Google Glass now helping doctors during emergency

Google Glass now helping doctors during emergency

 

New York: Although eye wearable device Google Glass did not take off as it was projected to be, the device is helping Emergency Medical Technicians (EMTs) and paramedics communicate with ease with doctors during emergencies.

The augmented-reality headset is being used by paramedics and EMTs assessing patients and them consult with surgeons and doctors at the hospital in real time, Popular Science reported.

"During disasters, emergency rooms typically get overwhelmed. So when truly injured patients show up later, we have nowhere to put them," said Peter Chai, emergency medical physician at the University of Massachusetts` Medical School (UMMS).

UMMS is set to organise a drill this fall with first responders wearing Google Glass to see if it improves emergency assessment.

The university will also deploy a drone equipped with heat sensors to help find patients and determine which ones need the most urgent attention.

Stanford University is also using Google Glass to help kids with autism.

The university`s Autism Glass Project provides families with facial recognition software that helps interpret facial expressions.

Scientists put a new twist on artificial muscles

UT Dallas scientists produced the fibers in this woven textile by highly twisting nylon sewing thread to produce coiled artificial muscles. The coiled muscles can contract by over 30 percent when thermally or electrically heated, and might one day be used to make intelligent textiles, such as clothing that adjusts its porosity in response to temperature.

Credit: Image courtesy of University of Texas at Dallas

In recent years, researchers at The University of Texas at Dallas and colleagues at the University of Wollongong in Australia have put a high-tech twist on the ancient art of fiber spinning, using modern materials to create ultra-strong, powerful, shape-shifting yarns.

In a perspective article published Sept. 26 online in theProceedings of the National Academy of Sciences, a team of scientists at UT Dallas' Alan G. MacDiarmid NanoTech Institute describes the path to developing a new class of artificial muscles made from highly twisted fibers of various materials, ranging from exotic carbon nanotubes to ordinary nylon thread and polymer fishing line.

Because the artificial muscles can be made in different sizes and configurations, potential applications range from robotics and prosthetics to consumer products such as smart textiles that change porosity and shape in response to temperature.

"We call these actuating fibers 'artificial muscles' because they mimic the fiber-like form-factor of natural muscles," said Dr. Carter Haines, associate research professor in the NanoTech Institute and co-lead author of the PNAS article, with research associate Dr. Na Li. "While the name evokes the idea of humanoid robots, we are very excited about their potential use for other practical applications, such as in next-generation intelligent textiles." Science Based on Ancient Art

Spinning animal fur and plant fibers to make thread and yarn goes back thousands of years. Aligning the fibers and then twisting them into yarn gives the yarn strength.

By exploiting this concept, and adding 21st-century science, the UT Dallas researchers have produced actuating muscle yarns that, like their wooly counterparts, can be woven, sewn and knitted into textiles.

For example, carbon nanotubes are essentially tendrils of tiny, hollow tubes that are super-strong and electrically conductive. In 2004, led by Dr. Ray Baughman, director of the NanoTech Institute and the Robert A. Welch Distinguished Chair in Chemistry at UT Dallas, the team developed a method to draw "forests" of nanotubes out into sheets of aligned fibers -- much like carded wool -- and then twist the sheets into yarns.

Next, the group turned to polymer fibers such as nylon sewing thread and fishing line, which consist of many individual molecules aligned along the fiber's length. Twisting the thread or fishing line orients these molecules into helices, producing torsional -- or rotational -- artificial muscles that can spin a heavy rotor more than 100,000 revolutions per minute.

When these muscles are so highly twisted that they coil like an over-twisted rubber band, they can produce tensile actuation, where the muscle dramatically contracts along its length when heated, and returns to its initial length when cooled. That research, published in 2014, showed that simple, low-cost muscles made from fishing line can lift 100 times more weight and generate 100 times higher mechanical power than a human skeletal muscle of the same length and weight.

"The success of our muscles derives from their special geometry and the fact that we start with materials that are anisotropic -- when they are heated, the materials expand in diameter much more than they expand along their length," said Baughman, senior author of the PNAS perspective. This anisotropy is an intrinsic property of high-strength polymer fibers, and is the same principle that drives powerful artificial muscles the researchers discovered in 2012, which they made by adding a thermally responsive "guest" material within a carbon nanotube yarn.

"When these fibers are then twisted and coiled, their internal geometry changes so that when they are heated, that diameter expansion results in a change in length," Baughman said. "The fiber's diameter only has to expand by about 5 percent to drive giant changes in length."

The Latest Twist

In their most recent experiments, described for the first time in the PNAS article, Haines and Li added a new twist to their artificial muscles. "The coiled artificial muscles we initially made from fishing line and nylon sewing thread were limited in the amount they could expand and contract along their length," Haines said. "Because of their geometry -- like a phone cord -- they could only contract so far before the coils began to collide with one another."

The solution: Form the coiled actuators into spirals.

"The advantage to the spiral shape is that now our muscle can contract into a flat state, expand out in the other direction, and return to its original length, all without getting stuck on itself," Li said. "Our experiments to date have been proof-of-concept, but have already shown that we can use heating and cooling to drive this back-and-forth motion across a giant range. This type of telescoping actuator can produce over an 8,600 percent change in length, compared to around 70 percent for our previous coils."

Smart Clothing

Li said one potential application for the spiral-shaped coil might be thermally responsive clothing. Instead of a down-filled jacket, a coat that incorporates many small coils could change the loft and insulating power of the garment in response to temperature.

In the laboratory, Haines and Li have produced spools of coiled polymer muscle threads suitable for sewing. "We have shown that these thermally responsive fibers can be used in conventional machines, such as looms, knitting machines and sewing machines," Li said. "As we move forward with our research, and scale it up, we hope to incorporate our ideas into functional fabrics and textiles for a variety of purposes, from clothing to environmentally responsive architecture to dynamic art sculptures."

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Story Source:

Materials provided by University of Texas at Dallas. Note: Content may be edited for style and length.

Journal Reference:

1. Carter S. Haines, Na Li, Geoffrey M. Spinks, Ali E. Aliev, Jiangtao Di, Ray H. Baughman. New twist on artificial muscles. Proceedings of the National Academy of Sciences, 2016; 201605273 DOI: 10.1073/pnas.1605273113

Cite This Page:

University of Texas at Dallas. "Scientists put a new twist on artificial muscles." ScienceDaily. ScienceDaily, 26 September 2016. <www.sciencedaily.com/releases/2016/09/160926221433.htm>.

Inexpensive semiconducting organic polymers can harvest sunlight to split carbon dioxide into alcohol fuels

Chemists at The University of Texas at Arlington have been the first to demonstrate that an organic semiconductor polymer called polyaniline is a promising photocathode material for the conversion of carbon dioxide into alcohol fuels without the need for a co-catalyst.

"This opens up a new field of research into new applications for inexpensive, readily available organic semiconducting polymers within solar fuel cells," said principal researcher Krishnan Rajeshwar, UTA distinguished professor of chemistry and biochemistry and co-Director of UTA's Center for Renewable Energy, Science & Technology.

"These organic semiconducting polymers also demonstrate several technical advantages, including that they do not need a co-catalyst to sustain the conversion to alcohol products and the conversion can take place at lower temperatures and use less energy, which would further reduce costs," Rajeshwar added.

Rajeshwar and his co-author Csaba Janaky, professor in the Department of Physical Chemistry and Materials Science at the University of Szeged, recently published their findings in The Royal Society of Chemistry journal ChemComm as "Polyaniline films photoelectrochemically reduce CO2 to alcohols."

In this proof-of-concept study, the researchers provide insights into the unique behavior of polyaniline obtained from photoelectrochemical measurements and adsorption studies, together with spectroscopic data. They also compared the behavior of several conducting polymers.

The stationary currents recorded after two hours during testing suggests that the polyaniline layer maintained its photoelectrochemical efficacy for the studied time period. While in the gas phase, only hydrogen was detected, but potential fuels such as methanol and ethanol were both detected in the solution for carbon dioxide-saturated samples.

"Apart from these technical qualities, as a polymer, polyaniline can also be easily made into fabrics and films that adapt to roofs or curved surfaces to create the large surface areas needed for photoelectrochemical reduction, eliminating the need for expensive and dangerous solar concentrators," Rajeshwar added.

Frederick MacDonnell, chair of UTA's Department of Chemistry and Biochemistry, underlined the importance of this research in the context of UTA's focus on global environmental impact within the Strategic Plan 2020: Bold Solutions|Global Impact.

"Dr. Rajeshwar's ongoing leadership in research around new materials for solar fuel generation is vital in a world where we all recognize the need to reduce the impact of carbon dioxide emissions," MacDonnell said. "Finding an inexpensive, readily-available photocathode material could open up new options to create cheaper, more energy-effective solar fuel cells."

Rajeshwar joined the College of Science in 1983 and is a charter member of the UTA Academy of Distinguished Scholars. He is the newly appointed president of the Electrochemical Society, an organization representing the nation's premier researchers dedicated to advancing solid state, electrochemical science and technology.

Story Source:

The above post is reprinted from materials provided byUniversity of Texas, Arlington. Note: Content may be edited for style and length.

Journal Reference:

1. Dorottya Hursán, Attila Kormányos, Krishnan Rajeshwar, Csaba Janáky. Polyaniline films photoelectrochemically reduce CO2 to alcohols. Chem. Commun., 2016; 52 (57): 8858 DOI: 10.1039/C6CC04050K

Cite This Page:University of Texas, Arlington. "Inexpensive semiconducting organic polymers can harvest sunlight to split carbon dioxide into alcohol fuels." ScienceDaily. ScienceDaily, 20 September 2016. <www.sciencedaily.com/releases/2016/09/160920115723.htm>.

Uniform 'hairy' nanorods have potential energy, biomedical applications

Image shows a vial containing water-soluble gold nanorods. Georgia Tech researchers have developed a new strategy for crafting one-dimensional nanorods based on cellulose using a wide range of precursor materials.

Credit: Rob Felt, Georgia Tech

Materials scientists have developed a new strategy for crafting one-dimensional nanorods from a wide range of precursor materials. Based on a cellulose backbone, the system relies on the growth of block copolymer "arms" that help create a compartment to serve as a nanometer-scale chemical reactor. The outer blocks of the arms prevent aggregation of the nanorods.

The produced structures resemble tiny bottlebrushes with polymer "hairs" on the nanorod surface. The nanorods range in size from a few hundred nanometers to a few micrometers in length, and a few tens of nanometers in diameter. This new technique enables tight control over diameter, length and surface properties of the nanorods, whose optical, electrical, magnetic and catalytic properties depend on the precursor materials used and the dimensions of the nanorods.

The nanorods could have applications in such areas as electronics, sensory devices, energy conversion and storage, drug delivery, and cancer treatment. Using their technique, the researchers have so far fabricated uniform metallic, ferroelectric, upconversion, semiconducting and thermoelectric nanocrystals, as well as combinations thereof. The research, supported by Air Force Office of Scientific Research, will be reported on September 16 in the journal Science.

"We have developed a very general and robust strategy to craft a rich variety of nanorods with precisely-controlled dimensions, compositions, architectures and surface chemistries," said Zhiqun Lin, a professor in the School of Materials Science and Engineering at the Georgia Institute of Technology. "To create these structures, we used nonlinear bottlebrush-like block copolymers as tiny reactors to template the growth of an exciting variety of inorganic nanorods."

Nanorod structures aren't new, but the technique used by Lin's lab produces nanorods of uniform sizes -- such as barium titanate and iron oxide, which have not yet been demonstrated via wet-chemistry approaches in the literature -- and highly-uniform core-shell nanorods made by combining two dissimilar materials. Lin and former postdoctoral research associate Xinchang Pang say the precursor materials applicable to the technique are virtually limitless.

"There are many precursors of different materials available that can be used with this robust system," Lin said. "By choosing a different outer block in the bottlebrush-like block copolymers, our nanorods can be dissolved and uniformly dispersed in organic solvents such as toluene or chloroform, or in water."

Fabrication of the nanorods begins with the functionalization of individual lengths of cellulose, an inexpensive long-chain biopolymer harvested from trees. Each unit of cellulose has three hydroxyl groups, which are chemically modified with a bromine atom. The brominated cellulose then serves as macroinitiator for the growth of the block copolymer arms with well-controlled lengths using the atom transfer radical polymerization (ATRP) process, with, for example, poly(acrylic acid)-block-polystyrene (PAA-b-PS) yielding cellulose densely grafted with PAA-b-PS (i.e., cellulose-g-[PAA-b-PS]) that give the bottlebrush appearance.

The next step involves the preferential partitioning of precursors in the inner PAA compartment that serves as a nanoreactor to initiate the nucleation and growth of nanorods. The densely grafted block copolymer arms, together with the rigid cellulose backbone, give researchers the ability to not only prevent aggregation of the resulting nanorods, but also to keep them from bending.

"The polymers are like long spaghetti and they want to coil up," Lin explained. "But they cannot do this in the complex macromolecules we make because with so many block copolymer arms formed, there is no space. This leads to the stretching of the arms, forming a very rigid structure."

By varying the chemistry and the number of blocks in the arms of the bottlebrush-like block copolymers, Lin and coworkers produced an array of oil-soluble and water-soluble plain nanorods, core-shell nanorods, and hollow nanorods -- nanotubes -- of different dimensions and compositions.

For example, by using bottlebrush-like triblock copolymers containing densely grafted amphiphilic triblock copolymer arms, the core-shell nanorods can be formed from two different materials. In most cases, a large lattice mismatch between core and shell materials would prevent the formation of high-quality core-shell structures, but the technique overcomes that limitation.

"By using this approach, we can grow the core and shell materials independently in their respective nanoreactors," Lin said. "This allows us to bypass the requirement for matching the crystal lattices and permits fabrication of a large variety of core-shell structures with different combinations that would otherwise be very challenging to obtain."

Lin sees many potential applications for the nanorods.

"With a broad range of physical properties -- optical, electrical, optoelectronic, catalytic, magnetic, and sensing -- that are dependent sensitively on their size and shape as well as their assemblies, the produced nanorods are of both fundamental and practical interest," Lin said. "Potential applications include optics, electronics, photonics, magnetic technologies, sensory materials and devices, lightweight structural materials, catalysis, drug delivery, and bio-nanotechnology."

For example, plain gold nanorods of different lengths may allow effective plasmonic absorption in the near-infrared range for use in solar energy conversion with improved harvesting of solar spectrum. The upconversion nanorods can preferentially harvest the IR solar photons, followed by the absorption of emitted high-energy photons to generate extra photocurrent in solar cells. They can also be used for biological labeling because of their low toxicity, chemical stability, and intense luminescence when excited by near-IR radiation, which can penetrate tissue much better than higher energy radiation such as ultraviolet, as is often required with quantum dot labels.

The gold-iron oxide core-shell nanorods may be useful in cancer therapy, with MRI imaging enabled by the iron oxide shell, and local heating created by the photothermal effect on the gold nanorod core killing cancer cells.

Story Source:

The above post is reprinted from materials provided by Georgia Institute of Technology. The original item was written by John Toon. Note: Content may be edited for style and length.

Journal Reference:

1. X. Pang, Y. He, J. Jung, Z. Lin. 1D nanocrystals with precisely controlled dimensions, compositions, and architectures. Science, 2016; 353 (6305): 1268 DOI:10.1126/science.aad8279

Cite This Page:Georgia Institute of Technology. "Uniform 'hairy' nanorods have potential energy, biomedical applications." ScienceDaily. ScienceDaily, 15 September 2016. <www.sciencedaily.com/releases/2016/09/160915144710.htm>.

Lighting the way to miniature devices

A team of scientists including researchers at Agency for Science, Technology and Research (A*STAR), Singapore, has captured tiny flashes of light from an ultrathin layer of organic molecules sandwiched between two electrodes that could replace lasers and LEDs as signal sources for future miniature, ultrafast quantum computing and light-based communication systems.

To investigate electromagnetic waves called plasmons, which skim along the interface between two materials, Nikodem Tomczak from the A*STAR Institute of Materials Research and Engineering and colleagues collaborated with Christian A. Nijhuis from the National University of Singapore to construct a junction consisting of a layer of thiol molecules on a metal electrode and liquid gallium-indium alloy as a top electrode.

The team created plasmons by applying a voltage across the thiol layer. Although thiol is an insulator, the layer was thin enough for electrons to quantum tunnel between the electrodes, exciting plasmons on the thiol layer's surface in the process. The plasmons then decayed into photons, tiny pulses of light that Tomczak and his colleagues were able to detect.

"We were surprised that the light did not come from the whole junction, but instead just from very small spots that blink at different frequencies," said Tomczak.

The team found that the light generated by the plasmons was polarized, and that both the polarization and the wavelength of the light varied with the voltage applied across the junction and the molecules used to form the organic layer.

"The spots are diffraction-limited, polarized and their blinking follows power-law statistics," said Tomczak. "We need further experiments to confirm, but it is very similar to emission from other single photon sources, such as quantum dots or nanodiamonds."

Further evidence that the light is from plasmons decaying into a single photon came from Chu Hong Son and his team at the A*STAR Institute of High Performance Computing who modeled the spots as the product of the smallest possible source, a single dipole emitter, and achieved results consistent with the experimental observations.

Story Source:

The above post is reprinted from materials provided by The Agency for Science, Technology and Research (A*STAR).Note: Content may be edited for style and length.

Journal Reference:

1. Ji Fang Tao, Hong Cai, Yuan Dong Gu, Jian Wu, Ai Qun Liu.Demonstration of a Photonic-Based Linear Temperature Sensor. IEEE Photonics Technology Letters, 2015; 27 (7): 767 DOI: 10.1109/LPT.2015.2392107 

Cite This Page:

The Agency for Science, Technology and Research (A*STAR). "Lighting the way to miniature devices." ScienceDaily. ScienceDaily, 13 September 2016. <www.sciencedaily.com/releases/2016/09/160913120920.htm>.

Lightweight, wearable tech efficiently converts body heat to electricity

Lightweight, wearable tech efficiently converts body heat to electricity

 

Researchers have developed a new design for harvesting body heat and converting it into electricity for use in wearable electronics. The tech can be embedded in a T-shirt, as shown here on study co-lead Haywood Hunter, an undergraduate at NC State University.

Researchers at North Carolina State University have developed a new design for harvesting body heat and converting it into electricity for use in wearable electronics. The experimental prototypes are lightweight, conform to the shape of the body, and can generate far more electricity than previous lightweight heat harvesting technologies.

The researchers also identified the optimal site on the body for heat harvesting.

"Wearable thermoelectric generators (TEGs) generate electricity by making use of the temperature differential between your body and the ambient air," says Daryoosh Vashaee, an associate professor of electrical and computer engineering at NC State and corresponding author of a paper on the work.

"Previous approaches either made use of heat sinks -- which are heavy, stiff and bulky -- or were able to generate only one microwatt or less of power per centimeter squared (μW/cm2). Our technology generates up to 20 μW/cm2 and doesn't use a heat sink, making it lighter and much more comfortable."

The new design begins with a layer of thermally conductive material that rests on the skin and spreads out the heat. The conductive material is topped with a polymer layer that prevents the heat from dissipating through to the outside air. This forces the body heat to pass through a centrally-located TEG that is one cm2. Heat that is not converted into electricity passes through the TEG into an outer layer of thermally conductive material, which rapidly dissipates the heat. The entire system is thin -- only 2 millimeters -- and flexible.

"In this prototype, the TEG is only one centimeter squared, but we can easily make it larger, depending on a device's power needs," says Vashaee, who worked on the project as part of the National Science Foundation's Nanosystems Engineering Research Center for Advanced Self-Powered Systems of Integrated Sensors and Technologies (ASSIST) at NC State.

The researchers also found that the upper arm was the optimal location for heat harvesting. While the skin temperature is higher around the wrist, the irregular contour of the wrist limited the surface area of contact between the TEG band and the skin. Meanwhile, wearing the band on the chest limited air flow -- limiting heat dissipation -- since the chest is normally covered by a shirt.

In addition, the researchers incorporated the TEG into T-shirts. The researchers found that the T-shirt TEGs were still capable of generating 6 μW/cm2 -- or as much as 16 μW/cm2 if a person is running.
"T-shirt TEGs are certainly viable for powering wearable technologies, but they're just not as efficient as the upper arm bands," Vashaee says.

"The goal of ASSIST is to make wearable technologies that can be used for long-term health monitoring, such as devices that track heart health or monitor physical and environmental variables to predict and prevent asthma attacks," he says.

"To do that, we want to make devices that don't rely on batteries. And we think this design and prototype moves us much closer to making that a reality."

Story Source:
The above post is reprinted from materials provided by North Carolina State University. Note: Content may be edited for style and length.

Journal Reference:

1. Melissa Hyland, Haywood Hunter, Jie Liu, Elena Veety, Daryoosh Vashaee. Wearable thermoelectric generators for human body heat harvesting. Applied Energy, 2016; 182: 518 DOI: 10.1016/j.apenergy.2016.08.150

Cite This Page:

North Carolina State University. "Lightweight, wearable tech efficiently converts body heat to electricity." ScienceDaily. ScienceDaily, 12 September 2016. <www.sciencedaily.com/releases/2016/09/160912132730.htm>.

 

New material to revolutionize water proofing

 

In addition to waterproofing, the new ability to control the properties of materials could be applied to a wide range of other coatings, said Mr Wong.

Credit: Image courtesy of Australian National University

Scientists at The Australian National University (ANU) have developed a new spray-on material with a remarkable ability to repel water.

The new protective coating could eventually be used to waterproof mobile phones, prevent ice from forming on aeroplanes or protect boat hulls from corroding.

"The surface is a layer of nanoparticles, which water slides off as if it's on a hot barbecue," said PhD student William Wong, from the Nanotechnology Research Laboratory at the ANU Research School of Engineering.
The team created a much more robust coating than previous materials by combining two plastics, one tough and one flexible.

"It's like two interwoven fishing nets, made of different materials," Mr Wong said.
The water-repellent or superhydrophobic coating is also transparent and extremely resistant to ultraviolet radiation.

Lead researcher and head of the Nanotechnology Research Laboratory, Associate Professor Antonio Tricoli, said the new material could change how we interact with liquids.
"It will keep skyscraper windows clean and prevent the mirror in the bathroom from fogging up," Associate Professor Tricoli said.

"The key innovation is that this transparent coating is able to stabilise very fragile nanomaterials resulting in ultra-durable nanotextures with numerous real-world applications."
The team developed two ways of creating the material, both of which are cheaper and easier than current manufacturing processes.

One method uses a flame to generate the nanoparticle constituents of the material. For lower temperature applications, the team dissolved the two components in a sprayable form.
In addition to waterproofing, the new ability to control the properties of materials could be applied to a wide range of other coatings, said Mr Wong.

"A lot of the functional coatings today are very weak, but we will be able to apply the same principles to make robust coatings that are, for example, anti-corrosive, self-cleaning or oil-repellent," he said.

Story Source:

The above post is reprinted from materials provided by Australian National University. Note: Content may be edited for style and length.

1. William S. Y. Wong, Zbigniew H. Stachurski, David R. Nisbet, Antonio Tricoli. Ultra-Durable and Transparent Self-Cleaning Surfaces by Large-Scale Self-Assembly of Hierarchical Interpenetrated Polymer Networks. ACS Applied Materials & Interfaces, 2016; 8 (21): 13615 DOI: 10.1021/acsami.6b03414

Cite This Page:

Australian National University. "New material to revolutionize water proofing." ScienceDaily. ScienceDaily, 8 September 2016. <www.sciencedaily.com/releases/2016/09/160908120439.htm>.

 

 

New perovskite research discoveries may lead to solar cell, LED advances

 

 

 

This image is a rendition of a one-dimensional, needle-like nanocrystal, such as the one prepared by Vela in collaboration with scientists Emily Smith and Jacob Petrich. Vela's team has prepared a family of highly luminescent perovskite nanocrystals with shape correlated emission.

 

"Promising" and "remarkable" are two words U.S. Department of Energy's Ames Laboratory scientist Javier Vela uses to describe recent research results on organolead mixed-halide perovskites.

Perovskites are optically active, semiconducting compounds that are known to display intriguing electronic, light-emitting and chemical properties. Over the last few years, lead-halide perovskites have become one of the most promising semiconductors for solar cells due to their low cost, easier processability and high power conversion efficiencies. Photovoltaics made of these materials now reach power conversion efficiencies of more than 20 percent.

Vela's research has focused on mixed-halide perovskites. Halides are simple and abundant, negatively charged compounds, such as iodide, bromide and chloride. Mixed-halide perovskites are of interest over single-halide perovskites for a variety of reasons. Mixed-halide perovskites appear to benefit from enhanced thermal and moisture stability, which makes them degrade less quickly than single-halide perovskites, Vela said. He added they can be fine-tuned to absorb sunlight at specific wavelengths, which makes them useful for tandem solar cells and many other applications, including light emitting diodes (LEDs).Using these compounds, scientists can control the color and efficiency of such energy conversion devices.

Speculating that these enhancements had something to do with the internal structure of mixed-halide perovskites, Vela, who is also an associate professor of chemistry at Iowa State University (ISU), worked with scientists with expertise in solid-state nuclear magnetic resonance (NMR) at both Ames Laboratory and ISU. NMR is an analytical chemistry technique that provides scientists with physical, chemical, structural and electronic information about complex samples.

"Our basic question was what it is about these materials in terms of their chemistry, composition, and structure that can affect their behavior," said Vela.

Scientists found that depending on how the material is made there can be significant nonstoichiometric impurities or "dopants" permeating the material, which could significantly affect the material's chemistry, moisture stability and transport properties.

The answers came via the combination of the use of optical absorption spectroscopy, powder X-ray diffraction and for the first time, the advanced probing capabilities of lead solid-state NMR.
"We were only able to see these dopants, along with other semicrystalline impurities, through the use of lead solid-state NMR," said Vela.

Another major discovery scientists made was that solid state synthesis is far superior to solution-phase synthesis in making mixed-halide perovskites. According to Vela, the advanced spectroscopy and materials capabilities of Ames Laboratory and ISU were critical in understanding how various synthetic procedures affect the true composition, speciation, stability and optoelectronic properties of these materials.

"We found you can make clean mixed halide perovskites without semi-crystalline impurities if you make them in the absence of a solvent," Vela said.

According to Vela, the significance of their findings is multifold and they are only beginning to grasp the implications of those findings.

"One obvious implication is that our understanding of the amazing opto-electronic properties of these semiconductors was incomplete," said Vela. "We're dealing with a compound that is not inherently as simple as people thought."

The research is further discussed in a paper, "Persistent Dopants and Phase Segregation in Organolead Mixed-Halide Perovskites," authored by Vela, Bryan A. Rosales, Long Men, Sarah D. Cady, Michael P. Hanrahan, and Aaron J. Rossini; and published online in Chemistry Materials. The work was supported by DOE's Office of Science.

Story Source:

The above post is reprinted from materials provided by DOE/Ames Laboratory. Note: Content may be edited for style and length.

Journal Reference:

1. Bryan A. Rosales, Long Men, Sarah D. Cady, Michael P. Hanrahan, Aaron J. Rossini, Javier Vela. Persistent Dopants and Phase Segregation in Organolead Mixed-Halide Perovskites. Chemistry of Materials, 2016; DOI: 10.1021/acs.chemmater.6b01874

Cite This Page:

DOE/Ames Laboratory. "New perovskite research discoveries may lead to solar cell, LED advances." ScienceDaily. ScienceDaily, 7 September 2016. <www.sciencedaily.com/releases/2016/09/160907113651.htm>.

 

'Materials that compute' advances as engineers demonstrate pattern recognition

 

 

This is a conceptual illustration of pattern recognition process performed by hybrid gel oscillator system.

 

The potential to develop "materials that compute" has taken another leap at the University of Pittsburgh's Swanson School of Engineering, where researchers for the first time have demonstrated that the material can be designed to recognize simple patterns. This responsive, hybrid material, powered by its own chemical reactions, could one day be integrated into clothing and used to monitor the human body, or developed as a skin for "squishy" robots.

"Pattern recognition for materials that compute," published in the AAAS journal Science Advances, continues the research of Anna C. Balazs, Distinguished Professor of Chemical and Petroleum Engineering, and Steven P. Levitan, the John A. Jurenko Professor of Electrical and Computer Engineering. Co-investigators are Yan Fang, lead author and graduate student researcher in the Department of Electrical and Computer Engineering; and Victor V. Yashin, Research Assistant Professor of Chemical and Petroleum Engineering.

The computations were modeled utilizing Belousov-Zhabotinsky (BZ) gels, a substance that oscillates in the absence of external stimuli, with an overlaying piezoelectric (PZ) cantilever. These so-called BZ-PZ units combine Dr. Balazs' research in BZ gels and Dr. Levitan's expertise in computational modeling and oscillator-based computing systems.

"BZ-PZ computations are not digital, like most people are familiar with, and so to recognize something like a blurred pattern within an image requires nonconventional computing," Dr. Balazs explained. "For the first time, we have been able to show how these materials would perform the computations for pattern recognition."

Dr. Levitan and Mr. Fang first stored a pattern of numbers as a set of polarities in the BZ-PZ units, and the input patterns are coded through the initial phase of the oscillations imposed on these units. The computational modeling revealed that the input pattern closest to the stored pattern exhibits the fastest convergence time to the stable synchronization behavior, and is the most effective at recognizing patterns. In this study, the materials were programmed to recognize black-and-white pixels in the shape of numbers that had been distorted.

Compared to a traditional computer, these computations are slow and take minutes. However, Dr. Yashin notes that the results are similar to nature, which moves at a "snail's pace."
"Individual events are slow because the period of the BZ oscillations is slow," Dr. Yashin said. "However, there are some tasks that need a longer analysis, and are more natural in function. That's why this type of system is perfect to monitor environments like the human body."

For example, Dr. Yashin said that patients recovering from a hand injury could wear a glove that monitors movement, and can inform doctors whether the hand is healing properly or if the patient has improved mobility. Another use would be to monitor individuals at risk for early onset Alzheimer's, by wearing footwear that would analyze gait and compare results against normal movements, or a garment that monitors cardiovascular activity for people at risk of heart disease or stroke.

Since the devices convert chemical reactions to electrical energy, there would be no need for external electrical power. This would also be ideal for a robot or other device that could utilize the material as a sensory skin.

"Our next goal is to expand from analyzing black-and-white pixels to grayscale and more complicated images and shapes, as well as to enhance the devices storage capability," Mr. Fang said. "This was an exciting step for us and reveals that the concept of "materials that compute" is viable."

The research is funded by a five-year National Science Foundation Integrated NSF Support Promoting Interdisciplinary Research and Education (INSPIRE) grant, which focuses on complex and pressing scientific problems that lie at the intersection of traditional disciplines.

"As computing performance technology is approaching the end of Moore's law growth, the demands and nature of computing are themselves evolving," noted Sankar Basu, NSF program director. "This work at the University of Pittsburgh, supported by the NSF, is an example of this groundbreaking shift away from traditional silicon CMOS-based digital computing to a non-von Neumann machine in a polymer substrate, with remarkable low power consumption. The project is a rare example of much needed interdisciplinary collaboration between material scientists and computer architects."

Story Source:
The above post is reprinted from materials provided by University of Pittsburgh. Note: Content may be edited for style and length.

Journal Reference:

1. Y. Fang, V. V. Yashin, S. P. Levitan, A. C. Balazs. Pattern recognition with "materials that compute". Science Advances, 2016; 2 (9): e1601114 DOI: 10.1126/sciadv.1601114

Cite This Page:

University of Pittsburgh. "'Materials that compute' advances as engineers demonstrate pattern recognition." ScienceDaily. ScienceDaily, 2 September 2016. <www.sciencedaily.com/releases/2016/09/160902152046.htm>.

 

Bosch’s New Technology Injects Water into Your Engine – On Purpose 

Water is typically something you want to keep out of your engine, but a new engine design from Bosch actually injects water into the combustion chamber to enhance performance. Called WaterBoost, which sounds like something you would have on a powerboat, not a car, injects distilled water into the intakes. You may be thinking that since water is incompressible that this helps maximize power output, but in fact it is used to cool down the combustion chambers faster. Check out the video below that will demonstrate how the process works.

https://youtu.be/o5yLPUVViXI

This water injection allows the engine to operate at higher compression ratios, which in turn increases efficiency. This increase in efficiency means that fuel consumption can be decreased by 13 percent during acceleration. WaterBoost can be fitted to most modern engines, as it is just an add-on modification that can significantly improve your engine’s performance. A distilled water talk is held in the engine compartment, and by Bosch’s estimations, it only needs to be refilled every 2000 miles.

Believe it or not, water injection in engines isn’t actually that new of a technology. BMW uses it in their M4 GTS, and it has been used for many years in military aviation engines, according to CNET.

Image Source: Autoengplus

Bosch is the first company to widely manufacture a water injection system that drivers can use to modify their engine’s efficiency. Don’t worry, when applied correctly in the WaterBoost system, the water only benefits your engine, not harm it.

 

Electronic circuits printed at one micron resolution

Formation of microcircuit lines using a selective coating technique. (a) Schematic of selective coating technique. Only a hydrophilic region created through irradiation of parallel vacuum ultraviolet (PVUV) is coated with metal ink. (b) Electronic circuit with a line width of 5 ?m formed through selective coating. (c) Electrode lines with different widths. Lines as narrow as 1 ?m can be formed.

Credit: Image courtesy of National Institute for Materials Science (NIMS)

A research team consisting of MANA Independent Scientist Takeo Minari, International Center for Materials Nanoarchitectonics (MANA), NIMS, and Colloidal Ink developed a printing technique for forming electronic circuits and thin-film transistors (TFTs) with line width and line spacing both being 1 μm. Using this technique, the research team formed fully-printed organic TFTs with a channel length of 1 μm on flexible substrates, and confirmed that the TFTs operate at a practical level.

Printed electronics -- printing techniques to fabricate electronic devices using functional materials dissolved in ink -- is drawing much attention in recent years as a promising new method to create large-area semiconductor devices at low cost. Because these techniques enable the formation of electronic devices even on flexible substrates, they are expected to be applicable to new fields such as wearable devices. In comparison, conventional printing technologies allow the formation of circuits and devices with line widths only as narrow as several dozen micrometers. Accordingly, they are not applicable to the creation of minute devices suitable for practical use. Thus, there were high expectations for developing new printing techniques capable of consistently fabricating circuits with line widths of several micrometers or less.

In this study, the research team developed a printing technique capable of forming metal circuits with line width being 1 μm on flexible substrates. Using this technique, they fabricated minute organic TFTs. The principle of this printing technique is as follows: First, form hydrophilic and hydrophobic micro-patterns on the substrate by irradiating it with parallel vacuum ultraviolet (PVUV) at a wavelength of 200 nm or less. Then, coat only the hydrophilic patterns with metal nanoparticle inks. The use of a PVUV light source (Ushio Inc.) enabled us to focus emitted light on much smaller targets than conventional light sources. Moreover, the use of DryCure-Au -- metal nanoparticle ink that can form a conductive film at room temperature developed by Colloidal Ink -- enabled us to form devices and circuits at room temperature during the entire process. As a result, we are able to fully prevent distortion of flexible substrates by heat, and form and laminate circuits within the accuracy of several microns. In addition, we precisely tuned the gate overlap lengths of the printed organic TFTs fabricated by this technique, which was previously impossible due to accuracy issues. As a result, a practical mobility level of 0.3 cm2 V-1 s-1 was accomplished for the organic TFTs with the channel length of 1 μm.

In future studies, we will aim to apply the technique in various fields such as large-area flexible displays and sensors. Since the process we developed is applicable to bio-related materials, the technique may also be useful in medical and bioelectronics fields.

Story Source:

The above post is reprinted from materials provided by National Institute for Materials Science (NIMS). Note: Content may be edited for style and length.

Journal Reference:

1. Xuying Liu, Masayuki Kanehara, Chuan Liu, Kenji Sakamoto, Takeshi Yasuda, Jun Takeya, Takeo Minari. Spontaneous Patterning of High-Resolution Electronics via Parallel Vacuum Ultraviolet. Advanced Materials, 2016; 28 (31): 6568 DOI: 10.1002/adma.201506151

Cite This Page:National Institute for Materials Science (NIMS). "Electronic circuits printed at one micron resolution." ScienceDaily. ScienceDaily, 1 September 2016. <www.sciencedaily.com/releases/2016/09/160901093000.htm>.

'Helix-to-tube' a simple strategy to synthesize covalent organic nanotubes

'Helix-to-tube' a simple strategy to synthesize covalent organic nanotubes

 

 

Synthesis of organic nanotubes by the "helix-to-tube" method.

 

Credit: Image courtesy of Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University

 

Organic nanotubes (ONTs) are tubular nanostructures composed of organic molecules that have unique properties and have found various applications, such as electro-conductive materials and organic photovoltaics.

 A group of scientists at Nagoya University have developed a simple and effective method for the formation of robust covalent ONTs from simple molecules. This method is expected to be useful in generating a range of nanotube-based materials with desirable properties.

Kaho Maeda, Dr. Hideto Ito, Professor Kenichiro Itami of the JST-ERATO Itami Molecular Nanocarbon Project and the Institute of Transformative Bio-Molecules (ITbM) of Nagoya University, and their colleagues have reported in the Journal of the American Chemical Society, on the development of a new and simple strategy, "helix-to-tube" to synthesize covalent organic nanotubes.

Organic nanotubes (ONTs) are organic molecules with tubular nanostructures. Nanostructures are structures that range between 1 nm and 100 nm, and ONTs have a nanometer-sized cavity. Various applications of ONTs have been reported, including molecular recognition materials, transmembrane ion channel/sensors, electro-conductive materials, and organic photovoltaics. Most ONTs are constructed by a self-assembly process based on weak non-covalent interactions such as hydrogen bonding, hydrophobic interactions and π-π interactions between aromatic rings. Due to these relatively weak interactions, most non-covalent ONTs possess a relatively fragile structure.

Covalent ONTs, whose tubular skeletons are cross-linked by covalent bonding (a bond made by sharing of electrons between atoms) could be synthesized from non-covalent ONTs. While covalent ONTs show higher stability and mechanical strength than non-covalent ONTs, the general synthetic strategy for covalent ONTs was yet to be established.

A team led by Hideto Ito and Kenichiro Itami has succeeded in developing a simple and effective method for the synthesis of robust covalent ONTs (tube) by an operationally simple light irradiation of a readily accessible helical polymer (helix). This so-called "helix-to-tube" strategy is based on the following steps: 1) polymerization of a small molecule (monomer) to make a helical polymer followed by, 2) light-induced cross-linking at longitudinally repeating pitches across the whole helix to form covalent nanotubes.

With their strategy, the team designed and synthesized diacetylene-based helical polymers (acetylenes are molecules that contain carbon-carbon triple bonds), poly(m-phenylene diethynylene)s (poly-PDEs), which has chiral amide side chains that are able to induce a helical folding through hydrogen-bonding interactions.

The researchers revealed that light-induced cross-linking at longitudinally aligned 1,3-butadiyne moieties (a group of molecules that contain four carbons with triple bonds at the first and third carbons) could generate the desired covalent ONT. "This is the first time in the world to show that the photochemical polymerization reaction of diynes is applicable to the cross-linking reaction of a helical polymer," says Maeda, a graduate student who mainly conducted the experiments.

The "helix-to-tube" method is expected to be able to generate a range of ONT-based materials by simply changing the arene (aromatic ring) unit in the monomer.

"One of the most difficult parts of this research was how to obtain scientific evidence on the structures of poly-PDEs and covalent ONTs," says Ito, one of the leaders of this study. "We had little experience with the analysis of polymers and macromolecules such as ONTs. Fortunately, thanks to the support of our collaborators in Nagoya University, who are specialists in these particular research fields, we finally succeeded in characterizing these macromolecules by various techniques including spectroscopy, X-ray diffraction, and microscopy."

"Although it took us about a year to synthesize the covalent ONT, it took another one and a half year to determine the structure of the nanotube," says Maeda. "I was extremely excited when I first saw the transmission electron microscopy (TEM) images, which indicated that we had actually made the covalent ONT that we were expecting," she continues.

"The best part of the research for me was finding that the photochemical cross-linking had taken place on the helix for the first time," says Maeda. "In addition, photochemical cross-linking is known to usually occur in the solid phase, but we were able to show that the reaction takes place in the solution phase as well. As the reactions have never been carried out before, I was dubious at first, but it was a wonderful feeling to succeed in making the reaction work for the first time in the world. I can say for sure that this was a moment where I really found research interesting."

"We were really excited to develop this simple yet powerful method to achieve the synthesis of covalent ONTs," says Itami, the director of the JST-ERATO project and the center director of ITbM. "The "helix-to-tube" method enables molecular level design and will lead to the synthesis of various covalent ONTs with fixed diameters and tube lengths with desirable functionalities."

"We envisage that ongoing advances in the "helix-to-tube" method may lead to the development of various ONT-based materials including electro-conductive materials and luminescent materials," says Ito. "We are currently carrying out work on the "helix-to-tube" methodology and we hope to synthesize covalent ONTs with interesting properties for various applications."

Story Source:

The above post is reprinted from materials provided by Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University. Note: Content may be edited for style and length.

Journal Reference:

1. Kaho Maeda, Liu Hong, Taishi Nishihara, Yusuke Nakanishi, Yuhei Miyauchi, Ryo Kitaura, Naoki Ousaka, Eiji Yashima, Hideto Ito, Kenichiro Itami. Construction of Covalent Organic Nanotubes by Light-Induced Cross-Linking of Diacetylene-Based Helical Polymers. Journal of the American Chemical Society, 2016; DOI: 10.1021/jacs.6b05582

Cite This Page:

Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University. "'Helix-to-tube' a simple strategy to synthesize covalent organic nanotubes." ScienceDaily. ScienceDaily, 30 August 2016. <www.sciencedaily.com/releases/2016/08/160830084008.htm>.

 

Better batteries: Next-generation smart separator membranes

Better batteries: Next-generation smart separator membranes

ULL STORY

From left are Sa Hoon Min, Jung-Hwan Kim, Prof. Sang-Young Lee (School of Energy and Chemical Engineering), Prof. Byeong-Su Kim (School of Natural Science), and Minsu-Gu.

 

Credit: UNIST

 

A team of Korean researchers, affiliated with UNIST is receiving the media spotlight as they have proposed a green material strategy for the development of smart battery separators beyond the current state-of-the-art counterparts.

The findings appear in the July 6th issue of Nano Letters, co-authored by Prof. Sang-Young Lee (School of Energy and Chemical Engineering), Prof. Byeong-Su Kim (School of Natural Science), the lead authors of the study Jung-Hwan Kim (School of Energy and Chemical Engineering) and Minsu Gu (School of Energy and Chemical Engineering), and four others.

In the study, the research team presented a new class of battery seperator based on the hierarchical/asymmetric porous structure of the heterolayered nanomat ("c-mat separator"), as an unprecedented membrane opportunity to enable remarkable advances in cell performance far beyond those accessible with conventional battery separators.

Among major battery components, separator membranes have not been the center of attention compared to other electrochemically active materials, despite their important roles in allowing ionic flow and preventing electrical contact between electrodes. This study introduces novel chemical functionalities to seperator membranes, thereby bringing unprecedented benefits to battery performance.

The c-mat separator consisted of a thin nanoporous TPY-CNF mat as the top layer and a thick macroporous electrospun PVP/PAN mat as the support layer. According to the research team, in addition to the aforementioned structural uniqueness, another salient feature of the c-mat separator is the higher ion conductivity compared with the existing PP/PE/PP separators.

"This ground-breaking discovery will pave the way towards next generation lithium-ion batteries, exhibiting significantly enhanced performance and increased energy efficiency," says JungHwan Kim, the lead author on the study.

The research team noted, "We envision that the c-mat separator, benefiting from its structural uniqueness and chemical functionalities, will open a new path for the development of high-performance smart separator membranes for potential use in next-generation power sources and in permselective membrane filtration systems for high mass flux/removal of heavy-metal ions."

Story Source:

The above post is reprinted from materials provided by Ulsan National Institute of Science and Technology(UNIST). Note: Content may be edited for style and length.

Journal Reference:

1. Jung-Hwan Kim, Minsu Gu, Do Hyun Lee, Jeong-Hoon Kim, Yeon-Su Oh, Sa Hoon Min, Byeong-Su Kim, Sang-Young Lee. Functionalized Nanocellulose-Integrated Heterolayered Nanomats toward Smart Battery Separators. Nano Letters, 2016; DOI: 10.1021/acs.nanolett.6b02069

Cite This Page:

Ulsan National Institute of Science and Technology(UNIST). "Better batteries: Next-generation smart separator membranes." ScienceDaily. ScienceDaily, 26 August 2016. <www.sciencedaily.com/releases/2016/08/160826092708.htm>.