Rice University researchers have discovered thin films of nanotubes created with ink-jet printers offer a new way to make field-effect transistors (FET), the basic element in integrated circuits.While the technique doesn't exactly scale down to the levels required for modern microprocessors, Rice's Robert Vajtai hopes it will be useful to inventors who wish to print transistors on materials of any kind, especially on flexible substrates.In results reported in the online edition of ACS Nano, Rice scientists working with researchers in Finland, Spain and Mexico have created nanotube-based circuitry using high-end ink-jet printers and custom inks.Vajtai, a faculty fellow in Rice's top-ranked Mechanical Engineering and Materials Science Department, led the study. Pulickel Ajayan, Rice's Benjamin M. and Mary Greenwood Anderson Professor in Mechanical Engineering and Materials Science and of chemistry, is a co-author.The process involved the painstaking analysis of sample circuits printed with single-walled carbon nanotubes functionalized with four types of molecules. The researchers found that a single layer of nanotubes-infused ink printed onto a transparent foil didn't conduct electricity very well. But adding layers increased the connections between nanotubes, and so increased conductivity. »

NASA's Wide-field Infrared Survey Explorer, or WISE, has captured a huge mosaic of two bubbling clouds in space, known as the Heart and Soul nebulae. The space telescope, which has completed about three-fourths of its infrared survey of the entire sky, has already captured nearly one million frames like the ones making up this newly released mosaic."This new image demonstrates the power of WISE to capture vast regions," said Ned Wright, the mission's principal investigator at UCLA, who presented the new picture at the American Astronomical Society meeting in Miami. "We're looking north, south, east and west to map the whole sky."The Heart nebula is named after its resemblance to a human heart; the nearby Soul nebula happens to resemble a heart too, but only the symbolic kind with two lobes. The nebulae, which lie about 6,000 light-years away in the constellation Cassiopeia, are both massive star-making factories, marked by giant bubbles blown into surrounding dust by radiation and winds from the stars. The infrared vision of WISE allows it to see into the cooler and dustier crevices of clouds like these, where gas and dust are just beginning to collect into new stars.The new image was captured as WISE circled over Earth's poles, scanning strips of the sky. It is stitched together from 1,147 frames, taken with a total exposure time of three-and-a-half hours.The mission will complete its first map of the sky in July 2010. It will then spend the next three months surveying much of the sky a second time, before the solid-hydrogen coolant needed to chill its infrared detectors runs dry. The first installment of the public WISE catalog will be released in summer 2011. »

The Internet, networks of connections between Hollywood actors, etc., are examples of complex networks, whose properties have been intensively studied in recent times. The 'small-world' property (that everyone has a few-step connection to celebrities), for instance, is a famous example.A group of scientists led by Prof. J.I. Cirac, Director at the Max Planck Institute of Quantum Optics (Garching near Munich) and Leader of the Theory Division, has now introduced complex networks in the quantum realm. In a study appearing in the journal Nature Physics, the scientists show that these quantum complex networks have surprising properties: even in a very weakly connected quantum network, performing some measurements and other simple quantum operations allows the generation of arbitrary graphs of connections that are otherwise impossible in their classical counterparts.The behaviour of networks has been widely explored in the context of classical statistical mechanics. Periodic networks, by definition, have a regular structure, in which each node is connected to a constant number of 'geometrical' neighbours. If one tries to enlarge these systems, their topology is not altered since the unit cell is just repeated ad aeternum. The construction of a random network is completely different: each node has a small probability of being connected to any other node. Depending on the connection probability and in the limit of infinite size, such networks exhibit some typical effects. For instance, if this probability is high enough, nearly all nodes will be part of one giant cluster; if it is too small only sparse groups of connected nodes will be present. »

New images of iron-based superconductors are providing telltale clues to the origin of superconductivity in a class of ceramic materials known as pnictides. The images reveal that electrons responsible for the superconducting currents in some pnictides tend to flow primarily along the boundaries between the crystal grains that make up the superconductors.The research, which is reported in a pair of papers appearing in the current issue of the journal Physical Review B, may help physicists to find new superconducting compounds that can carry current without the electrical resistance that plagues conventional metal conductors.In order to identify the stripes that represent regions with dense superconducting currents, a group of Stanford University researchers measured the depth that magnetic fields penetrated into a superconducting sample. When exposed to a magnetic field, currents in a superconductor flow in a way that creates a field inside the material that is the opposite of the applied field. When added together, the applied and internal fields cancel each other out inside the superconductor. Essentially, it's as if the superconductor prevents a magnetic field from penetrating it (this is the source of the Meissner effect, which allows strong magnets to levitate over a superconductor). The better the superconductor, the more completely it can exclude a magnetic field. By scanning an iron-pnictide superconductor with a probe that measures the depth that a magnetic field penetrates the material, the researchers could determine the regions where superconducting currents are strongest. »

Researchers from Rensselaer Polytechnic Institute have developed a new nanotechnology-based "microlens" that uses gold to boost the strength of infrared imaging and could lead to a new generation of ultra-powerful satellite cameras and night-vision devices.By leveraging the unique properties of nanoscale gold to "squeeze" light into tiny holes in the surface of the device, the researchers have doubled the detectivity of a quantum dot-based infrared detector. With some refinements, the researchers expect this new technology should be able to enhance detectivity by up to 20 times.This study is the first in more than a decade to demonstrate success in enhancing the signal of an infrared detector without also increasing the noise, said project leader Shawn-Yu Lin, professor of physics at Rensselaer and a member of the university's Future Chips Constellation and Smart Lighting Engineering Research Center."Infrared detection is a big priority right now, as more effective infrared satellite imaging technology holds the potential to benefit everything from homeland security to monitoring climate change and deforestation," said Lin, who in 2008 created the world's darkest material as well as a coating for solar panels that absorbs 99.9 percent of light from nearly all angles."We have shown that you can use nanoscopic gold to focus the light entering an infrared detector, which in turn enhances the absorption of photons and also enhances the capacity of the embedded quantum dots to convert those photons into electrons. This kind of behavior has never been seen before," he said. »

In what could set the stage for a fundamental shift in commercial aviation, an MIT-led team has designed a green airplane that is estimated to use 70 percent less fuel than current planes while also reducing noise and emission of nitrogen oxides (NOx).The design was one of two that the team, led by faculty from the Department of Aeronautics and Astronautics, presented to NASA last month as part of a $2.1 million research contract to develop environmental and performance concepts that will help guide the agency's aeronautics research over the next 25 years. Known as "N+3" to denote three generations beyond today's commercial transport fleet, the research program is aimed at identifying key technologies, such as advanced airframe configurations and propulsion systems, that will enable greener airplanes to take flight around 2035.MIT was the only university to lead one of the six U.S. teams that won contracts from NASA in October 2008. Four teams -- led by MIT, Boeing, GE Aviation and Northrop Grumman, respectively -- studied concepts for subsonic (slower than the speed of sound) commercial planes, while teams led by Boeing and Lockheed-Martin studied concepts for supersonic (faster than the speed of sound) commercial aircraft. Led by AeroAstro faculty and students, including principal investigator Ed Greitzer, the H. Nelson Slater Professor of Aeronautics and Astronautics, the MIT team members include Aurora Flight Sciences Corporation and Pratt & Whitney. »

Agricultural Research Service (ARS) scientists are tapping into the biochemistry of one of the world's most damaging insect pests to develop a biocontrol agent that may keep the pest away from gardens and farms.Aphids spread diseases that cost gardeners and farmers hundreds of millions of dollars each year. Some of the insecticides available are not environmentally friendly, and because aphids are developing insecticide resistance, some growers are being forced to use more of the chemicals.Ronald J. Nachman, a chemist with the ARS Southern Plains Agricultural Research Center at College Station, Texas, is working with chemical signals known as neuropeptides that aphids and other organisms use to control and regulate a wide range of body functions, such as digestion, respiration, water intake and excretions. The effect triggered by the chemical signal is normally turned off when the neuropeptide is broken down by enzymes in the body. Nachman is developing neuropeptide mimics, or analogues, with slightly altered molecular structures that will not break down. His goal is to kill the pest by disrupting its digestion, water intake or some other biological function.Nachman, along with Guy Smagghe of Ghent University in Belgium and other colleagues, mixed five candidate analogues into dietary solutions and fed each one to 20 caged pea aphid (Acyrthosiphon pisum) nymphs. The scientists found that one of the formulations killed 90 to 100 percent of the aphids within three days, at a rate and potency comparable to insecticides now on the market. The study was recently published in the journal Peptides. »

A collaboration between the Advanced Photon Source and Center for Nanoscale Materials at U.S. Department of Energy's (DOE) Argonne National Laboratory has enabled researchers to "see" the crystallization of nanoparticles in unprecedented detail."Nanoscience is a hot issue right now, and people are trying to create self-assembled nanoparticle arrays for data and memory storage," Argonne assistant physicist Zhang Jiang said. "In these devices, the degree of ordering is an important factor."In order to call up a specific bit of data, it is ideal to store information on a two-dimensional crystal lattice with well-defined graphical coordinates. For example, every bit of information of a song saved on a hard drive must be stored at specific locations, so it can be retrieved later. However, in most cases, defects are inherent in nanoparticle crystal lattices."Defects in a lattice are like potholes on a road," Argonne physicist Jin Wang said. "When you're driving on the highway, you would like to know whether it is going to be a smooth ride or if you will have to zigzag in order to avoid a flat tire. Also, you want to know how the potholes form in the first place, so we can eliminate them."Controlling the degree of ordering in nanoparticle arrays has been elusive.The number of nanoparticles a chemist can make in a small volume is astonishingly large."We can routinely produce 1014 particles in a few droplets of solution. That is more than the number of stars in the Milky Way Galaxy," Argonne nanoscientist Xiao-Min Lin. "To find conditions under which nanoparticles can self-assemble into a crystal lattice with a low number of defects is quite challenging."Because nanoparticles are so small, it is not easy to see how ordered the lattice is during the self-assembly process. Electron microscopy can see individual nanoparticles, but the field of view is too small for scientists to get a "big picture" of what the ordering is like in macroscopic length scale. It also doesn't work for wet solutions."With local ordering, one cannot assume the same order exists throughout the whole structure; it's like seeing a section of road and assuming it is straight and well constructed all the way to the end," Wang said. »

At extremely low temperatures atoms can aggregate into so-called Bose Einstein condensates forming coherent laser-like matter waves. Due to interactions between the atoms fundamental quantum dynamics emerge and give rise to periodic collapses and revivals of the matter wave field.A group of scientists led by Professor Immanuel Bloch (Chair of Experimental Physics at the Ludwig-Maximilians-Universität München (LMU) and Director of the Quantum Many Body Systems Division at the Max Planck Institute of Quantum Optics in Garching) has now succeeded to take a glance 'behind the scenes' of atomic interactions revealing the complex structure of these quantum dynamics. By generating thousands of miniature BECs ordered in an optical lattice the researchers were able to observe a large number of collapse and revival cycles over long periods of time.The research is published in the journal Nature.The experimental results imply that the atoms do not only interact pairwise -- as typically assumed -- but also perform exotic collisions involving three, four or more atoms at the same time. On the one hand, these results have fundamental importance for the understanding of quantum many-body systems. On the other hand, they pave the way for the generation of new exotic states of matter, based on such multi-body interactions. »

Massive stars end their lives in gigantic explosions, so called supernovae, and can become -- for a short time -- brighter than a whole galaxy, which is made up of billions of stars. Although supernovae have been studied theoretically by computer models for several decades, the physical processes happening during these blasts are so complex that until now astrophysicists could only simulate parts of the process and so far only in one or two dimensions. Researches at the Max Planck Institute for Astrophysics in Garching have now carried out the first fully three-dimensional computer simulations of a core collapse supernova over a timescale of hours after the initiation of the blast. They thus could answer the question of how initial asymmetries, which emerge deep in the dense core during the very early stages of the explosion, fold themselves into inhomogeneities observable during the supernova blast.While the great energy of the outburst makes these stellar explosions visible far out into the Universe, they are relatively rare. In a galaxy of the size of our Milky Way, on average only one supernova will occur in 50 years. About twenty years ago, a supernova could be seen even with the naked eye: SN 1987A in the Tarantula Nebula in the Large Magellanic Cloud, our neighbouring galaxy. This relative closeness -- "only" about 170,000 light years away -- allowed many detailed observations in different wavelength bands over weeks and even months. SN 1987A turned out to be a core-collapse supernova, a so-called Type II event. It occurs when a massive star, which is at least nine times heavier than the sun, has burned almost all its fuel. The fusion engine in the centre of the star begins to stutter, triggering an internal collapse and thus a violent explosion of the entire star. In the case of SN 1987A the star had about 20 solar masses at its birth. »