16 December 2017

MIT scientists borrow from fireflies to make glowing plants


'Our work very seriously opens up the doorway to street lamps that are nothing but treated trees'

Scientists have created plants that glow using embedded nanoparticles in leaves, potentially paving the way for trees to replace streetlights.

Experts at the Massachusetts Institute of Technology (MIT) hope their discovery could lead to traditional light sources being replaced with self-sustaining alternatives.

"The vision is to make a plant that will function as a desk lamp – a lamp that you don't have to plug in," said chemical engineer Professor Michael Strano, the senior author of the study.

"The light is ultimately powered by the energy metabolism of the plant itself."

To give the plants their glowing ability, Professor Strano and his colleagues used luciferase, the substance that gives fireflies their glow.

They created nanoparticles containing luciferase, as well as other, larger particles containing luciferin and coenzyme A, which combine with the luciferase to produce the desired effect.

After immersing the plants in a solution containing these particles and exposing them to high pressures, the scientists were able to produce plants that glowed for nearly four hours.


While the work is in its early stages, the team has lofty ambitions for how it could be applied in the future.

"Our target is to perform one treatment when the plant is a seedling or a mature plant, and have it last for the lifetime of the plant," said Professor Strano.

"Our work very seriously opens up the doorway to streetlamps that are nothing but treated trees, and to indirect lighting around homes."

The results of the research were published in the journal Nano Letters.

Other researchers have attempted to create glowing plants using genetic engineering.

These efforts resulted in limited success, and were restricted to a couple of species that are commonly used in genetic research.

The MIT team’s work, on the other hand, has already been tested on an array of salad leaves, including rocket, kale, spinach and watercress.

"Plants can self-repair, they have their own energy, and they are already adapted to the outdoor environment," said Professor Strano.

"We think this is an idea whose time has come.”

Source

14 December 2017

Researcher Claims New Battery Design Could Double Range, Battery Life



PR blasts about supposed innovation in battery design is a recent story about an MIT grad who founded a battery company is worth paying attention to. Qichao Hu is the CEO of SolidEnergy, a company that’s been working to improve lithium-ion energy density for the past five years.

The problem with lithium-ion is that whether you measure by energy per kilogram or energy per unit weight, Li-ion batteries aren’t very good. The graph below also illustrates why fossil fuels are so difficult to replace. It’s not just because they pack a relatively high amount of energy though they do but because fuels like ethanol, kerosene, gasoline, and diesel are stable at room temperature and pressure (even if you need to keep a lid on them) and don’t require specialized storage or pumping procedures. Lithium-ion batteries, meanwhile, are the tiny dot at the bottom-left side of the graph. Anything that can bump them upwards or outwards is therefore an improvement and Hu thinks he has the answer.
SolidEnergy’s technology works by substituting a thin lithium foil for the larger anode used in most lithium-ion batteries. This solves one problem, by shrinking the battery form factor by ~50 percent, but it creates others. As originally designed, the battery only worked above 80C, which makes it a non-starter for most commercial applications. Pang appears to have solved this problem by adding phosphorous and sulfur to the electrolyte, which forms a thin shield over the lithium metal electrode, protecting it from forming dendrites under use. According to Hu, “Combining the solid coating and new high-efficiency ionic liquid materials was the basis for SolidEnergy on the technology side.”
Will we see this technology come to market any time soon? I don’t know, but if it performs as advertised, we may. Battery capacity is the biggest single problem in many device designs; lithium-ion energy capacity has not nearly kept pace with device hunger. Removing the anode gives such a capacity boost, it could be a net positive even if the first commercial designs are below the predicted energy density.

There’s no word on how hard it is to build these structures, but they don’t appear to rely on expensive metals (another plus), and there’s nothing particularly expensive about sulfur or phosphorous. None of this proves we’ll be packing smartphones with 2x the battery life in a year or two, but there seem to be fewer barriers to commercial introduction for SolidEnergy than we’ve seen in the past.

Source

09 December 2017

Rippling Graphene Sheets May Be the Key to Clean, Unlimited Energy



Clean, Unlimited Energy

Physicists at the University of Arkansas have invented a nano-scale power generator that could potentially use the movement of graphene to produce clean, unlimited energy. Called a Vibration Energy Harvester, this development provides evidence for the theory that two-dimensional materials could be a source of usable energy.

Paul Thibado, a professor of physics at the university, got the idea for the generator after his team observed some strange, microscopic movements in sheets of graphene, which is made up of a single layer of carbon atoms. After laying out the sheets over a copper scaffold, the team was confused by the images they were collecting with a microscope.

Then they tried narrowed their focus and “separated each image into sub-images,” Thibado said in a Research Frontiers article. “Looking at large-scale averages hid the different patterns. Each region of a single image, when viewed over time, produced a more meaningful pattern.”

Once they started analyzing the sheets point-by-point, they made an amazing discovery — the graphene was essentially rippling, flipping up and down through a combination of small, random motions and larger, sudden movements known as Lévy flights. This was the first time such movement had been observed in an inorganic, atomic-scale system. The team determined that the movements were due to ambient heat at room temperature.

Because of graphene’s sheet-like nature, its atoms vibrated in tandem, which sets it apart from the random vibrations you would see in, say, molecules of a liquid. Thibado said to Research Frontiers, “This is the key to using the motion of 2D-materials as a source of harvestable energy.” The tandem vibrations cause ripples in the graphene sheet from which we can harness energy using the latest nanotechnology.

The researchers then designed a tiny generator to do just that. This device could have a drastic impact on our access to clean, unlimited energy. It could allow our tech to send, receive, process, or store information, powered solely by the heat available at room temperature. This clearly could have remarkable and widely varied applications.


Fantastical Technologies

Now, while Thibado has applied for a patent and is insistent on the potential of this device, it has yet to be proven effective. It has remarkable possibilities, but we will have to see how the prototype of the tiny electric generator turns out before we know whether it is a viable energy solution. But, if the claims of this team prove to be true, it could revolutionize not only how we create energy, but the devices that we are capable of creating.

One potential application is medical devices. Current medical implants often require batteries. And, while these batteries are long-lasting, a self-charging device that relies on microscopic graphene movement could allow devices to be both smaller and more effective in the long-run. Thibado remarked on this possibility to Research Frontiers, saying “Self-powering enables smart bio-implants, which would profoundly impact society.”

This could extend into a range of biomedical applications. Microscopic, self-powering capabilities could be remarkably helpful for hearing devices which often require frequent, expensive, bulky battery changes. Pace-makers and wearable sensors could also improve from such tech.

Graphene could also power non-medical wearable technologies. From “smart” graphene fashion to in-ear translators and wearable cryptocurrency, devices that blend with our organic shapes and movement are becoming increasingly popular and capable.

While this unique application of graphene is new and has yet to be fully proven, Thibado and his team will continue to explore the unique material’s potential as a clean, unlimited energy source. Such a power source would be game-changing, as it could immeasurably advance technologies that are becoming more compatible with our own human biology.

Source

Some high-temperature superconductors might not be so odd after all


Finding hidden swirls of electric current shows that the material’s behavior matches standard theory.
VORTEX FOUND  Newly observed swirls of electric current in a high-temperature superconductor (shown in an artist’s conception) may indicate that the unusual material fits within the standard theoretical picture.

A misfit gang of superconducting materials may be losing their outsider status.

Certain copper-based compounds superconduct, or transmit electricity without resistance, at unusually high temperatures. It was thought that the standard theory of superconductivity, known as Bardeen-Cooper-Schrieffer theory, couldn’t explain these oddballs. But new evidence suggests that the standard theory applies despite the materials’ quirks, researchers report in the Dec. 8 Physical Review Letters.

All known superconductors must be chilled to work. Most must be cooled to temperatures that hover above absolute zero (–273.15° Celsius). But some copper-based superconductors work at temperatures above the boiling point of liquid nitrogen (around –196° C). Finding a superconductor that functions at even higher temperatures above room temperature could provide massive energy savings and new technologies (SN: 12/26/15, p. 25). So scientists are intent upon understanding the physics behind known high-temperature superconductors.

When placed in a magnetic field, many superconductors display swirling vortices of electric current a hallmark of the standard superconductivity theory. But for the copper-based superconductors, known as cuprates, scientists couldn’t find whirls that matched the theory’s predictions, suggesting that a different theory was needed to explain how the materials superconduct. “This was one of the remaining mysteries,” says physicist Christoph Renner of the University of Geneva. Now, Renner and colleagues have found vortices that agree with the theory in a high-temperature copper-based superconductor, studying a compound of yttrium, barium, copper and oxygen.

Vortices in superconductors can be probed with a scanning tunneling microscope. As the microscope tip moves over a vortex, the instrument records a change in the electrical current. Renner and colleagues realized that, in their copper compound, there were two contributions to the current that the probe was measuring, one from superconducting electrons and one from nonsuperconducting ones. The nonsuperconducting contribution was present across the entire surface of the material and masked the signature of the vortices.

Subtracting the nonsuperconducting portion revealed the vortices, which behaved in agreement with the standard superconductivity theory. “That, I think, is quite astonishing; it's quite a feat,” says Mikael Fogelström of Chalmers University of Technology in Gothenburg, Sweden, who was not involved with the research.

The result lifts some of the fog surrounding cuprates, which have so far resisted theoretical explanation. But plenty of questions still surround the materials, Fogelström says. “It leaves many things still open, but it sort of gives a new picture.”

Source

04 December 2017

Diamond Batteries Made of Nuclear Waste Can Generate Power For Thousands of Years


IN BRIEF

  • Scientist have developed an ingenious means of converting nuclear power plant waste (76,430 metric tons in the US alone) into sustainable diamond batteries.
  • These long-lasting batteries could be a clean and safe way to power spacecraft, satellites, and even medical devices.


NUCLEAR DIAMONDS

Scientists from the University of Bristol Cabot Institute are hitting two birds with one stone, thanks to their lab-made diamond that can generate electricity and is made from upcycled radioactive waste.

In nuclear power plants, radioactive uranium is split in a process called nuclear fission. When the atoms are split, heat is generated, and that heat then vaporizes water into steam that turns electricity-generating turbines.

A severe downside of this process is the creation of dangerous radioactive waste, which ultimately deposits in the graphite core that it is housed in. Today, this nuclear contamination is safely stored away until it stops being radioactive…and with a half-life of 5,730 years, that takes quite a while.

The scientists found a way to heat the radioactive graphite to release most of the radioactivity in a gaseous form. The gas is subjected to high temperature and low pressures that turn it into a man-made diamond.


When these diamonds are placed near a radioactive field, they generate a small electrical current. The developers enclosed the diamond battery in another non-radioactive diamond to absorb the harmful emissions, which in turn allowed for the generation of even more electricity, making the battery nearly 100 percent efficient.


POWERING THE FUTURE

The nuclear diamond battery has an incredible lifetime, and will only be half used up by the year 7746. This makes it an ideal power solution for “situations where it is not feasible to charge or replace conventional batteries,” said Tom Scott, a materials science professor at Cabot Institute.

Flight times of planes, satellites, or spacecraft could increase with such a lasting battery. Medical devices like pacemakers and the artificial pancreas could become more reliable, empowering users to live their lives more fully.

The development also presents an incredibly efficient way to treat radioactive waste. Within the past 40 years, the US has amassed 76,430 metric tons (84,250 tons) of this waste.

Supplying the Earth with electricity is a daunting task even without a focus on sustainability. Now, it looks like experts are on the right track with this nuclear-powered diamond battery. It’s almost like the holy grail of electricity generation, or as Scott puts it, “no emissions generated and no maintenance required, just direct electricity generation.”

source

01 December 2017

Stealthy in-browser cryptomining continues even after you close window

In-browser cryptocurrency mining is, in theory, a neat idea: make users’ computers “mine” Monero for website owners so they don’t have to bombard users with ads in order to earn money.

Unfortunately, in this far-from-ideal world of ours, mining scripts – first offered by Coinhive but soon after by other outfits are mostly used by unscrupulous web admins and hackers silently compromising websites.

A lucrative enterprise


As ad-blocking services and antivirus vendors began blocking Coinhive’s original script, the developers created a new API that prevents website owners from forcing the cryptomining onto their visitors without their permission.

But, as the initial API still has yet to been retired, it’s not shocking that it’s still much more popular and widespread than the second one.

AdGuard researchers recently found 33,000 websites running cryptojacking scripts, and 95% of them run the Coinhive script.

“We estimate the joint profit at over US $150,000 per month. In case of Coinhive, 70% of this sum goes to the website owner, and 30% to the mining network,” they noted.

That’s $45,000 per month for Coinhive, and over half a million if the situation were to remain unchanged. This is also the most likely reason why Coinhive has not retired the original miner script.

Keeping those browsers mining


But, as adblockers and some AV vendors are ramping up their efforts to block cryptojacking scripts from running, the crooks have to come up with new ways to keep them unnoticed. They are also testing new ways for keeping browsers open and mining even if the users leave the mining website.

Malwarebytes’ researchers detailed one of these efforts, which involves covert pup-under windows, throttled mining, and an ad network that works hard on bypassing adblockers.

The “attack” unfolds like this: the user visits a website that silently loads cryptomining code and starts mining, but throttles it so that user’s CPU power is not used up completely. This prevents the machine from slowing down and heating up, and makes it more likely that the user won’t notice the covert mining.

But, when the user leaves the site and closes the browser window, another browser window remains open, made to hide under the taskbar, and continues mining.

“If your Windows theme allows for taskbar transparency, you can catch a glimpse of the rogue window. Otherwise, to expose it you can simply resize the taskbar and it will magically pop it back up,” Malwarebytes researcher Jerome Segura explained.


The rogue pop-under window can then be closed, and the mining stopped. Unfortunately, too many users won’t notice it or notice for a while that their computer has become somewhat sluggish.

“This type of pop-under is designed to bypass adblockers and is a lot harder to identify because of how cleverly it hides itself,” Segura noted.

“The more technical users will want to run Task Manager to ensure there is no remnant running browser processes and terminate them. Alternatively, the taskbar will still show the browser’s icon with slight highlighting, indicating that it is still running.”

The researchers tested the scheme by using the latest version of the Google Chrome browser on Windows. Results may vary with other browsers and other operating systems.

Chrome developers have been debating whether the browser should block or flag CPU mining attempts since early September, but a decision has still not been made.

source: helpnetsecurity

Samsung: Graphene Balls Boost Battery Charging Speed by 500 Percent


Mobile devices have long been hamstrung by lithium-ion batteries, which have been advancing much more slowly than other pieces of the hardware puzzle. Every few months we hear about a new battery design that might be able to replace the li-ion cells in our phones, but none of them have worked out yet. Maybe a newly published study from Samsung will be the one that finally frees us from archaic battery tech. According to Samsung, graphene balls can be used to boost battery capacity by 45 percent and charging speed by a whopping 500 percent.


The new experimental battery was developed by Samsung Advanced Institute of Technology (SAIT) and Samsung SDI in collaboration with researchers at Seoul National University. This battery tech has potential for several reasons. First, it addresses both capacity and charging speed. Many experimental batteries are only good at one or the other. Second, the materials needed for the battery aren’t exotic or hugely more expensive. Finally, Samsung believes it can incorporate graphene balls into batteries without completely retooling its manufacturing facilities.

Graphene comes up a lot in advanced materials science because it’s a remarkable substance it even earned its discoverers a Nobel Prize. Graphene is a hexagonal lattice of carbon just one atom thick. It exhibits high stability, thermal conductivity, and can act as a semiconductor. In this case, SAIT used readily available silica to process graphene into a 3D form the aforementioned balls. The graphene balls are used as a protective layer on the battery’s anode and cathode, and this is what allows for the higher capacity and charging speed. As a bonus, the battery should also maintain a lower temperature for improved safety. That’s certainly something that would appeal to Samsung after the issues it had with the Note 7 last year.


The increase in capacity should be able to push smartphone batteries to the 5,000-6,000mAh range, which we’ve previously only seen in larger devices like tablets. Samsung says the graphene ball battery is capable of recharging completely in about 12 minutes compared with a typical hour-long recharge cycle. Of course, the recharge time will be a little longer for a battery that also has a boosted capacity.

Most of the internal structure of the graphene ball batteries remains the same as it is now. Thus, adding the balls to existing smartphone battery production is something that could be worked out in the next few years. In addition to mobile devices, the graphene ball process could be useful in larger batteries like the ones used in electric cars. That’s not something Samsung manufactures right now, but it could license the technology to Tesla or another car maker.

Source: Etremetech

05 September 2017

Carbon nanotube “yarn” generates electricity when stretched


A new option for harvesting environmental energy that relies on internal static.

Spare energy is all around us, from the pressure exerted by every footfall to the heat given off by heavy machinery. In some cases, like regenerative braking in cars, it's easy to harvest, and the equipment needed to do so is simple and economic. In many others, however, we're not there yet.

It's not that we don't have the materials to do so. Piezoelectric generators can harvest stresses and strains, while triboelectric generators can harvest friction, to give two examples. The problem is that their efficiency is low and the cost of the materials is currently high, making them bad fits for any applications.

But a study in today's issue of Science describes a "yarn" made of carbon nanotubes that can produce electricity when stretched. Its developers go on to demonstrate its use in everything from wearable fabrics to ocean-based wave power generators. Given that the raw material for carbon nanotubes is cheap and there are lots of people trying to bring their price down, this seems to have the potential to find some economic applications.

Spinning yarns

The idea behind the new material is simple. The authors started with a collection of carbon nanotubes and spun them into a thread, much as you would with wool. There are several ways of spinning threads, and the authors chose one that created an internal structure that distributed stress evenly among the nanotubes. They then twisted the thread until it formed a coil similar to the ones you'd see on the headset cord of old land-line telephones.

When this coil is stretched, the internal strain and friction liberates charges from the carbon nanotubes. Which, of course, isn't particularly useful unless you can harvest them. To do so, the team dunked the whole thing in water with dissolved ions (they used hydrochloric acid but tested other salts). These would ferry the charges to nearby electrodes.

The most impressive thing is how many charges were liberated. During periods of peak strain, the yarn pumped out 250 watts per kilogram. For comparison, a professional bicyclist can only do peak exertions that are about 10 percent of that. And the yarn could sustain this when subjected to 30 stretch/relax cycles a second. Across the full cycle, the yarn could generate more than 40 joules of energy, although it was distributed unevenly, as the stretching and relaxation created a sine wave of alternating current.

One neat thing about this is that the researchers could also spin the yarn in the opposite direction. These strands produced currents at different points of the stretch-relaxation cycle. By mixing the two types of yarn in a single device, it would even out the current production (although it eliminated the smooth alternating current of a homogeneous device).

There’s an app(lication) for that

Having to keep the yarn submerged in an ionic solution the whole time it is operating is obviously a bit of an inconvenience. Unless, of course, the place you're looking to harvest energy from is one giant ionic liquid. The authors made a salt solution that mimicked the concentration found in the ocean. The setup worked just fine, and it had a peak power output of more than 90 watts/kg. So, they put a length of yarn between a weight and a float, and they dumped it into the ocean off South Korea. As waves rolled through, the device generated electricity, though it required a platinum electrode, given the corrosive nature of seawater.

In one of the weirder applications, the researchers hooked up some of the yarn to what they call an artificial muscle: a polymer that contracts when heated. The yarn produced electricity with every heating/cooling cycle.


But the most challenging application was incorporating the yarn into fabrics. Since the yarn needs an electrolyte and an external electrode to work, this isn't as simple as the word "yarn" implies. To manage this, the team put an electrolyte in a gel and used a conducting (but uncoiled) nanotube yarn as the electrode. All of these were bundled together to make a flexible material that could be incorporated into fabrics. When placed in a shirt, the device produced electricity every time someone wearing it breathed.

Overall, the material isn't exceptionally efficient at converting mechanical energy to electricity. But it is quite efficient when the incredibly light weight of the yarn is taken into account. It's also rare in that it can scale anywhere between individual fibers in clothing up to full-scale wave power generators. There seems to be a good chance that somewhere in that range is an effective, economical application provided the price of carbon nanotubes keeps dropping.

Science, 2017. DOI: 10.1126/science.aam8771  (Source).

03 September 2017

New Molten Salt Thorium Reactor Powers Up for First Time in Decades


Nuclear power was headed for something of a resurgence a few years back, but then the 2011 meltdown at Japan’s Fukushima reactor happened. Governments and investors around the world got cold feet, but there’s now renewed interest in a type of nuclear power that’s potentially much safer. A team from the Nuclear Research and Consultancy Group (NRG) the Netherlands has built the first molten salt reactor powered by thorium in decades.

There are several basic facts of nuclear power that have made it a tough sell around the world. For one, the uranium needed for nuclear power plants is rare and expensive. The uranium used in power plants can also be turned into weapons-grade material, requiring tight regulation. The other waste byproducts of nuclear energy are less useful, but still extremely dangerous. We don’t even know what to do with all that waste yet. Lastly, a nuclear power plant, no matter how well designed, could experience meltdown under certain circumstances.

You need different fissile material if you’re going to change any of that, and now we come to thorium (atomic number 90). Unlike uranium, thorium is abundant, and it’s not nearly as dangerous. Enrichment is not necessary, and thus it’s extremely difficult to create nuclear weapons with a thorium-based reactor. Most importantly, meltdowns aren’t possible with thorium reactors because the reaction is not self-sustaining.

That last safety advantage is also the main drawback of thorium. You need a little uranium and a neutron source to get the reaction kick started. Oak Ridge National Laboratory ran molten salt thorium reactor experiments from the 1960s until 1976. Now, the European team is giving it another shot.

Pure thorium salt
Pure thorium salt being loaded into a sample container.

When bombarded by neutrons, thorium becomes radioactive uranium-233, which is shorter-lived and less dangerous than the uranium-235 used in conventional reactors. The molten salt design being developed at NRG is known as the Salt Irradiation Experiment (SALIENT). This radioactive slurry could potentially reach very high temperatures, which translates to a lot of energy generation. However, the molten salt isn’t just the fuel; it’s the coolant as well.

There are still several problems that need solving before NRG’s thorium reactor designs will be scaled up to industrial levels. While the waste is safer, scientists still need to figure out how much of it there will be and what can be done with it. The environment inside a molten salt reactor is also extremely corrosive. So, some creative materials might be needed. If it works, we could generate more power without pumping more carbon into the atmosphere a win for everyone.



Source: Extremetech

07 January 2017

Lab-grown stomach gets scientists one step closer to a ‘human on a chip’

Lab-grown stomach

More people are affected by stomach diseases than heart disease. While in most cases this is in relatively minor ways, such as overproduction of acid or gastritis, in a growing number of instances it’s linked with gastric cancer which affects around 26,370 people a year in the United States alone.

To find out more about stomachs and the effect of bacteria such as helicobacter pylori, researchers at Cincinnati Children’s Hospital Medical Center created a “Petri dish stomach,” complete with the ability to produce acid and digestive enzymes.

“What my lab has been doing for over a decade is trying to generate human organ tissues in a Petri dish,” Dr. James Wells, lead investigator, told Digital Trends. “Organ tissues represent a really good way of investigating human disease on a level that you can’t do by studying patients.”

The work, published in the journal Nature, describes how a functioning “organoid” model of a mini stomach can be grown from pluripotent stem cells, which can be grown into any tissue in a person. By “growing” a stomach, researchers get to watch how exactly diseases affect that particular part of the body from what happens when too much acid builds up to how certain experimental drugs are able to help deal with inflammation.

human on a chip

A lab-grown piece of human stomach, as seen under a microscope.

“We turn the stem cells into something which is effectively a functioning mini-stomach,” Wells continued. “It’s only a few millimeters in size, but it can produce acid, digestive enzymes, and respond to the cues that trigger your stomach to respond in different ways. In other words, while they are small, [Petri dish stomachs] have the same physiological properties as an actual stomach.”

The eventual goal, he said, is to develop a “human on a chip,” which would take the form of a credit card-sized device containing similar organoids for every organ in the human body. Eventually, these could be used to help treat patients.

“Organs that have to be removed because of damage or disease are very hard to replace, outside of organ donors, who there are a real shortage of,” he said. “In the future, we think it should be possible to scale up these mini organs into something that is a therapeutic transplant. That is the direction we’re headed in.”

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