Tracking high impact progress to the technology future, future technology and especially advanced nanotechnology, nuclear and energy technology, quantum computers, life extension, space technology and AI. Proposing and tracking the best societal, business and technical choices to the next big things that will shape our future. Official Lifeboat Foundation news source.
Using home-built dedicated ray-tracing software, we simulate photorealistic images of sceneries in three dimensions including dielectric carpet cloaks – i.e., continuously varying refractive-index distributions that allow for invisibility cloaking of a bump in a metallic carpet. Results for the ideal and for a simplified cloak are shown. The presented material gives a visual and intuitive impression of the performance of different arrangements and might be ideally suited for communicating the concepts of transformation optics to the general public.
Even an ideal carpet cloak suffers from the “ostrich effect”, i.e., the cloak does make any object under the carpet invisible indeed, but the cloaking structure itself remains visible to some extent. (The ostrich is a large flightless bird native to Africa that sometimes sticks its head into the sand, leaving the rest of its body visible.) We will encounter the visual influence of the ostrich effect in our photorealistic images.
The researchers found that participants who have lived to a very old age have inherited mutant genes that make their telomerase-making system extra active and able to maintain telomere length more effectively. For the most part, these people were spared age-related diseases such as cardiovascular disease and diabetes, which cause most deaths among elderly people.
Genetic Variation in Human Telomerase is Associated with Telomere Length in Ashkenazi Centenarians Proceedings of the National Academy of Sciences, November 9, 2009
Customers are paying about $1.30 per month for the reactors; the charge will rise by that amount each year until it tops out at $9.00 per month. When the plants open in six years, the surcharge should stop.
EPRI study shows the cost of implementing major CO2 emissions reductions is significant, development and deployment of a full portfolio of technologies will reduce the cost to the U.S. economy by more than $1 trillion. Less than half of these savings would be achievable if the future electricity sector generation portfolio does not include advanced coal with CO2 capture and storage or advanced light water nuclear reactors.
Stewart Brand indicated:
It turns out that [Lovins’] arguments against the economics of nuclear power work only within the narrow commercial boundaries he defines, which increasingly no longer apply, and he focuses mainly on the US. His reasoning has no traction in relatively dirigiste economies like France, Japan, and most developing countries, especially China and India; if those governments want nukes, they build nukes. More important, the loom of climate change has altered everybody’s perspective on costs and risks.
“’Baseload,’” she [Gwyneth Cravens] explains in the book, “refers to the minimum amount of proven, consistent, around-the-clock, rain-or-shine power that utilities must supply to meet the demands of their millions of customers.”
Wind and solar, desirable as they are, aren’t part of baseload because they are intermittent—productive only when the wind blows or the sun shines. If some sort of massive energy storage is devised, then they can participate in baseload; without it, they remain supplemental, usually to gas-fired plants.
Three sources cited in the Lovins study concluded that nuclear uses much less land than solar and wind. Clearly, the authors of those studies consider the open areas between wind turbines and the large arrays for solar plants a requirement to function. Yet the Lovins study clearly manipulated the numbers from those sources to fit its own beliefs. Thus, it’s not Brand and Cravens who believe in a land footprint “myth”, it’s Mr. Lovins.
In a normal flu season the number of deaths for children is about 100.
Average US flu deaths in a year are about 30,000-40,000 and the numbers could be similar for H1N1. However, 90% of the deaths from H1N1 are for people younger than 65 while normal flu has 90% of deaths for people older than 65.
If there were 39,000 deaths from H1N1 in the USA then the expectation would be 5,400 deaths for children from H1N1. The death rate from H1N1 for children would be 20-40 times higher than regular flu for children. So getting a vaccination against H1N1 is the right choice. If you are under 65 then not getting a vaccination against H1N1 is taking 20-40 times the risk as not getting vaccinated against regular flu. Plus H1N1 could get more virulent (deadly in 2010-2011) so if you do not get it this time and get it next time it could be even worse. H1N1 could also become less deadly in 2010-2011, but that seems like a foolish gamble for something that is 20-40 times more deadly than regular flu.
41.6 million doses of H1N1 vaccine are now available, up from 38 million last week, but "not as much as we'd hoped to have by today." CDC told reporters last week that about 8 million new doses were expected this week. The Department of Health and Human Services has ordered 75 million doses of swine flu vaccine for delivery by year's end.
It takes 2 weeks after a vaccination injection for a body to develop immunity, so in early December the significant number of November vaccinations should significantly reduce the spread and deaths from H1N1.
22 million have gotten sick in the USA with swine flu. If they knew they had swine flu they would not need vaccination. It seems likely that 60 million people will be vaccinated and 35 million people will have gotten swine flu in the USA by the end of 2009. 66 million vaccinations would save about 12,000 lives from those directly vaccinated and also reduce the spread of the disease. 132 million vaccinations would save about 24,000 lives. Combined with those getting immunity from getting and surviving H1N1 would be approximately complete coverage of the USA.
The president granted Health and Human Services Secretary Kathleen Sebelius the power to lift some federal regulations for medical providers, including allowing hospitals to set up off-site facilities to increase the number of available beds and protect patients who are not infected.
This was a prudent action to reduce deaths from infectious disease. Although more people will die from heart disease and cancer, those are not infectious diseases.
In discussions of the road trains of 6-8 vehicles that are kept in close formation for higher fuel efficiency and as a step toward robotic driving there is concern that the long line of vehicles would present issues for vehicles entering and exiting the highway.
State regulations vary but legal permission for 65 foot long trucks is common. Certain sections of highway and other countries allow longer trucks up to 110 feet in some cases.
The road trains of 6-8 vehicles should be at least as safe as the long trucks. Signage and electronic indicators transmitted from the lead bus or truck could provide warning to other drivers of the road train behind. Electronic systems allow more adaptability and flexibility to increase the separation gap if needed in a middle section for safety and courtesy to other cars on the road.
They developed a semi pilot scale facility to produce radiation grafted sheets of 1 metre X 1 metre size. They collected about 800 microgrammes of uranium in five campaigns from CIRUS Jettyhead; about 1.8 milligrammes from the seawater intake and outfall canals at the Tarapur Atomic Power Station and around 200 microgrammes from Andaman and Nicobar Islands. Though these amounts are trivial, it gives confidence in the technology
Reviewing the Work in Japan
Dr Masao Tanada of the Japanese Atomic Energy Agency hopes to get funding to construct an under-water uranium farm covering nearly 400 square miles that would meet one-sixth of Japan’s annual uranium requirements.
Tanada asserts that Japan’s nuclear power industry can harvest the 8,000 tons it needs annually from the Kuroshio Current that flows along Japan’s eastern seaboard.
Japanese researchers found out that they can harvest uranium from sea by cultivating genetically engineered gulfweed which will grow in sea at an unbelievable rate of two metres an year. The weed selectively soaks up heavy metals including uranium.
What will you do with possibly the millions of tons of grass left over after recovering uranium? Convert it to bioethanol. Gulfweed is an ideal non-food source of bio-ethanol. Gulfweed traps carbondioxide from sea.
The Mitsubishi Research Institute (MRI) has recently recommended Japan mass-culture seaweed to collect natural resources such as bio-ethanol and uranium. In the “Apollo and Poseidon Initiative 2025,” MRI suggests that Japan cultures gulfweed, which can grow more than 2 metres high a year in the sea. The plants could also absorb carbon dioxide and purify the seawater, and can be used as non-food alternative energy sources for bio-ethanol. In April, MRI plans to inaugurate a consortium comprising public research institutes and manufacturers to move the plan forward. Using advanced molecular and gene-engineering technologies, MRI estimates that Japan would be capable of producing 65 million metric tons of gulfweed a year, and recovering a resource of 195 million tons of uranium. The annual rate of recovery is 40% of Japan’s total consumption. (19 February 2008, Nikkan Kogyo Shimbun)
Using polymers, the total amount of uranium recovered from three collection boxes containing 350 kg of fabric was >1 kg of yellowcake after 240 days of submersion in the ocean. So 65 million tons of seaweed might get 195,000 tons/year of uranium based on a comparable efficiency.
Dr Masao Tamada, of the Japan Atomic Energy Agency, has developed a fabric made primarily of irradiated polyethylene that is able to soak up the minute amounts of uranium – around 3.3 parts per billion – in the seawater.
Dr Tamada hopes to secure funding to construct an underwater uranium farm covering nearly 400 square miles that would meet one-sixth of Japan's annual uranium requirements.
"Other countries are conducting similar research but none are as advanced as we are," he said. "We need to conduct more development research and be able to produce the adsorbent material on a large scale, but we could achieve this within five years."
* Fusion is the combination of a GPU and CPU on one die. The graphics processor is now referred to as an Accelerated Processing Unit (APU). AMD expects to make the first silicon next year and ship by 2011. * AMD will have new APUs every year * The first product from AMD will be the "Maranello" server platform in the first half of 2010. It will consist of the new "Magny-Cours" Opteron 6100 processor, which will be a 12-core processor, and a new chipset. * For low-end solutions, there will be "San Marino," which consists of a four- and six-core "Lisbon" Opteron 4100 processor with a new chipset and single- or dual-socket designs. These will be for low-end servers, some running at just six watts.
* In 2011 comes "Bulldozer," an entirely new processor core for AMD. These will be 32nm processors using high-k metal gate technology, which runs much cooler than existing technologies. On the high end, they will be the Opteron 6200 line, codenamed "Interlagos," with 12 or 16 cores. The 4200 series will have six or eight cores. * There will also be a low-end "Bulldozer" line, called "Bobcat." It will be used in ultrathin and netbook form factors and is designed to be extremely small, highly flexible and single-threaded. It will run on as little as one watt of power. *There will be two new desktop platforms in the first half of 2010, "Leo" and "Dorado." Leo will introduce the six-core Athlon, likely the "Thuban," although AMD did not say it by name, while Dorado is a dual-, triple- and quad-core line with integrated graphics. * AMD is raising its performance claims for the notebook market. It launched "Puma," AMD's answer to Intel's popular Centrino mobile platform last year. Puma launched with four hours of battery life under regular use. When "Tigris" came out earlier this year, it was raised to five hours. *In 2011, the first Fusion notebooks hit. "Sabine" is the mainstream notebook platform with a quad-core CPU and the "Llano" APU. "Brazos" is AMD's ultra-thin notebook platform slated for 2011 using a dual-core Bobcat processor. * On the GPU side, AMD will launch three new graphics cards codenamed "Cedar," "Hemlock," and "Redwood" in the first half of 2010, offering high definition, high performance graphics for both desktops and notebooks.
Only a fraction of 1 percent of the electricity generated in the United States can currently be transferred between the grids, and there is no direct connection between Texas and the Western grid. The Tres Amigas station, which will connect all three grids together in one place for the first time, will initially more than double the ability to transfer power between them, providing five gigawatts of capacity. Eventually, the station is expected to transfer as much as 30 gigawatts of power.
A recent proposal to link the eastern, western and Texas grids together to create a national, alt-energy-friendly supergrid has sparked the interest of utilities and energy insiders, such as former energy secretary Bill Richardson. Can a high-tech substation in New Mexico create a smarter, unified grid? Not if Texas doesn't cooperate.
The larger number of deaths does not mean the virus is more dangerous. Rather, it is a new estimate made by combining deaths from laboratory-confirmed cases of the flu and deaths that appear to be brought on by flu, even though the patient may have ultimately died of bacterial pneumonia, other infections or organ failure.
A much higher death rate would mean more drastic measures to keep people apart and could mean, for example, adding immune-boosting adjuvants to the vaccine so more people could get it.
Unlike many government-sponsored efforts, however, Tri Alpha is working with fusion reactions that produce fewer neutrons and, thus, less radiation, Mr. Rothrock says. The company also uses a different method for containing and controlling fusion reactions, which happen at million-degree temperatures. “It’s a long way from reality, but the trend line is going in the right direction,” he says. “The science is rock-solid; the calculations continue to bear out the results.”
Mr. Prouty estimates it will take his company “not 15 to 20 [years], but not 3 to 5 either” to go from the research stage to power generation.
TriAlpha is the brainchild of Norman Rostoker, a senior fusion researcher. He had previously collaborated with another researcher, Maglitch, on the MIGMA approach to advanced fuels. This approach involved shooting two counter-circulating beams of ions at each other in a confining magnetic field. It was not very workable, as the ion densities would always be very low. Rostoker combined this idea with another device, the Field Reversed Configuration, sending the beams into the FRC.
The FRC is essentially a large-scale plasmoid centimeters rather microns across, with much lower densities and magnetic fields than with the DPF. It does not benefit from the magnetic field effect as its field are far too low. Scientifically, TriAlpha’s results so far are very modest compared with focus fusion’s. The average ion energy, a measure of plasma temperature is a few 10’s of eV. This is a factor of 10,000 short of what is required for pB11 fusion. Of course, we have already achieved the needed ion energies (100keV) with focus fusion, so in this sense are way ahead. In addition, it is by no means guaranteed that their confinement will remain stable if they can reach higher temperatures.
Dr. Hendrik Monkhorst of the Quantum Theory Project and his collaborator, Dr. Norman Rostoker of UC Irvine, designed a novel type of fusion reactor called the Colliding Beam Fusion Reactor (CBFR).
CBFR in Field Reversed configuration has a cylindrical shape, rotates at a high rate about its axis inside a solenoidal magnet, and thus produces a magnetic field that closes upon itself: a kind of self-confinement of fuel nuclei was established, with all confined particles flowing in the same direction. Protons rotate at a high rate, with an energy of about 1 MeV, and Boron 11 are slower, which causes the protons to literally ‘rear-end’ the Boron 11 with an energy at which fusion cross-section is highest. The collaborators found that plasma parameters could be set such that essentially all injected protons and Boron 11 undergo fusion to 4-Helium which were guided into Direct Energy Converter (DEC) devices. These devices turned their kinetic energy directly into electricity, unlike previous techniques where water was boiled, producing steam which drove turbines to eventually produce electricity. Resulting advantages included abundant fuel supply, nearly no radioactivity, no danger of runaway reactions or explosions, scalability of size and output power, easier engineering and maintainability. They have begun a multi-faceted study which is currently underway to establish the full feasibility of the design. Many calculations, theory development and nuclear polarization (to enhance the fusion reactivity), is centered in the UF Physics Department.
Surveyed atttitudes to three different types of road safety systems. These were those that: • Helped the driver (aid systems), • Imposed certain behaviour (alert and intervention systems), • Could be used by the police to enforce the law (regulatory systems
Below are videos: an animation of the SARTRE lead car following system and an existing real robot car automatically driving and parking in a parking lot.
The SARTRE project launched in EU testing autonomous driving technology.
Results of Survey on Attitudes to Road Safety Technology
Support for these various systems was very varied between countries. For example, less than half (41%) of Swiss drivers supported a system designed to prevent drivers exceeding the speed limit, while in Ireland, 81% support the introduction of such a system. However, this high level of support by the Irish drivers can be partly explained by recent publicity campaigns targeting speed behaviour. It appears that some countries do not like the idea that their behaviour is being controlled, e.g. Switzerland, Austria, Germany, and the Netherlands, although this is less the case in other countries, e.g. Ireland, France and the United Kingdom. In addition to automatic speed cameras, some countries already use cameras to detect drivers not stopping at red lights (‘red runners’) and some use camera technology to monitor ‘tail-gating’ - where drivers of vehicles fail to keep an adequate distance between their vehicle and the one in front of them. The rapid progress being made in new technologies means that in the future a wide variety of behaviour will be monitored, and perhaps enforced. At present, drivers are more likely to support new technologies designed to enforce red light violations than to detect speeding. As with other new technologies, Swiss drivers are the least favourably disposed to speed radars (at 42%) while the Irish (at 87%) are among the most supportive. In many countries, drivers declare themselves as being in favour of both types of system (e.g. Belgium, Finland, Ireland, Poland and the United Kingdom) or opposed to both (e.g. Austria, the Czech Republic, Germany, Spain, Sweden and Switzerland). These results are probably influenced by the current situation in each country and the drivers’ use of and experience with such devices. While existing vehicle identification devices make it possible to have access to some services (e.g. automatic payment of tolls) they may become increasingly useful to the police to, for example, identify those who exceed speed limits, or who infringe other laws. Overall, 61% of European drivers would be ready to install such an identification system in their cars, with the highest level of support being found in Italy and Slovenia; however, only 51% would support such systems being used by the police. There are significant differences between countries. The Irish were very supportive of such a system, while the German speaking countries, Germany, Austria and Switzerland, were typically against them. Drivers are more in favour of the use of ‘black boxes’, which could record vehicle speeds, steering, braking behaviours, etc., which could help to explain how an accident happened, than they are towards such devices which could be used by the police to enforce traffic laws.Three elements appeared to determine the drivers' attitude such towards new technologies: - What the system was to be used for; - Their familiarity with the systems; in some countries, drivers may feel that the use of speed cameras have reached saturation levels, while drivers unfamiliar with a given technological device can tend to overestimate both its advantages and drawbacks; - The drivers' attitudes towards enforcement and the importance they give to their freedom to behave as they wish
Given the current sophistication of these devices, and the potential uses to which they could be put in the future, it seems surprising that so many drivers support their introduction. It may be that we are already resigned to their introduction, as our society is becoming increasingly advanced technologically. Perhaps it is that automation is fair in that it works the same for everyone
A new EU project SARTRE is being launched to develop and test technology for vehicles that can drive themselves in long road trains on motorways. This technology has the potential to improve traffic flow and journey times, offer greater comfort to drivers, reduce accidents, and improve fuel consumption and hence lower CO2 emissions.
The first test cars equipped with this technology will roll on test tracks as early as 2011. The vehicles will be equipped with a navigation system and a transmitter/receiver unit that communicates with a lead vehicle. Since the system is built into the cars, there is no need to extend the infrastructure along the existing road network.
Lead vehicle
The idea is that each road train or platoon will have a lead vehicle that drives exactly as normal, with full control of all the various functions. This lead vehicle is driven by an experienced driver who is thoroughly familiar with the route. For instance, the lead may be taken by a taxi, a bus or a truck. Each such road train will consist of six to eight vehicles.
A driver approaching his destination takes over control of his own vehicle, leaves the convoy by exiting off to the side and then continues on his own to his destination. The other vehicles in the road train close the gap and continue on their way until the convoy splits up.
Many advantages
The advantage of such road trains is that all the other drivers in the convoy have time to get on with other business while on the road, for instance when driving to or from work. The road trains increase safety and reduce environmental impact thanks to lower fuel consumption compared with cars being driven individually. The reason is that the cars in the train are close to each other, exploiting the resultant lower air drag. The energy saving is expected to be in the region of 20 percent. Road capacity will also be able to be utilised more efficiently.
Dynamic Configuration of Light Car Modules Another advantage is that it would enable smaller single person modular cars, that still allow more non-driver passengers or empty follow cars with cargo. Why would this be an advantage ? Couldn't we just have a trailer hitch or a sidecar between your car and modules with another person or cargo ? There would be easier dynamic reconfiguration convenience and a module or pod could be dynamically handed off to follow a different vehicle with known destinations (such as buses or delivery trucks). You could start out from your home leading a car with driving controls disabled with a child and you can rendezvous with a school bus or a someone in your trusted network of friends who is communicating a path that will pass the child's destination.
A dynamically configurable set of car modules allows easier usage of only the amount of vehicle that is needed for a trip. You do not have to drive a seven passenger SUV that only has one passenger and no cargo 90% of the time.
The car modules can be cheaper and lighter and more easily fully electrified.
You could also dynamically lend public charging modules, that can be paged for a rendezvous and docked to provide a charging boost.
Safety
I noticed that some people are concerned about safety if the people do not take back control of the vehicle. The robotic driving cars that exist now have:
1. Automated parking 2. Developing dynamic cruise control to automatically adjust speed based on location 3. Have been able to navigate urban traffic and rural courses for dozens of miles of driving (DARPA challenge vehicles)
A road train enabled vehicle that does not get the proper alert response from a person who is ready to take over driving again would be able to safely drive the vehicle to the nearest place for a safe park to wait until the person is ready. This capability would be less challenging than the tasks already performed by the DARPA grand challenge vehicles. The sensors and systems for the DARPA grand challenge vehicles are getting cheaper and more capable.
Lowering of the huge stainless steel main vessel -- 12.9 metres in diameter and 12.94 metres in height, weighing 206 tonnes -- is considered a major step in completing the 500 MW power project by the September 2011 deadline.
The sodium-cooled fast reactor designed by the Indira Gandhi Centre for Atomic Research (IGCAR) has three vessels - a safety vessel, a main vessel and an inner vessel.
Outermost is the stainless steel safety vessel, which was lowered into the reactor vault last June - the first milestone.
The third and smallest of the three vessels is the inner vessel -- 11 metres tall. It houses pumps, heat exchangers and other equipment. Together, they all go inside the main vessel.
Kumar said the 11-metre-tall cone-shaped inner vessel, thermal baffle, grid plate and primary pipe were ready. The reactor control rods were being tested.
'By March next year the roof slab of the nuclear reactor vault will be erected,' Kumar said.
The other major project activities completed are the erection of four 12.5-metre-tall argon buffer tanks and the transfer of around 825 tonnes of sodium to the sodium storage tanks.
Full integration of graphene into conventional device circuitry would require a reproducible large scale graphene synthesis that is compatible with conventional thin film technology. We report the synthesis of large scale single layer graphene directly onto an evaporated copper film. A novel fabrication method was used to directly pattern these graphene sheets into devices by simply removing the underlying copper film. Raman and conductance measurements show that the mechanical and electrical properties of our single layer graphene are uniform over a large area, (Ferrari, A. C. et al. Phys. Rev. Lett. 2006, 97, 187401.) which leads to a high device yield and successful fabrication of ultra long (>0.5 mm) graphene channels. Our graphene based devices present excellent electrical properties including a promising carrier mobility of 700 cm^2/V·s and current saturation characteristics similar to devices based on exfoliated graphene (Meric, I.. et al. Nat Nanotechnol. 2008, 3, 654−659).
We report on a method to produce free-standing graphene sheets from epitaxial graphene on silicon carbide (SiC) substrate. Doubly clamped nanomechanical resonators with lengths up to 20 μm were patterned using this technique and their resonant motion was actuated and detected optically. Resonance frequencies of the order of tens of megahertz were measured for most devices, indicating that the resonators are much stiffer than expected for beams under no tension. Raman spectroscopy suggests that the graphene is not chemically modified during the release of the devices, demonstrating that the technique is a robust means of fabricating large-area suspended graphene structures
Graphene, a two-dimensional monolayer of sp2-bonded carbon atoms, has been attracting great interest due to its unique transport properties. One of the promising applications of graphene is as a transparent conductive electrode owing to its high optical transmittance and conductivity. In this paper, we report on an improved transfer process of large-area graphene grown on Cu foils by chemical vapor deposition. The transferred graphene films have high electrical conductivity and high optical transmittance that make them suitable for transparent conductive electrode applications. The improved transfer processes will also be of great value for the fabrication of electronic devices such as field effect transistor and bilayer pseudospin field effect transistor devices.
A central challenge in nanotechnology is the parallel fabrication of complex geometries for nanodevices. Here we report a general method for arranging single-walled carbon nanotubes in two dimensions using DNA origami—a technique in which a long single strand of DNA is folded into a predetermined shape. We synthesize rectangular origami templates (75 nm 95 nm) that display two lines of single-stranded DNA 'hooks' in a cross pattern with 6 nm resolution. The perpendicular lines of hooks serve as sequence-specific binding sites for two types of nanotubes, each functionalized non-covalently with a distinct DNA linker molecule. The hook-binding domain of each linker is protected to ensure efficient hybridization. When origami templates and DNA-functionalized nanotubes are mixed, strand displacement-mediated deprotection and binding aligns the nanotubes into cross-junctions. Of several cross-junctions synthesized by this method, one demonstrated stable field-effect transistor-like behaviour. In such organizations of electronic components, DNA origami serves as a programmable nanobreadboard; thus, DNA origami may allow the rapid prototyping of complex nanotube-based structures.
This work someday may lead to the development of novel types of nanoscale electronic devices, an interdisciplinary team of researchers at the California Institute of Technology (Caltech) has combined DNA's talent for self-assembly with the remarkable electronic properties of carbon nanotubes, thereby suggesting a solution to the long-standing problem of organizing carbon nanotubes into nanoscale electronic circuits.
"We expect that our approach can be improved and extended to reliably construct more complex circuits involving carbon nanotubes and perhaps other elements including electrodes and wiring," Goddard says, "which we anticipate will provide new ways to probe the behavior and properties of these remarkable molecules."
The real benefit of the approach, he points out, is that self-assembly doesn't just make one device at a time. "This is a scalable technology. That is, one can design the origami to construct complex logic units, and to do this for thousands or millions or billions of units that self-assemble in parallel."
In (a), single-wall carbon nanotubes labeled with "red" and "blue" DNA sequences attach to anti-red and anti-blue strands on a DNA origami, resulting in a self assembled electronic switch. In (b), an atomic force microscopey image of one such structure. The blue nanotube appear brighter because it is on top of the origami; the red nanotube sits below. Scale bar is 50 nm. In (c), a diagrammatic view of the structure shown in b. The gray rectangle is the DNA origami. A self-assembled DNA ribbon attached to the origami improves structural stability and ease of handling. Credit: Paul W. K. Rothemund, Hareem Maune, and Si-ping Han/Caltech/Nature Nanotechnology
The protocols described in this paper describe sufficient conditions for the creation of SWNT crossjunction devices. However, there remain open questions concerning what the simplest necessary procedure for creating cross-junction devices might be, as well as what parts of the protocol are most important for success:
1.LNA versus DNA toeholds
Five nucleotide LNA toeholds give good results. We have been unable to find conditions under which 7 and 8 nucleotide DNA toeholds give good results.
2.Plain origami versus origami with ribbons.
The use of ribbons with DNA origami appeared to increase the yield of observed. structures. This needs to be rigorously quantified and other options investigated.
3.Hooks with versus hooks without poly-T segments. Yield and alignment as a function of flexibility.
4. Schemes using strand displacement versus other protected schemes without strand displacement.
5.SWNT alignment as a function of NL-SWNT purity.
6.Why are the ends of nanotubes so often flush with the edges of DNA origami?
7. What is the detailed structure of the linkers on the SWNT and how does this affect alignment?
8. What is the nature of the barrier between SWNTs in our system? Can the intervening DNA layer act as a dielectric?
MIT Technology Review reports on a new method for assembling carbon nanotubes has been used to create fibers hundreds of meters long. Individual carbon nanotubes are strong, lightweight, and electrically conductive, and could be valuable as, among other things, electrical transmission wires. But aligning masses of the nanotubes into well-ordered materials such as fibers has proven challenging at a scale suitable for manufacturing. By processing carbon nanotubes in a solution called a superacid, researchers at Rice University have made long fibers that might be used as lightweight, efficient wires for the electrical grid or as the basis of structural materials and conductive textiles.
Using the Rice methods, well-aligned nanotube fibers can be made on a large scale, shot out from a nozzle similar to a showerhead. The Rice group has used acid processing methods to assemble carbon nanotubes into fibers 50 micrometers thick and hundreds of meters long. "There are no limitations on the fiber length," says Pasquali. The Rice group demonstrated its assembly method with high-quality, single-walled carbon nanotubes.
Translating the unique characteristics of individual single-walled carbon nanotubes into macroscopic materials such as fibres and sheets has been hindered by ineffective assembly. Fluid-phase assembly is particularly attractive, but the ability to dissolve nanotubes in solvents has eluded researchers for over a decade. Here, we show that single-walled nanotubes form true thermodynamic solutions in superacids, and report the full phase diagram, allowing the rational design of fluid-phase assembly processes. Single-walled nanotubes dissolve spontaneously in chlorosulphonic acid at weight concentrations of up to 0.5wt%, 1,000 times higher than previously reported in other acids. At higher concentrations, they form liquid-crystal phases that can be readily processed into fibres and sheets of controlled morphology. These results lay the foundation for bottom-up assembly of nanotubes and nanorods into functional materials.
The group has made fibers that are highly conductive but not as strong as other carbon materials. Pasquali says the strength of the fibers could probably be improved tenfold by using longer carbon nanotubes. "We're now working on a project for making electrical transmission lines," says Pasquali. "Metallic nanotubes conduct electricity better than copper, they're lighter, and they fail less often."
One important hurdle for large-scale manufacturing of carbon nanotubes remains: Today, there aren't any good methods for making the nanotubes themselves in large, pure batches. In order to make nanotube transmission lines, for example, the Rice group would need to start with a large batch of nanotubes containing all metallic nanotubes and no semiconducting ones. Last month, chemists at the Honda Research Institute published a paper in Science describing a method for making large amounts of metallic nanotubes that Pasquali says is promising. "For transmission lines you need to make tons, and there are no methods now to do that," he says. "We are one miracle away."
Nextbigfuture is the Lifeboat Foundation Technology Research News Website.
The Lifeboat Foundation is a nonprofit nongovernmental organization dedicated to encouraging scientific advancements while helping humanity survive existential risks and possible misuse of increasingly powerful technologies, including genetic engineering, nanotechnology, and robotics/AI, as we move towards a technological singularity. Technology is an important factor in solving and creating many of the Lifeboat relevant issues.
Editor/Authors are :
Brian Wang, Director of Research.
Sander Olson, Interviews and other articles
Phil Wolff, Communications and social technologist.
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