EPA Issues Significant New Use Rule For Nanotubes
3 July 2009, 15:24
Categories: nanotubes-wires-fullerenes responsible-nanotechnology
On June 24, the EPA issued a Significant New Use Rule (SNUR) for a variety of chemical substances, including single- and multi-walled carbon nanotubes. The rule requires companies that intend to make, import, or process nanotubes to give the EPA 90 days prior notice. Companies must also require employees to wear impervious gloves, protective clothing, and NIOSH-approved respirators. The full rule is available here.
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A Good Nano Guide
3 July 2009, 12:29
Categories: responsible-nanotechnology
The International Council on Nanotechnology (ICON) has introduced the GoodNanoGuide, an online, community-driven wiki for information about the safe handling of nanomaterials. This guide, based at Rice University, is a practical tool for people who handle nanomaterials, as well as an online repository of safety protocols. It has been developed by experts from the worlds of nanotechnology, occupational safety and business, and is governed by an implementation committee from North America and Europe. Financial support for the development of the beta site was provided by ICON, nanoAlberta, British Columbia Nanotechnology Alliance, Industry Canada, Institut de recherche Robert-Sauvé en santé et en sécurité du travail and NanoQuebec.
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Polyethylene Strengthened By Carbon Nanotubes
3 July 2009, 12:28
Categories: nanocomposites nanotubes-wires-fullerenes
A team of researchers from Rice University, Texas Southern University, and the University of Houston have created a couple of different types of single-walled carbon nanotubes (SWCNTs) that, when mixed into medium density polyethylene (MDPE), improve the strength of the MDPE. This is due to the superior strength of CNTs, afforded through their covalent carbon bonds, and non-covalent entanglements between the polymer molecular chains and “hairs” on the nanotubes.
The SWCNTs were mixed with MDPE at 1 wt%. Tensile tests performed on dogbone-shaped samples cut from moulded sheets showed the highest (52%) strength enhancement for polyethylene filled with a perfluorinated derivative (F-SWNT-C11FxHy), and a smaller (16%) enhancement for polyethylene processed with alkylated fluoronanotubes (F-SWNT-C11H23).
MDPE is a high-commodity thermoplastic material, which has good shock, drop and resistance properties and is used in gas pipes and fittings, and packaging applications. The group believes that the technology demonstrated for SWNT-reinforced MDPE composites in this work can be easily scaled up and transferred to industry.
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CNTs In Different Shapes
29 June 2009, 13:55
Categories: nanotubes-wires-fullerenes
Carbon nanotubes (CNTs) have been well studied theoretically and experimentally. Perfect CNTs really look like tubes; they’re made, in concept, by rolling graphene sheets into a seamless cylinder. CNTs exist as either single-wall nanotubes (SWNTs) or multi-walled nanotubes (MWNTs). The SWNT consists of a single graphene sheet, which is a planar array of benzene molecules, involving only hexagonal rings with double and single carbon-carbon bonding.
Defects in this crystalline structure of CNTs cause the tubules to curve. CNTs with different tubule morphologies have their own special properties and potential applications. So far, many different shapes have been predicted, observed, and synthesized. An article in the current issue of Materials Today reviews CNTs many of these morphologies and their possible applications, including:
Straight carbon nanotubes
Waved carbon nanotubes
Coiled carbon nanotubes
Regularly bent carbon nanotubes
Branched carbon nanotubes
Carbon nanotubes with beads
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Second International Conference on Smart Materials and Nanotechnology
29 June 2009, 13:15
Categories: other
The Second International Conference on Smart Materials and Nanotechnology in Engineering will take place in Weihai, China, 08-11 July 2009. The emphasis for this conference will be on applications in aerospace, however, this does not preclude novel developments in smart materials and nanotechnology for other areas as a means of greater understanding of the basic properties and capabilities of these novel materials.
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New Nanoparticles Kill Bacteria
28 June 2009, 13:17
Categories: nanoparticles
Brown University researchers have created 8 nm diameter nanoparticles that can penetrate a bacterial-produced film on prosthetics and kill the bacteria. The finding, published in the International Journal of Nanomedicine, is the first time that iron-oxide nanoparticles have been shown to eliminate a bacterial infection on an implanted prosthetic device. As an added benefit, the nanoparticles’ magnetic properties appear to promote natural bone cell growth on an implant’s surface, although this observation needs to be tested further.
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Engineering For Extreme Environments
28 June 2009, 12:39
Categories:
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MIT researchers are developing nanocomposite materials that can endure high temperatures, radiation and extreme mechanical loading. The ultimate goal is to use these materials in energy applications, including: nuclear power, fuel cells, solar energy, and carbon sequestration. Their first target is radiation-resistant materials, which could improve the efficiency and safety of nuclear power plants.
Normally, when metals are exposed to radiation, high-energy particles knock atoms out of their crystal lattice, spreading damage in the form of “vacancies” (holes where an atom is missing), and “interstitials” (an extra atom squeezed in where it shouldn’t be). Clusters of these defects can make the material brittle and weak. In some nanocomposites, however, vacancies and interstitials can get trapped at the interfaces between layers of different materials. When that happens, the extra atom fills in the hole and the crystal structure is restored. Materials resistant to radiation damage could eventually be used to line nuclear reactors, a function now performed by stainless steel.
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Of Risks And Regulations
26 June 2009, 17:49
Categories: responsible-nanotechnology
As reported in the online version of the Journal of Nanoparticle Research, researchers found that the public tends to focus on the benefits, rather than potential environmental and health risks, when making decisions about nanotechnology regulation, whereas scientists mainly focus on potential risks and economic values.
“We think that nanoscientists view regulations as protections for the public, and that’s part of the reason why they focus on the potential risks. On the other hand, the public seems to think of nanotechnology regulations as restricting their access to new products and other beneficial aspects of nanotechnology,” says Elizabeth Corley, Lincoln Professor of Public Policy, Ethics and Emerging Technologies at Arizona State University, and co-author of the study.
According to the study, leading U.S. scientists in nanotechnology believe regulations are most urgently needed in the areas of surveillance and privacy, human enhancement, medicine and the environment. It also found some gender and disciplinary differences among nanoscientists. Males are less supportive of nanotech regulation than their female peers and materials scientists are more supportive of nanotechnology regulation than scientists in other fields.
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Magnetic Monopoles Finally Found
26 June 2009, 17:44
Categories: quantum-mechanics
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A magnet has two poles – north and south – but cut a magnet in half and each half has its own north and south pole. However much you divide a magnet, you can never isolate a pole on its own. Yet if such isolated monopoles were to exist, they would explain a lot about the universe to scientists.
Now, a new study shows that if you lived inside a lump of spin ice – if spin ice was your universe – then you would be able to isolate magnetic monopoles, as they really exist within the material. “When we discovered spin ice in 1997,” says Professor Steven Bramwell, London Centre for Nanotechnology, “we never expected that it would contain anything so remarkable as magnetic monopoles, but studying this amazing material has taught us that in science, nothing is impossible!”
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Lithium-Air Batteries
26 June 2009, 17:31
Categories: energy
There have been a couple of recent reports on lithium-air batteries, which are lighter than conventional, rechargeable lithium batteries and might prove beneficial for mobiles devices and hybrid vehicles. Additionally, the theoretical maximum power density of lithium-air batteries is more than 10,000 Wh/kg, that’s ten times more than that of standard lithium batteries.
Researchers at the University of St. Andrews, UK, have created an early demonstration model of the STAIR (St. Andrews AIR) cell. It draws oxygen from the air during discharge, by replacing the common lithium cobalt oxide electrode with a porous carbon electrode that allows Li+ and e- in the cell to react with oxygen from the air. Not having to carry the chemicals around in the battery offers more energy for the same size battery, and the porous carbon is far less expensive than the lithium cobalt oxide it replaces.
A California company, PolyPlus, is also focusing on the development of lithium-air, aqueous-lithium, and lithium-sulfur batteries. Their Lithium-Aircell involves using a multi-layer thin membrane that completely protects the Li metal anode from the cathode’s solvent system. This innovation allows the use of electrodes in combination with highly aggressive liquid electrolytes, which results in unprecedented energy densities. For example, the gravimetric capacity of lithium is
3,800 mAh/g and the open circuit voltage for the Lithium-Aircell is around 3.05 volts, leading to a theoretical specific energy of 11,600 Wh/kg for Li-Air chemistry. The high specific energy of the Li-Air couple is close to that of liquid hydrocarbons, such as gasoline, and much higher than that of methanol.
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Josh Is Not Joshing
25 June 2009, 14:28
Categories: molecular-machines--devices molecular-manufacturing
J Storrs Hall, President of the Foresight Institute, considers what will be the likely situation with early nanofactories:
The first nanofactories will probably be DNA/RNA/protein gadgets requiring thousands of steps by skilled scientists to coax them to build a new gadget (which will consist only of DNA/RNA/protein), or diamondoid gadgets in high vacuum requiring thousands of steps by skilled scientists to coax them to build a new gadget (which will consist only of diamondoid), or possibly even tungsten carbide gadgets doing EDM with nanotubes, requiring thousands of steps by skilled scientists to coax them to build a new gadget (which will consist only of tungsten carbide, the nanotubes having to be supplied from outside). Early nanofactories will be cranky and experimental, expensive, require expensive inputs, be able to produce only very limited products, and be very lucky to replicate themselves before they break down.
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Future Mobile Phones
25 June 2009, 14:06
Categories: designers
Live Mint posted a couple of interviews on future mobile phones. They talked to Tapani Ryhanen of Nokia about the well-known Morph phone, of course, and Massimo Marrazzo described his Handphone, which may also benefit from nanotechnology:
I always thought that the gesture we make every time we ask our friends to call us could be used to design a phone. I was thinking of a phone that could be used and looked like a watch. The Handphone is just a bridge to the future cell phones, when, thanks to nanotechnology, all the elements of the phone will be a customized on a thin and flexible strip on the skin, like a plaster, and it will use the body heat as energy.
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Graphene From Wormy Expanded Graphite
25 June 2009, 13:48
Categories: nanotubes-wires-fullerenes techniques
Scientists at Tsinghua University in Beijing have developed a three-step process to make graphene (one atom-thick carbon sheets) from worm-like expanded graphite (WEG). WEG consists of a tall stack of graphene sheets, expanded, but not fully separated into individual layers. The graphite was mixed with sulfuric acid, which forced the graphite’s layers apart to create a structure with graphite sheets held together by sulfuric acid molecules.
The resulting compound was then heated to decompose the acid, which increased the distance between the graphite sheets even further. Ultrasonication and centrifugation were then used to peel away each sheet. The graphene was not damaged by these processes; in fact, the individual layers produced were shown to be almost unchanged from their state in the natural graphite precursor.
“Our exfoliation approach combined with advances in the large scale manufacturing of WEG could lead to the development of new and more effective graphene products, for instance, carbon-based flexible electronics,” Hongwei Zhu says, adding that his method would be easier and cheaper to scale up than existing techniques.
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Forming Interconnected Carbon Nanostructures
25 June 2009, 13:12
Categories: nanotubes-wires-fullerenes
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Scientists from the University of Pennsylvania, Sandia National Laboratories, and Rice University have demonstrated the formation of interconnected carbon nanostructures on a graphene substrate in a simple assembly process that may eventually lead to a new paradigm for building integrated carbon-based devices.
The researchers have constructed curvy nanostructures directly integrated on graphene, taking advantage of the fact that graphene, an atomically thin two-dimensional sheet, bends easily after open edges have been cut on it, which can then fuse with other open edges permanently, like a plumber connecting fittings.
Their “knife” and “welding torch” was an electric current from a scanning probe that generated up to 2000°C of heat. Upon applying the electrical current to few-layer graphene, they observed the in situ creation of many interconnected, curved carbon nanostructures. Few-layer graphene, such as a 10-layer stack, is advantageous over monolayers as the multiple layers spontaneously fuse together forming nanostructures on top of one or two electrically conductive, extended, graphene sheets.
The movie, above, was recorded at 1 frame per second and plays at 25x speed.
Read More
Paper
Movies (YouTube)
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A Metal That Pumps Liquid Uphill
25 June 2009, 12:46
Categories: gels--foams
Scientists at the University of Rochester have created a simple slab of metal that lifts liquid uphill. To do so, they changed the surface of the metal by exposing it to a burst of light from a femtosecond laser, which formed nanoscale and microscale pits, globules, and strands across the metal’s surface. The laser pulses last only a few quadrillionths of a second, but, during its brief burst, it unleashes as much power as the entire electric grid of North America does, all focused onto a spot the size of a needlepoint.
Currently, to alter an area of metal the size of a quarter takes 30 minutes or more, but Guo and Vorobyev are working on refining the technique to make it faster. Fortunately, despite the incredible intensity involved, the femtosecond laser can be powered by a simple wall outlet, meaning that when the process is refined, implementing it should be relatively simple.
“We’re able to change the surface structure of almost any piece of metal so that we can control how liquid responds to it,” says Chunlei Guo, associate professor of optics at the University of Rochester. “We can even control the direction in which the liquid flows, or whether liquid flows at all.”
The wicking process, which moves at one centimeter per second speed against gravity, is very similar to the phenomenon that pulls liquid into a paper towel; molecular attractions and evaporation combine to move a liquid against gravity, says Guo. Likewise, Guo’s nanostructures change the way molecules of a liquid interact with the molecules of the metal, allowing them to become more or less attracted to each other, depending on Guo’s settings. At a certain size, the metal nanostructures adhere more readily to the liquid’s molecules than the liquid’s molecules adhere to each other, causing the liquid to quickly spread out across the metal. Combined with the effects of evaporation as the liquid spreads, this molecular interaction creates the fast wicking effect in Guo’s metals.
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World's First Commercial Quantum Dot / LED Lamps Released
25 June 2009, 11:59
Categories: Quantum-Dots
Nexxus Lighting and QD Vision have released the world’s first quantum dot lighting solution that combines the efficiency of LED lighting with the warm color of incandescent bulbs. The new lamp integrates a quantum dot optic with cool white LEDs to produce color-rich, true incandescent, warm white light which can provide over 80% energy savings and lasts up to 25 times longer than halogen lighting.
“We are excited to add this new high color rendering, true incandescent warm white color choice to our successful Array™ LED lamp product offering,” stated Mike Bauer of Nexxus. “The architectural lighting community has been clear in its demand for better color rendering performance in LED lighting, without sacrificing the efficacy gains you can achieve through solid state solutions.”
The product resulting from the Nexxus Lighting/QD Vision partnership was recently demonstrated at a White House ceremony, in which President Obama announced a $1.6 billion disbursement of research funds for clean energy products. The Nexxus Lighting/QD Vision project was one of only four technologies spun out of MIT that were demonstrated at the event.
Because the Nexxus Lighting Array lamps with Quantum LightTM are compatible with a standard, screw-in base, they can easily replace incandescent and halogen lamps in existing downlight fixtures. Just in the US, the DoE estimates, the number of down lights and track heads with Edison base lamp installations equal over 139 million in commercial applications and over 262 million in residential lighting applications. Both companies expect that commercial availability of their high efficiency lamps with high color quality will overcome a major barrier to LEDs and will accelerate the penetration of LEDs in the $4 billion U.S. lamp market. The potential impact on the environment could be significant, a full conversion to LEDs of existing downlights and trackheads in the US (~10% of US fixtures) represents an annual savings of more than 35 billion KW hours (nearly $4 billion), which is the equivalent of nearly 6 power plants or more than 60 million barrels of oil per year.
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Record OLED Display Lifetime
24 June 2009, 15:47
Categories:
DuPont is reporting that its Gen-3 organic light emitting diode (OLED) material has achieved a record lifetime of more than 1 million hours. Furthermore, the material can be cheaply printed over large areas, which will help manufacturers develop longer lasting, low-cost displays for mobile devices, notebook PCs and televisions. OLED displays are so thin, efficient and simple, they can be made flexible and transparent. They also provide brighter, crisper displays and use less power than the conventional light-emitting diodes (LEDs) or liquid crystal displays (LCDs) being used today.
“Printing OLEDs significantly lowers the cost to manufacture displays, and with our advances in material technology, display manufacturers can see the material lifetimes and performance required for commercialization,” said William Feehery, global business director of DuPont OLED Displays. “With lifetime five times better than just a couple years ago, these new materials will allow solution OLEDs to be used in mobile displays, and also to begin to penetrate the television and general lighting markets at a lower cost than today’s evaporated OLED technology.”
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Glowing Probe Detects Ozone
24 June 2009, 15:32
Categories: smt-luminescent-light-emit sensors
Ground-level ozone is formed from pollutants and can be a cause for concern during Summer months, as it creates respiratory problems. Researchers at the University of Pittsburgh have identified ground-level ozone as a growing global health problem, particularly in urban environments, and are trying to do something about it by developing a novel sensor that unambiguously detects the presence of ozone around us.
The sensor is a fluorescent molecular probe that can be used indoors or outdoors. The device is a material composite consisting of a solution that has been added to an absorbent paper substrate. After the material has been exposed to ozone, it is observed under UV light; the brighter the fluorescence, the more ozone the material has absorbed.
The researchers performed a variety of tests. For indoor ozone detection, a couple of compound solutions (one was indigo carmine) were tested on 11×9 cm strips, by placing them in a poorly ventilated photocopy room for 8 hours. The room contained a couple of photocopiers and a couple of laser printers. For outdoor ozone detection, samples were placed in four locations near the university campus for 8 hours, but were not exposed to direct sunlight.
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New Fabricated Material Changes Color Instantly In Response to External Magnetic Field
23 June 2009, 17:10
Categories: smt-chromism-color-change
A research team from the University of California, Riverside, and Seoul National University, South Korea, has fabricated microscopic polymer beads that change color instantly and reversibly when external magnetic fields acting upon the microspheres change orientation. Their small magnetochromatic microspheres have excellent structural stability. They also are highly compatible with various types of dispersion media such as water, alcohol, hexane and polymer solutions, allowing them to retain tunable colors in a variety of chemical environments.
“Unlike many conventional approaches, the instantaneous color change occurs with no change in the structure or intrinsic properties of the microspheres themselves,” said Yadong Yin. “What changes instead are the magnetic fields acting externally on the orientation of these microspheres, these photonic crystals. Our work provides a new mechanism for inducing color change in materials. Now, for the first time, stable photonic materials with tunable colors can be fabricated on a large scale.”
Applications of the new material include display type units such as rewritable or reusable signage, posters, papers and labels, and other magnetically activated security features. The new material also can be used to make environmentally friendly pigments for paints and cosmetics, as well as ink materials for color printing.
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Larger Structures From Glued Particles
23 June 2009, 16:56
Categories: self-assembly nanoparticles
Researchers at New York University have created a method to precisely bind nano- and micrometer-sized particles together into larger-scale structures with useful materials properties. Their work overcomes the problem of uncontrollable sticking, which had been a barrier to the successful creation of stable microscopic and macroscopic structures with a sophisticated architecture.
“We can finely tune and even switch off the attractions between particles, rendering them inert unless they are heated or held together—like a nano-contact glue,” said Mirjam Leunissen, a post-doctoral fellow in the Center for Soft Matter Research.
The long-term goal of the NYU researchers is to create non-biological materials that have the ability to self-replicate. In the process of self-replication, the number of objects doubles every cycle. This exponential growth stands in sharp contrast to conventional materials production, where doubling the amount of product requires twice the production time.
In order to obtain self-replication, the researchers coat micrometer-sized particles with short stretches of DNA, so-called “sticky ends”. Each sticky end consists of a particular sequence of DNA building blocks and sticky ends with complementary sequences form very specific bonds that are reversible. Below a certain temperature, the particles recognize each other and bind together, while they unbind again above that temperature. This enables a scheme in which the particles spontaneously organize into an exact copy on top of a template, which can then be released by elevating the temperature.
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