Posts belonging to Category coatings



Thin Films Power Electronics Mixed In Fabrics

Scientists at the U.S. Department of Energy’s National Renewable Energy Laboratory (NREL) reported significant advances in the thermoelectric performance of organic semiconductors based on carbon nanotube thin films that could be integrated into fabrics to convert waste heat into electricity or serve as a small power source.

The research demonstrates significant potential for semiconducting single-walled carbon nanotubes (SWCNTs) as the primary material for efficient thermoelectric generators, rather than being used as a component in a “compositethermoelectric material containing, for example, carbon nanotubes and a polymer. The discovery is outlined in the new Energy & Environmental Science paper, Large n- and p-type thermoelectric power factors from doped semiconducting single-walled carbon nanotube thin films.

There are some inherent advantages to doing things this way,” said Jeffrey Blackburn, a senior scientist in NREL’s Chemical and Materials Science and Technology center and co-lead author of the paper with Andrew Ferguson. These advantages include the promise of solution-processed semiconductors that are lightweight and flexible and inexpensive to manufacture. Other NREL authors are Bradley MacLeod, Rachelle Ihly, Zbyslaw Owczarczyk, and Katherine Hurst. The NREL authors also teamed with collaborators from the University of Denver and partners at International Thermodyne, Inc., based in Charlotte, N.C.

Ferguson, also a senior scientist in the Chemical and Materials Science and Technology center, said the introduction of SWCNT into fabrics could serve an important function for “wearable” personal electronics. By capturing body heat and converting it into electricity, the semiconductor could power portable electronics or sensors embedded in clothing.

Source: https://www.nrel.gov/

Invisible Glass

If you have ever watched television in anything but total darkness, used a computer while sitting underneath overhead lighting or near a window, or taken a photo outside on a sunny day with your smartphone, you have experienced a major nuisance of modern display screens: glare. Most of today’s electronics devices are equipped with glass or plastic covers for protection against dust, moisture, and other environmental contaminants, but light reflection from these surfaces can make information displayed on the screens difficult to see. Now, scientists at the Center for Functional Nanomaterials (CFN) — a U.S. Department of Energy Office of Science User Facility at Brookhaven National Laboratory — have demonstrated a method for reducing the surface reflections from glass surfaces to nearly zero by etching tiny nanoscale features into them.

Whenever light encounters an abrupt change in refractive index (how much a ray of light bends as it crosses from one material to another, such as between air and glass), a portion of the light is reflected. The nanoscale features have the effect of making the refractive index change gradually from that of air to that of glass, thereby avoiding reflections. The ultra-transparent nanotextured glass is antireflective over a broad wavelength range (the entire visible and near-infrared spectrum) and across a wide range of viewing angles. Reflections are reduced so much that the glass essentially becomes invisible.

This “invisible glass” could do more than improve the user experience for consumer electronic displays. It could enhance the energy-conversion efficiency of solar cells by minimizing the amount of sunlight lost to refection. It could also be a promising alternative to the damage-prone antireflective coatings conventionally used in lasers that emit powerful pulses of light, such as those applied to the manufacture of medical devices and aerospace components.

We’re excited about the possibilities,” said CFN Director Charles Black, corresponding author on the paper published online on October 30 in Applied Physics Letters. “Not only is the performance of these nanostructured materials extremely high, but we’re also implementing ideas from nanoscience in a manner that we believe is conducive to large-scale manufacturing.”

Our role in the CFN is to demonstrate how nanoscience can facilitate the design of new materials with improved properties,” concluded Black. “This work is a great example of that–we’d love to find a partner to help advance these remarkable materials toward technology.”

Source: https://www.eurekalert.org/

How To Charge Lithium Batteries 20 Times Faster

A touch of asphalt may be the secret to high-capacity lithium metal batteries that charge 10 to 20 times faster than commercial lithium-ion batteries, according to Rice University scientists. The Rice lab of chemist James Tour developed anodes comprising porous carbon made from asphalt that showed exceptional stability after more than 500 charge-discharge cycles. A high-current density of 20 milliamps per square centimeter demonstrated the material’s promise for use in rapid charge and discharge devices that require high-power density.

Scanning electron microscope images show an anode of asphalt, graphene nanoribbons and lithium at left and the same material without lithium at right. The material was developed at Rice University and shows promise for high-capacity lithium batteries that charge 20 times faster than commercial lithium-ion batteries

The capacity of these batteries is enormous, but what is equally remarkable is that we can bring them from zero charge to full charge in five minutes, rather than the typical two hours or more needed with other batteries,” Tour said.

The Tour lab previously used a derivative of asphalt — specifically, untreated gilsonite, the same type used for the battery — to capture greenhouse gases from natural gas. This time, the researchers mixed asphalt with conductive graphene nanoribbons and coated the composite with lithium metal through electrochemical deposition. The lab combined the anode with a sulfurized-carbon cathode to make full batteries for testing. The batteries showed a high-power density of 1,322 watts per kilogram and high-energy density of 943 watt-hours per kilogram.

Testing revealed another significant benefit: The carbon mitigated the formation of lithium dendrites. These mossy deposits invade a battery’s electrolyte. If they extend far enough, they short-circuit the anode and cathode and can cause the battery to fail, catch fire or explode. But the asphalt-derived carbon prevents any dendrite formation.

The finding is reported in the American Chemical Society journal ACS Nano.

Source: http://news.rice.edu/

How To Track Blood Flow In Tiny Vessels

Scientists have designed gold nanoparticles, no bigger than 100 nanometres, which can be coated and used to track blood flow in the smallest blood vessels in the body. By improving our understanding of blood flow in vivo the nanoprobes represent an opportunity to help in the early diagnosis of diseaseLight microscopy is a rapidly evolving field for understanding in vivo systems where high resolution is required. It is particularly crucial for cardiovascular research, where clinical studies are based on ultrasound technologies which inherently have lower resolution and provide limited information.

The ability to monitor blood flow in the sophisticated vascular tree (notably in the smallest elements of the microvasculaturecapillaries) can provide invaluable information to understand disease processes such as thrombosis and vascular inflammation. There are further applications for the improved delivery of therapeutics, such as targeting tumours.

Currently, blood flow in the microvasculature is poorly understood. Nanoscience is uniquely placed to help understand the processes happening in the micron-dimensioned vessels. Designing probes to monitor blood flow is challenging because of the environment; the high protein levels in plasma and the high red blood cell concentrations are detrimental to optical imaging. Conventional techniques rely on staining red blood cells, using organic dyes with short-lived usage due to photobleaching, as the tracking motif. The relatively large size of the red blood cells (7-8 micrometres), which are effectively the probes, limits the resolution in imaging and analysis of flow dynamics of the smallest vessels which are of a similar width. Therefore, to have more detailed resolution and information about the blood flow in the microvasculature, even smaller probes are required.

The key to these iridium-coated nanoparticles lies in both their small size, and in the characteristic luminescent properties. The iridium gives a luminescent signal in the visible spectrum, providing an optical window which can be detected in blood. It is also long-lived compared to organic fluorophores, while the tiny gold particles are shown to be ideal for tracking flow and detect clearly in tissues“, explains Professor Zoe Pikramenou, from the School of Chemistry at  the University of Birmingham.

The findings have been published in the journal Nanomedicine.

Source: https://www.birmingham.ac.uk/

Within 10 years Planes Could Move Up To 10 Times The Speed Of Sound

An average flight from Miami to Seattle takes about six hours and 40 minutes, but imagine being able to reduce that time to 50 minutes or less. A recent study by NASA and Binghamton University researchers could lead to a drastic decrease in flight times. The study, funded in part by the U.S. Air Force, is one of the first steps toward the creation of planes able to move at hypersonic speeds, five to 10 times the speed of soundBinghamton University Associate Professor of Mechanical Engineering Changhong Ke explained that there are currently quite a few obstacles when it comes to building these super planes. The first of which is finding a material that can hold up to hypersonic travel.

Our study used what are called boron nitride nanotubes (BNNTs). NASA currently owns one of the few facilities in the world able to produce quality BNNTs.” Typically, carbon nanotubes have been used in planes for their strength — they’re stronger than steel — and their ability to conduct heat. However, BNNTs are the wave of the future when it comes to air travel. “While carbon nanotubes can stay stable at temperatures up to 400 degrees Celsius, our study found that BNNTs can withstand up to 900 degrees Celsius,” said Ke. BNNTs are also able to handle high amounts of stress and are extremely lightweight.

Withstanding high temperatures is an important requirement for any material meant to build the world’s next super planes, however, Ke clarified that the material has to be able to maintain both structural and mechanical properties in an oxygen environment. “We weren’t testing this material in a vacuum like what you would experience in space. Materials can withstand much higher temperatures in space. We wanted to see if BNNTs could hold up in the type of environment an average fighter jet or commercial plane would experience.”

While the study has brought new light to the strength and stability of BNNTs, their use on planes may not be a reality for another five to 10 years. “Right now, BNNTs cost about $1,000 per gram. It would be impractical to use a product that expensive,” added Ke. But, that does not mean it will never happen. Carbon nanotubes were about the same price 20 years ago. As more studies indicated the usefulness of carbon nanotubes, the production rates increased and prices went down to the current rate, between $10 and $20 per gram. Ke sees the same fate coming down the line for BNNTs.

Source: https://www.binghamton.edu/

Paper Supercapacitor

By coating ordinary paper with layers of gold nanoparticles and other materials, researchers have fabricated flexible paper supercapacitors that exhibit the best performance of any textile-type supercapacitor to date. In particular, the paper supercapacitors address one of the biggest challenges in this area, which is to achieve a high energy density in addition to an already high power density, since both properties are essential for realizing high-performance energy-storage devices. In the future, flexible paper supercapacitors could be used in wearable electronics for biomedical, consumer, and military applications. The researchers, led by Seung Woo Lee at the Georgia Institute of Technology and Jinhan Cho at Korea University, have published a paper on the flexible paper supercapacitor electrodes in a recent issue of Nature Communications. As energy-storage devices, supercapacitors have several advantages over batteries, such as a higher power density, rapid charge/discharge rate, and longer lifetime, yet they lag behind batteries in energy density (the amount of energy that can be stored in a given amount of space). Although several methods have been attempted to improve the energy density of paper supercapacitors by coating them with various conductive materials, often these methods have the drawback of reducing the power density.

The paper electrodes based on layer-by-layer-assembled metal nanoparticles exhibit metal-like electric conductivity, paper-like mechanical properties, and a large surface area without any thermal treatment and/or mechanical pressing,” explains coauthor Yongmin Ko at Korea University. “The periodic insertion of metal nanoparticles within high-energy nanoparticle-based paper electrodes could resolve the critical tradeoff in which an increase in the loading amount of materials to enhance the energy density of supercapacitors decreases the power density.”
Tests  showed that the flexible paper supercapacitors had a maximum capacitance that is higher than any previously reported textile-based supercapacitor. In addition, the new devices exhibits an excellent capacity retention, demonstrated by a 90% capacity retention after 5,000 bending cycles.

Source: http://me.gatech.edu/

One-Two Knockout Punch To Eradicate Super Bugs

Light-activated nanoparticles, also known as quantum dots, can provide a crucial boost in effectiveness for antibiotic treatments used to combat drug-resistant superbugs such as E. coli and Salmonella, new CU Boulder research shows. Multi-drug resistant pathogens, which evolve their defenses faster than new antibiotic treatments can be developed to treat them, cost the United States an estimated $20 billion in direct healthcare costs and an additional $35 billion in lost productivity in 2013. Rather than attacking the infecting bacteria conventionally, the dots release superoxide, a chemical species that interferes with the bacteria’s metabolic and cellular processes, triggering a fight response that makes it more susceptible to the original antibiotic.

We’ve developed a one-two knockout punch,” said Prashant Nagpal, an assistant professor in CU Boulder’s Department of Chemical and Biological Engineering (CHBE) and the co-lead author of the study. “The bacteria’s natural fight reaction [to the dots] actually leaves it more vulnerable.”

We are thinking more like the bug,” explains Anushree Chatterjee, an assistant professor in CHBE and the co-lead author of the study. “This is a novel strategy that plays against the infection’s normal strength and catalyzes the antibiotic instead.” The dots reduced the effective antibiotic resistance of the clinical isolate infections by a factor of 1,000 without producing adverse side effects.

The findings have been published today in the journal Science Advances.

Source: http://www.colorado.edu/

The Ultra Smart Community Of The Future

Japan’s largest electronics show CEATEC – showcasing its version of our future – in a connected world with intelligent robots And cars that know when the driver is falling asleep. This is Omron‘s “Onboard Driving Monitoring Sensor,” checking its driver isn’t distracted.

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We are developing sensors that help the car judge what state the driver is in, with regards to driving. For example, if the driver has his eyes open and set on things he should be looking at, if the driver is distracted or looking at smartphones, and these types of situations,” explains Masaki Suwa, Omron Corp. Chief Technologist.

After 18 years of consumer electronics, CEATEC is changing focus to the Internet of Things and what it calls ‘the ultra-smart community of the future‘ A future where machines take on more important roles – machines like Panasonic‘s CaloRieco – pop in your plate and know exactly what you are about to consume.

By placing freshly cooked food inside the machine, you can measure total calories and the three main nutrients: protein, fat and carbohydrate. By using this machine, you can easily manage your diet,” says Panasonic staff engineer Ryota Sato.

Even playtime will see machines more involved – like Forpheus the ping playing robot – here taking on a Olympic bronze medalist – and learning with every stroke.
Rio Olympics Table Tennis player , Jun Mizutani, Bronze Medalist, reports: “It wasn’t any different from playing with a human being. The robot kept improving and getting better as we played, and to be honest, I wanted to play with it when it had reached its maximum level, to see how good it is.”

Biomaterial To Replace Plastics And Reduce Pollution

An inexpensive biomaterial that can be used to sustainably replace plastic barrier coatings in packaging and many other applications has been developed by Penn State researchers, who predict its adoption would greatly reduce pollution. Completely compostable, the material — a polysaccharide polyelectrolyte complex — is comprised of nearly equal parts of treated cellulose pulp from wood or cotton, and chitosan, which is derived from chitin — the primary ingredient in the exoskeletons of arthropods and crustaceans. The main source of chitin is the mountains of leftover shells from lobsters, crabs and shrimp consumed by humans.

These environmentally friendly barrier coatings have numerous applications ranging from water-resistant paper, to coatings for ceiling tiles and wallboard, to food coatings to seal in freshness, according to lead researcher Jeffrey Catchmark, professor of agricultural and biological engineering, College of Agricultural Sciences.

In the research, paperboard coated with the biomaterial exhibited strong oil and water barrier properties. The coating also resisted toluene, heptane and salt solutions and exhibited improved wet and dry mechanical and water vapor barrier properties.

The material’s unexpected strong, insoluble adhesive properties are useful for packaging as well as other applications, such as better performing, fully natural wood-fiber composites for construction and even flooring,” Jeffrey Catchmark said. “And the technology has the potential to be incorporated into foods to reduce fat uptake during frying and maintain crispness. Since the coating is essentially fiber-based, it is a means of adding fiber to diets.”

Source: http://news.psu.edu/

Robots With The Sense Of Touch

A team of researchers from the University of Houston (UH) has reported a breakthrough in stretchable electronics that can serve as an artificial skin, allowing a robotic hand to sense the difference between hot and cold, while also offering advantages for a wide range of biomedical devices.

Cunjiang Yu, Bill D. Cook Assistant Professor of mechanical engineering and lead author for the paper, said the work is the first to create a semiconductor in a rubber composite format, designed to allow the electronic components to retain functionality even after the material is stretched by 50 percent. The semiconductor in rubber composite format enables stretchability without any special mechanical structure. Yu noted that traditional semiconductors are brittle and using them in otherwise stretchable materials has required a complicated system of mechanical accommodations. “That’s both more complex and less stable than the new discovery, as well as more expensive.”

Our strategy has advantages for simple fabrication, scalable manufacturing, high-density integration, large strain tolerance and low cost,” he said.

Yu and the rest of the team – co-authors include first author Hae-Jin Kim, Kyoseung Sim and Anish Thukral, all with the UH Cullen College of Engineering – created the electronic skin and used it to demonstrate that a robotic hand could sense the temperature of hot and iced water in a cup. The skin also was able to interpret computer signals sent to the hand and reproduce the signals as .

The robotic skin can translate the gesture to readable letters that a person like me can understand and read,” Yu said.

The work is reported in the journal Science Advances.

Source: http://www.uh.edu/

Urban Farming At Home

Growing your own vegetables and herbs can be a laborious process. Lack of space in urban environments makes it even harder. But this smart garden is bringing the window box into the modern age. Much like Nespresso coffee capsules, users ‘plant’ this soil pod… containing the seeds and all the nutrients which are released in sync with the plant’s life cycle.

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This is the plastic container they put the growing substrate in here. It has a wick solution, so basically it starts to drain the water from the water tank, and the lamp does the rest of the job. The lamp imitates daylight time, so it’s 16 hours on and 8 hours off. So far we have tested some 7,000 different plants and each growing substrate is designed specifically for this plant,” says Karel Kask, sales Manager, Click and Grow. Estonia-based ‘Click and Grow‘ says it’s tested up to a thousand lighting solutions to ensure optimal growth. The red and white lights deliver the perfect spectrum they say, speeding up growth by 30 to 50 percent, depending on the plant. Each soil pod provides up to 3 harvests. ‘Click and Grow‘ was inspired by NASA technology used to grow food in space. Here, astronauts aboard the International Space Station sample lettuce they’ve grown.

They’re using quite similar soil-based solutions; so they take the soil substrate into space and grow them already in there. They have an automated watering solution. So it’s quite similar to the solution that we do.The Smart Garden 9, its latest and most advanced model, was displayed at this week’s IFA tech fair in Berlin,” adds Kask.

Nano-based Yarns Generate Electricity

An international research team led by scientists at The University of Texas at Dallas and Hanyang University in South Korea has developed high-tech yarns that generate electricity when they are stretched or twisted.

In a study published in the journal Science, researchers describe “twistronyarns and their possible applications, such as harvesting energy from the motion of ocean waves or from temperature fluctuations. When sewn into a shirt, these yarns served as a self-powered breathing monitor.

The easiest way to think of twistron harvesters is, you have a piece of yarn, you stretch it, and out comes electricity,” said Dr. Carter Haines BS’11, PhD’15, associate research professor in the Alan G. MacDiarmid NanoTech Institute at UT Dallas and co-lead author of the article. The article also includes researchers from South Korea, Virginia Tech, Wright-Patterson Air Force Base and China.

Coiled carbon nanotube yarns, created at The University of Texas at Dallas and imaged here with a scanning electron microscope, generate electrical energy when stretched or twisted.
The yarns are constructed from carbon nanotubes, which are hollow cylinders of carbon 10,000 times smaller in diameter than a human hair. The researchers first twist-spun the nanotubes into high-strength, lightweight yarns. To make the yarns highly elastic, they introduced so much twist that the yarns coiled like an over-twisted rubber band.

In order to generate electricity, the yarns must be either submerged in or coated with an ionically conducting material, or electrolyte, which can be as simple as a mixture of ordinary table salt and water.

Fundamentally, these yarns are supercapacitors,” said Dr. Na Li, a research scientist at the NanoTech Institute and co-lead author of the study. “In a normal capacitor, you use energy — like from a battery — to add charges to the capacitor. But in our case, when you insert the carbon nanotube yarn into an electrolyte bath, the yarns are charged by the electrolyte itself. No external battery, or voltage, is needed.

When a harvester yarn is twisted or stretched, the volume of the carbon nanotube yarn decreases, bringing the electric charges on the yarn closer together and increasing their energy, Haines said. This increases the voltage associated with the charge stored in the yarn, enabling the harvesting of electricity.

Source: http://www.utdallas.edu/