Nanocoatings boost industrial energy efficiency
12/01/2008
Researchers at the US Department of Energy’s Ames Laboratory are collaborating with other research labs, universities, and industrial partners to develop a coating for machine components to give them a tough, “slippery” surface that reduces friction, reduces input energy, and extends the parts’ lifetimes.
“If you consider a pump, like a water pump or a hydraulic pump, it has a turbine that moves the fluid,” according to Bruce Cook, an Ames Laboratory scientist and co-principal investigator on the four-year, $3 million project. “When the rotor spins, there’s friction generated at the contacting surface between the vanes and the housing, or stator. This friction translates into additional torque needed to operate the pump, particularly at start-up.” It also results in surface degradation that lowers efficiency and pump lifetime, he added–starting the pump takes extra energy, and it can’t be run at optimum speeds due to accelerated wear and tear.
Applying a coating to the blades to reduce friction and increase wear resistance could have a significant effect in boosting the efficiency of pump. According to Cook, government calculations show that a modest increase in pump efficiency resulting from use of these nanocoatings could reduce US industrial energy usage by 31 trillion BTUs annually by 2030, or a savings of $179 million a year.
Tests on the AlMgB14-based coating at the DOE’s Oak Ridge National Laboratory show at least an order-of-magnitude decrease in friction relative to an uncoated surface. It also appears to outperform other coatings such as diamond-like carbon and TiB2.
The group is working with Greenleaf Corp. to put a longer-lasting coating on industrial cutting tools. If a tool cuts with reduced friction, less applied force is needed, which directly translates to a reduction in the energy required for the machining operation.
Cold atoms could replace hot gallium in FIB
Scientists at the National Institute of Standards and Technology (NIST) have developed a new method of cooling a cloud of atoms to very low temperature with a magnetic field, from which to generate and focus a stream of ions into a point as small as 1nm. The versatile approach is expected to have broad application in nanotechnology both for carving smaller features on semiconductors than now are possible and for nondestructive imaging of nanoscale structures with finer resolution than currently possible with electron microscopes.
In principle, ion beams could produce better images of nanoscale surface features than conventional electron microscopy–but in the most widely used method, a metal-coated needle generates a narrowly focused beam of gallium ions. The high energies needed to focus gallium for milling tasks end up burying small amounts in the sample, contaminating the material, and the heavy gallium ions can inadvertently damage the sample surface under observation. Other types of ions couldn’t produce the brightness or intensity necessary for the ion beam to cut into most materials.
Instead of starting with a sharp metal point, the NIST team generated a small “cloud” of atoms and then combined magnetic fields with laser light to trap and cool the atoms to extremely low temperatures. Another laser was used to ionize the atoms; the charged particles were then accelerated through a small hole to create a small but energetic beam of ions. Researchers have named the device a magneto-optical trap ion source, a.k.a. “MOTIS.”
“Because the lasers cool the atoms to a very low temperature, they’re not moving around in random directions very much. As a result, when we accelerate them the ions travel in a highly parallel beam, which is necessary for focusing them down to a very small spot,” explained Jabez McClelland of the NIST Center for Nanoscale Science and Technology.
The initial demonstration used chromium atoms, establishing that other elements besides gallium can achieve the brightness and intensity to work as a focused ion beam “nano-scalpel.” The same technique can be used with a wide variety of other atoms for special tasks such as milling nanoscale features without introducing contaminants, or to enhance contrast for ion beam microscopy, McClelland added.
European taskforce releases Emerging Nanophotonics Roadmap
A new Emerging Nanophotonics Roadmap targeting development of concepts, technologies, and devices in nanophotonics has been released within the framework of the Photonics21 strategic research agenda and promoted by the EU Network of Excellence on nanophotonics (PhOREMOST), composed by 34 partners and over 300 researchers.
In the “concept”s section of the roadmap addresses themes such as microcavities, plasmonics, non-linear optical effects in nanostructures, optical trapping and sorting, metamaterials, and random lasers. The “technologies” section deals with self-assembly of colloidal structures, nanoimprint lithography as well as functionalization, infiltration methods and organic-inorganic hybridization. A final section on “devices” addresses nanophotonic developments of photovoltaics, components for the automobile industry, hybrid waveguides and amplifiers as well as plasmonics-based sensors.
NIST: More, smaller nanoparticles generated in the home
Ultrafine nanoscale particles (UFP) released by common kitchen appliances greatly outnumber the previously detected, larger-size nanoparticles emitted by these appliances, according to new findings by researchers at NIST.
Previous studies examining gas and electric stoves and electric toaster ovens have been limited to measuring >10nm dia. particles, but new technology used in these experiments allowed researchers to measure down to 2nm particles. This previously unexplored range of 2-10nm (also present in motor vehicle emissions) was found to contribute more than 90% of all the particles produced by the electric and gas stovetop burners/coils; the gas and electric ovens and the toaster oven produced most of their UFP in the 10-30nm range.
Researchers will continue to explore the production of UFP by indoor sources. Many common small appliances such as hair dryers, steam irons, and electric power tools include heating elements or motors that may produce UFP.
Nanoparticles target skin cancer genes, shrink tumors more effectively
Nanoparticles filled with small interfering RNA (siRNA) molecules targeting two genes that trigger melanoma have shown that they can inhibit the development of melanoma, the most dangerous type of skin cancer, according to researchers from the Penn State College of Medicine. The research appears in the journal Cancer Research.
“It is a very selective and targeted approach,” said Gavin Robertson, who led the researchers from the Penn State College of Medicine. “And unlike most other cancer drugs that inadvertently affect a bunch of proteins, we are able to knock out single genes.”
When the researchers exposed lab-generated skin containing early cancerous lesions to the treatment 10 days after the skin was created, the siRNA reduced the ability of cells containing the mutant B-Raf to multiply by nearly 60%-70% and more than halved the size of lesions after three weeks. Mice with melanoma that underwent the same treatment had their tumors shrink by nearly 30% when only the mutant B-Raf was targeted. There was no difference in the development of melanoma when the Akt3 gene alone was targeted, although existing tumors shrank by about 10%-15% in two weeks. However, when the researchers targeted both Akt3 and mutant B-Raf at the same time, they found that tumors in the mice shrank about 60%-70% more than when either gene was targeted alone.
“If you knock down each of these two genes separately, you are able to reduce tumor development somewhat,” Robertson said. “But knocking them down together leads to synergistic reduction of tumor development.”
Physicists extend quantum lifetime of electrons
Physicists in the USA and the UK have found a way to extend the quantum lifetime of electrons by more than 5000%, as reported in the Nov. 14 edition of Physical Review Letters.
Electrons exhibit a property called ‘spin’ and work like tiny magnets which can point up, down, or a quantum superposition of both. The state of the spin can be used to store information and so by extending their life the research provides a significant step towards building a usable quantum computer.
“The most sensitive way to see the quantum behavior of electrons held in silicon chips uses electrical currents. Unfortunately, the problem has always been that these currents damage the quantum features under study, degrading their usefulness,” according to Gavin Morley, lead author of the paper, from the London Centre for Nanotechnology (LCN) at University College London (UCL).
To achieve the record quantum lifetime, the team used a magnetic field 25× stronger than those used in previous experiments. This powerful field also provided an additional advantage in the quest for practical quantum computing–it put the electron spins into a convenient starting state by aligning them all in one direction.
“This new work takes us closer to solving the problem by showing how we might read out the state of electron spins in a silicon-based quantum computer,” added Marshall Stoneham, UCL professor of physics.
Nanotechnology boosts war on superbugs
Meanwhile, Scientists from the LCN also are using a novel nanomechanical approach to investigate the workings of vancomycin, one of the few antibiotics that can be used to combat increasingly resistant infections such as MRSA..
The work, discussed in the October 12, 2008 issue of Nature Nanotechnology, developed ultra-sensitive probes capable of providing new insight into how antibiotics work, paving the way for the development of more effective new drugs. Coating cantilever arrays with mucopeptides from bacterial cell walls, they found that as the antibiotic attaches itself it generates a surface stress on the bacteria which can be detected by a tiny bending of the levers. This stress, they say, contributes to the disruption of the cell walls and the breakdown of the bacteria. This weakening effect is particularly interesting when looking at resistant strains of bacteria such as MRSA and vancomycin-resistant Enterococci (VRE), notes LCN’s Rachel McKendry, in which simple mutations make it harder for antibiotics to attach themselves and disrupt the cells’ structure.
“Our research on cantilever sensors suggests that the cell wall is disrupted by a combination of local antibiotic-mucopeptide binding and the spatial mechanical connectivity of these events. Investigating both these binding and mechanical influences on the cells’ structure could lead to the development of more powerful and effective antibiotics in the future.”
EPA issues notice on carbon nanotubes
The US Environmental Protection Agency (EPA) has issued a Federal Register notice regarding carbon nanotubes (CNTs), in what may be a sign the agency intends to flex its muscles more than rely on voluntary industry efforts.
The document gives notice of the Toxic Substances Control Act (TSCA) requirements potentially applicable to CNTs, reminding manufacturers and importers that they must notify the EPA 90 days prior to the manufacture or import of new chemical CNTs for commercial purposes, in accordance with TSCA Section 5 regulations for new chemicals at 40 C.F.R. 720.22.
EPA generally considers CNTs to be chemical substances distinct from graphite or other allotropes of carbon listed on the TSCA Inventory. Many CNTs may therefore be new chemicals under TSCA section 5.
Nano industry shifts from R&D to commercialization
With nanotechnology shifting from an emphasis on R&D to a focus on commercialization–$147 biillion worth of products enabled by nanotech was sold in 2007–the strategies of global corporations and start-ups working on nanotechnology have shifted, according to a report by Lux Research.
“Executives at global corporations are no longer in the dark on nanotechnology,” said Jurron Bradley, senior analyst at Lux Research. “While some skepticism still exists, they have learned from past flops and instituted an ‘open innovation’ model to minimize risk.”
To analyze the strategies of global corporations and nanomaterial specialists, Lux Research conducted a survey of top executives at 31 global corporations active in nanotechnology, and drew on data from over 1,000 primary interviews with technology developers.
Among the study’s conclusions:
- Awareness of nanotech is still growing. Some 65% of global corporations say senior management has high awareness of nanotechnology, almost double what companies said two years ago.
- Virtually every large company has an explicit nanotech strategy, most often decentralized. A solid 94% of respondents report having a specific strategy for exploiting nanotech innovation, and 65% described a decentralized organizational structure to nanotech.
- Corporations are looking to external innovators to complement internal nanotech efforts. 100% of the companies interviewed cited external cooperation with universities, start-ups, or corporations as key to their strategies. Companies see such collaborations as attractive alternatives to share costs and risks.
- Nanomaterial environmental, health, and safety (EHS) issues are both an increasing priority for start-ups to address, and for large companies to manage.
“Nanotech EHS remains Topic A for companies developing nanomaterial applications,” noted Kristin Abkemeier, analyst at Lux Research. “If they can’t deal with real risks, perceptual risks, and regulations, they won’t be able to profit. However, after several years of growing debate and ongoing uncertainty, the picture is finally beginning to clear up.”