Sharing All of The World

Sandia-induced changes elevate the plentiful, 37-cents-a-gram molly from being a welterweight outsider in the energy-catalyst field -- put crudely, a lazy bum that never amounted to much -- to a possible contender with the heavyweight champ.
The improved catalyst, expected to be the subject of an Oct. 7 Nature Communications paper, has already released four times the amount of hydrogen ever produced by molly from water.
To Sandia postdoctoral fellow and lead author Stan Chou, this is just the beginning: "We should get far more output as we learn to better integrate molly with, for example, fuel-cell systems," he said.
An additional benefit is that molly's action can be triggered by sunlight, a feature which eventually may provide users an off-the-grid means of securing hydrogen fuel.
Hydrogen fuel is desirable because, unlike gasoline, it doesn't release carbon into the atmosphere when burned. The combustion of hydrogen with oxygen produces an exhaust of only water.
In Chou's measured words, "The idea was to understand the changes in the molecular structure of molybdenum disulfide (MOS?), so that it can be a better catalyst for hydrogen production: closer to platinum in efficiency, but earth-abundant and cheap. We did this by investigating the structural transformations of MOS? at the atomic scale, so that all of the materials parts that were 'dead' can now work to make H? [hydrogen]."
The rind of an orange
in what sense were the parts "dead," one might ask?
Visualize an orange slice where only the rind of the orange is useful; the rest -- the edible bulk of the orange -- must be thrown away. Molly exists as a stack of flat nanostructures, like a pile of orange slices. These layers are not molecularly bolted together like a metal but instead are loose enough to slide over one another -- a kind of grease, similar to the structure of graphene, and with huge internal surface areas.
But here's the rub: While the edges of these nanostructures match platinum in their ability to catalyze hydrogen, the relative immense surface area of their sliding interiors are useless because their molecular arrangements are different from their edges. Because of this excess baggage, a commercial catalyst would require a huge amount of molly. The slender edges would work hard like Cinderella, but the stepsister interiors would just hang out, doing nothing.
Chou, who works on two-dimensional materials and their properties, thought the intent should be to get these stepsisters jobs.
Empowering the center
"There are many ways to do this," said co-author Bryan Kaehr, "but the most scalable way is to separate the nanosheets in solution using lithium. With this method, as you pull the material apart, its molecular lattice changes into different forms; the end product, as it turns out, is catalytically active like the edge structure."
To determine what was happening, and the best way to make it happen, the Sandia team used computer simulations generated by coauthor Na Sai from the University of Texas at Austin that suggested which molecular changes to look for. The team also observed changes with the most advanced microscopes at Sandia. including the FEI Titan, an aberration-corrected transmission electron microscope able to view atoms normally too small to see on most scopes.
"The extended test period made possible by the combined skills of our group allowed the reactions to be observed with the amount of detail needed," said Chou.
Lacking these tools, researchers at other labs had ended their tests before the reaction could complete itself, like a cook taking sugar and water off the stove before syrup is produced, resulting in a variety of conflicting intermediate results.
Ending confusion
"Why Stan's work is impactful is that there was so much confusion as to how this process works and what structures are actually formed," said Kaehr. "He unambiguously showed that this desirable catalytic form is the end result of the completed reaction."
Said Sandia Fellow and University of New Mexico professor Jeff Brinker, another paper author, "People want a non-platinum catalyst. Molly is dirt cheap and abundant. By making these relatively enormous surface areas catalytically active, Stan established understanding of the structural relation of these two-dimensional materials that will determine how they will be used in the long run. You have to basically understand the material before you can move forward in changing industrial use."
Kaehr cautions that what's been established is a fundamental proof of principle, not an industrial process. "Water splitting is a challenging reaction. It can be poisoned, stopping the molly reaction after some time period. Then you can restart it with acid. There are many intricacies to be worked out.
"But getting inexpensive molly to work this much more efficiently could drive hydrogen production costs way down."
'Green' inorganic photosynthesis
Not requiring electricity to prompt the reaction may be convenient in some circumstances and also keep costs down.
"A molly catalyst is essentially a 'green' technology," said Chou. "We used sunlight for the experiment's motive power. The light is processed through a dye, which harvests the light. A photocatalytic process stores that energy in the chemical bonds of the liberated hydrogen molecule.
"It's a kind of photosynthesis, but using inorganic materials rather than plants," Chou continued. "Plants use enzymes powered by sunlight to break up water into hydrogen and oxygen in a delicate process. We're proposing a similar thing here, but in a more rapid reaction and with sturdier components."
Kaehr said, "You could generate hydrogen and use it whenever. Hydrogen doesn't lose charge over time or suffer from conversion inefficiencies as do batteries in a solar car."
Other paper authors were Ping Lu, Eric Coker, Sheng Liu and Ting Luk, all from Sandia Labs, and Kateryna Artyushkova from the University of New Mexico.
The work was supported by the Department of Energy's Office of Science, and through its user facilities at the Sandia/Los Alamos-run Center for Integrated Nanotechnologies and National Energy Research Scientific Computing Center. The Texas Advanced Computing Center also added value.

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"The material created by us is considerably cheaper and the process of its synthesis is less complicated than that of the currently used analogue material. Also, both materials have very similar efficiency of converting solar energy into electricity. That means that our semiconductors have similar characteristics to the known alternatives, but are much cheaper," says professor Vytautas Getautis, head of the chemistry research group responsible for the discovery.
The solar cells containing organic semiconductors created at KTU were constructed and tested by physicists at Lausanne. The tests revealed outstanding results: the effectivity of the cells' converting solar energy into electricity was 16.9 percent. There are only a few organic semiconductors in the world affording such a high solar cell efficiency.
Prof Getautis says that the material created at KTU will be used in the construction of future solar cells: almost all solar cells are made from inorganic semiconductors. Hybrid, semi-organic solar cells are still being developed and perfected at the research centres all over the world.
KTU and Swiss Federal Institute of Technology Lausanne registered the invention at the European Patent Office.
The work was featured in Angewandte Chemie International Edition.

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"This work means there's an opportunity to use composite metal foam to develop safer systems for transporting nuclear waste, more efficient designs for spacecraft and nuclear structures, and new shielding for use in CT scanners," says Afsaneh Rabiei, a professor of mechanical and aerospace engineering at NC State and corresponding author of a paper on the work.
Rabiei first developed the strong, lightweight metal foam for use in transportation and military applications. But she wanted to determine whether the foam could be used for nuclear or space exploration applications -- could it provide structural support, protect against high impacts and provide shielding against various forms of radiation?
To that end, she and her colleagues conducted multiple tests to see how effective it was at blocking X-rays, gamma rays and neutron radiation. She then compared the material's performance to the performance of bulk materials that are currently used in shielding applications. The comparison was made using samples of the same "areal" density -- meaning that each sample had the same weight, but varied in volume.
The most effective composite metal foam against all three forms of radiation is called "high-Z steel-steel" and was made up largely of stainless steel, but incorporated a small amount of tungsten. However, the structure of the high-Z foam was modified so that the composite foam that included tungsten was not denser than metal foam made entirely of stainless steel.
The researchers tested shielding performance against several kinds of gamma ray radiation. Different source materials produce gamma rays with different energies. For example, cesium and cobalt emit higher-energy gamma rays, while barium and americium emit lower-energy gamma rays.
The researchers found that the high-Z foam was comparable to bulk materials at blocking high-energy gamma rays, but was much better than bulk materials -- even bulk steel -- at blocking low-energy gamma rays.
Similarly, the high-Z foam outperformed other materials at blocking neutron radiation.
The high-Z foam performed better than most materials at blocking X-rays, but was not quite as effective as lead.
"However, we are working to modify the composition of the metal foam to be even more effective than lead at blocking X-rays -- and our early results are promising," Rabiei says. "And our foams have the advantage of being non-toxic, which means that they are easier to manufacture and recycle. In addition, the extraordinary mechanical and thermal properties of composite metal foams, and their energy absorption capabilities, make the material a good candidate for various nuclear structural applications."
The paper, "Attenuation efficiency of X-ray and comparison to gamma ray and neutrons in composite metal foams," is published in Radiation Physics and Chemistry. Lead author is Shuo Chen, a recent Ph.D. graduate at NC State. The paper was co-authored by Mohamed Bourham, a professor of nuclear engineering at NC State. The work was supported by DOE's Office of Nuclear Energy under Nuclear Energy University Program grant number CFP-11-1643.

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The above post is reprinted from materials provided by North Carolina State University. The original item was written by Afsaneh Rabiei. Note: Materials may be edited for content and length.

The electricity produced by a solar cell can be used to set off chemical reactions. If this generates a fuel, then one speaks of solar fuels -- a hugely promising replacement for polluting fuels. One of the possibilities is to split liquid water using the electricity that is generated (electrolysis). Among oxygen, this produces hydrogen gas that can be used as a clean fuel in the chemical industry or combusted in fuel cells -- in cars for example -- to drive engines.
Solar fuel cell
To connect an existing silicon solar cell to a battery that splits the water may well be an efficient solution now but it is a very expensive one. Many researchers are therefore targeting their search at a semiconductor material that is able to both convert sunlight into an electrical charge and split the water, all in one; a kind of 'solar fuel cell'. Researchers at TU/e and FOM see their dream candidate in gallium phosphide (GaP), a compound of gallium and phosphide that also serves as the basis for specific colored leds.
A tenfold boost
GaP has good electrical properties but the drawback that it cannot easily absorb light when it is a large flat surface as used in GaP solar cells. The researchers have overcome this problem by making a grid of very small GaP nanowires, measuring five hundred nanometers (a millionth of a millimeter) long and ninety nanometers thick. This immediately boosted the yield of hydrogen by a factor of ten to 2.9 percent. A record for GaP cells, even though this is still some way off the fifteen percent achieved by silicon cells coupled to a battery.
Ten thousand times less material
According to Bakkers, it's not simply about the yield -- where there is still a lot of scope for improvement he points out: "For the nanowires we needed ten thousand less precious GaP material than in cells with a flat surface. That makes these kinds of cells potentially a great deal cheaper," Bakkers says. "In addition, GaP is also able to extract oxygen from the water -- so you then actually have a fuel cell in which you can temporarily store your solar energy. In short, for a solar fuels future we cannot ignore gallium phosphide any longer."

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In collaboration with the farming community of the Indian Creek Watershed in central Illinois, these researchers are finding ways to simultaneously meet three objectives: maximize a farmer's production, grow feedstock for bioenergy and protect the environment. These goals, as it turns out, are not necessarily mutually exclusive.
All it takes is a multifunctional landscape, where resources are allocated efficiently and crops are situated in their ideal soil and landscape position. Planting bioenergy crops like willows or switchgrass in rows where commodity crops are having difficulty growing could both provide biomass feedstock and also limit the runoff of nitrogen fertilizer into waterways -- all without hurting a farmer's profits. This is what a group of Argonne scientists has discovered through careful data collection and modeling at a cornfield in Fairbury.
"The issue we're working to address is how to design bioenergy systems that are sustainable" said Cristina Negri, principal agronomist and environmental engineer at Argonne. "It's not idealistic. We wanted to show that it's doable; if we design for specific outcomes, we'll see real results."
So Negri and her team created a pilot farm site that balances the priorities of economic feasibility, bioenergy and environmental health.
Meeting this challenge called for a change in perspective. Rather than looking at whole fields as the unit of planting decisions, researchers analyzed subareas of the cornfield. They found that subareas with the lowest yield also had the lowest nitrogen retention. These sections of land are doubly taxing -- unprofitable for the farmer and damaging to the environment.
Negri explained what happens in the underproductive land: "Imagine pouring a nice, nutrient-rich solution through a fertile soil with plants growing in it," she said. These nutrients would be retained by the soil long enough to be taken up by plants, minimizing any leakage. "Now imagine pouring this same solution through a colander: If nutrients filter through the soil too quickly, they're no longer available for plants. The corn grows less, and more nitrogen is leached into groundwater."
But planting bioenergy crops in the colander-like soil could solve both problems -- environmental and economic -- as the Argonne team showed with the Denitrification Decomposition simulation.
Willows and switchgrass are perennial bioenergy crops, meaning their life cycle spans multiple years. These plants have a more extensive root system than annual plants, which start their growth from scratch every year. Deeper roots are better able to absorb nitrogen as it seeps deeper into the soil.
The loss of nitrogen from agricultural land is a major environmental concern. If not retained by soil or taken up by plants, nitrogen escapes into air or water. It is released into the atmosphere as nitrous oxide, a greenhouse gas with 310 times the warming potential of carbon dioxide. Nitrate leaking into water spurs oxygen depletion that harms aquatic ecosystems and can lead to toxic algal blooms, as seen in Lake Erie. The Fairbury cornfield is located within the Indian Creek Watershed, draining to the Vermilion River and eventually to the Gulf of Mexico, which for years has been suffering from oxygen depletion caused by nutrient runoff.
While scientists may be invested in energy and environment, the team recognized that farmers -- the true agents of change -- have to think first and foremost about their economic bottom line.
"Across the entire field your farm might be profitable, but by collecting more specific data we can identify subareas where the farmer is not recovering his or her investment," said Argonne postdoctoral researcher Herbert Ssegane.
The money lost comes from farmers cropping and applying expensive nitrogen fertilizers to patches of the field that are just not producing enough. Inserting rows of bioenergy crops where there is low corn yield means the farmer is not sacrificing substantial profit from row crops. As a cost-saving bonus, the deep-rooted bioenergy crops naturally accumulate the lost nitrogen as a free fertilizer.
Argonne scientists planted willows at the Fairbury site in 2013 and will continue collecting data through next year to see how results compare to their predictions. "We've already reached a 28 percent reduction in nitrate, even with two full growing seasons still ahead of us," Ssegane said. Willow growth has also been good, without the researchers applying any fertilizer.
According to Ssegane, this project is about proving a concept. It shows farmers that strategic planting of bioenergy crops can increase productivity and save money, while demonstrating to the scientific community that bioenergy will be sustainable if we match plants to their optimal position within a landscape.
"Before this work, the popular idea was 'dedicated fields,' where you might convert a large area from corn to switchgrass," Ssegane said. "But dedicated fields of bioenergy crops are currently inviable in an agricultural setting where the economy is tied to grain. What does pass the cost-benefit test is converting underproductive subareas to an alternative crop."
A multifunctional landscape finds the happy, efficient medium between a dedicated bioenergy field and a farm growing continuous acres of the same cash crop.
The scientists are exploring how these design principles can be scaled up to the entire watershed. Eventually, they hope this research informs agricultural planning for scientists and farmers alike.

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A team of researchers from the Univerit¨¤ degli Studi di Milano and Politecnico di Milano in Italy, have demonstrated the possibility to perform a first important step in the biogas upgrading to biomethane using cost-effective conditions in terms of pressure and temperature by physical absorption column technology. The work was developed both from an experimental and computational point of view. The experimental work was made by the experimental apparatus reported in the figure, while the simulation study was performed by using PRO II SIMSCI simulation software.
"We propose a well-known technology for the separation of CO₂ from biogas mixture, but using different operating conditions relative to the traditional one. Our idea is to perform the absorption of CO₂ in water by using low temperature (in the range 5 -- 15C) coupled with atmospheric pressure. This technology involves the use of two absorption columns: the first at atmospheric pressure for the removal of the main part of CO₂ and the second one, of reduced dimension, for the final purification of biomethane. This study demonstrated the feasibility of the first step of this approach, while ongoing research to validate the whole process of the double column configuration is now in process," says Professor Carlo Pirola, Ph.D., of the Universit¨¤ degli Stuidi di Milano and Principal Investigator of this paper.

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Earlier this year, the U.S.S. Independence was rediscovered by a team of researchers led by James Delgado, the director of Maritime Heritage at the National Oceanic and Atmospheric Administration (NOAA). The marine archaeologists used sonar from an autonomous submarine to find the wreckage, but with the ship's radioactive past, the scientists wondered how safe it would be to actually explore.
Delgado turned to Berkeley Lab's Kai Vetter to better understand the radiation hazards. Vetter is the head of applied nuclear physics at Berkeley Lab, nuclear engineering professor at the University of California, Berkeley, and the co-founder of the Institute for Resilient Communities. "They wanted to know if we could ensure the safety of their equipment," says Vetter, "and to see if you'd pick up contamination if you went down there."
The short answers, Vetter says, was that neither the submersible nor the team was ever in danger of contamination.
One reason is that water is an excellent radiation shield. Under water, radiation will only extend several inches from contaminated materials, says Vetter. The unmanned research submarine stayed at least 100 feet away from the wreck.
Another reason has to do with the size of the contaminated site with respect to the size of the ocean. While contaminated rust particles from the ship are released and transported by water, the dilution factor of the ocean is enormous, essentially nullifying any radioactive effect.
Relatedly, while a relatively small number of organisms close to the wreck might take up some of these rust particles, the effects of radioactivity are diluted through the food chain because the number of organisms exposed is so small. In contrast, mercury is much more prevalent and widely distributed in the ocean, and this is why its concentration builds up the food chain.
And finally, says Vetter, it's important to consider the half-life of the radioactive materials. In this case, the isotopes of concern are cesium 137 and strontium 90, which both have a half-life of about 30 years. This means that after 30 years, half the isotopes responsible for the initial contamination transmute into other non-radioactive isotopes. It's been over 60 years since the U.S.S Independence was scuttled, which means that less than a quarter of the initial radioactive isotopes remain.
Still, to demonstrate with data, Vetter brought a team of researchers and students to the harbor in Half Moon Bay, CA to test the submersible after it had captured sonar images of the aircraft carrier. Armed with instruments called dosimeters that pick up ionizing radiation, the researchers found no evidence of contamination on the submersible. It wasn't a surprise, says Vetter, since the craft never got close enough to the ship and even if it had, the contamination would have diluted away as it was tugged back to shore.
The NOAA expedition collected its sonar images from a distance, but Vetter hopes to someday work with a submersible that gets an up-close view of the ship, the 55-gallon barrels, and the radioactivity. Such a project would require a specially designed detector to read the radiation on site, Vetter explains. "It would be exciting to build a dedicated system with some advanced technologies to figure out what is sitting down there in that old vessel," he says.

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Molecular wires composed of only inorganic materials have attracted significant attention due to their stable structures, tunable chemical compositions, and tunable properties. However, there have only been a few reports regarding the development of all-inorganic molecular nanowires.
Dr. Zhenxin Zhang and Prof. Wataru Ueda at the Catalysis Research Center at Hokkaido University (Prof. Ueda is currently working for Kanagawa University) and their collaborators at Hokkaido University, Hiroshima University, and Japan Synchrotron Radiation Research Institute/SPring-8 successfully created ultrathin all-inorganic molecular nanowires, composed of a repeating hexagonal molecular unit made of Mo and Te; the diameters of these wires were only 1.2 nm. These nanowires were obtained by the disassembly of the corresponding crystals through cation exchange and subsequent ultrasound treatment.
Furthermore, the researchers have shown that the ultrathin molecular wire-based material exhibits high activity as an acid catalyst, and the band gap of the molecular wire-based crystal is easily tuned via heat treatment. It is expected that the metal oxide molecular wire-based materials will open up new fields of research in heterogeneous catalysts, thermochromic materials, and semiconductors, as well as other related fields.
"This is a very rare isolated molecular nanowire based on transition metal-oxygen octahedra, and is an attractive catalyst due to the large surface area," said Professor Masahiro Sadakane, a coauthor of this study, from Hiroshima University.

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"Using bone formation as a guide, the Tian group has developed a synthetic material from silicon that shows potential for improving interaction between soft tissue and hard materials," said Joe Akkara, a program director in the National Science Foundation materials research division, which funds this research. "This is the power of basic scientific research. The Tian group has created a material that preliminarily seems to enhance soft tissue function."
In a Science paper published on June 26, Tian and his co-authors from UChicago and Northwestern University described their new method for the syntheses and fabrication of mesocopic three-dimensional semiconductors (intermediate between the nanometer and macroscopic scales).
"This opens up a new opportunity for building electronics for enhanced sensing and stimulation at bio-interfaces," said lead author Zhiqiang Luo, a postdoctoral scholar in Tian's laboratory.
The team achieved three advances in the development of semiconductor and biological materials. One advance was the demonstration, by strictly chemical means, of three-dimensional lithography. Existing lithographic techniques create features over flat surfaces. The laboratory system mimics the natural reaction-diffusion process that leads to symmetry-breaking forms in nature: the grooved and notched form of a bee stinger, for example.
Tian's team developed a pressure modulation synthesis, to promote the growth of silicon nanowires and to induce gold-based patterns in the silicon. Gold acts as silicon's growth catalyst. By repeatedly increasing and decreasing the pressure on their samples, the researchers were able to control the gold's precipitation and diffusion along the silicon's faceted surfaces.
"The idea of utilizing deposition-diffusion cycles can be applied to synthesizing more complex 3D semiconductors," said co-lead author Yuanwen Jiang, a Seymour Goodman Fellow in chemistry at UChicago.
3D silicon etching
The semiconductor industry uses wet chemical etching with an etch-resist to create planar patterns on silicon wafers. Portions of the wafer masked with thin film physically block the etching from being carried out except on the open surface areas.
In another advance, Tian and his associates developed a novel chemical method that instead depends upon the uncanny ability of gold atoms to trap silicon-carrying electrons to selectively prevent the etching.
Much to their surprise, the researchers found that even a sparse cover of gold atoms over the silicon matrix would prevent etching from occurring in their proximity. This method also applies to the 3D lithography of many other semiconductor compounds.
"This is a fundamentally new mechanism for etch mask or etch resist," Tian said. "The entire process is chemical."
Further testing revealed the project's third advance. The testing showed that the synthetic silicon spicules displayed stronger interactions with collagen fibers--a skin-like stand-in for biological tissue--than did currently available silicon structures. Tian and his associates inserted the synthetic spicules and the other silicon structures into the collagen fibers, then pulled them out. An Atomic Force Microscope measured the force required to accomplish each action.
"One of the major hurdles in the area of bioelectronics or implants is that the interface between the electronic device and the tissue or organ is not robust," Tian said.
The spicules show promise for clearing this hurdle. They penetrated easily into the collagen, then became deeply rooted, much like a bee stinger in human skin.

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The "natural concrete" at the Campi Flegrei volcano is similar to Roman concrete, a legendary compound invented by the Romans and used to construct the Pantheon, the Coliseum, and ancient shipping ports throughout the Mediterranean.
"This implies the existence of a natural process in the subsurface of Campi Flegrei that is similar to the one that is used to produce concrete," said Tiziana Vanorio, an experimental geophysicist at Stanford's School of Earth, Energy & Environmental Sciences.
Campi Flegrei lies at the center of a large depression, or caldera, that is pockmarked by craters formed during past eruptions, the last of which occurred nearly 500 years ago. Nestled within this caldera is the colorful port city of Pozzuoli, which was founded in 600 B.C. by the Greeks and called "Puteoli" by the Romans.
Beginning in 1982, the ground beneath Pozzuoli began rising at an alarming rate. Within a two-year span, the uplift exceeded six feet-an amount unprecedented anywhere in the world. "The rising sea bottom rendered the Bay of Pozzuoli too shallow for large craft," Vanorio said.
Making matters worse, the ground swelling was accompanied by swarms of micro-earthquakes. Many of the tremors were too small to be felt, but when a magnitude 4 quake juddered Pozzuoli, officials evacuated the city's historic downtown. Pozzuoli became a ghost town overnight.
A teenager at the time, Vanorio was among the approximately 40,000 residents forced to flee Pozzuoli and settle in towns scattered between Naples and Rome. The event made an impression on the young Vanorio, and inspired her interests in the geosciences. Now an assistant professor at Stanford, Vanorio decided to apply her knowledge about how rocks in the deep Earth respond to mechanical and chemical changes to investigate how the ground beneath Pozzuoli was able to withstand so much warping before cracking and setting off micro-earthquakes.
"Ground swelling occurs at other calderas such as Yellowstone or Long Valley in the United States, but never to this degree, and it usually requires far less uplift to trigger earthquakes at other places," Vanorio said. "At Campi Flegrei, the micro-earthquakes were delayed by months despite really large ground deformations."
To understand why the surface of the caldera was able to accommodate incredible strain without suddenly cracking, Vanorio and a post-doctoral associate, Waruntorn Kanitpanyacharoen, studied rock cores from the region. In the early 1980s, a deep drilling program probed the active geothermal system of Campi Flegrei to a depth of about 2 miles. When the pair analyzed the rock samples, they discovered that Campi Flegrei's caprock-a hard rock layer located near the caldera's surface-is rich in pozzolana, or volcanic ash from the region.
The scientists also noticed that the caprock contained tobermorite and ettringite-fibrous minerals that are also found in humanmade concrete. These minerals would have made Campi Flegrei's caprock more ductile, and their presence explains why the ground beneath Pozzuoli was able to withstand significant bending before breaking and shearing. But how did tobermorite and ettringite come to form in the caprock?
Once again, the drill cores provided the crucial clue. The samples showed that the deep basement of the caldera-the "wall" of the bowl-like depression-consisted of carbonate-bearing rocks similar to limestone, and that interspersed within the carbonate rocks was a needle-shaped mineral called actinolite.
"The actinolite was the key to understanding all of the other chemical reactions that had to take place to form the natural cement at Campi Flegrei," said Kanitpanyacharoen, who is now at Chulalongkorn University in Thailand.
From the actinolite and graphite, the scientists deduced that a chemical reaction called decarbonation was occurring beneath Campi Flegrei. They believe that the combination of heat and circulating mineral-rich waters decarbonates the deep basement, prompting the formation of actinolite as well as carbon dioxide gas. As the CO₂ mixes with calcium-carbonate and hydrogen in the basement rocks, it triggers a chemical cascade that produces several compounds, one of which is calcium hydroxide. Calcium hydroxide, also known as portlandite or hydrated lime, is one of the two key ingredients in humanmade concrete, including Roman concrete. Circulating geothermal fluids transport this naturally occurring lime up to shallower depths, where it combines with the pozzolana ash in the caprock to form an impenetrable, concrete-like rock capable of withstanding very strong forces.
"This is the same chemical reaction that the ancient Romans unwittingly exploited to create their famous concrete, but in Campi Flegrei it happens naturally," Vanorio said.
In fact, Vanorio suspects that the inspiration for Roman concrete came from observing interactions between the volcanic ash at Pozzuoli and seawater in the region. The Roman philosopher Seneca, for example, noted that the "dust at Puteoli becomes stone if it touches water."
"The Romans were keen observers of the natural world and fine empiricists," Vanorio said. "Seneca, and before him Vitruvius, understood that there was something special about the ash at Pozzuoli, and the Romans used the pozzolana to create their own concrete, albeit with a different source of lime."
Pozzuoli was the main commercial and military port for the Roman Empire, and it was common for ships to use pozzolana as ballast while trading grain from the eastern Mediterranean. As a result of this practice, volcanic ash from Campi Flegrei-and the use of Roman concrete-spread across the ancient world. Archeologists have recently found that piers in Alexandria, Caesarea, and Cyprus are all made from Roman concrete and have pozzolana as a primary ingredient.
Interestingly, the same chemical reaction that is responsible for the unique properties of the Campi Flegrei's caprock can also trigger its downfall. If too much decarbonation occurs-as might happen if a large amount of saltwater, or brine, gets injected into the system-an excess of carbon dioxide, methane and steam is produced. As these gases rise toward the surface, they bump up against the natural cement layer, warping the caprock. This is what lifted Pozzuoli in the 1980s. When strain from the pressure buildup exceeded the strength of the caprock, the rock sheared and cracked, setting off swarms of micro-earthquakes. As pent-up gases and fluids vent into the atmosphere, the ground swelling subsided. Vanorio and Kanitpanyacharoen suspect that as more calcium hydroxide was produced at depth and transported to the surface, the damaged caprock was slowly repaired, its cracks "healed" as more natural cement was produced.
Vanorio believes the conditions and processes responsible for the exceptional rock properties at Campi Flegrei could be present at other calderas around the world. A better understanding of the conditions and processes that formed Campi Flegrei's caprock could also allow scientists to recreate it in the lab, and perhaps even improve upon it to engineer more durable and resilient concretes that are better able to withstand large stresses and shaking, or to heal themselves after damage.
"There is a need for eco-friendly materials and concretes that can accommodate stresses more easily," Vanorio said. "For example, extracting natural gas by hydraulic fracturing can cause rapid stress changes that cause concrete well casings to fail and lead to gas leaks and water contamination."
Video: https://www.youtube.com/watch?v=LrL5ARjmFSs

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The compounds, di-isononyl phthalate (DINP) and di-isodecyl phthalate (DIDP), are both in a class of chemicals known as phthalates. Ironically, the two chemicals were used as replacements for another chemical, di-2-ethylhexylphlatate, or DEHP, which the same researchers proved in previous research to have similar adverse effects.
"Our research adds to growing concerns that environmental chemicals might be independent contributors to insulin resistance, elevated blood pressure and other metabolic disorders," says study lead investigator Leonardo Trasande, MD, MPP, a professor at NYU Langone.
Trasande says the series of studies are believed to be the first to examine potential health risks from DEHP replacements. In the most recent one, described in the journal Hypertension online July 9, the investigators report a "significant association" between high blood pressure and the presence of DINP and DIDP levels in study subjects. Specifically, they say, for every tenfold increase in the amount of phthalates consumed, there was a 1.1 millimeters of mercury increase in blood pressure.
In the earlier study, published in May in the Journal of Clinical Endocrinology and Metabolism, the same NYU investigators found an association between DINP and DIDP concentrations and increased insulin resistance, a precursor to diabetes. One in three adolescents with the highest DINP levels had the highest insulin resistance, while for those with the lowest concentrations of the chemicals, only one in four had insulin resistance.
DEHP, the original chemical used as a plasticizer, was banned in 2004 in Europe after researchers elsewhere found a link between exposure to the plasticizer and detrimental effects on human health. In the United States, manufacturers voluntarily began to replace DEHP with DINP and DIDP over the last decade. Trasande's own research in 2013 confirmed the link between DEHP exposure and hypertension in Americans.
For the new study research, the NYU team reviewed blood sample and urine analyses from participants in the National Health and Nutrition Examination Survey. Since 1999, NHANES, as it is known, gathers information about the prevalence and risk factors of major diseases by annually surveying 5,000 volunteers. As part of the NYU Langone investigation, blood samples of a diverse group of 356 children and adolescents ages 12 to 19 were measured and evaluated for phthalates and glucose based on their urinary levels of the substances.
Blood and urine samples were collected once between 2008 and 2012, and the study volunteers' blood pressure was similarly measured. Diet, physical activity, gender, race/ethnicity, income, and other factors independently associated with insulin resistance and hypertension were also factored into the researchers' analysis.
"Alternatives to DIDP and DINP include wax paper and aluminum wrap; indeed, a dietary intervention that introduced fresh foods that were not canned or packaged in plastic reduced phthalate metabolites substantially," says Trasande. "Our study adds further concern for the need to test chemicals for toxicity prior to their broad and widespread use, which is not required under current federal law (the 1976 Toxic Substances Control Act)," he says.
Trasande says there are "safe and simple" steps families can take to limit exposure to phthalates. These include not microwaving food in plastic containers or covered by plastic wrap, and washing plastic food containers by hand instead of putting them in the dishwasher, where harsh chemicals can lead to increased leaching of plasticizers into food. He says people can also avoid using plastic containers labeled on the bottom with the numbers 3, 6 or 7 (inside the recycle symbol), in which chemicals such as phthalates are used.
Trasande says his team now plans to study the long-term effects of exposure to these chemicals, in particular during pregnancy and early childhood, which might reveal different and/or more persistent effects on health.

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The new findings, published July 3 in two papers in the Journal of Biological Chemistry, can help scientists create tailor-made proteins optimized for use in optogenetics, said David Kliger, senior author of both papers and a professor of chemistry and biochemistry at UC Santa Cruz.
"Little was known about the functional mechanism of these proteins even though they are widely used in optogenetics," Kliger said.
The researchers used fast laser spectroscopy to study the function of Channelrhodopsin-2, which is found in a type of marine algae and is widely used in optogenetics experiments. Channelrhodopsins are ion channels that control the flow of ions across cell membranes. There are many kinds of ion channels that serve different purposes in different types of cells. Nerve signals involve ion flow across the membranes of nerve cells, and the breakthrough of optogenetics was the discovery that inserting the genes for light-gated ion channels such as channelrhodopsin into neurons would make them fire in response to light.
The first paper describes the mechanism of channelrhodopsin function in terms of intermediate states the protein goes through in the process of opening the ion channel. In the second paper, the researchers showed that the mechanism revealed in the first paper can explain patterns of ion currents observed in optogenetics experiments.
"It is exciting because this opens up a methodology to start selecting mutant proteins with properties optimized for optogenetics, which is important for brain research and for studying neurological processes in general," Kliger said.
There are several types of modifications that could be useful for optogenetics, such as making the proteins more efficient so that less light is needed to trigger currents in neurons, he said. In some cases, researchers might want to speed up the channel opening or slow it down, or they might want to speed up or slow down the channel closing. Depending on the tissues being studied, they might also want to shift the spectrum of light needed to activate the protein.
"These basic biophysics experiments can help in optimizing how the proteins function in optogenetics experiments," Kliger said.

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The above post is reprinted from materials provided by University of California - Santa Cruz. The original item was written by Tim Stephens. Note: Materials may be edited for content and length.

In a study published today in Nature Communications, the researchers report that when electrons move in a phosphorus transistor, they do so only in two dimensions. The finding suggests that black phosphorus could help engineers surmount one of the big challenges for future electronics: designing energy-efficient transistors.
"Transistors work more efficiently when they are thin, with electrons moving in only two dimensions," says Thomas Szkopek, an associate professor in McGill's Department of Electrical and Computer Engineering and senior author of the new study. "Nothing gets thinner than a single layer of atoms."
In 2004, physicists at the University of Manchester in the U.K. first isolated and explored the remarkable properties of graphene -- a one-atom-thick layer of carbon. Since then scientists have rushed to to investigate a range of other two-dimensional materials. One of those is black phosphorus, a form of phosphorus that is similar to graphite and can be separated easily into single atomic layers, known as phosphorene.
Phosphorene has sparked growing interest because it overcomes many of the challenges of using graphene in electronics. Unlike graphene, which acts like a metal, black phosphorus is a natural semiconductor: it can be readily switched on and off.
"To lower the operating voltage of transistors, and thereby reduce the heat they generate, we have to get closer and closer to designing the transistor at the atomic level," Szkopek says. "The toolbox of the future for transistor designers will require a variety of atomic-layered materials: an ideal semiconductor, an ideal metal, and an ideal dielectric. All three components must be optimized for a well designed transistor. Black phosphorus fills the semiconducting-material role."
The work resulted from a multidisciplinary collaboration among Szkopek's nanoelectronics research group, the nanoscience lab of McGill Physics Prof. Guillaume Gervais, and the nanostructures research group of Prof. Richard Martel in Université de Montréal's Department of Chemistry.
To examine how the electrons move in a phosphorus transistor, the researchers observed them under the influence of a magnetic field in experiments performed at the National High Magnetic Field Laboratory in Tallahassee, FL, the largest and highest-powered magnet laboratory in the world. This research "provides important insights into the fundamental physics that dictate the behavior of black phosphorus," says Tim Murphy, DC Field Facility Director at the Florida facility.
"What's surprising in these results is that the electrons are able to be pulled into a sheet of charge which is two-dimensional, even though they occupy a volume that is several atomic layers in thickness," Szkopek says. That finding is significant because it could potentially facilitate manufacturing the material -- though at this point "no one knows how to manufacture this material on a large scale."
"There is a great emerging interest around the world in black phosphorus," Szkopek says. "We are still a long way from seeing atomic layer transistors in a commercial product, but we have now moved one step closer."
This work was funded by the Natural Sciences and Engineering Research Council of Canada, the Canadian Institute for Advanced Research, the Fonds de recherche du Québec -- Nature et technologies, Le regroupement québécois sur les matériaux de pointe, and the Canada Research Chairs program. A portion of the work was performed at the National High Magnetic Field Laboratory which is supported by the National Science Foundation, the State of Florida and the U.S. Department of Energy.

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Called active sites, the spots help rip apart and rearrange molecules as they pass through nanometer-sized channels, like an assembly line in a factory. A process called steaming causes these active sites to cluster, effectively shutting down the factory, the scientists reported in Nature Communications. This knowledge could help devise how to keep the factory running longer, so to speak, and improve catalysts that help produce fuel, biofuel and other chemicals.
The team included scientists from the Department of Energy's Pacific Northwest National Laboratory, petroleum refining technology company UOP LLC and Utrecht University. To make this discovery, they reconstructed the first 3-D atomic map of an industrially relevant zeolite material to track down its key element, aluminum.
When things get steamy, structure changes
Zeolites are minerals made up of aluminum, silicon and oxygen atoms arranged in a three-dimensional crystalline structure. Though they look like white powder to the naked eye, zeolites have a sponge-like network of molecule-size pores. Aluminum atoms along these pores act like workers on an assembly line--they create active sites that give zeolites their catalytic properties.
Industry uses about a dozen synthetic zeolites as catalysts to process petroleum and chemicals. One major conversion process, called fluid catalytic cracking, depends on zeolites to produce the majority of the world's gasoline.
To awaken active sites within zeolites, industry pretreats the material with heat and water, a process called steaming. But too much steaming somehow switches the sites off. Changing the conditions of steaming could extend the catalyst's life, thus producing fuel more efficiently.
Scientists have long suspected that steaming causes aluminum to move around within the material, thus changing its properties. But until now aluminum has evaded detailed analysis.
Strip away the atoms
Most studies of zeolite structure rely on electron microscopy, which can't easily distinguish aluminum from silicon because of their similar masses. Worse, the instrument's intense electron beam tends to damage the material, changing its inherent structure before it's seen.
Instead, the team of scientists turned to a characterization technique that had never before been successfully applied to zeolites. Called atom probe tomography, it works by zapping a sample with a pulsing laser, providing just enough energy to knock off one atom at a time. Time-of-flight mass spectrometers analyze each atom--at a rate of about 1,000 atoms per second. Unlike an electron microscope, this technique can distinguish aluminum from silicon.
Though atom probe tomography has been around for 50 years, it was originally designed to look at conductive materials, such as metals. Less conductive zeolites presented a problem.
PNNL materials scientist Danny Perea and his colleagues overcame this hurdle by adapting a Local Electrode Atom Probe at EMSL, the Environmental Molecular Sciences Laboratory, a DOE Office of Science User Facility accessible to scientists around the world. Most attempts to image the material ended prematurely, when electromagnetic forces within the instrument vaporized the entire sample. The key to success was to find the right conditions to prepare a sample and then to coat it with a layer of metal to help provide conductivity and strength to withstand analysis.
After hours of blasting tens-of-millions of atoms, the scientists could reconstruct an atomic map of a sample about a thousand times smaller than the width of a human hair. These maps hold clues as to why the catalyst fails.
A place to cluster
The images confirmed what scientists have long suspected: Steaming causes aluminum atoms to cluster. Like workers crowded around one spot on the assembly line, this clustering effectively shuts down the catalytic factory.
The scientists even pinpointed the place where aluminum likes to cluster. Zeolite crystals often grow in overlapping sub-units, forming something like a 3-D Venn diagram. Scientists call the edge between two sub-units a grain boundary, and that's where the aluminum clustered. The scientists suspect that open space along grain boundaries attracted the aluminum.
With the guidance of these atomic maps, industry could one day modify how it steams zeolites to produce a more efficient, longer lasting catalyst. The research team will next examine other industrially important zeolites at different stages of steaming to provide a more detailed map of this transformation.
This research was supported by the Netherlands Research School Combination-Catalysis, the Netherlands Research Council and PNNL's Laboratory Directed Research Development program.

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The bioplastic PLA is derived from renewable resources, including the sugar in maize and sugarcane. Fermentation turns the sugar into lactic acid, which in turn is a building block for polylactic acid. PLA degrades after a number of years in certain environments. If it is collected and sorted correctly, it is both industrially compostable and recyclable. In addition, PLA is biocompatible and thus suitable for medical use, for instance in absorbable suture threads. PLA is also one of the few plastics that are suitable for 3D printing.
However, PLA is not yet a full alternative for petroleum-based plastics due to its cost. The production process for PLA is expensive because of the intermediary steps. "First, lactic acid is fed into a reactor and converted into a type of pre-plastic under high temperature and in a vacuum," Professor Bert Sels explains. "This is an expensive process. The pre-plastic -- a low-quality plastic -- is then broken down into building blocks for PLA. In other words, you are first producing an inferior plastic before you end up with a high-quality plastic. And even though PLA is considered a green plastic, the various intermediary steps in the production process still require metals and produce waste."
The KU Leuven researchers developed a new technique. "We have applied a petrochemical concept to biomass," says postdoctoral researcher Michiel Dusselier. "We speed up and guide the chemical process in the reactor with a zeolite as a catalyst. Zeolites are porous minerals. By selecting a specific type on the basis of its pore shape, we were able to convert lactic acid directly into the building blocks for PLA without making the larger by-products that do not fit into the zeolite pores. Our new method has several advantages compared to the traditional technique: we produce more PLA with less waste and without using metals. In addition, the production process is cheaper, because we can skip a step."
Professor Sels is confident that the new technology will soon take hold. "The KU Leuven patent on our discovery was recently sold to a chemical company that intends to apply the production process on an industrial scale. Of course, PLA will never fully replace petroleum-based plastics. For one thing, some objects, such as toilet drain pipes, are not meant to be biodegradable. And it is not our intention to promote disposable plastic. But products made of PLA can now become cheaper and greener. Our method is a great example of how the chemical industry and biotechnology can join forces."

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In recent decades, physicists have been actively studying so-called two-dimensional materials. Andrei Geim and Konstantin Novoselov received the Nobel Prize for their research on graphene, the most well-known among them. The properties of such materials, which can be described as "sheets" with a thickness of a few atoms, strongly differ from their three-dimensional analogues. For example, graphene is transparent, conducts current better than copper and has good thermal conductivity. Scientists believe that other types of two-dimensional materials may possess even more exotic properties.
A group of scientists from Russia and the USA, including Pavel Sorokin and Liubov Antipina from MIPT, recently conducted research on the properties of the crystals of one such material,Nb3SiTe6, a compound of niobium telluride. In their structure, the crystals resemble sandwiches with a thickness of three atoms (around 4 angstroms): a layer of tellurium, a layer of niobium mixed with silicon atoms and then another layer of tellurium. This substance belongs to a class of materials known as dichalcogenides, which many scientists view as promising two-dimensional semiconductors.
The scientists synthesized Nb3SiTe6 crystals in a laboratory at Tulane University (New Orleans). They then separated them into two-dimensional layers, taking samples for further analysis by transmission electron microscopy, X-ray crystal analysis and other methods. The goal of the researchers was to investigate electron-phonon interaction changes in two-dimensional substances.
Quasi particles, quanta of crystal lattice oscillations, are called phonons. Physicists introduced the concept of phonons because it helped simplify the description of processes in crystals, and tracking of electron-phonon interaction is fundamentally important for description of the different conducting properties in matter.
"We developed a theory that predicts that electron-phonon interaction is suppressed due to dimensional effects in two-dimensional material. In other words, these materials obstruct the flow of electrons to a lesser extent," says Pavel Sorokin, a co-author of the study, doctor of physical and mathematical sciences, and lecturer at the MIPT Section of the Physics and Chemistry of Nanostructures (DMCP).
American colleagues confirmed this prediction in related experiments. "They conducted measurements where the same effect was observed. Our calculations allowed the ruling out of other explanations; we managed to prove that changes in electron-phonon interaction occur specifically because of the two-dimensionality of the membrane," Sorokin adds.

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Random packing materials are used in many chemical reactors and heat storage systems as catalytic support media or adsorbents. Several million tons of these functional materials are consumed every year in industrial processes to produce chemical feedstock. To ensure that these processes produce the desired results, the packing materials have to be able to conduct heat efficiently. This is not always easy, because the gaps between the millimeter-scale particles prevent heat from being conducted optimally throughout the packed bed. Chemical companies therefore have to build special heatconducting structures into their reactors. "This is time-consuming and expensive," says Jörg Adler, a researcher at the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden. Together with colleagues at the Fraunhofer Institutes for Machine Tools and Forming Technology IWU in Chemnitz and for Interfacial Engineering and Biotechnology IGB in Stuttgart, Adler has developed a concept that increases the heat transfer capacity of the packing material fivefold. Their concept involves encapsulating cylindrical filler particles in metal. The points of contact between the metal-encapsulated particles form a metal framework that enables heat to be conducted throughout the packed bed faster and more efficiently.
Five times more efficient
The scientists have conducted tests in the laboratory that prove that this efficiency gain is realizable, using a heat storage system consisting of an eight-liter packed bed of aluminum-encapsulated zeolite pellets. Adler lists the advantages: "The packed bed is heated to an even temperature more rapidly. It takes significantly less time to load and unload the heat storage medium. This makes it possible to enhance the efficiency of chemical reactions and hence increase product quality." The researchers expect that it will be possible to obtain even better results using a metal with a higher thermal conductivity, such as copper. The particles of packing material used in the laboratory tests are five millimeters long and encapsulated in a layer of aluminum with a thickness of 0.25 millimeters. The scientists produce them using a specially developed process that could be easily adapted to mass production. The packing material is poured into long, thin metal tubes, compacted to prevent it from spilling out, and the tubes are then cut into sections to form cylindrical particles no more than a few millimeters in length.
"The chemical industry uses large quantities of packing materials which, ideally, are expected to remain in the reactors for many years. One of the problems is that they are subject to powder abrasion during shipping and when in use, caused by particles rubbing against one another. This no longer happens when they are encapsulated in metal, and so the packing material lasts longer," says Adler.
Applying heat to zeolite pellets that are saturated with water causes the pellets to dry and absorb heat. When the pellets are rehydrated, the absorbed heat is released. This physical effect makes them suitable for use in heat storage systems. In this application too, says Adler, "the efficiency of the process depends on the thermal conductivity of the zeolite material. It is often necessary to install very complicated heat-exchanger units, which are expensive and reduce the volume available for actual heat storage. The metal-encapsulated packing material could be a valuable improvement here. In the laboratory, we have been able to significantly shorten the heat storage cycle time."
Now that the researchers have demonstrated the feasibility and functionality of the encapsulation technique in the lab, they want to move on to the next step on the way to industrial application. "We need to further optimize the material and the manufacturing process, and gather data so as to determine exactly to what extent the advantages of higher thermal conductivity outweigh the additional costs of metal encapsulation," says Adler.
The chemical industry uses large quantities of packing materials as catalytic support media and adsorbents. A catalyst is a substance that accelerates a chemical reaction without undergoing any chemical change itself. An adsorbent removes and stores specific products of a chemical reaction. As well as being used to optimize chemical reactions, packing materials also play a role in modern heat storage systems. In a packed bed reactor, a gas or liquid flows through the material and triggers a chemical reaction on the surface of the tiny particles.

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South Korean researchers at the Center for Self-assembly and Complexity, Institute for Basic Science (IBS), Department of Chemistry and Division of Advanced Materials Science at Pohang University, have created a new LIB made from a porous solid which greatly improves its performance as well as reducing the risks due to overheating.
Since 2002 there have been over 40 recalls in the US alone due to fire or explosion risk from LIBs used in consumer electronic devices. These types of batteries, in all of their different lithium-anode combinations, continue to be an essential part of modern consumer electronics despite their poor track record at high temperatures.
The Korean team tried a totally new approach in making the batteries. According to Dr. Kimoon Kim at IBS, "we have already investigated high and highly anisotropic [directionally dependent] proton conducting behaviors in porous CB[6] for fuel cell electrolytes. It is possible for this lithium ion conduction following porous CB[6] to be safer than existing solid lithium electrolyte -based organic-molecular porous-materials utilizing the simple soaking method." Current LIB technology relies on intercalated lithium which functions well, but due to ever increasing demands from electronic devices to be lighter and more powerful, investigation of novel electrolytes is necessary in order.
The new battery is built from pumpkin-shaped molecules called cucurbit[6]uril (CB[6]) which are organized in a honeycomb-like structure. The molecules have an incredibly thin 1D-channel, only averaging 7.5 Å [a single lithium ion is 0.76 Å, or .76 x 10-10 m] that runs through them. The physical structure of the porous CB[6] enables the lithium ions to battery to diffuse more freely than in conventional LIBs and exist without the separators found in other batteries.
In tests, the porous CB[6] solid electrolytes showed impressive lithium ion conductivity. To compare this to existing battery electrolytes, the team used a measurement of the lithium transference number (tLi+) which was recorded at 0.7-0.8 compared to 0.2-0.5 of existing electrolytes. They also subjected the batteries to extreme temperatures of up to 373 K (99.85° C), well above the 80° C typical upper temperature window for exiting LIBs. In the tests, the batteries were cycled at temperatures between 298 K and 373 K ( 24.85° C and 99.85° C) for a duration of four days and after each cycle the results showed no thermal runaway and hardly any change in conductivity.
Various conventional liquid electrolytes can incorporate in a porous CB[6] framework and converted to safer solid lithium electrolytes. Additionally, electrolyte usage is not limited to use only in LIBs, but a lithium air battery potentially feasible. What makes this new technique most exciting is that it is a new method of preparing a solid lithium electrolyte which starts as a liquid but no post-synthetic modification or chemical treatment is needed.

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The above post is reprinted from materials provided by Institute for Basic Science. The original item was written by Daniel Kopperud. Note: Materials may be edited for content and length.

The exhaust gas masses that arise from steel manufacturing plants are gigantic: the chimneys of the Duisburg Stahlwerke alone unleash several million tons of carbon dioxide. Fraunhofer has developed a process by which these exhaust fumes can be reclaimed and recycled into fuels and specialty chemicals. With the aid of genetically modified bacterial strains, the research team ferments the gas into alcohols and acetone, convert both substances catalytically into a kind of intermediary diesel product, and from this they produce kerosene and special chemicals. Participants include the Fraunhofer Institute for Molecular Biology and Applied Ecology IME in Aachen, as well as the Institute for Environment, Safety, and Energy Technology UMSICHT in Oberhausen and the Institute for Chemical Technology ICT in Pfinztal. The technology came about during one of Fraunhofer's internal preliminary research projects and through individual projects with industrial partners. The patented process currently operates on the laboratory scale.
Business model instead of problem
"From our viewpoint, the quantities of carbon alone -- which rise as smoke from the Duisburg steelworks as carbon dioxide -- would suffice to cover the entire need for kerosene of a major airline. Of course, we still have got a bit to go to reach this vision. But we have demonstrated on the laboratory scale that this concept works and could be of interest commercially. In addition to the exhaust gases, syngas -- similar gas mixtures from home and industrial waste incineration -- can also be used for the engineered process," explains Stefan Jennewein of IME, who is coordinating the project.
The biochemists at IME use syngas -- a mixture of carbon monoxide, carbon dioxide and hydrogen -- as a carbon resource for fermentation. Using bacterial strains of the Clostridium species, the syngas transforms either into short-chain alcohols like butanol and hexanol, or into acetone. To do so, IME engineered new genetic processes for the efficient integration of large gene clusters in the Clostridium genome. At the same time, Fraunhofer further expanded its syngas fermentation system and used it for experiments with the steel and chemicals industry.
The chemists around Axel Kraft at UMSICHT evaporate the residual fermentation products and in a continuous catalytic process, couple the fermentation molecules into an intermediate product consisting of long-chain alcohols and ketones. This interim product already meets the standards for ship diesel, and, like fats and oils, can be converted through hydrogenation into diesel fuel for cars or kerosene for planes. Kristian Kowollik from the environmental engineering department at ICT obtains specialty chemicals from the interim product connected with this, which already can now directly replace petroleum-based products. For example, amines can be used in the pharmaceutical industry or the production of tensides and dying agents. "The products synthetically produced by us can be used both as fuels as well as speciality chemicals. Exactly like this has worked until now with petroleum as the raw material source," states Jennewein.
In the next stage, the scientists strive to demonstrate that their technology also works with large quantities. "Over the next one-and-a-half years, we aim at gaining a better understanding of the processes, and to optimize them. Our goal is to apply for certification processes for the fuels. That is how its viability for practical use will be officially validated. For vehicle diesel, that takes about one year, and for kerosene about three years," Axel Kraft adds.

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The findings are published June 19 in the journal Science.
The new design is inspired by the way that plants generate energy through photosynthesis.
'Biology does a very good job of creating energy from sunlight,' said Sarah Tolbert, a UCLA professor of chemistry and one of the senior authors of the research. 'Plants do this through photosynthesis with extremely high efficiency.'
'In photosynthesis, plants that are exposed to sunlight use carefully organized nanoscale structures within their cells to rapidly separate charges -- pulling electrons away from the positively charged molecule that is left behind, and keeping positive and negative charges separated,' Tolbert said. 'That separation is the key to making the process so efficient.'
To capture energy from sunlight, conventional rooftop solar cells use silicon, a fairly expensive material. There is currently a big push to make lower-cost solar cells using plastics, rather than silicon, but today's plastic solar cells are relatively inefficient, in large part because the separated positive and negative electric charges often recombine before they can become electrical energy.
'Modern plastic solar cells don't have well-defined structures like plants do because we never knew how to make them before,' Tolbert said. 'But this new system pulls charges apart and keeps them separated for days, or even weeks. Once you make the right structure, you can vastly improve the retention of energy.'
The two components that make the UCLA-developed system work are a polymer donor and a nano-scale fullerene acceptor. The polymer donor absorbs sunlight and passes electrons to the fullerene acceptor; the process generates electrical energy.
The plastic materials, called organic photovoltaics, are typically organized like a plate of cooked pasta -- a disorganized mass of long, skinny polymer 'spaghetti' with random fullerene 'meatballs.' But this arrangement makes it difficult to get current out of the cell because the electrons sometimes hop back to the polymer spaghetti and are lost.
The UCLA technology arranges the elements more neatly -- like small bundles of uncooked spaghetti with precisely placed meatballs. Some fullerene meatballs are designed to sit inside the spaghetti bundles, but others are forced to stay on the outside. The fullerenes inside the structure take electrons from the polymers and toss them to the outside fullerene, which can effectively keep the electrons away from the polymer for weeks.
'When the charges never come back together, the system works far better,' said Benjamin Schwartz, a UCLA professor of chemistry and another senior co-author. 'This is the first time this has been shown using modern synthetic organic photovoltaic materials.'
In the new system, the materials self-assemble just by being placed in close proximity.
'We worked really hard to design something so we don't have to work very hard,' Tolbert said.
The new design is also more environmentally friendly than current technology, because the materials can assemble in water instead of more toxic organic solutions that are widely used today.
'Once you make the materials, you can dump them into water and they assemble into the appropriate structure because of the way the materials are designed,' Schwartz said. 'So there's no additional work.'
The researchers are already working on how to incorporate the technology into actual solar cells.
Yves Rubin, a UCLA professor of chemistry and another senior co-author of the study, led the team that created the uniquely designed molecules. 'We don't have these materials in a real device yet; this is all in solution,' he said. 'When we can put them together and make a closed circuit, then we will really be somewhere.'
For now, though, the UCLA research has proven that inexpensive photovoltaic materials can be organized in a way that greatly improves their ability to retain energy from sunlight.
Tolbert and Schwartz also are members of UCLA's California NanoSystems Institute. The study's other co-lead authors were UCLA graduate students Rachel Huber and Amy Ferreira. UCLA's Electron Imaging Center for NanoMachines imaged the assembled structure in a lab led by Hong Zhou.
The research was supported by the National Science Foundation (grant CHE-1112569) and by the Center for Molecularly Engineered Energy Materials, an Energy Frontier Research Center funded by the U.S. Department of Energy (DE-AC06-76RLO-1830). Ferreira received support from the Clean Green IGERT (grant DGE-0903720).

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The above post is reprinted from materials provided by University of California - Los Angeles. The original item was written by Melody Pupols. Note: Materials may be edited for content and length.