Posts belonging to Category Materials



Memristors Retain Data 10 Years Without Power

The internet of things ( IoT) is coming, that much we know. But still it won’t; not until we have components and chips that can handle the explosion of data that comes with IoT. In 2020, there will already be 50 billion industrial internet sensors in place all around us. A single autonomous device – a smart watch, a cleaning robot, or a driverless car – can produce gigabytes of data each day, whereas an airbus may have over 10 000 sensors in one wing alone.

Two hurdles need to be overcome. First, current transistors in computer chips must be miniaturized to the size of only few nanometres; the problem is they won’t work anymore then. Second, analysing and storing unprecedented amounts of data will require equally huge amounts of energy. Sayani Majumdar, Academy Fellow at Aalto University (Finland), along with her colleagues, is designing technology to tackle both issues.

Majumdar has with her colleagues designed and fabricated the basic building blocks of future components in what are called “neuromorphiccomputers inspired by the human brain. It’s a field of research on which the largest ICT companies in the world and also the EU are investing heavily. Still, no one has yet come up with a nano-scale hardware architecture that could be scaled to industrial manufacture and use.

The probe-station device (the full instrument, left, and a closer view of the device connection, right) which measures the electrical responses of the basic components for computers mimicking the human brain. The tunnel junctions are on a thin film on the substrate plate.

The technology and design of neuromorphic computing is advancing more rapidly than its rival revolution, quantum computing. There is already wide speculation both in academia and company R&D about ways to inscribe heavy computing capabilities in the hardware of smart phones, tablets and laptops. The key is to achieve the extreme energy-efficiency of a biological brain and mimic the way neural networks process information through electric impulses,” explains Majumdar.

In their recent article in Advanced Functional Materials, Majumdar and her team show how they have fabricated a new breed of “ferroelectric tunnel junctions”, that is, few-nanometre-thick ferroelectric thin films sandwiched between two electrodes. They have abilities beyond existing technologies and bode well for energy-efficient and stable neuromorphic computing.

The junctions work in low voltages of less than five volts and with a variety of electrode materials – including silicon used in chips in most of our electronics. They also can retain data for more than 10 years without power and be manufactured in normal conditions.

Tunnel junctions have up to this point mostly been made of metal oxides and require 700 degree Celsius temperatures and high vacuums to manufacture. Ferroelectric materials also contain lead which makes them – and all our computers – a serious environmental hazard.

Our junctions are made out of organic hydro-carbon materials and they would reduce the amount of toxic heavy metal waste in electronics. We can also make thousands of junctions a day in room temperature without them suffering from the water or oxygen in the air”, explains Majumdar.

What makes ferroelectric thin film components great for neuromorphic computers is their ability to switch between not only binary states – 0 and 1 – but a large number of intermediate states as well. This allows them to ‘memoriseinformation not unlike the brain: to store it for a long time with minute amounts of energy and to retain the information they have once received – even after being switched off and on again.

We are no longer talking of transistors, but ‘memristors’. They are ideal for computation similar to that in biological brains.  Take for example the Mars 2020 Rover about to go chart the composition of another planet. For the Rover to work and process data on its own using only a single solar panel as an energy source, the unsupervised algorithms in it will need to use an artificial brain in the hardware.

What we are striving for now, is to integrate millions of our tunnel junction memristors into a network on a one square centimetre area. We can expect to pack so many in such a small space because we have now achieved a record-high difference in the current between on and off-states in the junctions and that provides functional stability. The memristors could then perform complex tasks like image and pattern recognition and make decisions autonomously,” says Majumdar.

Source: http://www.aalto.fi/

Flat Lens Boost Virtual Reality

Metalensesflat surfaces that use nanostructures to focus light — promise to revolutionize optics by replacing the bulky, curved lenses currently used in optical devices with a simple, flat surface.  But, these metalenses have remained limited in the spectrum of light they can focus well Now a team of researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) has developed the first single lens that can focus the entire visible spectrum of light — including white light — in the same spot and in high resolution. This has only ever been achieved in conventional lenses by stacking multiple lenses.

Focusing the entire visible spectrum and white light – combination of all the colors of the spectrum — is so challenging because each wavelength moves through materials at different speeds. Red wavelengths, for example, will move through glass faster than the blue, so the two colors will reach the same location at different times resulting in different foci. This creates image distortions known as chromatic aberrations.

Cameras and optical instruments use multiple curved lenses of different thicknesses and materials to correct these aberrations, which, of course, adds to the bulk of the device.

Metalenses have advantages over traditional lenses,” says Federico Capasso, Professor of Applied Physics at SEAS and senior author of the research. “Metalenses are thin, easy to fabricate and cost effective. This breakthrough extends those advantages across the whole visible range of light. This is the next big step. Using our achromatic lens, we are able to perform high quality, white light imaging. This brings us one step closer to the goal of incorporating them into common optical devices such as cameras“.

The research is published in Nature Nanotechnology.

Source: https://www.seas.harvard.edu/

Nano-based Chip Detects Explosives

Technical University of Denmark (DTU) is ready with a prototype for a chemical “sniffer system” for the detection of criminal substances like narcotics and explosivesDogs have an eminent sense of smell. Their snouts use a specific sniffing technique which almost grabs hold of scents. Elephants’ snouts are even better than those of dogs, but obviously these are attached to elephants which are difficult to carry around. Consequently, today dogs are employed to track narcotics, money and explosives. Sometimes dogs are able to sense explosives in very small doses, however, they are not always 100 percent reliable as they are also sensitive to changes in their surroundings. A technological solution is therefore to be preferred in the tracking of stocks of narcotics or explosive materials.

Researchers at DTU have developed the prototype of a chip able to sniff molecular structures from a number of known substances. A special camera visualises the results from the chip (with 24 megapixels per 15 second) and newly developed software interprets these images according to changes in colour (i.e. the difference between two pictures), caused by the impact of the scents in the air.

We have conducted experiments by sucking air from smaller containers like e.g. handbags or pieces of luggage and from large industrial sized containers typically used for smuggling. In both cases, we arrived at promising results”, says Mogens Havsteen Jakobsen, Senior Researcher at DTU Nanotech.

By using the so-called colorimetric sensing technique, the artificial nose is able to detect different substances like explosives, narcotics, the ripeness of cheese, rotten meat and fish, the quality of wine and coffee or bad indoor climate of a room.

The project has specifically targeted explosives which are a growing safety risk in our society. The Chemical Division of the Danish Emergency Management Agency has been an important collaborator because they are authorised to produce and handle explosives. “We have test laboratories which have been made available during the course of the project”, says Jesper Mogensen, civil engineer and analysis chemist at the Chemical Division and therefore used to handling explosives.

There will be some evident advantages in using a technology such as CRIM-TRACK, compared to the instruments available today,” Jesper Mogensen says. “Firstly, the preparation time is short in that what you largely need to do is switch on the tracker and use it. This is valuable time saved. Secondly and perhaps the most important advantage is the fact that the EOD (the Explosive Ordnance Disposal) does not need to collect a sample. Today when we are called to a ransacking if e.g. a kilo of white powder has been found and we have to analyse its chemistry by way of GC-MS (i.e. gas chromatography-mass spectrometry), a sample of the substance must be collected on a fibre. In other words, it is necessary to collect physically a sample with all the risks this entails. With DTU’s sniffer system, it is possible to collect samples in the air. It sniffs for the drug much like a dog and indicates whether there are any explosives or not. This will increase the safety of our EOD”.

Source: http://www.nanotech.dtu.dk/

How To Detect Cancer With a Urine Test

Researchers centered at Nagoya University (Japan) develop a nanowire device able to detect microscopic levels of urinary markers potentially implicated in cancerCells communicate with each other through a number of different mechanisms. Some of these mechanisms are well-known: in animals, for example, predatory threats can drive the release of norepinephrine, a hormone that travels through the bloodstream and triggers heart and muscle cells to initiate a “fight-or-flight” response. A far less familiar mode of cellular transport is the extracellular vesicle (EV). EVs can be thought of as small “chunks” of a cell that are able to pinch off and circulate throughout the body to deliver messenger cargo to other cells. These messengers have become increasingly recognized as crucial mediators of cell-to-cell communication.

In a new study reported in Science Advances, researchers centered at Nagoya University have developed a novel medical device that can efficiently capture these EVs, and potentially use them to screen for cancer.

CLICK ON THE IMAGE TO ENJOY THE VIDEO

EVs are potentially useful as clinical markers. The composition of the molecules contained in an EV may provide a diagnostic signature for certain diseases,” lead author Takao Yasui explains. “The ongoing challenge for physicians in any field is to find a non-invasive diagnostic tool that allows them to monitor their patients on a regular basis–for example, a simple urine test.”

Among the many molecules EVs have been found to harbor are microRNAs, which are short pieces of ribonucleic acid that play diverse roles in normal cellular biology. Critically, the presence of certain microRNAs in urine might serve as a red flag for serious conditions such as bladder and prostate cancer. While this important cargo could therefore theoretically aid physicians in cancer diagnoses, there are still many technological hurdles that need to be overcome. One such hurdle: finding a feasible method to capture EVs in sufficient quantities to analyze them in a routine clinical setting.

The content of EVs in urine is extremely low, at less than 0.01% of the total fluid volume. This is a major barrier to their diagnostic utility,” Yasui notes. “Our solution was to embed zinc oxide nanowires into a specialized polymer to create a material that we believed would be highly efficient at capturing these vesicles. Our findings suggest that the device is indeed quite efficient. We obtained a collection rate of over 99%, surpassing ultracentrifugation as well as other methods that are currently being used in the field.

Source: http://en.nagoya-u.ac.jp/

In 2025 Humanity Could Benefit From A Major New Source Of Clean Power

An international project to generate energy from nuclear fusion has reached a key milestone, with half of the infrastructure required now built. Bernard Bigot, the director-general of the International Thermonuclear Experimental Reactor (Iter), the main facility of which is based in southern France, said the completion of half of the project meant the effort was back on track, after a series of difficulties. This would mean that power could be produced from the experimental site from 2025.

Nuclear fusion occurs when two atoms combine to form a new atom and a neutron. The atoms are fired into a plasma where extreme temperatures overcome their repulsion and forces them together. The fusion releases about four times the energy produced when an atom is split in conventional nuclear fission

The effort to bring nuclear fusion power closer to operation is backed by some of the world’s biggest developed and emerging economies, including the EU, the US, China, India, Japan, Korea and Russia. However, a review of the long-running project in 2013 found problems with its running and organisation. This led to the appointment of Bigot, and a reorganisation that subsequent reviews have broadly endorsed.

Fusion power is one of the most sought-after technological goals in the pursuit of clean energy. Nuclear fusion is the natural phenomenon that powers the sun, converting hydrogen into helium atoms through a process that occurs at extreme temperatures.

Replicating that process on earth at sufficient scale could unleash more energy than is likely to be needed by humanity, but the problem is creating the extreme conditions necessary for such reactions to occur, harnessing the resulting energy in a useful way, and controlling the reactions once they have been induced.

The Iter project aims to use hydrogen fusion, controlled by large superconducting magnets, to produce massive heat energy which would drive turbines – in a similar way to the coal-fired and gas-fired power stations of today – that would produce electricity. This would produce power free from carbon emissions, and potentially at low cost, if the technology can be made to work at a large scale.

For instance, according to Iter scientists, an amount of hydrogen the size of a pineapple could be used to produce as much energy as 10,000 tonnes of coal.

Source: https://www.theguardian.com/

How To Store Solar Energy In A Non-Electric Battery

Materials chemists have been trying for years to make a new type of battery that can store solar or other light-sourced energy in chemical bonds rather than electrons, one that will release the energy on demand as heat instead of electricity–addressing the need for long-term, stable, efficient storage of solar power.

Now a group of materials chemists at the University of Massachusetts Amherst led by Dhandapani Venkataraman, with Ph.D. student and first author Seung Pyo Jeong, Ph.D. students Larry Renna, Connor Boyle and others, report that they have solved one of the major hurdles in the field by developing a polymer-based system. It can yield energy storage density – the amount of energy stored – more than two times higher than previous polymer systems. Details appear in the current issue of Scientific Reports.

Venkataraman and Boyle say that previous high energy storage density achieved in a polymeric system was in the range of 200 Joules per gram, while their new system is able to reach an average of 510 Joules per gram, with a maximum of 690. Venkataraman says, “Theory says that we should be able to achieve 800 Joules per gram, but nobody could do it. This paper reports that we’ve reached one of the highest energy densities stored per gram in a polymeric system, and how we did it.”

Source: https://www.umass.edu/

Thermoelectric Power Generation

Thermoelectric (TE) materials could play a key role in future technologies. Although the applications of these remarkable compounds have long been explored, they are mostly limited to high-temperature devices. Recently, researchers at Osaka University, in collaboration with Hitachi, Ltd., developed a new TE material with an improved power factor at room temperature. Their study, published in Physica Status Solidi RRL, could help bring these materials out of the high-temperature niche and into the mainstream.

TE materials display the thermoelectric effect: apply heat on one side, and an electric current starts to flow. Conversely, run an external current through the device, and a  temperature gradient forms; i.e., one side becomes hotter than the other. By interconverting heat and electricity, TE materials can be used as either power generators (given a heat source) or refrigerators (given a power supply).

The ideal TE material combines high electrical conductivity, allowing the current to flow, with low thermal conductivity, which prevents the temperature gradient from evening out. The power generation performance mainly depends on the “power factor,” which is proportional to both electrical conductivity and a term called the Seebeck coefficient.

Unfortunately, most TE materials are often based on rare or toxic elements,” according to study co-author Sora-at Tanusilp. “To address this, we combined silicon – which is common in TE materials – with ytterbium, to create ytterbium silicide [YbSi2]. We chose ytterbium over other metals for several reasons. First, its compounds are good electrical conductors. Second, YbSi2 is non-toxic. Moreover, this compound has a specific property called valence fluctuation that make it a good TE material at low temperatures.

Source: http://resou.osaka-u.ac.jp/

Virgin Hyperloop One’s System Over 240 mph (387 km/h)

In a recent test, Virgin Hyperloop One‘s system beat all previous speed records, hitting nearly 387 kilometers per hour (240 miles per hour). With Richard Branson now in their corner, the company could dominate the future of hyperloop transportation. On December 18, Virgin Hyperloop One announced the completion of third phase testing on the DevLoop, the world’s first full-scale hyperloop test site. During these tests, the system clocked a lightning-fast speed of nearly 387 kmh (240 mph), breaking the 355 kmh (220 mph) hyperloop speed record set by Elon Musk’s hyperloop in August.

During this phase of testing, the company experimented with using a new airlock that helps test pods transition between atmospheric and vacuum conditions. By combining magnetic levitation, extremely low aerodynamic drag, and the level of air pressure experienced at 200,000 feet above sea level, the system proved that it is capable of reaching airline speeds over long distances.

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The recent phase three testing continues to prove the incredible persistence and determination of our DevLoop team — the close to 200 engineers, machinists, welders, and fabricators who collaborated to make hyperloop a reality today,” Josh Giegel, Virgin Hyperloop One’s co-founder and chief technology officer, stated in a press release announcing the new hyperloop speed record.

Source: https://hyperloop-one.com/

Gilded fuel cells boost electric car efficiency

To make modern-day fuel cells less expensive and more powerful, a team led by Johns Hopkins chemical engineers has drawn inspiration from the ancient Egyptian tradition of gilding. Egyptian artists at the time of King Tutankhamun often covered cheaper metals (copper, for instance) with a thin layer of a gleaming precious metal such as gold to create extravagant masks and jewelry. In a modern-day twist, the Johns Hopkins-led researchers have applied a tiny coating of costly platinum just one nanometer thick—100,000 times thinner than a human hair—to a core of much cheaper cobalt. This microscopic marriage could become a crucial catalyst in new fuel cells that generate electric current to power cars and other machines.

The new fuel cell design would save money because it would require far less platinum, a very rare and expensive metal that is commonly used as a catalyst in present-day fuel-cell electric cars. The researchers, who published their work earlier this year in Nano Letters, say that by making electric cars more affordable, this innovation could curb the emission of carbon dioxide and other pollutants from gasoline– or diesel-powered vehicles.

This technique could accelerate our launch out of the fossil fuel era,” said Chao Wang, a Johns Hopkins assistant professor in the Department of Chemical and Biomolecular Engineering and senior author of the study. “It will not only reduce the cost of fuel cells. It will also improve the energy efficiency and power performance of clean electric vehicles powered by hydrogen.”

In their journal article, the authors tipped their hats to the ancient Egyptian artisans who used a similar plating technique to give copper masks and other metallic works of art a lustrous final coat of silver or gold.The idea,” Wang said, “is to put a little bit of the precious treasure on top of the cheap stuff.”

He pointed out that platinum, frequently used in jewelry, also is a critical material in modern industry. It catalyzes essential reactions in activities including petroleum processing, petrochemical synthesis, and emission control in combustion vehicles, and is used in fuel cells. But, he said, platinum’s high cost and limited availability have made its use in clean energy technologies largely impractical—until now.

Source: https://hub.jhu.edu/

AI Machine Beats Champion Chess Program


AlphaZero
, the game-playing AI created by Google sibling DeepMind, has beaten the world’s best chess-playing computer program, having taught itself how to play in under four hours. The repurposed AI, which has repeatedly beaten the world’s best Go players as AlphaGo, has been generalised so that it can now learn other games. It took just four hours to learn the rules to chess before beating the world champion chess program, Stockfish 8, in a 100-game match up. AlphaZero won or drew all 100 games, according to a non-peer-reviewed research paper published with Cornell University Library’s arXiv.

CLICK ON THE IMAGE AND SEE ALPHA ZERO DEVOURING  STOCKFISH

Starting from random play, and given no domain knowledge except the game rules, AlphaZero achieved within 24 hours a superhuman level of play in the games of chess and shogi [a similar Japanese board game] as well as Go, and convincingly defeated a world-champion program in each case,” said the paper’s authors that include DeepMind founder Demis Hassabis, who was a child chess prodigy reaching master standard at the age of 13.

“It’s a remarkable achievement, even if we should have expected it after AlphaGo,” former world chess champion Garry Kasparov told Chess.com. “We have always assumed that chess required too much empirical knowledge for a machine to play so well from scratch, with no human knowledge added at all.

Computer programs have been able to beat the best human chess players ever since IBM’s Deep Blue supercomputer defeated Kasparov on 12 May 1997DeepMind said the difference between AlphaZero and its competitors is that its machine-learning approach is given no human input apart from the basic rules of chess. The rest it works out by playing itself over and over with self-reinforced knowledge. The result, according to DeepMind, is that AlphaZero took an “arguably more human-like approach” to the search for moves, processing around 80,000 positions per second in chess compared to Stockfish 8’s 70m.

After winning 25 games of chess versus Stockfish 8 starting as white, with first-mover advantage, a further three starting with black and drawing a further 72 games, AlphaZero also learned shogi in two hours before beating the leading program Elmo in a 100-game matchup. AlphaZero won 90 games, lost eight and drew 2. The new generalised AlphaZero was also able to beat the “super human” former version of itself AlphaGo at the Chinese game of Go after only eight-hours of self-training, winning 60 games and losing 40 games.

While experts said the results are impressive, and have potential across a wide-range of applications to complement human knowledge, professor Joanna Bryson, a computer scientist and AI researcher at the University of Bath, warned that it was “still a discrete task“.

Source: https://www.theguardian.com/

Nobel Prize Nanotechnologist Launches His Own Anti-Aging Cosmetic Line

In 2016, J. Fraser Stoddart won the Nobel Prize in Chemistry for his part in designing a molecular machine. Now as chief technology officer and cofounder of nanotechnology firm PanaceaNano, he has introduced the “Noble” line of antiaging cosmetics, including a $524 formula described as an “anti-wrinkle repair” night cream. The firm says the cream contains Nobel Prize-winning “organic nano-cubes” loaded with ingredients that reverse skin damage and reduce the appearance of wrinkles. Other prize-winning chemists have founded companies, but Stoddart’s backing of the antiaging cosmetic line takes the promotion of a new company by an award-winning scientist to the next level.

The nano-cubes are made of carbohydrate molecules known as cyclodextrins. The cubes, of various sizes and shapes, release ingredients such as vitamins and peptides onto the skin “at predefined times with molecular precision,” according to the Noble skin care website. PanaceaNano cofounder Youssry Botros, former nanotechnology research director at Intel, contends that the metering technology makes the product line “far superior to comparable products in the market today.” However, the nanocubes aren’t molecular machines, for which Stoddart won his Nobel prize.

While acknowledging the product line trades on his Nobel prize, Stoddart points out that “we’re not spelling our product name, Noble, the way the Swedish Nobel Foundation does.Ethicist Michael Kalichman has a different perspective. Use of the word Noble, even though spelled differently than the prize, is “unseemly but not illegal,” he says. Kalichman, who is director of the Research Ethics Program at the University of California, San Diego, adds, “If his goal is to make money, this may work. But if his goal is to retain credibility and pursue other more laudable goals, maybe he should stay focused on those goals.”

Botros says PanaceaNano is also developing nanotechnology materials for markets including hydrogen storage, flexible batteries, and molecular memory based on technology from Stoddart’s lab and licensed from Northwestern University. But PanaceaNano chose to make its first commercial product a line of cosmetics because of the high margins and the ease of market entry.

Source: https://cen.acs.org/

The Smell Of Death

Scientists in Korea have developed a bioelectronicnose’ that can specifically detect a key compound produced in decaying substances. When food begins to rot, the smell that we find repulsive comes from a compound known as cadaverine. That is also the substance responsible for the stench of rotting bodies, or cadavers—hence the name. The compound is the result of a bacterial reaction involving lysine, which is an amino acid commonly found in various food products. A previous study has shown that a receptor in zebrafish has an affinity for cadaverine. To make this receptor in the laboratory, scientists have turned to Escherichia coli bacteria as a host cell because it can easily produce large quantities of proteins. However, the production of this receptor in E. coli has been a challenge because it needs to be embedded in a membrane.

In this study, a team of researchers led by Associate Professor Hong Seunghun at Seoul National University packaged the cadaverine receptor from the zebrafish into nanodiscs, which are water friendly, membrane-like structures. The researchers then placed the receptor-containing nanodiscs in a special orientation on a carbon nanotube transistor, completing the bioelectronic nose. During testing with purified test compounds and real-world salmon and beef samples, the nose was selective and sensitive for cadaverine, even at low levels. The researchers suggest that the detector could someday prove useful in natural disaster scenarios, to recover corpses for identification.

The findings have been published in the journal ACS Nano.

Source: http://pubs.acs.org/