Researchers at Nagoya University develop a composite material that, by adjusting its composition and exposing it to different types of light, can mimic animals’ changes in color.
Nagoya, Japan – A range of creatures, including chameleons, octopuses, and frogs, can change color in response to changes in the environment. Some insights into the mechanisms behind this at the anatomical, cellular, and molecular levels have been obtained. However, much work is still required to obtain sufficient understanding of this phenomenon and to translate it into useful artificial applications.
As reported in the journal Small, researchers at Nagoya University’s Department of Molecular Design and Engineering developed a material containing dyes and crystals that can change the colors and patterns it displays depending on the background color used within it and its exposure to visible or ultraviolet light.
The team was inspired to develop this material by findings obtained in the skin of certain frogs, in which different layers of cells with different properties combine to enable remarkable color changes.
For the first time, researchers have created a nanocomposite of ceramics and a two-dimensional material, opening the door for new designs of nanocomposites with such applications as solid-state batteries, thermoelectrics, varistors, catalysts, chemical sensors and much more.
Sintering uses high heat to compact powder materials into a solid form. Widely used in industry, ceramic powders are typically compacted at temperatures of 1472 degrees Fahrenheit or higher. Many low-dimensional materials cannot survive at those temperatures.
But a sintering process developed by a team of researchers at Penn State, called the cold sintering process (CSP), can sinter ceramics at much lower temperatures, less than 572 degrees F, saving energy and enabling a new form of material with high commercial potential.
“We have industry people who are already very interested in this work,” said Jing Guo, a post-doctoral scholar working in the group of Clive Randall, professor of materials science and engineering, Penn State. “They are interested in developing some new material applications with this system and, in general, using CSP to sinter nanocomposites.” Guo is first coauthor on the paper appearing online in Advanced Materials.
A new form of 3-D-printed material made by combining commonly-used plastics with carbon nanotubes is tougher and lighter than similar forms of aluminium, scientists say.
The material could lead to the development of safer, lighter and more durable structures for use in the aerospace, automotive, renewables and marine industries.
In a new paper published in the journal Materials & Design, a team led by University of Glasgow engineers describe how they have developed a new plate-lattice cellular metamaterial capable of impressive resistance to impacts.
Metamaterials are a class of artificially-created cellular solids, designed and engineered to manifest properties which do not occur in the natural world.
Even today, clean water is a privilege for many people across the world. According to the World Health Organization (WHO), at least 1.8 billion people consume water contaminated with feces, and by 2040, a large portion of the world will endure water stress because of insufficient resources of drinking water. Meanwhile, the United Nations Children’s Fund (UNICEF), around 1,800 children die every day from diarrhea because of unsafe water supply, which causes diseases like cholera.
It has become imperative then that we develop efficient and cost-efficient ways to decontaminate water. And that is exactly what a team of scientists led by László Forró at EPFL have accomplished, with a new water purification filter that combines titanium dioxide (TiO2) nanowires and carbon nanotubes powered by nothing but sunlight.
The scientists first show that the TiO2nanowires by themselves can efficiently purify water in the presence of sunlight. But interweaving the nanowires with carbon nanotubes forms a composite material that adds an extra layer of decontamination by pasteurizing the water – killing off human pathogens such as bacteria and large viruses.
Composite materials are a driving force in sports technology, as Ellis Davies found out.
The sports sector was one of the first to take up composite materials, and is a significant consumer of carbon fibre, accounting for 14% of industry consumption. Composites in Sport, an event presented by NetComposites, UK, heavily focused on presentations by various composite related professionals covering the technical aspect of recent developments in sports equipment.
Dr Paul Sherratt of the Sports Technology Institute at Loughborough University began the series of presentations, giving an overview of the 460-acre campus and its extensive range of sporting facilities. Sherratt posited that the reason for the high level of composites in sport is because of lower levels of regulation, quick concept-to-market turnaround, multiple niches and general enthusiasm from consumers.
A skin-like polymeric material is using carbon nanotubes (CNTs) to bring a sense of touch to robotic and prosthetic devices. Developed by researchers at Stanford University and Xerox Palo Alto Research Center, the flexible, polymeric skin or ‘digital tactile system’ (DiTact) incorporates CNT pressure sensors and flexible organic printed circuits to mimic human response [Tee et al., Science 350 (2015) 313].
‘‘We wanted to make a sensor skin that communicates in the same way as the body,’’ explains research student Alex Chortos, one of the lead authors of the work. ‘‘The goal is to make skin for prosthetics that can feel touch in a natural way and communicate that information to the person wearing the prosthetic device.’’
In the body, receptors in the skin relay sensing information directly to the brain in a series of voltage pulses rather like Morse code. Artificial devices employ tactile sensing to improve the control of neuroprosthetics and relieve phantom limb pain. But, to date, prosthetic skin devices have had to use a computer or microprocessor to turn the output from sensors into a signal compatible with neurons.
The new approach, by contrast, combines these operations in a single system of piezoresistive pressure sensors embedded in a flexible circuit layer. The sensors are made from a CNT composite dispersed in a flexible polyurethane plastic and molded into pyramidal structures. The pyramidal shape is crucial because it allows the pressure range of the sensor to be tuned to that of skin.
Self-compacting high-performance concrete (SCHPC) has till now suffered from one weakness: when exposed to fire it flakes and splits, which reduces its loadbearing capacity. Empa scientists have now developed a method of manufacturing fire-resistant self-compacting high-performance concrete which maintains its mechanical integrity under these conditions.
Wood crackles as it burns in a chimney or campfire. When concrete is exposed to fire it chips and flakes – a process known as spalling. Both effects are due to the same phenomenon: water trapped within the piece of wood or concrete element vaporizes due to the high temperature. As more water vapour is produced the pressure within the wood or concrete structure increases. In wood this causes the cells to burst with a crackling sound, creating cracks in the logs. In concrete structures, chips split away from ceilings, walls, and supporting pillars, reducing their loadbearing capacity and increasing the risk of collapse in a burning building.
The resistance of conventional vibrated concrete to the heat of a fire can be optimized by adding a few kilograms of polypropylene (PP) fiber per cubic meter of concrete mixture. When exposed to fire the fibers melt, creating a network of fine canals throughout the concrete structure. These allow the water vapour to escape without increasing the internal pressure, so the concrete structure remains intact.
NUST MISIS scientists have proposed a technology that can double the strength of composites obtained by 3-D printing from aluminum powder, and advance the characteristics of these products to the quality of titanium alloys: titanium’s strength is about six times higher than that of aluminum, but the density of titanium is 1.7 times higher.
The developed modifiers for 3-D printing can be used in products for the aerospace industry.
The developed modifying-precursors, based on nitrides and aluminum oxides and obtained through combustion, have become the basis of the new composite. The research results have been published in the highly rated scientific journal Sustainable Materials and Technologies.
Two decades ago, molding was considered the only cost-effective way to manufacture bulk products. Today, 3-D printers for metal are a worthy competitor to metallurgical methods. 3-D printers have a chance to replace traditional methods of metallurgical production in the future. Using additive technologies with 3-D printing creates a whole array of advantages, from creating more difficult forms and designs to the technology’s cheaper cost and theoretical edge.
Studies have shown that hybrid powder materials based on natural layered silicates developed by the chemists of the Far Eastern Federal University (FEFU) and the Far Eastern Branch of the Russian Academy of Sciences (FEB RAS) decrease the friction ratio in metals sevenfold. These new materials offer new prospects for the development of more efficient anti-friction additives, increasing the durability of spare parts for equipment and vehicles.
The work was carried out by research associates of the School of Natural Sciences and Engineering School of FEFU, as well as the Institute of Chemistry of FEB RAS. The research running led by Nikolay Shapkin, professor of the Department of General, Inorganic, and Organoelement chemistry at FEFU. The results were published in Inorganic Materials.
The scientists report two hybrid composite materials based on natural layered silicates and plant products. The first was obtained from nontronite silicate isolated from Popov Island in the vicinity of Vladivostok and modified with alkaline rice husk hydrolysate. Experiments have shown that applying this powder reduces the deterioration of friction-producing parts 2.5 to seven times. Another material based on vermiculite from Karelia and modified with regular cellulose reduced the friction ratio 1.6 times.
One-dimensional nanomaterials with highly anisotropicoptoelectronic properties can be used within energy harvesting applications, flexible electronics and biomedical imaging devices. In materials science and nanotechnology, 3-D patterning methods can be used to precisely assemble nanowires with locally controlled composition and orientation to allow new optoelectronic device designs. In a recent report, Nanjia Zhou and an interdisciplinary research team at the Harvard University, Wyss Institute of Biologically Inspired Engineering, Lawrence Berkeley National Laboratory and the Kavli Energy Nanoscience Institute developed and 3-D printed nanocomposite inks composed of brightly emitting colloidal cesium lead halide perovskite (CsPbX3, where X= Cl, Br, or I) nanowires.
They suspended the bright nanowires in a polystyrene-polyisoprene-polystyrene block copolymer matrix and defined the nanowire alignment using a programmed print path. The scientist produced optical nanocomposites that exhibited highly polarized absorption and emission properties. To highlight the versatility of the technique they produced several devices, including optical storage, encryption, sensing and full color displays. The work is now published on Science Advances.
Composite materials are increasingly popular. One of the primary composite materials for modern structures is glass fiber reinforced plastic (GFRP), which is commonly used in aviation, modern transport and wind power plants. Scientists of South Ural State University have carried out extensive studies of ballistic properties of GFRP to improve the efficiency of its use.
GFRP is relatively cheap and has high strength. However, practically all well-known results regarding ballistic characteristics of GFRP do not take into account various loads occurring when operating the structures or consider comparatively low-impact loading speeds. At the same time, a more frequently encountered problem is impacts at high speed. The team of scientists from SUSU’s Institute of Engineering and Technology have determined ballistic characteristics of glass fiber reinforced plastic under exposure to operational loads at a high speed of impact loading.
“Often, noses of modern trains, which are produced out of composite materials, are exposed to impacts during the train’s movement. We have studied the influence of the impact force on a plate made of composite material under the normal operational load. We stretched the sample, creating a strained condition, and then determined its ballistic properties in an impact,” says one of the project authors, Mikhail Zhikharev.
The research team of Dr. Jae-woo Choi and Dr. Kyung-won Jung of the Korea Institute of Science and Technology’s (KIST, president: Byung-gwon Lee) Water Cycle Research Center announced that it has developed a wastewater treatment process that uses a common agricultural byproduct to effectively remove pollutants and environmental hormones, which are known to be endocrine disruptors.
The sewage and wastewater that are inevitably produced at any industrial worksite often contain large quantities of pollutants and environmental hormones (endocrine disruptors). Because environmental hormones do not break down easily, they can have a significant negative effect on not only the environment but also the human body. To prevent this, a means of removing environmental hormones is required.
The performance of the catalyst that is currently being used to process sewage and wastewater drops significantly with time. Because high efficiency is difficult to achieve given the conditions, the biggest disadvantage of the existing process is the high cost involved. Furthermore, the research done thus far has mostly focused on the development of single-substance catalysts and the enhancement of their performance. Little research has been done on the development of eco-friendly nanocomposite catalysts that are capable of removing environmental hormones from sewage and wastewater.
The KIST research team, led by Dr. Jae-woo Choi and Dr. Kyung-won Jung, utilized biochar, which is eco-friendly and made from agricultural byproducts, to develop a wastewater treatment process that effectively removes pollutants and environmental hormones. The team used rice hulls, which are discarded during rice harvesting, to create a biochar** that is both eco-friendly and economical. The surface of the biochar was coated with nano-sized manganese dioxide to create a nanocomposite. The high efficiency and low cost of the biochar-nanocomposite catalyst is based on the combination of the advantages of the biochar and manganese dioxide.
A new device being developed by Washington State University physicist Yi Gu could one day turn the heat generated by a wide array of electronics into a usable fuel source.
The device is a multicomponent, multilayered composite material called a van der Waals Schottky diode. It converts heat into electricity up to three times more efficiently than silicon – a semiconductor material widely used in the electronics industry. While still in an early stage of development, the new diode could eventually provide an extra source of power for everything from smartphones to automobiles.
“The ability of our diode to convert heat into electricity is very large compared to other bulk materials currently used in electronics,” said Gu, an associate professor in WSU’s Department of Physics and Astronomy. “In the future, one layer could be attached to something hot like a car exhaust or a computer motor and another to a surface at room temperature. The diode would then use the heat differential between the two surfaces to create an electric current that could be stored in a battery and used when needed.”
Gu recently published a paper on the Schottky diode in The Journal of Physical Chemistry Letters.
SEM imaging of our newly electrospun nanofibre composites. Fibre diameters from Sample 3 (images 2 and 4 here) have projected diameters of 40 - 100 nm, which are excellent results for this stage in the research.
The other images just look really, really cool, so I thought I’d share them as well!
A fine ash, made from pulverised volcanic rocks, can be added to traditional cement to improve its sustainability.
Who is involved?
MIT engineers working with scientists from the Kuwait Institute for Scientific Research and Kuwait University. The paper, Impact of Embodied Energy on materials/buildings with partial replacement of ordinary Portland Cement (OPC) by natural Pozzolanic Volcanic Ash, can be viewed here bit.ly/2EwZQwr
How is it novel?
By replacing a percentage of traditional cement materials with volcanic ash, researchers reduced the total energy required to make concrete. Building 26 concrete buildings, using cement with 50% volcanic ash, required 16% less energy than if traditional Portland cement was use, according to calculations.
The researchers also found that concrete mixed with a very fine ash was stronger than concrete made from just Portland cement. However, the process of pulverising volcanic ash to a very fine particle size requires energy. Therefore, if stronger concrete is made using this method, it becomes less sustainable in terms of energy use.
Oral Buyukozturk, a professor in MIT’s Department of Civil and Environmental Engineering, commented, ‘You can customise this. If it is for a traffic block, for example, where you may not need as much strength as, say, for a high-rise building. So you could produce those things with much less energy. That is huge if you think of the amount of concrete that’s used over the world.’
Rock West Composites (RWC) has launched a new system of aircraft-grade, aluminum connector joints that make it possible to construct an extensive variety of structures made of prefabricated carbon fiber composite tubes and plates.
Structures made with Carbon Erector joints will be reportedly stronger and lighter in weight.
The initial Carbon Erector product line comprises a series of 24 different connector kits, which include connectors made of CNC-machined, aircraft-grade 6061-T6 black anodized aluminum and screws with 170,000 PSI tensile strength. The construction method is mechanical and requires no adhesives or bonding. The product line currently supports construction using 1 inch, 1.5 inch and 2.0 inch interior diameter round carbon fiber composite tubing of varying thicknesses and any plate thickness.
The joints are designed to facilitate an almost infinite number of connections on planes, intersections and corners. The kits will allow the rapid construction and reconfiguration of modular structures utilizing pre-manufactured and readily available carbon fiber composite tubing and plates. Rock West Composites is also able to design connectors for other tube sizes based on customers’ specific needs.
The mantis shrimp is able to repeatedly pummel the shells of prey using a hammer-like appendage that can withstand rapid-fire blows by neutralizing certain frequencies of “shear waves,” according to a new research paper by University of California, Riverside and Purdue University engineers. A man…
The Airbus A350 XWB and the Boeing 787-9 Dreamliner are currently perhaps the two most advanced passenger jets in the world.
They are both at the Paris Air Show, and they both carry GE technologies and materials. The GEnx engines that power the Dreamliner, for example, have fan blades and fan cases engineered from carbon fiber composites. The fixed trailing edge on the Airbus A350 XWB is made from a similar advanced material . In fact, more than a half of that jet’s body is made from composites.
“GE’s contribution to the structure of the A350 XWB plays a major role in the efficiency of the A350 wing fixed trailing edge,” says Mike Bausor, Airbus marketing director for the A350 XWB plane.“The [fixed trailing edge] is an integral part of the wing structure. Built predominantly from composite material, it is one of the most complex, highly loaded parts of the wing that requires utmost precision and mastery in the assembly process, as well as in the design and stress calculation.”
The fixed trailing edge makes the back part of the wing of the Airbus A350 XWB. Image credit: GE Reports/Adam Senatori.
Bausor says that composites are lighter than traditional aluminun alloys and also also extremely resistant. “But carbon fibre composite has other very valuable properties that bring major benefits to airlines,” he says. “This material does not corrode or fatigue. The maintenance tasks related to corrosion or fatigue on the airframe are therefore greatly reduced. The heavy maintenance interval can be extended to 12 years, versus 6 years for conventional airframes, significantly reducing maintenance cost and ensuring continued revenue generation for a much longer period.”
Both planes have been making afternoon flyovers at Paris Air Show this week. Photographer Adam Senatori captured some of the best moments.
Adam Senatori captured the A350 XWB (top) and the bird-like Boeing 787-9 Dreamliner (above) during flyovers at the Paris Air Show this week. Both planes feature GE materials and technologies. Image credits: GE Reports/Adam Senatori
The A350 XWB over Paris. Image credit: GE Reports/Adam Senatori
The Dreamliner in black & white. Image credit: GE Reports/Adam Senatori
Material sciences have long influenced decision-making in the design and engineering of products. From vernacular architecture that sources local materials to the revolutionary introduction of plastics in the mid-20th century, there is no mistake that material properties guide building and manufacturing processes.
What if it also works the other way around? Eli Block (Brown Biology & RISD Industrial Design ’17) is a current student that thinks of material sciences and design as a two-way street. Having taken a few classes with him, I’ve witnessed his diverse range of geekery from alchemy to geology, and it’s awesome.
“I think the capabilities, functionality, and certainly aesthetics of designed objects are always influenced by the materials from which they’re made,” Eli said. “Still, the water can flow in the other direction and design can influence the creation of new materials.”
It’s a great point that man-made and natural materials are no longer as separate as we think. Because we have designed objects that force foreign materials together in new, unique combinations, this may give rise to novel sediments in the future. However, today we understand that this process can often be disruptive to natural processes and ecosystems.
One project that addresses this is the International Genetically Engineered Machines (iGEM) competition, for which Eli teamed up with other students to compete in 2014. Their goal was to create a biologically-produced industrial plastic material that could be used in a number of applications, which they hoped to achieve by producing cellulose acetate (a hard, durable plastic) from cellulose (commonly produced by various bacteria and plants).
“We wanted to be able to produce desirable materials as organisms do without traditional, harsh manufacturing,” Eli said. “And since our team was sponsored by the exobiology department at the NASA Ames Research Center, we were interested to see if it would be possible to produce bioplastic in space without a lot of equipment.”
Because everything is better in space! His team engaged in a complex process to achieve a fairly simple objective, aiming to transfer genes for cellulose acetylation into bacteria that could produce a high volume of bacterial cellulose. From there, they sought a high bioplastic output. Though they encountered hurdles along the way, Eli thought it was interesting to learn and experiment as they went.
Just as biology and design can form a nearly symbiotic relationship, so can geology and design. Ceramics is an age-old practice deeply tied to material properties, from mixing the clay to firing to the right temperature to applying glaze. Eli put his own spin to it when he 3D printed a series of strange, lumpy rocks and cast them in porcelain. These cast bowls are now being used as a canvas for glaze experimentation.
“I wanted to make something that mashed up result and process and randomness, kind of like Earth systems,” Eli said. “I wanted to explore texture and color at the same time that I learned about firing minerals and mixing functional glazes.”
If you’ve ever glazed ceramics, you would agree that it takes experience to understand what colors you’re going to end up with when your work is fired. Eli plans to make use of the wide range of pigments, fluxes, and fillers in the RISD glaze room to explore the possibilities. Next, he’d like to experiment with clay and mix his own blends with his collection of rocks and minerals.
When we’re so tied in the realistic constraints of materials, it’s also helpful to take a step back to be inspired by fictitious materials. Rhino is a 3D modeling and rendering program that can create images of impossible objects, so Eli employed it to create a series of strange artifacts in a number of unrealistic material combinations. Some of the composites included chrome metal with glass, or plastic with porcelain.
“The results were super weird. It’s something I’d like to pursue further.”
Yeah, the results were pretty strange, but millions of years of natural processes have given rise to much stranger creatures and formations. Yet as Eli said and many scientists and designers would agree, “many biological structures are an ideal marriage of material form and function.” So perhaps we can all take some biophilic inspiration and do something a little weird. We might just discover something new.
Nanyang Technological University (NTU Singapore) scientists from the NTU-JTC Industrial Infrastructure Innovation Centre (I³C) have invented a new type of concrete called ConFlexPave that is bendable yet stronger and longer lasting than regular concrete which is heavy, brittle and breaks under tension.
This innovation allows the creation of slim precast pavement slabs for quick installation, thus halving the time needed for road works and new pavements. It is also more sustainable, requiring less maintenance.
NTU Professor Chu Jian, Interim Co-Director of the NTU-JTC I³C, said, “We developed a new type of concrete that can greatly reduce the thickness and weight of precast pavement slabs, hence enabling speedy plug-and-play installation, where new concrete slabs prepared off-site can easily replace worn out ones.”
Mr Koh Chwee, Director, Technical Services Division of JTC and Co-Director of the NTU-JTC I3C, said that the invention of this game-changing technology will not only enable the construction industry to reduce labour intensive on-site work, enhance workers’ safety and reduce construction time, it also benefits road users by cutting down the inconvenience caused by road resurfacing and construction works.
