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Hong Kong team develops 4D printing for ceramics

Mon, 2018-08-20 15:59

Elastomeric precursor allows 4D printing of mechanically robust shapes with complex geometry to be printed, with potential applications in electronics, decorative arts and aerospace

Four-dimensional printing refers to the manufacture of geometries that can reshape or self assemble over time, with the influence of external stimuli such as force, temperature or magnetism. It is particularly applicable to ceramics which, because of their tendency to stiffness and brittleness, are very difficult to print in complex shapes.

(Above and below) two complex shapes made by ceramic 4D printing

This has been a barrier to the structural application of ceramics, with the result that they have been largely excluded from the revolution that 3D printing has brought to the use of polymers and metals. The development from City University of Hong Kong (CityU) is to use a “ceramic ink” to print flexible forms that can be turned into a conventional ceramic material with heat treatment.

In a paper in the journal Science Advances, a team led by material scientist Prof Lu Jian describes how the ink, made from elastomeric poly (dimethylsiloxane) mixed with crystalline nanoparticles of zinc oxide, 20 to 50nm in diameter, could be printed and then deformed through stretching, origami-like folding, or by using pre-defined joints and creases into complex shapes and then heat treated to turn them into rigid ceramic bodies.

“The whole process sounds simple, but it’s not,” said Professor Lu. “From making the ink to developing the printing system, we tried many times and different methods. Like squeezing icing on a cake, there are a lot of factors that can affect the outcome, ranging from the type of cream and the size of the nozzle, to the speed and force of squeezing, and the temperature.”

The various stages involved in forming a complex shape from flexible ceramic ink

The team developed two techniques for shaping the bodies. In the first, two forms  – a 3D-printed ceramic precursor and substrate – were first made with the new ink. The substrate was stretched and joints for connecting it to the precursor were printed onto it. The precursor was then placed onto the stretched substrate, which was allowed to relax, morphing the materials into the desired shape.

In the second method, a pattern was directly printed onto the stretched ceramic precursor. It was then released under computer control to morph into the final form. Both techniques can produce complexly curved and textured forms which were not accessible through previous additive manufacturing techniques.

Prof Lu believes that electronic devices will be an important application sector for this technology. Ceramics transmit electromagnetic signals much better than metals, and they are expected to play a much more important role in the manufacture of housings for products such as mobile phones when 5G networks come into use.

The resistance of ceramics to defamation and heat means that these products will also be attractive to the aerospace industry, particularly in space applications. “Since ceramic is a mechanically robust material that can tolerate high temperatures, the 4D-printed ceramic has high potential to be used as a propulsion component in the aerospace field,” said Prof Lu.

The 4D printing project has taken two and a half years to reach this stage, but is not yet complete. Prof Lu now hopes to improve the mechanical properties of the material, in particular by reducing its brittleness.


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D-shaped design eradicates instabilities in high-power lasers

Mon, 2018-08-20 15:42

An international team of scientists believes it has overcome a long-standing limitation in conventional high-powered lasers with a D-shaped laser design that limits beam instabilities.

D-shaped laser cavity tackles instability in high-powered lasers (Credit: Yale University)

High-powered lasers are used in materials processing, large-scale displays, laser surgery and LiDar, but instabilities can occur in the laser that limit their usage. This instability poses no problems for applications such as laser pointers, but becomes problematic for lasers operating at high power.

The scientists from Nanyang Technological University, Singapore (NTU Singapore), Yale University and Imperial College London and Cardiff University have developed a D-shaped laser that regulates the light emission patterns and eliminates such laser instabilities to potentially reduce the degree of fluctuations in the laser output. The team’s findings are published online in Science.

“Traditional lasers emit fluctuations in light waves that limit their usefulness,” said NTU Associate Professor Wang Qijie. “To prevent them from forming, we created an irregular-shaped laser cavity that causes light to bounce off the walls of the cavity in an unpredictable manner that however results in a stable light stream. It’s like using chaos to deal with chaos.”

The research was conducted on the sort of semiconductor laser found in barcode scanners and laser printers, but the team believes their findings could be extended to other types of lasers including gas and solid-state lasers.

Most traditional laser devices take on a cuboid shape, with mirrors placed parallel to each other. This allows light to reflect back and forth between the mirrors, which leads to laser instability, particularly in high-powered lasers, creating irregular peaks and troughs as light is emitted from the laser. These varying peaks could deteriorate the formation of images.

Yale’s Professor Hui Cao said previous strategies to reduce interference have usually involved reducing the power of the laser. “As a result, none of the previous approaches are scalable to the power levels required for practical applications,” said the Frederick W Beinecke Professor of Applied Physics at Yale. Professor Ortwin Hess, Co-Director of the Centre for Plasmonics and Metamaterials in Imperial College London, is the other principal investigator of the study.

To tackle this anomaly, Prof Wang led Zeng Yongquan and Hu Xiaonan, his two PhD students at the time, to build a D-shaped laser cavity. The NTU researchers joined the international research team two years ago.

Inside the D-shaped laser device, light is forced to bounce off mirrors along the irregular shape walls, making it travel in a disorderly manner. However, this seemingly chaotic method results in a stable pattern of light emission.

Assoc Prof Wang said imaging applications such as next-generation high-tech microscopes, laser projectors and biomedical imagery are the end goal for the joint research team.

“We have found that a D-shaped laser cavity is easy to fabricate, and is effective in significantly reducing the problematic laser instabilities. Our next step will be to find out if there are other cavity shapes that could make the laser more efficient,” he said.


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Paper-based biobattery uses bacteria to power IoT sensors

Mon, 2018-08-20 15:21

Researchers at the State University of New York, Binghamton have created a biobattery made from paper that uses bacteria as its power source.

(Credit: Seokheun Choi)

In remote parts of the world, access to batteries for medical devices and diagnostic equipment is often limited. Paper-based biosensors have long been used in these environments, but without a power source, they generally lack the sensitivity to provide accurate results. In light of this, the researchers went in search of a low-power bio-based alternative that could power these sensors and other IoT-connected devices.

“Paper has unique advantages as a material for biosensors,” said the university’s Seokheun (Sean) Choi, PhD, who is presenting the work at this week’s National Meeting & Exposition of the American Chemical Society (ACS). “It is inexpensive, disposable, flexible and has a high surface area. However, sophisticated sensors require a power supply. Commercial batteries are too wasteful and expensive, and they can’t be integrated into paper substrates. The best solution is a paper-based biobattery.”

To create the biobattery, the team first printed thin layers of metals and other materials onto a paper surface. For the power source, a quantity of freeze-dried bacteria known as exoelectrogens was then added. Exoelectrogens transfer electrons outside of their cell membranes as the bacteria produce energy for themselves, activated by water or saliva. As the electrons pass through the paper to the electrodes, enough power is generated to run a calculator and an LED. The team found that oxygen slightly diminished the power output, but as the exoelectrogens were tightly packed next to the paper, the effect was minimal.

The biobattery, which is designed for single use, has a shelf-life of around four months. Choi and his colleagues are currently working on new methods of treating the bacteria to extend the survival and performance of the device.

“The power performance also needs to be improved by about 1,000-fold for most practical applications,” he said.

Choi has applied for a patent for the technology and is looking to commercialise the device with the help of industry partners.


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The material difference

Fri, 2018-08-17 17:30

Giles Salt, CEO of M&I Materials, discusses moving from development to commercialisation in demanding material applications

Thousands of new materials are developed each year, many of which could be game-changing. But even with the concept proven – even with the huge hurdles in figuring out how to produce a lab-proven material at scale surmounted – there is still a long way to go. How do you commercialise materials for use in demanding applications?

Start with a double take

In the excitement of having developed an innovative, new material it’s easy to get carried away. But whether in the context of a multinational’s research and development department or a couple of post-grads tinkering in the lab, it’s important to start by taking two things: a breath, and a step back.

Now is the time to invest in developing a deeper understanding of the material’s potential customers, markets and applications. The hard work is not over yet.

The hard work isn’t over with laboratory research

Working specifically in demanding applications can be a blessing and a curse. On the one hand, competition may be less fierce and the ‘where to start’ element less bewildering than a more commoditised material. But if you’ve developed a marginally stronger but otherwise undifferentiated plastic polymer where would you start? It could be applied anywhere from chairs to toys to packaging and there would be ruthless competition at every stage.

By operating in the demanding applications space, there is less likely to be closely comparable competition, but it also means the fit has to be just right. Yet higher specificity means more effort is required to understand precisely where commercial opportunity lies. The business model for demanding, niche applications is often likely to be one of high value, low volume; so, understanding each potential customer and their specific needs is doubly important.

As an example, one of our brands, Wolfmet, produces a tungsten heavy alloy that found its niche in providing fine balance to Formula 1 cars and Boeing 737s on the one hand, and radiation shielding on the other. The two applications aren’t closely related so finding these commercial opportunities depended on judicious and comprehensive research.

It is easy to be blinkered when it comes to a material you have spent years developing. Having worked with it every day, its benefits and applications may have become second-nature and seem obvious, and it’s easy to forget that they may not be so apparent to others. Putting in the effort to research potential customers and their needs is crucial.

Market making

Of course, researching a market for a new material implies that it already exists. In fact, it often doesn’t – yet. Sometimes it’s not as simple as saying: “I’ve got a great material, what do you think” – it’s about creating the market.

This could involve working with companies who are developing new technologies so that the materials become integral to the design. For our MIDEL transformer fluids, we work closely with transformer manufacturers as they looked to design new models; our product helps to push their design in terms of performance.

These sorts of opportunities don’t occur by themselves. It involves going out and collaborating to create the market, providing benefits for all.

Commercial skills

Developing a new material and its early use cases calls for very specific types of technical expertise. Commercialising it requires a different set of skills. Chief among these are patience and tenacity.

For materials designed for specialist, demanding applications it can feel like forever getting the first customer, signing the contracts and putting the supply chains in place. Engineers can be risk averse, preferring to stick to what’s tried and tested; tenacity is required at every step to bring them around. But it can also go the other way. Conversely, certain applications, such as Formula 1, are always looking for something that can give them an edge, making them more receptive to innovation.

Pick your partners

Frequently manufacturers need to seek out organisations with complementary expertise to bring a new product to market. More often than not, commercialising new materials is a collaborative effort. Manufacturers looking to take a new material to market often need to seek out organisations with complementary expertise to their own.

This might take the form of research from universities or private laboratories, collaboration with potential customers, or even other private companies.

There are also a host of agencies that exist purely to help promising, young technologies scale by providing tailormade, commercial support.

Keep innovating

Perhaps the most important thing to do is to never stand still. New applications may still be developed for successfully commercialised products. At M&I Materials, we’ve been making Apiezon, a range of high vacuum greases, sealants and lubricants, for over 80 years. Yet we recently created a new grease to work at a wider range of temperatures replacing several products.

Commercialising a material for demanding applications is a complex process with no set formula, the key is to remembering that the material itself is only ever the start.

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The world’s most wear-resistant alloy consists of platinum and gold

Fri, 2018-08-17 16:08

A new alloy developed at Sandia National Laboratories could represent a huge savings for the electronics industry

Although to the general public metals are most durable materials, engineers know that this is not the case. Without specialised coatings or lubricants, wear, deformation and corrosion inevitably follows when metal moves directly against metal.

Chasndross (left) and Argibay with their computer simulation and testing equipment for their high durability alloy. Image: Randy Montoya

Engineers at Sandia National Laboratories in Albuquerque, New Mexico have been studying this problem, and a new approach to the mechanics of frictional wear has led them to develop an alloy of platinum and gold which, they believe, is the world’s most wear-resistant metal as it is more durable than high-strength steel and in the same class as diamond and sapphire. They describe their work in a paper in Advanced Materials.

In general, wear resistance is believed to be related to hardness. However, the Sandia team, led by Nic Argibay and Michael Chandross, proposed a new theory stating that wear is related to how metals react to heat. Using computer simulations to calculate how individual atoms were affecting large-scale properties of the material, in particular how they affected the stability of the nanocrystalline structure of the alloy, they chose a mixture of 90 per cent platinum with 10 per cent gold. Although expensive, these metals have the advantage of being “noble” – that is, far less reactive than other metals and therefore available in very high purity with no need to worry about oxide formation.

“We’re getting down to fundamental atomic mechanisms and microstructure and tying all these things together to understand why you get good performance or why you get bad performance, and then engineering an alloy that gives you good performance,” Chandross said.

Stability of nanocrystals was crucial to the alloy’s properties. “Many traditional alloys were developed to increase the strength of a material by reducing grain size,” said John Curry, first author on the paper. “Even still, in the presence of extreme stresses and temperatures many alloys will coarsen or soften, especially under fatigue. We saw that with our platinum-gold alloy the mechanical and thermal stability is excellent, and we did not see much change to the microstructure over immensely long periods of cyclic stress during sliding.”

The alloy was made using high-tech methods, depositing films atom by atom using a magnetron. The structure of these films consisted of columns with grain sizes about 40nm. The alloy appears like pure platinum, silvery white in colour and little heavier than gold, and is no harder than other platinum gold alloys but is much better at resisting heat and much more wear resistant.

The material had another surprise in store. While measuring its properties in sliding tests, the team noticed that a black film was forming on the surface of the alloy. This turned out to be diamond -like carbon, a highly efficient solid lubricant that is used in high-performance internal combustion engines. Normally, this requires special conditions to manufacture, but the Sandia alloy forms are spontaneously.

“We believe the stability and inherent resistance to wear allows carbon-containing molecules from the environment to stick and degrade during sliding to ultimately form diamond-like carbon,” Curry said. “Industry has other methods of doing this, but they typically involve vacuum chambers with high temperature plasmas of carbon species. It can get very expensive.” This phenomenon is described in a separate paper in the journal Carbon.

The alloy could be highly significant for the electronics industry, where sliding metal contacts are common components in many devices. Because these contacts tend to be very small, they wear out quickly and either need to have expensive protective coatings or be replaced regularly. Using the super durable alloy, even though it is made of expensive materials, could save hundreds of millions of dollars every year materials alone, according to Argibay. Applications can be found in many other industries, including aerospace systems and wind turbines.

Moreover, the diamond-like carbon discovery could lead to simpler and cheaper ways of making this lubricant material, the team added.


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Nanocomposite coatings turn fabrics into pressure sensors

Fri, 2018-08-17 15:46

Engineers are developing smart textiles by integrating flexible nanocomposite coatings on natural and synthetic fibres, an advance that could turn shoes and clothes into pressure sensors.

Sagar Doshi (left) and Erik Thostenson test an elbow sleeve outfitted with one of their novel sensors (credit: Kathy F. Atkinson)

The team at the University of Delaware is said to have demonstrated the ability to measure pressure ranging from the light touch of a fingertip to being driven over by a forklift truck. Their work is reported in ACS Sensors.

Fabric coated with this sensing technology could be used in future “smart garments” where the sensors are inserted into the soles of shoes or stitched into clothing for detecting human motion.

“As a sensor, it’s very sensitive to forces ranging from touch to tons,” said Erik Thostenson, an associate professor in the Departments of Mechanical Engineering and Materials Science and Engineering.

Nerve-like electrically conductive nanocomposite coatings are created on the fibres using electrophoretic deposition (EPD) of polyethyleneimine functionalised carbon nanotubes.

“The films act much like a dye that adds electrical sensing functionality,” said Thostenson. “The EPD process developed in my lab creates this very uniform nanocomposite coating that is strongly bonded to the surface of the fibre. The process is industrially scalable for future applications.”

Researchers can add these sensors to fabric in a way that is claimed to be superior to current methods for making smart textiles.

Existing techniques, such as plating fibres with metal or knitting fibre and metal strands together, can decrease the comfort and durability of fabrics, said Thostenson.

A sensor could be inserted into the sole of a shoe

The flexible nanocomposite coating has been tested on fibres including Kevlar, cotton, wool, nylon, Spandex and polyester. The coatings are 250nm to 750nm thick and would add about a gram of weight to a typical shoe or garment. Moreover, the materials used to make the sensor coating are inexpensive and can be processed at room temperature with water as a solvent.

One potential application of the sensor-coated fabric is to measure forces on people’s feet as they walk. This data could help doctors assess imbalances after injury, or help to prevent injury in athletes.

Sagar Doshi, a doctoral student in mechanical engineering at UD, is the lead author on the paper. He worked on making the sensors, optimising their sensitivity, testing their mechanical properties and integrating them into sandals and shoes.

He has worn the sensors in preliminary tests and found that they collect data that is comparable to that collected by a force plate, a laboratory device that can cost thousands of dollars.

“Because the low-cost sensor is thin and flexible the possibility exists to create custom footwear and other garments with integrated electronics to store data during their day-to-day lives,” Doshi said. “This data could be analysed later by researchers or therapists to assess performance and ultimately bring down the cost of healthcare.”

This technology could also be promising for sports medicine applications, post-surgical recovery, and for assessing movement disorders in children.


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ASTERIA CubeSat becomes first to observe an exoplanet

Fri, 2018-08-17 15:46

A CubeSat called ASTERIA – Arcsecond Space Telescope Enabling Research in Astrophysics – has become the first to detect an exoplanet transit, demonstrating the growing capabilities of small satellites.

Members of the ASTERIA team prepare the petite satellite for its journey to space (Credit: NASA/JPL-Caltech)

Built by MIT and NASA’s Jet Propulsion Laboratory, ASTERIA started in 2010 as an undergraduate class project in Space Systems Engineering. Having launched onboard a resupply mission to the International Space Station (ISS) in August 2017, it was deployed from the ISS in November last year. After successfully completing its initial 90-day mission, the CubeSat then observed the transit of 55 Cancri e, a previously discovered exoplanet in the orbit of the Sun-like star, 55 Cancri A. As the exoplanet passed by the star, the CubeSat’s precision photometry detected a change in brightness of around 0.04 per cent.

The ASTERIA mission was designed to demonstrate key technologies, including very stable pointing and thermal control for making extremely precise measurements of stellar brightness in a tiny satellite. Earlier this year- as part of its primary mission – ASTERIA achieved pointing stability of 0.5 arcseconds and thermal stability of 0.01 degrees Celsius. These technologies are fundamental for precision photometry – the measurement of stellar brightness over time – and enabled the CubeSat to hunt for exoplanets.

ASTERIA’s success is further evidence of the impact that small satellites can have, and the results of the mission were presented at the recent Small Satellite Conference in Logan, Utah. The project was awarded “Mission of the Year” at the conference, an award presented annually to a mission that has demonstrated a significant improvement in the capability of small satellites, which must weigh less than 150kg. Having demonstrated an ability to detect exoplanets that were already known, ASTERIA will now be deployed to hunt for undiscovered transiting exoplanets, focusing its gaze on two nearby bright stars.


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UK urged to make more of its IP

Thu, 2018-08-16 19:51

The head of In-Comm Training is urging businesses and the government to step up efforts to commercialise Intellectual Property (IP) created in Britain.

Gareth Jones, joint managing director of the Walsall-based training and business services company, believes the recent £19bn warship contract between BAE Systems and Australia highlights a trend of UK design and value added engineering being exported overseas for others to complete the manufacturing work.

“On the surface, we should all be rejoicing in the news of British defence giant BAE Systems securing a multi-billion contract to build new warships for the Australian Government,” said Jones.

“The perfect shot in the arm for potential life after Brexit it seems, or is it? There is definitely good news in the fact that UK expertise has been chosen ahead of Spanish and Italian rivals and there will be some benefits financially to our economy.

“However, look a little bit closer at the detail of the story and you realise that the majority of the manufacturing and the jobs will be gobbled up by the Australians – no doubt written into the contract to protect their own interests,” he added.

“What it does highlight is another example of how the UK and its treasure chest of Intellectual Property (IP) continues to be exported around the globe for others to take full advantage of.

“Yes, it’s great that our expertise is in demand, but wouldn’t it be better if that initial design, knowledge and technology is actually delivered here, creating jobs and blooding new engineers…that’s not even taking into consideration the indirect economic benefits?”

Many of these thoughts were debated during the first In-Comm Training & Manufacturing Group event held recently at the Marches Centre of Manufacturing & Technology.

Reaction to the BAE Systems news was on the whole positive, but the nagging doubt of a missed opportunity was prevalent, along with SMEs feeling even further detached from being able to supply into significant contracts.

“Undoubtedly, there is work to be done to unpick the barriers and give small to medium sized manufacturers the chance to be involved,” added Jones.

“There was also a common desire for the government’s current Industrial Strategy to be sustained and a concerted call for politicians to ignore ‘party loyalty’ to place their backing behind sectors that play to the UK’s greatest competitive strengths.

He concluded: “The message is simple. Cultivate and celebrate our Intellectual Property, but don’t forget about the industry and supply chain benefits that can be gleaned from making the most of the ‘IP’ in this country.”


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Bath drone team takes rookie award at European robotics event

Thu, 2018-08-16 16:30

Team Bath Drone Marine (TBDM) has been awarded the Best Rookie prize at the Emergency Robotics Challenge, a pan-European student event.

Run by the European Robotics League (ERL), the competition challenged teams to design and build drones to carry out untethered, autonomous missions on land and underwater. The Bath University students were the sole UK representatives and competed against a number of other international teams from France, Germany, Italy, Spain, and Poland.

Each mission related to an emergency-response theme – such as a nuclear disaster – and some missions required collaboration between drones in different domains, for example detecting a leaking underwater pipeline and closing the appropriate valve on land. Points were awarded for goals completed successfully and the team with the highest score at the end was the winner.

The TBDM underwater robot had been developed over several years – beginning from a group design and business project, followed by implementation within a number of final year projects, and then many more hours of extracurricular effort. Though the Bath team failed to place at this year’s event, it was awarded the Best Rookie prize on its competition debut.

“Participating in the ERL Emergency Robotics Challenge has been a huge step forward for TBDM and an excellent learning experience for the students. The bar has been set for next year’s team,” said Dr Alan Hunter, academic lead and lecturer at Bath’s Department of Mechanical Engineering.

“We are extremely grateful to the support we have received, especially the funding provided by the Department of Mechanical Engineering and Bath Alumni fund, as well as in-kind support from Blueprint Subsea and the University of Bath Sports Training Village. Lastly, we wouldn’t have been able to get and stay there without the support of ERL who generously funded our travel and accommodation.”


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Magnetic nanoparticles pull oil from well production water

Thu, 2018-08-16 15:42

Researchers from Rice University have used magnetic nanoparticles to separate the last drops of oil from the production water that results from hydrocarbon extraction.

Oil production can be water-intensive, especially when fracking is used to force the oil to the surface. Under pressure, and with the additional presence of soapy surfactants that can lower the surface tension of chemicals, oil and water mix to form an emulsion. Though techniques exist to separate most of the oil from this ‘produced water’, the last five per cent tends to be particularly stubborn and virtually impossible to recover. Now, however, the Rice team claims it can reliably remove over 99 per cent of emulsified oil using a magnetic particle solution that binds to the oil.

“Injected chemicals and natural surfactants in crude oil can oftentimes chemically stabilise the oil-water interface, leading to small droplets of oil in water which are challenging to break up,” said Sibani Lisa Biswal, an associate professor of chemical and biomolecular engineering and of materials science and nanoengineering at Rice.

To create the solution, the researchers added amines to magnetic iron nanoparticles. Amines carry a positive charge that helps the nanoparticles find negatively charged oil droplets. Once they do, the nanoparticles bind the oil. Magnets are then able to pull the droplets and nanoparticles out of the solution.

The enhanced nanoparticles were tested on emulsions made in the lab with model oil as well as crude oil. In both cases, researchers simply added nanoparticles into the emulsions, which they shook by hand and machine to break the oil-water bonds and create oil-nanoparticle bonds in their place. Some of the oil floated to the top, while placing the test tube on a magnet pulled the infused nanotubes to the bottom, leaving clear water in between. The work is published in Environmental Science: Water Research & Technology

“It’s often hard to design nanoparticles that don’t simply aggregate in the high salinities that are typically found in reservoir fluids, but these are quite stable in the produced water,” Biswal said.

According to the Rice team, the magnetic nanoparticles can be washed with a solvent and reused, while the oil can be recovered. Biswal’s lab is currently designing a flow-through reactor to process produced water at scale and automatically recycle the nanoparticles. If successful, the device could be used for sites like offshore rigs, where treated water could be returned to the ocean.


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Tricking amputees into accepting their prosthetic

Thu, 2018-08-16 15:36

A sensory trick is helping prosthetic arm users feel as though their false limb is part of their body

One of the biggest challenges faced by amputees who use prosthetics is getting over the feeling that their prosthetic is not part of their body. It’s partly a counter-intuitive problem: of course, the prosthetic is not part of the body, but it’s essential for the user to imagine it is if they are to get the best use from it. One particular problem is that amputees can often ‘feel’ their missing limb; or at least, a distorted version of it.

The technique used simultaneous nerve stimulation and virtual reality visualisation

Researchers at Lausanne Polytechnic University (EPFL) have experimented with sensory illusions to determine whether amputees’ nervous systems can be “tricked” into accepting the prosthetic limb. The technique relies on the axiom that “seeing is believing”.

This can itself be a reason that amputees opt out of prolonged use of prosthetics, especially of artificial hands: essentially, their own perception of the missing limb – or the sensation of it – does not match up with what they can see of the prosthesis. Part of the problem is that the phantom limb often perceived by amputees is much smaller than the actual lost limb; and as the prosthetic does not provide sensory feedback, the user can only tell it is being used correctly by watching it. The mismatch between vision and sensation can be an overwhelming stumbling block.

The EPFL research, published in the Journal of Neurology, Neurosurgery and Psychiatry, combines physical stimulation with virtual reality. The team, from EPFL’s laboratory of cognitive neuroprosthetics in collaboration with Scuola Superiore Sant’Anna in Italy, produced an artificial tactile sensation at the tip of the index finger of the phantom limb by stimulating nerves in the remaining stump of an amputee patient, while simultaneously showing the index finger of the prosthetic limb glowing on a display in virtual reality goggles.

The experiment was only carried out on two patients, however, both of them reported feeling as though the index finger sensation was occurring in a prosthetic hand that belonged to their body. Moreover, they felt as though their phantom limb had extended into the prosthetic limb. This feeling persisted for 10 minutes after the experiment.

“The brain regularly uses its senses to evaluate what belongs to the body and what is external to the body. We showed exactly how vision and touch can be combined to trick the amputee’s brain into feeling what it sees, inducing embodiment of the prosthetic hand with an additional effect that the phantom limb grows into the prosthetic one,” explains Giulio Rognini of the Laboratory of Cognitive Neuroprosthetics. “The setup is portable and could one day be turned into a therapy to help patients embody their prosthetic limb permanently.”


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Rechargeable battery technology promises to extend range of electric vehicles

Thu, 2018-08-16 15:32

Ceramic, solid-state electrolyte helps overcome limitations of lithium batteries

Nathan Taylor, a post-doctoral fellow in mechanical engineering, inspects a piece of lithium metal (Credit: Evan Dougherty, Michigan Engineering)

A new rechargeable battery technology could double the output of current lithium ion cells, an advance that promises to extend electric vehicle ranges and the time between mobile phone charges.

By using a ceramic, solid-state electrolyte, engineers at the University of Michigan have harnessed the power of lithium metal batteries without the historic issues of poor durability and short-circuiting. Their breakthrough could lead to longer-lasting drop-in replacements for lithium ion batteries.

“This could be a game-changer – a paradigm shift in how a battery operates,” said Jeff Sakamoto, a U-M associate professor of mechanical engineering who led the work.

The first rechargeable lithium metal batteries contained combustible liquid electrolytes. Furthermore, lithium atoms that moved between the electrodes tended to build dendrites on the electrode surfaces, eventually shorting the battery and igniting the electrolyte.

Lithium ion batteries followed, replacing lithium metal with graphite anodes, which absorb the lithium and prevent dendrites from forming. This increased safety at the cost of energy density.

According to U-M, graphite anodes in lithium ion batteries hold one lithium ion for every six carbon atoms, giving it a specific capacity of approximately 350mAh/g. The lithium metal in a solid-state battery has a specific capacity of 3,800mAh/g.

Current lithium ion batteries have a total energy density around 600Wh/L at the cell level. In principle, solid-state batteries can reach 1,200Wh/L.

To solve lithium metal’s combustion problem, U-M engineers created a ceramic layer that stabilises the surface by preventing the build-up of dendrites, which allows batteries to harness the energy density and high-conductivity of lithium metal without the inherent dangers of fire or degradation over time.

A demonstration of a machine that uses heat to densify a ceramic known as LLZO at 1,225 deg C (Credit: Evan Dougherty, Michigan Engineering)

“What we’ve come up with is a different approach – physically stabilising the lithium metal surface with a ceramic,” Sakamoto said. “It’s not combustible. We make it at over 1,800oF in air. And there’s no liquid, which is what typically fuels the battery fires you see. You get rid of that fuel, you get rid of the combustion.”

In earlier solid-state electrolyte tests, lithium metal grew through the ceramic electrolyte at low charging rates, causing a short circuit. U-M researchers are said to have overcome this with chemical and mechanical treatments that provide a pristine surface for lithium to plate evenly, effectively suppressing the formation of dendrites or filaments. Not only does this improve safety, it enables a dramatic improvement in charging rates, Sakamoto said.

“Up until now, the rates at which you could plate lithium would mean you’d have to charge a lithium metal car battery over 20 to 50 hours [for full power],” Sakamoto said. “With this breakthrough, we demonstrated we can charge the battery in three hours or less.

“We’re talking a factor of 10 increase in charging speed compared to previous reports for solid state lithium metal batteries. We’re now on par with lithium ion cells in terms of charging rates, but with additional benefits. ”

Repeatedly exchanging ions between the cathode and anode produces visible degradation.

In tests on the ceramic electrolyte no visible degradation was observed after long term cycling.

“We did the same test for 22 days,” said Nathan Taylor, a U-M post-doctoral fellow in mechanical engineering. “The battery was just the same at the start as it was at the end. We didn’t see any degradation. We aren’t aware of any other bulk solid-state electrolyte performing this well for this long.”

The group’s findings are published in the Journal of Power Sources.


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Teeside team races for space with tiny rocket

Wed, 2018-08-15 17:29

Students past and present from Teeside University are aiming to launch a tiny rocket into space from the North East of England this autumn.

James Dent, who now works for Express Engineering, was a team leader on the project when he attended Teeside

The group is aiming to become the first university team to build and launch a rocket into space from the UK. Its TU2Space rocket, which stands at just 30cm tall and weighs 650g, will first be flown to 32,000m using a helium balloon. From there, the rocket’s motor will kick in, taking the tiny vehicle to an altitude of 120km at speeds of up to Mach 5.

Altogether over 50 students have been involved in the collaborative experiment, carrying out everything from research and testing, to simulations, balloon trials, manufacturing rocket fuel and marketing.  The initiative has also contributed to space and technology engineering research in the North East. James Dent, a former Teeside University student now working at Tyneside-based Express Engineering, was one of the project’s team leaders while he attended the university. A former banker, James worked part-time when he was transitioning from finance to follow his dream of becoming an aerospace engineer.

“I have thoroughly enjoyed the challenge and received support, mentoring and flexible working opportunities from Express to help me complete my course and be part of the rocket project,” said 37- year-old James, from Blaydon, just outside Newcastle.

“I am excited to have graduated and am looking forward to new opportunities at work and continuing professional development with a goal to achieve chartered engineer status. I have always been fascinated by flight and thinking about how things that fly are made and assembled. I am STEM (science, technology, engineering and maths) by default so to be working in the aerospace team at Express is just a dream come true.”

John A Patterson, CEO with Express, added: “James first joined our team as an intern but he quickly showed great aptitude and attitude and so we were pleased to be able to provide him proper employment.

“His enthusiasm for his work is infectious and I am sure that he will continue to be a valued member of our team as he increases his skills and knowledge of the engineering industry.”


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Morandi bridge tragedy claims 37 lives

Wed, 2018-08-15 16:21

A partial collapse of the Morandi bridge in Genoa, Italy has led so far to the deaths of 37 people after their vehicles fell from the wrecked structure.

Italian Red Cross search for survivors

An approximately 210m long section of the Morandi bridge collapsed yesterday, August 14, 2018, at 11.30, injuring a further 16 people. Members of the Italian Red Cross are using sniffer dogs to find people trapped in the wreckage.

The bridge, which is part of the Polcevera Creek Viaduct, was built in a densely crowded urban area occupied by two railroad yards and large industrial facilities. The structure, designed by Riccardo Morandi, was opened in 1967 and was said to be undergoing structural repairs at the time of collapse.

According to Dr Maria Rosaria Marsico, senior lecturer in structural engineering at Exeter University, the viaduct includes three cable-stayed spans and a series of minor spans for a total length of about 1182m. The three largest spans consist of independent cable-stayed structures, each carried by an individual reinforced concrete pier and tower 90m high.

“The cable-stayed systems were characterised by the adoption of prestressed concrete stays, a common feature of bridges designed by Morandi in the sixties,” she said. “The viaduct was subject to maintenance work since it was built, and in the nineties a complex intervention of repair was carried out involving the installation of conventional steel tendons which are flanking the existing concrete stays.”

Ian Firth, FREng, past president of The Institution of Structural Engineers, said it is too early to say what caused the collapse of Morandi bridge, but corrosion of tendons or reinforcement may be a contributory factor given the age of the bridge.

According to recent research, corrosion of reinforcement changes the long-term behaviour of ageing reinforced concrete bridges, said Dr Mehdi Kashani, associate professor in structural mechanics at Southampton University.

“In addition, bridges are constantly subjected to cyclic dynamic loading due to highway traffic, wind and/or major/minor earthquake, which will result in fatigue damage in bridge components,” said Dr Kashani. “It is reported that this bridge collapsed during a heavy storm. Therefore, dynamic wind loading, combined with additional loading due to on-going work on the bridge, and reduced capacity due to corrosion and fatigue might be the cause of failure. However, there is need for further detailed investigation to fully understand the cause of failure.”

Firth said the A-frame towers which support the concrete-encased stay cables combine with V-shaped supports below the deck of the bridge to create a stiff arrangement which is not common in cable-stayed bridges.

“This deals with potential unbalanced loads which arise due to the multi-span nature of the structure,” he said.  “As yet, there is no evidence to say whether any impact occurred; it is too early to say what triggered the collapse.”


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Using light to create bacteria-fighting polymers

Wed, 2018-08-15 16:01

Warwick University team devises lights-mediated method to make and test polymers that can kill “superbugs” on contact

The method would allow the synthesis of large libraries of related polymers

The evolution of bacteria resistant to established methods of controlling them has become an increasingly urgent problem in hospitals and elsewhere. Antimicrobial substances are vital components for fighting diseases and infections in the body, but are also used in personal care products and, for example, contact lens solutions. Bacteria that are immune to their effects can lead to infections.

The Warwick team, led by Prof Matthew Gibson, was investigating whether combinatorial chemistry, a technique used to generate large libraries of related chemical compounds which is widely used in the pharmaceutical industry to determine which compounds have the highest activity, could be used to find new antimicrobial agents. This would allow researchers to “go fishing” for new properties.

The main thrust of the research was to mimic naturally occurring peptides – fragments of large proteins – that have bacteria killing properties. “Whilst many people have successfully mimicked antimicrobial peptides with polymers, the limiting step was the number of different combinations of building blocks you can use,” he said. “We used simple robotics and a light controlled polymerisation, which lets us do the chemistry open to air, without any sealed vials which are essential for most polymer syntheses.”

In a paper in the journal Chemistry: A European Journal, the team explains how they synthesised a variety of polymers based upon methacrylate monomers. Having made their polymers, the group used a robotic method to mix them directly with bacteria to observe how they behaved.

These polymethacrylates were expected to have a different mode of action from antibiotics like penicillin, which work by inhibiting processes within the bacterial cells. Instead, the polymethacrylates should have mimicked the action of peptides that break apart the membranes of bacteria. However, in tests, the peptides made by the team seemed to inhibit the growth of bacteria rather than bursting them open. Team member Sarah-Jane Richards said the group is now investigating this mode of action.


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Public WiFi could be used to screen bags for weapons and bombs

Wed, 2018-08-15 15:22

US engineers have developed a system that uses regular WiFi signals to passively screen bags for weapons, chemicals and bombs.

Led by Rutgers University’s Wireless Information Network Laboratory (WINLAB), the study describes how fine-grained channel state information (CSI) from off-the-shelf WiFi is used to first detect what material an object in a bag is made of. This CSI, which includes amplitude and phase information, is then used to calculate the dimensions of the item, whether that be the volume of liquid or the size of a metal object. According to the researchers, the low-cost system requires a WiFi device with two to three antennas and can be integrated into existing WiFi networks.

“This could have a great impact in protecting the public from dangerous objects,” said Yingying (Jennifer) Chen, study co-author and a professor in the Department of Electrical and Computer Engineering in Rutgers-New Brunswick’s School of Engineering. “There’s a growing need for that now.”

The team, which also included engineers from Indiana University-Purdue University Indianapolis (IUPUI) and Binghamton University, carried out experiments with 15 types of objects and six different types of bags. According to the paper which supports the work, the system achieved detection accuracy rates of 99 per cent for dangerous objects, 98 per cent for metal and 95 per cent for liquid. For typical backpacks, the accuracy rate exceeded 95 per cent but dropped to about 90 per cent when objects inside bags were wrapped. In comparison to screening at airports that requires special equipment and lots of manpower, the system is non-invasive and could be used to scan bags at museums, stadiums and schools.

“In large public areas, it’s hard to set up expensive screening infrastructure like what’s in airports,” said Chen. “Manpower is always needed to check bags and we wanted to develop a complementary method to try to reduce manpower.”

The research recently received a best paper award at the 2018 IEEE Conference on Communications and Network Security, which took place in Beijing.


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Flextensional transducers could be key enabler of complex ultrasonic surgery

Wed, 2018-08-15 13:22

Flextensional transducers used in underwater sonar could be key in the development of flexible, tentacle-like robots that help carry out surgery

Intuitive Surgical Inc – developers of the Da Vinci Xi – are project partners

Going under the knife could one day become a thing of the past, thanks to the development of robotic surgical tools that could ultimately carry out even complex procedures using ultrasound.

Ultrasonic devices are already used to perform some forms of surgery, but design restrictions mean they are limited to procedures where access to the operating site is through a simple, direct route.

However, accessing many points in the human body requires the surgical device to take a complicated path, limiting the use of minimally-invasive ultrasonic tools.

Now a team of UK researchers, funded by EPSRC, are developing a new generation of miniaturised ultrasonic devices that, when integrated with flexible, tentacle-like surgical robots, will be capable of performing procedures deep inside the human body.

The ultrasonic tools could allow minimally-invasive surgery to be carried out with higher precision and much lower force, while protecting delicate structures, according to project leader Prof. Margaret Lucas at Glasgow University.

“If you are trying to penetrate bone, for instance, [with traditional surgical tools] it requires quite a large force, whereas with ultrasonics it requires almost no force,” said Lucas.

“Ultrasonics can also be tissue-selective, so if you have the surgical tip operating at the right frequency and vibration amplitude, it will cut through one material, but will stop when it hits another type of material,” she said.

The technology could allow more procedures to be carried out on an out-patient basis.

To develop the tools, the researchers are investigating ways to overcome some of the existing constraints of ultrasonic surgical tools. Crucially, existing surgical tips must be in resonance with the transducer that is producing the vibration, which limits how small the devices can be built, said Lucas.

“Once you decide what frequency you will be operating at, that determines what the size of the transducer has to be, and it also dictates to some extent what size your surgical tip has to be, and that can be a big restriction,” she said.

So, for example, existing ultrasonic surgical devices often tend to be long and straight, restricting the type of procedures they can be used for.

Instead, the team have been investigating ways to adapt a type of transducer known as flextensional transducers, which are more commonly used for underwater sonar applications, for use in surgery.

Flextensional transducers can produce enough vibration that the surgical tip does not need to be in resonance with it, allowing the device to be miniaturised.

It could then be attached to a flexible, tentacle-like robot, to allow it to reach any part of the body.

“So you would have a tentacle-like robot with an ultrasonic surgical device on the end of it, and you could bring that into the human body along quite tortuous pathways to the site of surgery, and then the ultrasonic device would be activated to perform the surgical procedure,” said Lucas.

The devices will be tailored to deliver the exact amount of ultrasonic energy to the precise location required for the surgery.

To this end, the researchers will also be investigating the effects of ultrasound on tissue, at and around the site of surgery, using ultra-high speed imaging techniques.

By better understanding the biological impact of ultrasound on tissue, they hope to be able to optimise the design of the ultrasonic devices.

The project includes researchers from Southampton, Edinburgh, Leeds and Birmingham Universities, plus the NHS, Shanghai Institute of Ceramics, and medical technology companies including Stryker, Active Needle Technology and Intuitive Surgical.


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UK firm claims haptic VR surgery simulation can cost less than a cadaver

Tue, 2018-08-14 20:47

London startup FundamentalVR claims its surgery simulation technology, which merges VR with haptics, can be acquired for less than the cost of a single cadaver.

The company’s Surgical Haptic Intelligence Engine (SHIE) is designed to mimic the feel of operating on various types of human tissue, from subcutaneous fat to muscle and bone. Combined with off-the-shelf VR devices and standard haptic hardware, the platform can act as an immersive training tool for surgeons in waiting. Already available in the UK, the platform has now launched in the US, where the initial rollout will feature training packages for orthopaedic surgery, including spinal pedicle screw placement, posterior hip replacement and total knee arthroplasty.

“It involves creating ‘Haptic Actions’ which define the interactions between the surgical tools and the patient’s virtual anatomy,” Richard Vincent, CEO of FundamentalVR, told The Engineer. “To do this we create haptic baselines through close consultation with our Global Medical Panel, senior clinicians, comprising a range of surgical specialisms and then, with our unique calibration tools we are able to refine these through the development process to achieve the appropriate interaction. This requires a deep understanding of tissue behaviour under various conditions aligned with deep physics and mathematical computation.”

Current training for surgeons is largely confined to classroom lessons and viewing cadaver-based teaching, with limited hands-on time actually spent on cadavers by students themselves. According to FundameltalVR, a single cadaver can cost upwards of £10,000 and can only be used to train between four and six students. While haptic surgery simulation solutions do exist, these can cost in the region of £80,000, and less than 0.5 per cent of the world’s surgeons enjoy access to them. In the US, the company is pitching an entry point of $350 per month for its SaaS (Software as a Service) simulation platform.

“Our mission is to democratise surgical training by placing safe, affordable and authentic simulations within arm’s reach of every surgeon in the world,” said Vincent.

As well as being compatible with standard VR and haptic equipment, FundamentalVR says that its software is future-proofed, designed to work in tandem with new developments in the fast-growing haptics space.

“As we continue to develop and deploy our Haptic Intelligence Engine (SHIE) we are in effect building a hardware agnostic haptic map of the human body, which as other hardware solutions such as haptic gloves become economically viable for wide-scale medical use, we will be able to port directly into.”


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Smart cement mixture turns buildings into batteries

Tue, 2018-08-14 18:57

A smart cement mixture that can store electrical energy and discharge it on demand could convert buildings, bridges, curb stones and even street lamps into batteries.

Researchers at Lancaster University have developed a cement mixture, consisting of the waste material flyash and an alkaline solution, which is capable of conducting electricity.

Unlike existing smart concretes, which are typically based on graphene and carbon nanotubes, the new mixture does not contain any expensive materials, and is even cheaper to produce than conventional Portland cement.

In the mixture, known as a potassium-geopolymetric (KGP) composite, electricity is conducted via potassium ions that hop through the crystalline structure, according to project leader Professor Mohamed Saafi, from Lancaster University’s Engineering Department.

“To make cement you have to mix the flyash with an alkaline solution, in this case we use potassium hydroxide and potassium silicate,” he said. “When you mix them together they form a cement material, containing potassium ions that act as the electrolyte.”

The mixture could ultimately store and discharge between 200 to 500W/m2.

A house constructed with exterior or partition walls made with KGP, for example, could store electricity from solar panels during the day, and discharge it at night. Panels built from KGP could also be retrofitted onto homes and other buildings.

A six-metre tall lamppost built from KGP would be capable of storing enough renewable energy to power itself through the evening – typically around 700W.

Meanwhile curb stones could provide power to sensors capable of monitoring traffic, drainage and pollution levels.

Large numbers of KGP-built structures could also be used to balance the grid, storing excess renewable energy and releasing it when demand is high.

“We’re trying to turn buildings and bridges into batteries to reduce the cost of energy,” said Saafi. “At the moment we have a lot of renewable energy sources, but we don’t have a large-scale storage system for all that energy.”

The smart cement mixture can also be used to sense mechanical stress on the structures. Changes in stress, cause by cracks, for example, alter the way potassium ions move through the structure, and therefore the material’s conductivity.

By measuring the material’s conductivity, changes in the structural health of the building could be detected automatically and instantaneously, without the need to install additional sensors.

The researchers are now carrying out further work to optimise the performance of the KGP mixtures, and investigating the use of 3D printing techniques to create different shapes from the smart cement.

The research, which will be published in the journal Composite Structures in October, has been funded by the European Commission’s Horizon 2020 programme, as part of the SAFERUP (Sustainable, Accessible, Safe, Resilient and Smart Urban Pavements) project, led by the University of Bologna.


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This week’s Poll: what price palm oil

Tue, 2018-08-14 17:06

Palm oil is used in numerous products but what price are we prepared to pay for its cultivation? 

The ubiquity of palm oil cannot be understated, given its presence in numerous foodstuffs and products including soap, pharmaceuticals, fuels and cosmetics.

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Its use can be put down to its all-round efficiency. According to CommodityBasis, the fruit of the oil palm has an oil content of about 50 per cent and the palm kernel has an oil content of around 45 per cent. This high oil yield makes palm oil ‘by far the most efficient vegetable oil crop in the world.’

Furthermore, the oil palm can be planted at any time of the year for a useful life of between 20 and 25 years. Its fruits can be harvested year-round too, producing 10 times as much oil per hectare as soybeans and five times as much oil as rapeseed.

Nearly all palm oil is produced in Malaysia and Indonesia but potential expansion in Africa – where the plant originates – has led a research team to warn against growing the plant at the expense of indigenous wildlife, specifically primates.

In a paper titled ‘Small room for compromise between oil palm cultivation and primate conservation in Africa’ a research team, including Simon Stringer from Liverpool John Moores University, acknowledge that palm oil production can be an important source of income, but to the detriment of primate habitats.

They’ve identified ‘a high overlap between areas of high oil palm suitability and areas of high conservation priority for primates’, adding that oil palms could only be cultivated in ‘a few small areas where oil palms could be cultivated in Africa with a low impact on primates’.

Back in South East Asia, researchers from EPFL and the Swiss Federal Institute for Forest, Snow and Landscape Research warned in June 2018 that turning rainforests into oil palm plantations produces staggering levels of CO2 emissions.

Palm oil clearly has a role to play in our day-to-day lives, given its high yields, utility, and relatively easy husbandry. But where do we draw a line in relation to its environmental impact and a nation’s right to literally grow a new industrial sector? Should palm oil plantations be mandated to grow the crop sustainably? Should we ban palm oil in the UK and concentrate on alternative vegetable oils? Is it a matter of consumer choice, with individuals free to boycott products that contain palm oil? And can engineering play a role via precision agriculture or synthetic alternatives?

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