ANSTO has contributed to research led by the University of Sydney, involving doping transition metals in a polymorph of bismuth oxide in a search for more structural stability.
Cubic high-temperature polymorph of bismuth oxide, δ-Bi2O3, is the best known oxide ionic conductor but its narrow stability range (729—817 °C), which is close to its melting temperature of 817 °C precludes its practical use.
A large collaboration, led by Professor Chris Ling and Dr. Julia Wind (as part of her Ph.D.) from the University of Sydney involving researchers from ANSTO and two other universities, has achieved the design and understanding of the complex crystal structure and chemistry behind a commensurate structure within the fast-ion conducting stabilised bismuth oxide, co-doped with chromium and niobium, Bi23CrNb3O45.
The study was published in the Chemistry of Materials.
Professor Hiromi Nakano of the Toyohashi University of Technology has collaborated with a company to develop a small, lightweight air-pressure control atmosphere furnace that can rapidly and uniformly synthesize periodical structures of Li2O-Nb2O5-TiO2 (LNT) solid solution materials at 3x ordinary pressure. The underlying mechanism was discovered using detailed composition/structure analysis. As the sintering process is reduced by one-fourth compared to conventional electric furnaces, this technology can also be applied to other materials.
The air-pressure control atmosphere furnace is a sintering furnace that uses a regular 100 V AC power outlet and saves up to 800 W of energy. With this furnace, pressurized gas is supplied/controlled using a compressor or gas flow and materials can be heated up to 1,100 degrees C. (FIG. 1)
Chameleon-Like Material Spiked With Boron Comes Closer To Mimicking Brain Cells
In a new study, Texas A&M researchers in the Department of Materials Science and Engineering describe a new material that comes close to mimicking how brain cells perform computations.
Each waking moment, our brain processes a massive amount of data to make sense of the outside world. By imitating the way the human brain solves everyday problems, neuromorphic systems have tremendous potential to revolutionize big data analysis and pattern recognition problems that are a struggle for current digital technologies.
But for artificial systems to be more brain-like, they need to replicate how nerve cells communicate at their terminals, called the synapses.
Current silicon-based computing technology is energy-inefficient. Information and communications technology is projected to use over 20% of global electricity production by 2030. So finding ways to decarbonise technology is an obvious target for energy savings. Professor Paolo Radaelli from Oxford’s Department of Physics, working with Diamond Light Source, the U.K.“s national synchrotron, has been leading research into more efficient alternatives to silicon. His group’s surprising findings are published in Nature in an article titled "Antiferromagnetic half-skyrmions and bimerons at room temperature.” Some of the antiferromagnetic textures they have found could emerge as prime candidates for low-energy antiferromagnetic spintronics at room temperature.
Researchers have been working for a long time on alternative technologies to silicon. Oxides of common metals such as iron and copper are natural targets because they are already a technology staple, present in silicon-based computers, meaning there is a high chance of compatibility between the two technologies. Although oxides are great for storing information, they are not good at moving information around—a necessity for computation. However, one property of oxides that has emerged is that many are magnetic, which means it might be possible to move magnetic bits around, both in oxides and in other magnets, with very little energy required.
Improving the sensitivity of light sensors or the efficiency of solar cells requires fine-tuning of light capturing. KAUST researchers have used complex geometry to develop tiny shell-shaped coverings that can increase the efficiency and speed of photodetectors.
Many optical-cavity designs have been investigated to seek efficiencies of light: either by trapping the electromagnetic wave or by confining light to the active region of the device to increase absorption. Most employ simple micrometer- or nanometer-scale spheres in which the light propagates around in circles on the inside of the surface, known as a whispering gallery mode.
Former KAUST scientist Der-Hsien Lien, now a postdoctoral researcher at the University of California, Berkeley, and his colleagues from China, Australia and the U.S. demonstrate that a more complex geometry comprising convex nanoscale shells improves the performance of photodetectors by increasing the speed at which they operate and enabling them to detect light from all directions.
Surface effects play an important role in the operation of some devices, explains KAUST principal investigator, Jr-Hau He. Nanomaterials offer a way to improve performance because of their high surface-to-volume ratio. “However, although nanomaterials have greater sensitivity in light detection compared to the bulk, the light–matter interactions are weaker because they are thinner,” describes He. “To improve this, we design structures for trapping light.”
Scientists have succeeded in observing the first long-distance transfer of information in a magnetic group of materials known as antiferromagnets. These materials make it possible to achieve computing speeds much faster than existing devices. Conventional devices using current technologies have the unwelcome side effect of getting hot and being limited in speed. This is slowing down the progress of information technology.
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The emerging field of magnon spintronics aims to use insulating magnets capable of carrying magnetic waves, known as magnons, to help solve these problems. Magnon waves are able to carry information without the disadvantage of the production of excess heat. Physicists at Johannes Gutenberg University Mainz (JGU) in Germany, in cooperation with theorists from Utrecht University in the Netherlands and the Center for Quantum Spintronics (QuSpin) at the Norwegian University of Science and Technology (NTNU) in Norway, demonstrated that antiferromagnetic iron oxide, which is the main component of rust, is a cheap and promising material to transport information with low excess heating at increased speeds. Their study has been published recently in the scientific journal Nature.
Computers may be growing smaller and more powerful, but they require a great deal of energy to operate. The total amount of energy the U.S. dedicates to computing has risen dramatically over the last decade and is quickly approaching that of other major sectors, like transportation.
In a study published online this week the journal Nature, University of California, Berkeley, engineers describe a major breakthrough in the design of a component of transistors—the tiny electrical switches that form the building blocks of computers—that could significantly reduce their energy consumption without sacrificing speed, size or performance. The component, called the gate oxide, plays a key role in switching the transistor on and off.
“We have been able to show that our gate-oxide technology is better than commercially available transistors: What the trillion-dollar semiconductor industry can do today—we can essentially beat them,” said study senior author Sayeef Salahuddin, the TSMC Distinguished professor of Electrical Engineering and Computer Sciences at UC Berkeley.
A new publication from Opto-Electronic Advances reviews laser additive manufacturing of Si/ZrO2 tunable crystalline phase 3D nanostructures.
A route for laser nano-printing of 3D crystalline structures was developed employing ultrafast laser lithography, used as additive manufacturing tool for producing true 3D nanostructures, and combined with high temperature thermal post-treatment, converting the printed material into fully inorganic substance.
The inter-disciplinary experimental work revealed the potential of tuning the resulting ceramic structure into distinct crystalline phases, such as cristobalite, SiO2, ZrSiO4, m-ZrO2, t-ZrO2. The proposed approach achieved below 60 nm for individual feature dimensions without any beam shaping or complex exposure techniques, thus making it reproducible with other established standard or custom-made laser direct writing setups. The principle is compatible with commercially available platforms (for instance: Nanoscribe, MultiPhoton Optics, Femtika, Workshop of Photonics, UpNano, MicroLight, and others). Figure 1 graphically summarizes the approach, involved procedure steps, and resulting outcome.
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.
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.
Scientists at the University of Basel have found a way to change the spatial arrangement of bipyridine molecules on a surface. These potential components of dye-sensitized solar cells form complexes with metals and thereby alter their chemical conformation. The results of this interdisciplinary collaboration between chemists and physicists from Basel were recently published in the scientific journal ACS Omega.
Dye-sensitized solar cells have been considered a sustainable alternative to conventional solar cells for many years, even if their energy yield is not yet fully satisfactory. The efficiency can be increased with the use of tandem solar cells, where the dye-sensitized solar cells are stacked on top of each other.
The way in which the dye, which absorbs sunlight, is anchored to the semiconductor plays a crucial role in the effectiveness of these solar cells. However, the anchoring of the dyes on nickel oxide surfaces – which are particularly suitable for tandem dye-sensitized cells – is not yet sufficiently understood.
Novel materials can considerably improve storage capacity and cycling stability of rechargeable batteries. Among these materials are high-entropy oxides (HEO), whose stability results from a disordered distribution of the elements. With HEO, electrochemical properties can be tailored, as was found by scientists of the team of nanotechnology expert Horst Hahn at Karlsruhe Institute of Technology (KIT). The researchers report their findings in the journal Nature Communications.
Sustainable energy supply requires reliable storage systems. Demand for rechargeable electrochemical energy storage devices for both stationary and mobile applications has increased rapidly in the past years and is expected to continue to grow in the future. Among the most important properties of batteries are their storage capacity and their cycling stability, i.e. the number of possible charging and discharging processes without any loss of capacity. Thanks to its high stability, an entirely new class of materials called high-entropy oxides (HEO) is expected to result in major improvements. Moreover, electrochemical properties of HEO can be customized by varying their compositions. For the first time, scientists of KIT’s Institute of Nanotechnology (INT) and Karlsruhe Nano Micro Facility (KNMF), of the Helmholtz Institute Ulm (HIU) established jointly by KIT and Ulm University, and of the Indian Institute of Technology in Madras have now demonstrated the suitability of HEO as conversion materials for reversible lithium storage. Conversion batteries based on electrochemical material conversion allow for an increase of the stored amount of energy, while battery weight is reduced. The scientists used HEO to produce conversion-based electrodes that survived more than 500 charging cycles without any significant degradation of capacity.
University of Illinois electrical engineers have cleared another hurdle in high-power semiconductor fabrication by adding the field’s hottest material – beta-gallium oxide – to their arsenal. Beta-gallium oxide is readily available and promises to convert power faster and more efficiently than today’s leading semiconductor materials – gallium nitride and silicon, the researchers said.
Their findings are published in the journal ACS Nano.
Flat transistors have become about as small as is physically possible, but researchers addressed this problem by going vertical. With a technique called metal-assisted chemical etching – or MacEtch – U. of I. engineers used a chemical solution to etch semiconductor into 3D fin structures. The fins increase the surface area on a chip, allowing for more transistors or current, and can therefore handle more power while keeping the chip’s footprint the same size.
Developed at the U. of I., the MacEtch method is superior to traditional “dry” etching techniques because it is far less damaging to delicate semiconductor surfaces, such as beta-gallium oxide, researchers said.
“Gallium oxide has a wider energy gap in which electrons can move freely,” said the study’s lead author Xiuling Li, a professor of electrical and computer engineering. “This energy gap needs to be large for electronics with higher voltages and even low-voltage ones with fast switching frequencies, so we are very interested in this type of material for use in modern devices. However, it has a more complex crystal structure than pure silicon, making it difficult to control during the etching process.”
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.
Prof. Ye Jichun’s team at the Ningbo Institute of Materials Technology and Engineering (NIMTE) of the Chinese Academy of Sciences (CAS), collaborating with researchers at the University of Nottingham Ningbo China, has revealed the underlying dynamics of Silicon oxide (SiOx) tunneling junctions, including pinhole formation processes and charge-carrier transport mechanisms. The study was published in Cell Reports Physical Science.
As one of the most promising alternatives to reduce the cost and improve the efficiency of devices, tunnel oxide passivating contact (TOPCon) technology has attracted considerable attention in the photovoltaic (PV) community. However, the physical mechanism of the core structures of TOPCon, i.e., polycrystalline silicon (poly-Si)/ SiOx/ crystalline silicon (c-Si) junctions, has not been clarified, restricting the further improvement of device efficiency.
To address this problem, researchers at NIMTE conducted extensive experiments and simulations, unraveling the underlying charge carrier dynamics of the SiOx tunneling junctions.
So this is a Scanning Electron Microscope (SEM) photo I took today of one of my samples of tungsten (VI) oxide, this is the sample marketed as <20 micrometers (10^-6 m ) in diameter. As you can see there are some particles that at bigger than this which tells you that suppliers can’t be trusted with what they say…
But It also shows that the particles are not regular shapes which can effect the stability of the emulsions formed with them. This was what the powder looks like as it has been supplied, if I was to sonicate this the particles should be much smaller on average
I just thought it was a really nice picture and there you go
Lithium nickel manganese cobalt oxide, or NMC, is one of the most promising chemistries for better lithium batteries, especially for electric vehicle applications, but scientists have been struggling to get higher capacity out of them. Now researchers at Lawrence Berkeley National Laboratory…
For the first time, researchers have fabricated sensing elements known as fiber Bragg gratings inside optical fibers designed to dissolve completely inside the body. The bioresorbable fiber Bragg gratings could be used for in-body monitoring of bone fracture healing and for safer exploration of sensitive organs such as the brain.
A fiber Bragg grating is an optical element inscribed in an optical fiber, which is widely used as a sensing instrument. Although fiber Bragg gratings are commonly used for applications such as real-time monitoring of the structural health of bridges or tracking the integrity of airplane wings, until now they didn’t exhibit characteristics preferred for use in the body. With a design that allows them to break down similarly to dissolvable stitches, the new glass fibers should be safe for patients even if they accidently break, according to the researchers.
“Our work paves the way toward optical fiber sensors that can be safely inserted into the human body,” said Maria Konstantaki, a member of the research team from the Institute of Electronic Structure and Laser (IESL) of the Foundation of Research and Technology - Hellas (FORTH), Greece, that fabricated and characterized the new gratings. “Because they dissolve, these sensors don’t need to be removed after use and would enable new ways to perform efficient treatments and diagnoses in the body.”
Both hobbyists’ pottery and engineered high-performance ceramics are only useable after they are fired for hours at high temperatures, usually above 1000 °C. The sintering process that takes place causes the individual particles to “bake” together, making the material more compact and giving it the required properties, like mechanical strength.
In the journal Angewandte Chemie, American researchers have now demonstrated that sintering can also take place at significantly lower temperatures. This cold sintering process is based on the addition of small amounts of water to aid the key transport processes that densify the material.
“Since the stone age, ceramics have been fabricated by sintering at high temperatures,” reports Clive A. Randall from Pennsylvania State University (USA). “This includes the Venus of Doli Vestonice, one of the oldest ceramic objects.” The traditional firing process may now become unnecessary for many ceramic materials, because a broad spectrum of inorganic materials and composites can also be sintered between room temperature and 200 °C.
Unfortunately, I don’t see the part where they talk about oxides. Abstract says it’s in the supporting information, but idk.
They used a die press to compact their samples to very high pressure, in the range of 80-570 MPa (11.6k - 86k psi). Cold isostatic pressing could make this work for more complex shapes. I wonder if the mechanical compaction of the particles is important, or if perhaps this could be done in an autoclave?
Thanks for the links! As far as I can tell, they don’t actually talk much about oxides. I think they just meant that to inform the reader that they had tried the process on several oxides (such as the ones listed in table 1 of the supporting information like ZnO2, ZrO, WO3, and MgO) and that it worked.
As for cold isostatic pressing vs. autoclaving? I don’t know. I am far from an expert, but autoclaves are typically used at higher temperatures and use steam to sterilize the samples. I’m not sure if that would work for samples like these, though, like I said, I don’t know much about the topic.
A redesigned metastable phase of vanadium pentoxide (V2O5) shows extraordinary performance as a cathode material for magnesium batteries. The graphic compares the conventional (right) and metastable structures of V2O5.
Credit: Justin Andrews, Texas A&M University
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A team of scientists, led by Texas A&M University, USA, chemist Sarbajit Banerjee, has discovered a metal-oxide magnesium battery cathode material, that could be used to produce batteries that promise higher density of energy storage on top of transformative advances in safety, cost and performance in comparison to their ubiquitous lithium-ion (Li-ion) counterparts.
The team’s solution relies on a redesigned form of an old Li-ion cathode material, vanadium pentoxide, which they proved is capable of reversibly inserting magnesium ions. They reconfigured the atoms to provide a different pathway for the magnesium ions to travel along, which creates a viable cathode material in which they can readily be inserted and extracted during discharging and charging of the battery.
This is achieved by limiting the location of the magnesium ions to relatively uncomfortable atomic positions by design, based on the way the vanadium pentoxide is made – a property known as metastability. This metastability helps prevent the magnesium ions from getting trapped within the material and promotes complete harvesting of their charge-storing capacity with negligible degradation of the material after many charge-recharge cycles.
The development could be a turning point in the field as it highlights the inherent advantages of using more imaginative, metastable materials like this new form of vanadium pentoxide.
