wear additives in oil, which can damage catalytic converters.
Here at InnovOil we rarely tire of microbot-related news.
Most recently, a team from the Ecole Polytechnique Fédérale de Lausanne (EPFL) unveiled a raft of new medical microbot designs, as well as a corresponding test platform. In a paper published in Nature Communications, EPFL scientist Selman Sakar and Hen-Wei Huang and Bradley Nelson of the Swiss Federal Institute of Technology in Zurich (ETHZ) detailed how they built an integrated manipulation platform that can remotely control the robots’ mobility with electromagnetic fields, and cause them to shape-shift using heat.
Their designs are made of “biocompatible hydrogel and magnetic nanoparticles,” meaning they are flexible and do not have any motors. Instead, the magnetic nanoparticles are manipulated when an electromagnetic field is applied, allowing the robots to move and swim.
Further tests will be required before these can be used in real-world medical applications – for example, the team do not yet know if they could cause any side-effects in the human body – but if successful, they could be used to deliver drugs or even perform surgical procedures.
As sensor technology becomes cheaper and more complex, it is increasingly moving into homes and businesses. One example is Walabot, a 3-D sensor designed for consumer DIY which allows users to see up to 4 inches (10cm) through concrete and drywall with their smartphone.
The magnetic sensor can be clipped onto the back of an Android device and has multiple sensing modes to display plastic and metal piping, wires and studs, their exact depth and even movement behind walls.
The product of 3-D sensor firm Vayyar Imaging, Walabot can also be used to enhance other applications which could benefit from sensing, such as collision detection in drones and cars, or movement tracking.
The company is also encouraging developers to create their own sensing apps using the technology. Vayyar Imaging CEO and co-founder Raviv Melamed said: “Walabot makes highly sophisticated imaging technology approachable, affordable and usable for everyone. We can't wait to see what other kinds of applications makers and curious inventors around the world will create for Walabot.”