Tech Radar | What caught our attention outside the world of oil and gas this month
November 28, 2017
Researchers at the University of Pennsylvania’s School of Engineering and Applied Science have devised a new method of making filtration membranes which could help prevent biofouling. Their method allows them to add in a host of new capabilities via functional nanoparticles that adhere to the surface of the mesh.
In a paper recently published in the journal Nature Communications, the team described their method, which allows for membranes to be made from a range of polymers and nanoparticles. Their “antifouling” properties would be useful in applications such as filtering drinking water, but could also be used to separate oil compounds and pollutants from fracking wastewater.
It may even be possible to use other nanoparticles to catalyse reactions with the contaminants, destroying them or even converting them into something useful.
The method uses a liquid mixture known as a “bicontinuous interfacially jammed emulsion gel,” or “bijel.” Unlike emulsions, which consist of isolated droplets, the oil and water phases of bijels are intertwined and fully connected. Nanoparticles used in this mixture then move to the interface between the oil and water.
Tests were performed using doped silica nanoparticles, made into tubes and altered to offer different functions – in this case antifouling properties. The team demonstrated the filtering and antifouling using water containing gold nanoparticles of various sizes.
The study was led by Penn Engineering Department of Chemical and Biomolecular Engineering Professor Daeyeon Lee, and Penn Engineering’s Deputy Dean for Research and Richer & Elizabeth Goodwin Professor of Chemical and Biomolecular Engineering Kathleen Stebe, as well as Martin F. Haase, an assistant professor at Rowan University who developed the technology as a postdoctoral researcher in the labs of Stebe and Lee. Harim Jeon, Noah Hough and Jong Hak Kim also contributed to the study.
“In our experiment, we were able to filter out very small gold nanoparticles, in sizes equivalent to viruses,” said Lee. “The tube shape also works well in large-scale implementation of these filter membranes. Because they have large surface-area-to-volume ratios and don’t get clogged, we can draw in fluid from the sides and suck it out from the end, allowing for continuous filtration,” explained Lee.
MIT researchers have used pulverised irradiated plastic to strengthen concrete, in a process which could enable better flexibility when using the material in construction – reducing carbon emissions. The process uses discarded plastic bottles which would otherwise have ended up in landfill.
Initially, the use of flakes of plastic – in this case polyethylene terephthalate – actually weakened concrete in experiments. However, the team of undergraduates found that by exposing these flakes to low and high doses of radiation and then crushing them into a powder, the resulting cement mixture (together with common additives fly ash and silica) produced concrete that was up to 15% stronger.
Using X-ray diffraction, backscattered electron microscopy and X-ray microtomography, they discovered that the irradiated plastic produced more cross-linked, crystalline structures within the mixture, making it denser, less porous and therefore stronger.
“At a nano-level, this irradiated plastic affects the crystallinity of concrete,” said one of the students, Kunal Kupwade-Patil. “The irradiated plastic has some reactivity, and when it mixes with Portland cement and fly ash, all three together give the magic formula, and you get stronger concrete.”
“We have observed that within the parameters of our test programme, the higher the irradiated dose, the higher the strength of concrete, so further research is needed to tailor the mixture and optimise the process with irradiation for the most effective results,” Kupwade-Patil added. “The method has the potential to achieve sustainable solutions with improved performance for both structural and non-structural applications.”
The team included Carolyn Schaefer and MIT senior Michael Ortega (who began the research as a class project), as well as research scientist Kunal Kupwade-Patil, Department of Nuclear Science and Engineering Assistant Professor Michael Short, Associate Professor Anne White, the Department of Civil and Environmental Engineering Professor Oral Büyüköztürk and Carmen Soriano of Argonne National Laboratory.
Canada’s Centre for Cold Ocean Resource Engineering (C-CORE) and Norwegian NOC Statoil have launched a competition to crowdsource better techniques for identifying icebergs based on satellite imaging.
The Statoil/C-CORE Iceberg Classifier Challenge was posted on Google-backed data problems website Kaggle, and offers a price of up to US$25,000 to the winning systems, capable of identifying potentially threatening icebergs drifting towards the Grand Banks area in Newfoundland.
While current satellite radar detection systems are functional, they can sometimes struggle to tell the difference between ships and icebergs; the goal here is to create a smarter algorithm which can. C-CORE has thus provided a large database of images for interested scientists to use in their pursuit of an automated detection system.
"We've got a database of 5,000 targets that we've uploaded to this website and the competition, which has prize money of US$50,000, will give people the incentive to look very closely at our database," said Desmond Power, C-CORE's vice president of remote sensing, was quoted by CBC News as saying.
“To keep operations safe and efficient, Statoil is interested in getting a fresh new perspective on how to use machine learning to more accurately detect and discriminate against threatening icebergs as early as possible,” the post added.
As of late November, there are already over 1,500 teams with just under two months to go until the application deadline of January 16, 2018, and a final submission deadline of January 23.
The groups are hopeful that these teams can generate interesting solutions. "It's an interesting thing to try out for them, I guess,” Power told CBC. “Icebergs are cool, satellite images are cool."
Wetting – the description of how liquid spreads on a surface – is a vital area of study for manufacturers of paints, coatings and other products. They will likely be buoyed by the news that Aalto University researchers have developed a new measurement technique dubbed “Scanning Droplet Adhesion Microscopy” (SDAM) to understand and characterise the wetting properties of water-averse or “superhydrophobic” materials.
Claimed to be 1,000 times more precise than current techniques, the microscope can measure tiny surface features and flaws down to the microscale. Existing instruments for measuring droplet adhesion forces only detect forces down to a micronewton level, but SDAM can detect forces in nanonewtons.
“Our novel microscope will promote the understanding of how wetting emerges from surface microstructures. The measuring instrument can also detect microscopic defects of the surface, which could allow coating manufacturers to control the quality of materials. Defects in self-cleaning, anti-icing, anti-fogging, anti-corrosion or anti-biofouling products can impeach the functional integrity of the whole surface,” Professor Robin Ras from Aalto University School of Science commented.
“We have used a droplet of water to measure the water-repellent properties of a surface by recording the very tiny nanonewton force when the droplet touches the surface and when it separates from the surface. By measuring on many locations with micrometre spacing between the measurement points, we can construct a two-dimensional image of the surface’s repellency, called a wetting map,” added School of Electrical Engineering Professor Quan Zhou.
The method also offers an alternative to contact angle measurement, the previous standard method for wettability calculation, but one which is prone to inaccuracy on superhydrophobic surfaces. SDAM can also detect wetting properties of microscopic functional features that were previously very hard to measure. Those microscopic features are important in many biochips, chemical sensors and microelectromechanical components and systems.