NSF Funding Opportunity - Research and Evaluation on Education in Science and Engineering

The Division of Research, Evaluation and Communication in the Directorate for Education and Human Resources of the National Science Foundation (NSF) supports basic and applied research and evaluation that enhances science, technology, engineering and mathematics (STEM) learning and teaching. This solicitation calls for two types of proposals -- synthesis and empirical. For either type of proposal, areas of interest include behavioral, cognitive, social, and technological aspects of learning and education; learning in formal and informal settings; diffusion, implementation, and the role of context in educational and learning innovations; and theoretical, methodological, and statistical issues of importance in advancing research and evaluation. Investigators from across the broad range of disciplines supported by the NSF are invited to submit proposals. Interdisciplinary proposals are particularly welcome. Read more

High-Tech Fabric Lights Up the Catwalk

ZDNet News, 27 Sep 2006 It's one thing to light up the catwalk with innovative design, but what about producing designs that actually light up the catwalk? Philips, the Dutch electronics giant, and German fashion designer Anke Loh aim to try. Loh this week launched a new collection, "Dressing Light," in which each garment incorporates Philips' new photonic fabric -- which has arrays of light-emitting diodes that can display text, graphics and animation. Read more

Balanced Vehicular Traffic at a Bottleneck

by F. Siebel et al. arXiv.org E-print Archive, 27 Sep 2006 The balanced vehicular traffic model is a macroscopic model for vehicular traffic flow. We use this model to study the traffic dynamics at highway bottlenecks either caused by the restriction of the number of lanes or by on-ramps or off-ramps. The coupling conditions for the Riemann problem of the system are applied in order to treat the interface between different road sections consistently. Our numerical simulations show the appearance of synchronized flow at highway bottlenecks. Read more

Fabry-Perot Otical Binary Switch for Aircraft Applications

by Z. Xie & H.F. Taylor Optics Letters, September 2006 An optical binary switch for aircraft applications is demonstrated. A fiber Fabry-Perot interferometer (FFPI) bonded to a cantilever is used as the sensing element. A white-light interferometry system with two bulk Michelson interferometers sharing the same motor-driven translation stage is utilized to monitor the elongation of the FFPI. The system exhibits excellent linearity as a force sensor; the experimental results are in good agreement with theoretical calculated values. With a properly set threshold value, the system produces a binary output. Read more

The Ascent of Wind Power

by K. Bradsher New York Times, 28 Sep 2006 Dilip Pantosh Patil uses an ox-drawn wooden plow to till the same land as his father, grandfather and great-grandfather. But now he has a new neighbor: a shiny white wind turbine taller than a 20-story building, generating electricity at the edge of his bean field. Wind power may still have an image as something of a plaything of environmentalists more concerned with clean energy than saving money. But it is quickly emerging as a serious alternative not just in affluent areas of the world but in fast-growing countries like India and China that are avidly seeking new energy sources. Read more

Carbon Nanotube Forests: A Non-Stick Workbench for Nanomanipulation

by K. Gjerde et al. Nanotechnology, 14 Oct 2006 The ubiquitous static friction (stiction) and adhesion forces comprise a major obstacle in the manipulation of matter at the nanoscale. In this work it is shown that a surface coated with vertically aligned carbon nanotubes -- a nanotube forest -- acts as an effective non-stick workbench for the manipulation of micro-objects and fibres/wires with one or more dimensions in the nano-range. These include organic nanofibres and microsized latex beads, which adhere strongly even to a conventional low surface-energy material like Teflon. Although organic nanofibres are attractive as device components due to their chemical adaptability, adhesion forces nearly always rule out manipulation as a route to assembly of prototype devices based on such materials, because organic materials are soft and fragile, and tend to stick to any surface. We demonstrate here that the nanotube forest due to its roughness not only exhibits very low stiction and dynamic friction; it also acts as a springy and mechanically compliant surface, making it possible to lift up and manipulate delicate nanostructures such as organic nanofibres in ways not possible on planar, rigid surfaces. Read more

Modelling and Simulation of Scheduling Policies Implemented in Ethernet Switch

by B. Brahimi, C. Aubrun, & E. Rondeau arXiv.org E-print Archive, 27 Sep 2006 The objective of this paper is to propose models enabling to study the behaviour of Ethernet switch for Networked Control Systems. Two scheduler policies are analyzed: the static priority and the Weighted Round Robin. The modelling work is based on Coloured Petri Nets. A temporal validation step based on the simulation of these modelling, shows that the obtained results are near to the expected behaviour of these scheduler policies. Read more

Technologies That Will Shape Our Future

What technologies are most likely to have the greatest impact over the next 20 years? This month, IEEE Spectrum teams up with The Institute for the Future to survey over 700 IEEE fellows to find out what scientific and technological innovations can be expected to have the greatest impact on the way we live in future years since they have so much to do with making them come about. Included in the list of influential technologies are a commercially available universal language translator, lifelike interactive computer graphics, and routine global video conferencing. Read more

Amplification and Increased Duration of Earthquake Motion on Uneven Stress-Free Ground

by A. Wirgin & J.-P. Groby arXiv.org E-print Archive, 22 Sep 2006 When a flat stress-free surface separating air from a isotropic, homogeneous or horizontally-layered, solid substratum is solicited by a shear horizontal plane body wave incident in the substratum, the response in the substratum is a single specularly-reflected body wave. When the stress-free condition, equivalent to vanishing surface impedance, is relaxed by the introduction of a spatially-constant, non-vanishing surface impedance, the response in the substratum is again a single reflected body wave whose amplitude is less than the one in the situation of a stress-free ground. When the stress-free condition is relaxed by the introduction of a spatially-modulated surface impedance, which simulates the action of an uneven ground, the frequency-domain response takes the form of a spectrum of plane body waves and surface waves and resonances are produced at the frequencies of which one or several surface wave amplitudes can become large. It is shown, that at resonance, the amplitude of one, or of several, components of the motion on the surface can be amplified with respect to the situation in which the surface impedance is either constant or vanishes. Also, when the solicitation is pulse-like, the integrated time history of the square of surface displacement and of the square of velocity can be larger, and the duration of the signal can be considerably longer, for a spatially-modulated impedance surface than for a constant, or vanishing, impedance surface. Read more

Seismic Motion in Urban Sites

by J.-P. Groby & A. Wirgin arXiv.org E-print Archive, 26 Sep 2006 We address the problem of the response to a seismic wave of an urban site consisting of N non-identical, non-equispaced blocks overlying a soft layer underlain by a hard substratum. The results of a theoretical analysis, appealing to a space-frequency mode-matching technique, are compared to those obtained by a space-time finite element technique. The two methods are shown to give rise to the same prediction of the seismic response for N=1 and N=2 blocks. The mechanism of the interaction between blocks and the ground, as well as that of the mutual interaction between blocks, are studied. It is shown that the presence of a small number of blocks modifies the seismic disturbance in a manner which evokes qualitatively, but not quantitatively, what was observed during the 1985 Michoacan earthquake in Mexico City. Read more

Even on the Ground, Space Elevators May Have Uses

by K. Young NewScientist.com, 26 Sep 2006 Balloon-borne platforms developed as precursors to space elevators could be used as high-altitude relay stations for wireless communications, a 60-day field test suggests. The hope is that one day a space elevator, comprised of a robot that will climb a strong tether about 60,000 miles long, will be able to send humans or other cargo cheaply into space. Read more

MIT's Intelligent Aircraft Fly and Cooperate Autonomously

Massachusetts Institute of Technology Press Release, 26 Sep 2006 The U.S. military depends on small, unmanned aerial vehicles (UAVs) to perform such tasks as serving as "eyes in the sky" for battalion commanders planning maneuvers. While some of these UAVs can be easily carried in a backpack and launched by hand, they typically require a team of trained operators on the ground, and they perform only short-term tasks individually rather than sustained missions in coordinated groups. MIT researchers, in collaboration with Boeing's advanced research and development arm, Phantom Works, are working to change that. Read more

UNH Space Scientists to Build Sensor for Next-Generation Weather Satellites

University of New Hampshire Press Release, 26 Sep 2006 With an award in excess of $10 million, scientists from the University of New Hampshire's Space Science Center have been selected to build an instrument for the National Oceanic and Atmospheric Administration's third-generation weather satellites under the Geostationary Operational Environmental Satellite Program. The principal parties involved in the mission will hold their first operational meeting next week. UNH scientists and engineers will design and build the Energetic Heavy Ion Sensor for the Space Environment In-Situ Suite, which will monitor potentially dangerous energetic atomic nuclei and electrons as they hurtle through space near Earth. Read more

Intel Tips Teraflops Programmable Processor

by M. LaPedus EE Times, 26 Sep 2006 Intel Corp. revealed the first details of its terascale research silicon program, including the development of the world's first programmable processor said to deliver 1 trillion floating point operations per second. They also tipped an SRAM and a silicon laser chip, as part of its ongoing research into terascale technology. Earlier this year, the company disclosed details about its internal terascale research program that promises to usher in the next wave of computing. Read more

Intel Offers Prize for Sexiest PC

BBC News, 27 Sep 2006 Intel is offering $1m in prizes to designers and manufacturers who can come up with sexier alternatives to the "big, beige box." The Intel Core Processor Challenge is looking for smaller, more stylish multimedia PCs. The only condition is that entries must be powered by Intel Viiv technology, using the chip giant's Core 2 Duo processors. Beyond that, Intel urges potential applicants to "think outside the box." Read more

'Tower of Babel' Technology Nears

BBC News, 27 Sep 2006 The problem of compatibility between wireless devices is being addressed at an international conference this week. Scientists will be discussing what has been dubbed "Tower of Babel" technology -- software that can converge different wireless gadgets into a single device. The aim for Software Defined Radio (SDR) is to be able to translate and understand any kind of radio wave signal, such as 3G or Wi-Fi. Researchers say SDR gadgets could become commonplace in five to 10 years. Read more

Quick and Easy Enrichment of Metallic Carbon Nanotubes

by H. Kataura & Y. Miyata SPIE Newsroom, accessed 26 Sep 2006 A carbon nanotube (CNT) can exhibit either metal or semiconductor electronic behavior, depending on the molecule's chirality. The metallic variety is used in conductive films and transparent electrodes, while the semiconducting type is in great demand for high-performance field effect transistors (FETs). Unfortunately, current synthesis methods can't produce pure batches of either type, probably because of structural similarities, and instead generally produce twice as many semiconducting nanotubes as metallic nanotubes. This mixture can degrade application performances. For example, metallic CNTs reduce an FET's on/off current ratio, while semiconducting CNTs lower a thin film's overall conductivity. Thus, it is essential to have an effective way to separate the two types in order to better realize CNT potential. Read more

Stochastic Model for Power Grid Dynamics

by M. Anghel, K.A. Werley, & A.E. Motter arXiv.org E-print Archive, 24 Sep 2006 We introduce a stochastic model that describes the quasi-static dynamics of an electric transmission network under perturbations introduced by random load fluctuations, random removing of system components from service, random repair times for the failed components, and random response times to implement optimal system corrections for removing line overloads in a damaged or stressed transmission network. We use a linear approximation to the network flow equations and apply linear programming techniques that optimize the dispatching of generators and loads in order to eliminate the network overloads associated with a damaged system. We also provide a simple model for the operator's response to various contingency events that is not always optimal due to either failure of the state estimation system or due to the incorrect subjective assessment of the severity associated with these events. This further allows us to use a game theoretic framework for casting the optimization of the operator's response into the choice of the optimal strategy which minimizes the operating cost. We use a simple strategy space which is the degree of tolerance to line overloads and which is an automatic control parameter that can be adjusted to trade off automatic load shed without propagating cascades versus reduced load shed and an increased risk of propagating cascades. The tolerance parameter is chosen to describes a smooth transition from a risk averse to a risk taken strategy. Read more

A Unifying Approach to Left Handed Material Design

by J. Zhou et al. arXiv.org E-print Archive, 23 Sep 2006 In this letter we show that equivalent circuits offer a qualitative and even quantitative simple explanation for the behavior of various types of left-handed (or negative index) meta-materials. This allows us to optimize design features and parameters, while avoiding trial and error simulations or fabrications. In particular we apply this unifying circuit approach in accounting for the features and in optimizing the structure employing parallel metallic bars on the two sides of a dielectric film. Read more

Google to Push for More Electrical Efficiency in PC’s

by J. Markoff New York Times, 26 Sep 2006 Google is calling on the computer industry to create a simpler and more efficient power supply standard that it says will save billions of kilowatt-hours of energy annually. In a white paper to be presented Tuesday on the opening day of the Intel Developer Forum here, two leading data center designers at Google will argue that the industry is mired in inefficiency for historical reasons, dating to the introduction of the first I.B.M. PC in 1981. Read more

Prequel to a Hydrogen Future: Driving G.M.’s Fuel Cell Prototype

by L. Brooke New York Times, 24 Sep 2006 If an afternoon behind the wheel of General Motors’ latest prototype hydrogen fuel cell vehicle, the Sequel, is any indication, automotive powertrains of the future will not feel much different from the engines that drive today’s cars and trucks. By a seat-of-the-pants evaluation, the Sequel feels reasonably peppy; acceleration is smooth and nearly silent. And it is capable of reaching 90 miles an hour. Read more

IEEE Developing Lithium-Ion Battery Standard

EE Times, 25 Sep 2006 The IEEE is developing a standard to enhance performance for lithium-ion and lithium-ion polymer batteries used in digital cameras and camcorders. Designated IEEE P1825, the standard will set uniform criteria for the design, production and evaluation of lithium-ion and lithium-ion polymer batteries. Read more

Motion Primitives for Robotic Flight Control

by B.E. Perk & J. J. E. Slotine arXiv.org E-print Archive, 25 Sep 2006 We introduce a simple framework for learning aggressive maneuvers in robotic flight control. Standard movement primitive techniques are analyzed and extended using nonlinear contraction theory. Accordingly, dynamic primitives, approximated and regenerated from an observed movement, can be stably combined or concatenated for various purposes. We demonstrate our results experimentally on the Quanser Helicopter, in which we first imitate aggressive maneuvers performed by a human, and then use these primitives to achieve new maneuvers that can pass an obstacle. Read more

Cooperative Wireless Systems

by M. Yuksel & E. Erkip arXiv.org E-print Archive, 21 Sep 2006 We consider a general multiple antenna network with multiple sources, multiple destinations and multiple relays in terms of diversity-multiplexing tradeoff (DMT). We examine several projections of this most general problem taking into account the network geometry, the processing capability of the relays, and the number of antennas the nodes have. We first study a system with a single source-destination pair and multiple relays, each node with a single antenna, and show that even under idealistic assumptions, this virtual multi-input multi-output (MIMO) system can never fully mimic a real MIMO DMT. We provide communication strategies that achieve the best DMT of this relay system. We extend our work to cover cooperative systems with multiple sources and multiple destinations. We next study the relay channel with multiple antenna nodes for full-duplex relays to understand the effect of increased degrees of freedom in the direct link. We find DMT upper bounds and investigate the achievable performance of decode-and-forward, and compress-and-forward (CF) protocols. As having a full-duplex relay is an idealistic assumption, we also study the multiple antenna relay channel with half-duplex relays. We also study the multiple-access relay channel (MARC) as a subproblem of the most general network, and evaluate how CF works in MARC. Read more

Device Seeks to Detect Concussions during Games

CNN.com, 25 Sep 2006 Concussions in football, and sports in general, are a relatively common injury. According to Dr. David Wright, a researcher at Emory University in Atlanta, "There's 1.2 million concussions [in this country] every year, and the problem is they are very difficult to diagnose." Wright and Michelle LaPlaca, an associate professor at Georgia Tech, are trying to make it easier to detect possible concussions. They are working on a device that could be used on the sidelines of a football game or in the locker room. Read more

Internet's Future in 2020 Debated

BBC News, 4 Sep 2006 The Pew report on the future internet surveyed 742 experts in the fields of computing, politics and business. More than half of respondents had a positive vision of the net's future but 46% had serious reservations. Almost 60% said that a counter culture of Luddites would emerge, some resorting to violence. The Pew Internet and American Life report canvassed opinions from the experts on seven broad scenarios about the future internet, based on developments in the technology in recent years. Read more

Army to Test Hydrogen Fuel Cell Vehicle

by Ken Thomas USATODAY.com, 22 Sep 2006 The Army and General Motors Corp. are collaborating to help the military learn more about the uses of hydrogen fuel cell vehicles, a potential aid for soldiers on future battlefields. The Army received the keys Thursday to a Chevrolet Equinox fuel cell vehicle, beginning a year of tests to see how the hydrogen power might support the armed services. Read more

Self-Aligning Liquid Crystal Technique Could Simplify Manufacture of Display Devices

PhysOrg.com, accessed 22 Sep 2006 Liquid crystals are a key component of the displays used in most laptop computers and the increasingly-popular flat panel televisions. Controlled by a network of transistors, the liquid crystals change their optical characteristics in response to electrical signals to create the text and images we see. A new technique for creating vertical alignment among liquid crystal molecules could allow development of less-costly flexible displays and lead to a better understanding of the factors that govern operation of the popular liquid crystal display systems. Read more

Virtual Reality Simulator Lands at McMaster University

PhysOrg.com, accessed 21 Sep 2006 McMaster University has unveiled the first interactive motion simulator in Canada to be used for teaching undergraduate students how to develop software for simulated flight, driving, real-time game design, medical research, virtual reality systems, and a host of other applications. Read more

Cycloaddition Functionalizations to Preserve or Control the Conductance of Carbon Nanotubes

by Young-Su Lee & Nicola Marzari Physical Review Letters, 11 Sep 2006 We identify a class of covalent functionalizations that preserve or control the conductance of single-walled metallic carbon nanotubes. [2+1] cycloadditions can induce bond cleaving between adjacent sidewall carbons, recovering in the process the sp2 hybridization and the ideal conductance of the pristine tubes. This is radically at variance with the damage permanently induced by other common ligands, where a single covalent bond is formed with a sidewall carbon. Chirality, curvature, and chemistry determine bond cleaving, and in turn the electrical transport properties of a functionalized tube. A well-defined range of diameters can be found for which certain addends exhibit a bistable state, where the opening or closing of the sidewall bond, accompanied by a switch in the conductance, could be directed with chemical, optical, or thermal means. Read more

2006 Science and Engineering Visualization Challenge Winners Announced

Sometimes the best way to express a scientific idea is through an image that grabs the eye and invites viewers to wonder what they're seeing. Fourteen images and multimedia presentations, each using innovative approaches to encapsulate a scientific story, have won the 2006 Science and Engineering Visualization Challenge, sponsored jointly by the National Science Foundation and the journal Science. The contest recognizes outstanding achievement in the use of visual media to promote understanding of research results and scientific phenomena. The winning entries communicate information about complex mathematical concepts, the intricacies of the human body, air flight patterns, the latest scientific imaging technologies to analyze Leonardo da Vinci's art, and more. The 22 Sep 2006 issue of Science will feature all of these entries, and will be freely available online. Read more

Environmental, Health, and Safety Research Needs for Engineered Nanoscale Materials

The Nanoscale Science, Engineering, andTechnology Subcommittee of the National Science and Technology Council's Committee on Technology has released a document identifying environmental, health, and safety research and information needs related to understanding and management of potential risks of engineered nanoscale materials. The document will be used by Federal agencies participating in the National Nanotechnology Initiative to inform and guide research programs. It also communicates to industry, universities, and other nongovernment research entities approaches for obtaining the knowledge and understanding necessary to enable risk assessment and management of nanomaterials. Read more

Industry Renews Call to Study Nanotechnology Risks

by Spencer Chin EE Times, 21 Sep 2006 Government and environmental leaders renewed calls for greater federal scrutiny of the health effects of nanotechnology. Testifying before the House Science Committee on September 21 about the environmental and safety effects of nanotechnology, experts said the government needs to invest more in risk research. Read more

Virtual Bees Help Robots See in 3D

by Tom Simonite NewScientist.com, 21 Sep 2006 Copying the humble honeybee's foraging methods could give robots better 3D vision, researchers say. Robot explorers could identify points of interest by mimicking the way bees alert others of promising foraging spots. Read more

Choosing Techniques for the Optical Characterization of Thin Films

by Ivan Ohlidal & Daniel Franta SPIE Newsroom, accessed 21 Sep 2006 The optical properties of thin films are very important for many applications, including interference devices, as well as optoelectronics, integrated optics, solar power engineering, microelectronics, and optical sensor technology. The end application of a film determines the reflectance and transmittance properties required during fabrication. Numerous methods are used for characterization and these can be classified in the following categories: spectrophotometric, ellipsometric, interferometric, photothermal, and combined methods. We describe these methods, and how they are best used, briefly here. Read more

A Biomimetic Approach to Efficient Underwater Propulsion

by Thomas Bliss, Hilary Bart-Smith, & Tetsuya Iwasaki SPIE Newsroom, accessed 21 Sep 2006 As the applications of underwater robots grow, finding efficient propulsion techniques is of the utmost importance. For the most part, this effort has concentrated on the hydrodynamic screw, which has many inherent problems, such as cavitation and efficiency. To overcome these shortcomings, current research has focused on the use of biomimetic propulsion, which simulates the undulation of fish tails, or the sinusoidal oscillation of the stingray or cuttlefish. Our objective is to mimic the propulsion technique the manta ray uses to swim efficiently over large distances at impressive speeds. Read more

AMD's New Chip Ploy

by Darrell Dunn EE Times, 21 Sep 2006 Advanced Micro Device plans to publish its Opteron socket specification in a move that it hopes will boost sales by letting other chip makers design application-specific co-processors to be integrated alongside Opteron for optimized performance. Read more

Self-Assembled Single-Crystal Silicon Circuits on Plastic

by S.A. Stauth & B.A. Parviz Proceedings of the National Academy of Sciences, 19 Sep 2006 We demonstrate the use of self-assembly for the integration of freestanding micrometer-scale components, including single-crystal, silicon field-effect transistors (FETs) and diffusion resistors, onto flexible plastic substrates. Preferential self-assembly of multiple microcomponent types onto a common platform is achieved through complementary shape recognition and aided by capillary, fluidic, and gravitational forces. We outline a microfabrication process that yields single-crystal, silicon FETs in a freestanding, powder-like collection for use with self-assembly. Demonstrations of self-assembled FETs on plastic include logic inverters and measured electron mobility of 592 cm²/V-s. Finally, we extend the self-assembly process to substrates each containing 10,000 binding sites and realize 97% self-assembly yield within 25 min for 100-µm-sized elements. High-yield self-assembly of micrometer-scale functional devices as outlined here provides a powerful approach for production of macroelectronic systems. Read more

Laser on a Chip

by R.F. Service ScienceNOW Daily News, 18 Sep 2006 Researchers at the electronics giant Intel and the University of California, Santa Barbara announced today that they have created electrically driven lasers on silicon. The new lasers open the door for integrating optical and electrical components together on computer chips, an advance that could dramatically boost computing speeds and data transmission rates. Read more

Complex Spaces In Hydrodynamics: Complex Navier-Stokes Equations

by A.N. Panchenkov arXiv.org E-print Archive, 19 Sep 2006 The study is devoted to the development of new effective tools and methods of analytical hydrodynamics, including problems of existence, smoothness and structure of laminar and turbulent flows. The main problem is complex Navier-Stokes equations and turbulence in complex spaces. The necessity of introducing complex spaces in hydrodynamics is determined by the mechanism of transition of a laminar flow into a turbulent flow. The author proposes a non-traditional scenario of the transition: the cause of turbulence is in destruction of a laminar flow. The article contains the mathematical rationale for the necessity of development of the theory of turbulence in the complex configurational space: the complex configurational space is the natural area of existence of turbulence. Hydrodynamic flows are regarded as flows on entropy manifolds that [flows] are supported by the two symmetries: the symmetry of conservation of general entropy and the symmetry of duality of impulse representation. The new symmetry has been introduced and studied: the form invariance of Helmholtz matrix of impulse density. The strict foundation has been provided for the known fact of chaotic mechanics: appearance of the new structure (a turbulent flow) is a result of interaction of two entities: dissipation and vorticity. On the deep level the phenomenology of turbulence in complex spaces is based on the transition from the mechanics of a material point to the mechanics of an oriented material point, that [transition] takes place in a current period of time. Read more

Engine on a Chip Promises to Best the Battery

PhysOrg.com, accessed 20 Sep 2006 MIT researchers are putting a tiny gas-turbine engine inside a silicon chip about the size of a quarter. The resulting device could run 10 times longer than a battery of the same weight can, powering laptops, cell phones, radios and other electronic devices. It could also dramatically lighten the load for people who can't connect to a power grid, including soldiers who now must carry many pounds of batteries for a three-day mission -- all at a reasonable price. The researchers say that in the long term, mass-production could bring the per-unit cost of power from microengines close to that for power from today's large gas-turbine power plants. Read more

Superconductivity Project Addresses Urban Power Challenges

PhysOrg.com, accessed 20 Sep 2006 A new technology that holds promise to transform the global transmission and distribution of electric power was formally energized near Columbus, Ohio. The $9 million project uses a second-generation High Temperature Superconducting (HTS) cable system to efficiently deliver electric power to approximately 8,600 homes and businesses in suburban Columbus. The Columbus project is the first demonstration of the new Triax HTS cable design, which dramatically reduces the cost of superconducting systems and brings the technology one step closer to commercial viability. Read more

When Networks Collide: Putting the T into MPLS

fibers.org News, 20 Sep 2006 by Mark Lunn Transport MultiProtocol Label Switching (T-MPLS) is a new model of packet networking that could provide a key evolution path for next-generation Synchronous Digital Hierarchy (SDH) networks. We look at the potential implications of T-MPLS for optical and SDH networking, and outlines its possible future relationship with MPLS and other Carrier Ethernet technologies. Read more

Throughput Optimal Distributed Control of Stochastic Wireless Networks

by Y. Xi & E.M. Yeh arXiv.org E-print Archive, 18 Sep 2006 The Maximum Differential Backlog (MDB) control policy of Tassiulas and Ephremides has been shown to adaptively maximize the stable throughput of multi-hop wireless networks with random traffic arrivals and queueing. The practical implementation of the MDB policy in wireless networks with mutually interfering links, however, requires the development of distributed optimization algorithms. Within the context of CDMA-based multi-hop wireless networks, we develop a set of node-based scaled gradient projection power control algorithms which solves the MDB optimization problem in a distributed manner using low communication overhead. As these algorithms require time to converge to a neighborhood of the optimum, the optimal rates determined by the MDB policy can only be found iteratively over time. For this, we show that the iterative MDB policy with convergence time remains throughput optimal. Read more

Quantum Pattern Retrieval by Qubit Networks with Hebb Interactions

by M.C. Diamantini & C.A. Trugenberger arXiv.org E-print Archive, 15 Sep 2006 Qubit networks with long-range interactions inspired by the Hebb rule can be used as quantum associative memories. Starting from a uniform superposition, the unitary evolution generated by these interactions drives the network through a quantum phase transition at a critical computation time, after which ferromagnetic order guarantees that a measurement retrieves the stored memory. The maximum memory capacity p of these qubit networks is reached at a memory density p/n=1. Read more

To the Strength First Problem Full Solution

by S. L. Arsenjev arXiv.org E-print Archive, 17 Sep 2006 Essentially new approach to analysis of internal forces, arising in cylindrical rod under action of an axial tension force, has allowed to detect the three-dimensional axisymmetric stress state. According to the new conceptual model the axial tension force causes the tangential -- hoop and radial -- stresses side by side with axial stress in the rod volume. A completion of Lame's solution of the problem on the stress state in the thickwalled cylinder has allowed to ascertain a mutual direct and reverse connection of the tangential and radial stresses with the axial stress also in the rod under action of an axial tension force. The new approach for the first time has allowed to give the full physically adequate and mathematically sufficiently strict description of a change of the initial cylindrical form of a mild steel rod under action of an axial tension force on all stages of its deforming, including the necking, the fracture process and a view of the fracture surface. The new approach has allowed on the united methodological base to elucidate also a number of the questions, bound with an axisymmetric form of the soap solution film between two rings, with the breaking up of a liquid free jet nto drops, with the causes of a buckling of the long tube under action of internal pressure, created in it by the rested and moved fluid in it and others. Read more

Researchers Developing More Powerful Solar Cells

PhysOrg.com, accessed 19 Sep 2006 Sure, Iowa has its share of rainy, snowy and cloudy days. But look out the window. “We have a lot of sunlight,” said Vikram Dalal as sunshine lit up a late-summer morning and the south-facing windows of his office at Iowa State University’s Applied Sciences Complex. Dalal, the director of Iowa State’s Microelectronics Research Center and the Thomas M. Whitney Professor in electrical and computer engineering, has spent more than three decades finding ways for that sunlight to generate more and more electricity. He thinks his latest project can boost the performance of an Iowa company’s solar cells by 40 to 50 percent. Read more

Time to Move the Mississippi, Experts Say

by Cornelia Dean New York Times, 19 Sep 2006 Scientists have long said the only way to restore Louisiana’s vanishing wetlands is to undo the elaborate levee system that controls the Mississippi River, not with the small projects that have been tried here and there, but with a massive diversion that would send the muddy river flooding wholesale into the state’s sediment-starved marshes. And most of them have long dismissed the idea as impractical, unaffordable and lethal to the region’s economy. Now, they are reconsidering. In fact, when a group of researchers convened last April to consider the fate of the Louisiana coast, their recommendation was unanimous: divert the river. Far from rejecting the idea, state officials have embraced it, motivated not just by the lessons of Hurricane Katrina but also by growing fears that global climate change will bring rising seas, accelerating land loss and worse weather. Read more

Deformation Studies Lead to New Understanding of Materials at Extreme Conditions

DOE/Lawrence Livermore National Laboratory Press Release, 18 Sep 2006 Researchers have found a new tool to explore materials at extreme conditions. By combining very large-scale molecular dynamics simulations with time-resolved data from laser experiments of shock wave propagation through specific metals, scientists at the Lawrence Livermore National Laboratory are now able to better understand the evolution of high-strain-rate plasticity. Read more

From Neuron to Neural Networks Dynamics

by B. Cessac & M. Samuelides arXiv.org E-print Archive, 15 Sep 2006 This paper presents an overview of some techniques and concepts coming from dynamical system theory and used for the analysis of dynamical neural networks models. In a first section, we describe the dynamics of the neuron, starting from the Hodgkin-Huxley description, which is somehow the canonical description for the "biological neuron." We discuss some models reducing the Hodgkin-Huxley model to a two dimensional dynamical system, keeping one of the main feature of the neuron: its excitability. We present then examples of phase diagram and bifurcation analysis for the Hodgin-Huxley equations. Finally, we end this section by a dynamical system analysis for the nervous flux propagation along the axon. We then consider neuron couplings, with a brief description of synapses, synaptic plasticiy and learning, in a second section. We also briefly discuss the delicate issue of causal action from one neuron to another when complex feedback effects and non linear dynamics are involved. The third section presents the limit of weak coupling and the use of normal forms technics to handle this situation. We consider then several examples of recurrent models with different type of synaptic interactions. We introduce various techniques coming from statistical physics and dynamical systems theory. A last section is devoted to a detailed example of recurrent model where we go in deep in the analysis of the dynamics and discuss the effect of learning on the neuron dynamics. We also present recent methods allowing the analysis of the non linear effects of the neural dynamics on signal propagation and causal action. An appendix, presenting the main notions of dynamical systems theory useful for the comprehension of the chapter, has been added for the convenience of the reader. Read more

Coding for Parallel Channels: Gallager Bounds and Applications to Repeat-Accumulate Codes

by Igal Sason & Idan Goldenberg arXiv.org E-print Archive, 18 Sep 2006 This paper is focused on the performance analysis of binary linear block codes whose transmission takes place over independent and memoryless parallel channels. New upper bounds on the maximum-likelihood (ML) decoding error probability are derived. The framework of the second version of the Duman and Salehi (DS2) bounds is generalized to the case of parallel channels, along with the derivation of optimized tilting measures. The connection between the generalized DS2 and the 1961 Gallager bounds, known previously for a single channel, is revisited for the case of parallel channels. The new bounds are used to obtain improved inner bounds on the attainable channel regions under ML decoding. These improved bounds are applied to ensembles of turbo-like codes, focusing on repeat-accumulate codes and their recent variations. Read more

MIT Designs 'Invisible,' Floating Wind Turbines

PhysOrg. com, accessed 18 Sep 2006 An MIT researcher has a vision: four hundred huge offshore wind turbines are providing onshore customers with enough electricity to power several hundred thousand homes, and nobody standing onshore can see them. The trick? The wind turbines are floating on platforms a hundred miles out to sea, where the winds are strong and steady. Read more

'Sticky' Silicon Could Speed Data

BBC News, 18 Sep 2006 Intel researchers have solved a manufacturing problem that has delayed the creation of devices that can both generate and route light. The breakthrough, which revolves around the fusing of the two materials commonly used in computer chips and high-speed optical networks (silicon and indium phosphide), could mean cheaper and higher speed computer networks and help to speed up the transfer of data inside computers. Intel said commercial versions of the hybrid chip may not appear until 2010. Read more

Scientist Plans Tail Prosthetic for Dolphin

USATODAY.com, 15 Sep 2006 The news from Indian River Lagoon was too familiar -- another dolphin gravely injured by human thoughtlessness. But marine scientist Steve McCulloch saw immediately this rescue was unique. The baby bottlenose dolphin -- dubbed Winter -- lost her tail, but maybe her life could be saved. The solution for Winter may be a prosthetic tail. If the logistics can be worked out, Winter's prosthesis would be the first for a dolphin who lost its tail and the key joint that allows it to move in powerful up and down strokes. Read more

Nissan to Test 'Intelligent Transportation' System

PhysOrg.com, accessed 18 Sep 2006 Japanese carmaker Nissan said Friday it will mobilize 10,000 drivers in a 30-month experiment to develop an "intelligent transportation system" that sends wireless messages to passing cars. "Car approaching from left" and "School ahead. Watch your speed," are two voice messages which drivers will receive through the system which uses information obtained from nearby vehicles and roadside optical beacons. The information is received by an onboard antenna on the vehicle to alert drivers to potential danger from approaching vehicles or inform them of traffic congestion ahead. The test will start on October 1 on public roads in Kanagawa, just south of Tokyo, with the number-two Japanese carmaker hoping to commercialize the system in 2010. Read more

The Art of Engineering

NSF News, 11 Sep 2006 On a college campus, it would be difficult to find two subjects more different from each other than art and engineering. Yet on the campus of the University of South Florida, one engineering professor responsible for teaching classes about differential equations and electromagnetism has created a popular course that merges his research world with the world of fine art. Read more

A Chip That Can Transfer Data Using Laser Light

by John Markoff New York Times, 18 Sep 2006 Researchers plan to announce on Monday that they have created a silicon-based chip that can produce laser beams. The advance will make it possible to use laser light rather than wires to send data between chips, removing the most significant bottleneck in computer design. As a result, chip makers may be able to put the high-speed data communications industry on the same curve of increased processing speed and diminishing costs -- the phenomenon known as Moore’s law -- that has driven the computer industry for the last four decades. Read more

Capacity of Flat and Self-Organized Ad Hoc and Hybrid Networks

by Hervé Rivano, Fabrice Theoleyre, & Fabrice Valois arXiv.org E-print Archive, 15 Sep 2006 Ad hoc networking specific challenges foster a strong research effort on efficient protocols design. Routing protocols based on a self-organized structure have been studied principally for the robustness and the scalability they provide. On the other hand, self-organization schemes may decrease the network capacity since they concentrate the traffic on privileged links. This paper presents four models for evaluating the capacity of a routing schemes on 802.11 like networks. Our approach consists in modeling the radio resource sharing principles of 802.11 like MAC protocols as a set of linear constraints. We have implemented two models of fairness. The first one assumes that nodes have a fair access to the channel, while the second one assumes that on the radio links. We then develop a pessimistic and an optimistic scenarii of spatial re-utilization of the medium, yielding a lower bound and an upper bound on the network capacity for each fairness case. Our models are independent of the routing protocols and provide therefore a relevant framework for their comparison. We apply our models to a comparative analysis of the well-known shortest path base flat routing protocol OLSR against two main self-organized structure approaches, VSR, and Wu & Li's protocols. This study concludes on the relevance of self-organized approaches from the network capacity point of view. Read more

Snake-Arm Robots Slither Forward

by Jonathan Fildes BBC News, 13 Sept 2006 Increasingly, precise jobs in difficult-to-reach or hazardous places, are done by robots. The army use them for bomb disposal and space agencies use them to explore distant planets. But many robots are bulky and most are relatively inflexible. To access really difficult parts, engineers must turn to a different breed of machine. Snake-arm robots are lightweight, flexible manipulator arms. They look like a spinal column, made of lots of individual vertebrae, and can contort to any desired shape. One day it is hoped that their slender tentacles could be used to control intricate operations deep within the recesses of the human brain. Read more

The Flow Dimension and Capacity for Structuring Urban Street Networks

by Bin Jiang arXiv.org E-print Archive, 12 Sep 2006 This paper proposes a novel concept of flow to measure the efficiency of urban street networks for travel or shipping goods. More specifically, we define two quantities: flow dimension and flow capacity, to characterize structure of urban street networks. To our surprise for the topologies of urban street networks, previously confirmed as a form of small world and scale-free networks, we find that (1) the range of their flow dimension is rather wider than their random and regular counterparts, (2) their flow dimension shows a power-law distribution, and (3) they has a higher flow capacity than their random and regular counterparts. The findings confirm that (1) the wider range of flow dimension and the higher flow capacity both can be a signature of small world networks, and (2) the flow capacity can be an alternative quantity for measuring the efficiency of networks or that of the individual nodes. The findings are illustrated using three urban street networks (two in the Europe and one in the USA), and three other non-spatial networks. We further conjecture that the flow capacity of living organisms is higher than that of static systems. In other words, living organisms are more efficient than static systems. Read more

Surface Transfer Doping of Semiconductors

by Jürgen Ristein Science, 25 Aug 2006 "Doping" of semiconductors -- that is, the local manipulation of their conductivity -- is a key technology for electronic devices. Without doping, for example, a gallium nitride sample larger than the White House would be needed to host a single mobile charge at room temperature; for diamond, not even the volume of the globe would be sufficient. It is only through doping that semiconductors become useful electronic materials. Recent studies have revealed an unconventional way to achieve doping through surface engineering. Read more

Anomalous Spiral Motion of Steps Near Dislocations on Silicon Surfaces

by J. B. Hannon, V. B. Shenoy, & K. W. Schwarz Science, 1 Sep 2006 We have used low-energy electron microscopy to measure step motion on Si(111) and Si(001) near dislocations during growth and sublimation. Steps on Si(111) exhibit the classic rotating Archimedean spiral motion, however, move in a strikingly different manner. Thestrain-relieving anomalous behavior can be understood in detail by considering how the local step velocity is affected by the nonuniform strain field arising from the dislocation. We show how the dynamic step-flow pattern is related to the dislocation slip system. Read more

Biomass Ethanol to Fuel Honda?

ZDNet News, 14 Sep 2006 Honda Motor on Thursday said it has co-developed the world's first practical process for producing ethanol out of cellulosic biomass in what would be a big step toward using nonedible plant materials as fuel. Honda and partner Research Institute of Innovative Technology for the Earth said the new method allows large volumes of ethanol to be produced from widely available waste wood, leaves, and other so-called soft biomass. Read more

Will Fiber Optics Replace the Lightbulb?

by Michael Kanellos ZDNet News, 31 Aug 2006 The Solon, Ohio-based company has come up with a way to combine industrial-grade lamps with fiber-optic technology to create interior lighting systems that consume far less energy than traditional fluorescent or incandescent bulbs. A single 70-watt metal halide high-intensity discharge lamp from Fiberstars linked to the company's fiber system can provide as much lighting as eight 50-watt incandescent bulbs. Read more

Turbulence Theory Gets a Bit Choppy

by Dan Vergano USATODAY.com, 10 Sep 2006 Turbulence does more than toss around luggage on airplanes and spill coffee on traveler's laps -- it confuses the heck out of scientists. A new experiment may suggest why -- fluid dynamicists may have been missing something fundamental about turbulence for a good long time. Read more

Probing Nanoscale Ferroelectricity by Ultraviolet Raman Spectroscopy

by D. A. Tenne et al. Science, 15 Sep 2006 We demonstrated that ultraviolet Raman spectroscopy is an effective technique to measure the transition temperature (T_c) in ferroelectric ultrathin films and superlattices. We showed that one-unit-cell-thick BaTiO₃ layers in BaTiO₃/SrTiO₃ superlattices are not only ferroelectric (with T_c as high as 250 kelvin) but also polarize the quantum paraelectric SrTiO₃ layers adjacent to them. T_c was tuned by ~500 kelvin by varying the thicknesses of the BaTiO₃ and SrTiO₃ layers, revealing the essential roles of electrical and mechanical boundary conditions for nanoscale ferroelectricity. Read more

Anomalous Resonance in a Nanomechanical Biosensor

by Amit K. Guptaet al. Proceedings of the National Academy of Sciences, 5 Sep 2006 The decrease in resonant frequency of a classical cantilever provides a sensitive measure of the mass of entities attached on its surface. This elementary phenomenon has been the basis of a new class of bio-nanomechanical devices as sensing components of integrated microsystems that can perform rapid, sensitive, and selective detection of biological and biochemical entities. Based on classical analysis, there is a widespread perception that smaller sensors are more sensitive, and this notion has motivated scaling of biosensors to nanoscale dimensions. In this work, we show that the response of a nanomechanical biosensor is far more complex than previously anticipated. Indeed, in contrast to classical microscale sensors, the resonant frequencies of the nanosensor may actually decrease or increase after attachment of protein molecules. We demonstrate theoretically and experimentally that the direction of the frequency change arises from a size-specific modification of diffusion and attachment kinetics of biomolecules on the cantilevers. This work may have broad impact on microscale and nanoscale biosensor design, especially when predicting the characteristics of bio-nanoelectromechanical sensors functionalized with biological capture molecules. Read more

Ultrahigh Frequency Nanotube Resonators

by H. B. Peng et al. Physical Review Letters, 22 Aug 2006 We report carbon-nanotube-based electromechanical resonators with the fundamental mode frequency over 1.3 GHz, operated in air at room temperature. A new combination of drive and detection methods allows for unprecedented measurement of both oscillation amplitude and phase and elucidates the relative mobility of static charges near the nanotube. The resonator serves as an exceptionally sensitive mass detector capable of ~10^-18 g resolution. Read more

Photoinduced Reversible Formation of Microfibrils on a Photochromic Diarylethene Microcrystalline Surface

by Kingo Uchida et al. Angewandte Chemie International Edition, 22 Aug 2006 (online) Scientists in Japan have developed a material that becomes water repellent when it is illuminated with ultraviolet light. The properties of the material mimic those of the lotus blossom -- a flower which is renowned for being immaculately clean. What's more, the effect is reversible as team can switch the material back to its original state using visible light. The secret behind the lotus effect is a special microstructure on the plant's leaves. This structure forces water droplets to form beads which roll off of the surface picking up any dirt particles they encounter. Read more

Nanotube 'Forest' Makes Super Slippery Surface

by Tom Simonite NewScientist.com, 14 Sept 2006 A material less sticky than Teflon has been created by covering a surface with a "forest" of carbon nanotubes. It could find use in the construction of microscopic machines and devices, which are prone to inter-molecular forces. A team of researchers coated a silicon wafer with a layer of upright nanotubes, spaced 100 nanometres apart through a process called chemical vapour deposition. This produced a thick "forest" of tubes, with each tube 1000 nm tall and 100 nm wide. They then used tiny levers to push 5-microns-wide polystyrene beads over the surface. The team repeated the test on flat surfaces of gold, silicon, diamond-like carbon and Teflon. They found the nanotube-covered surface to be four times less sticky than its nearest rival, Teflon. Read more

Intentional Attacks and Protections in Complex Communication Networks

by Shi Xiao & Gaoxi Xiao arXiv.org E-print Archive, 13 Sep 2006 Being motivated by recent developments in the theory of complex networks, we examine the robustness of communication networks under intentional attack that takes down network nodes in a decreasing order of their nodal degrees. In this paper, we study two different effects that have been largely missed in the existing results: (i) some communication networks, like Internet, are too large for anyone to have global information of their topologies, which makes the accurate intentional attack practically impossible; and (ii) most attacks in communication networks are propagated from one node to its neighborhood node(s), utilizing local network-topology information only. We show that incomplete global information has different impacts to the intentional attack in different circumstances, while local information-based attacks can be actually highly efficient. Such insights would be helpful for the future developments of efficient network attack/protection schemes. Read more

A Non-Anchored Unified Naming System for Ad Hoc Computing Environments

by Yoo Chul Chung & Dongman Lee arXiv.org E-print Archive, 13 Sep 2006 A ubiquitous computing environment consists of many resources that need to be identified by users and applications. Users and developers require some way to identify resources by human readable names. In addition, ubiquitous computing environments impose additional requirements such as the ability to work well with ad hoc situations and the provision of names that depend on context. The Non-anchored Unified Naming system was designed to satisfy these requirements. It is based on relative naming among resources and provides the ability to name arbitrary types of resources. By having resources themselves take part in naming, resources are able to able contribute their specialized knowledge into the name resolution process, making context-dependent mapping of names to resources possible. The ease of which new resource types can be added makes it simple to incorporate new types of contextual information within names. In this paper, we describe the naming system and evaluate its use. Read more

Bionic Arm Provides Hope for Amputees

CNN.com, 14 Sep 2006 Jesse Sullivan has two prosthetic arms, but he can climb a ladder at his house and roll on a fresh coat of paint. He's also good with a weed-whacker, bending his elbow and rotating his forearm to guide the machine. He's even mastered a more sensitive maneuver -- hugging his grandchildren. The motions are coordinated and smooth because his left arm is a bionic device controlled by his brain. Doctors describe Sullivan as the first amputee with a thought-controlled artificial arm. Read more

Woman Fitted with 'Bionic' Arm

BBC News, 15 Sept 2006 A former US Marine has become the first woman in the world to be fitted with a "bionic" arm that she can control by her thoughts alone. Claudia Mitchell lost her left arm at the shoulder in a motorbike accident. Her new arm works by detecting movements of a chest muscle that has been connected to the remains of nerves that once went to her real arm. Read more

Power-Grid Blackouts

The September/October issue of IEEE Power & Energy Magazine examines power-grid blackouts and fighting grid failures. Articles in this special feature look at the anatomy of a blackout, the role of measurement systems in postmortem analysis, blackout countermeasures, restoration challenges, and several related topics. Read more

Smart Antennas

The August special issue of IEEE Wireless Communications takes an in-depth look at advances in smart antennas. The issue explores topics such as the industrial embrace of smart antennas and MIMO; coding over space and time for wireless systems; MIMO-OFDM systems: basics, perspectives, and challenges; dynamic multi-user resource allocation and adaptation; the interplay of link layer and physical layer under MIMO enhancement; and network coordination for spectrally efficient communications. Read more

Ultimate Body Armour

by Barry Fox NewScientist.com, 11 Sep 2006 A lightweight bulletproof vest that protects against armour-piercing rounds is being developed by the U.S. government's Army Soldiers System Command. The new vest has three layers: a top ceramic section, a middle layer of aluminium, and bottom layer of woven nylon. The aluminium is pre-scored to define interlocking plugs, like the pieces of a jigsaw. As an armour-piercing bullet hits the top layer, the ceramic strike the aluminium below like a hammer, and frees one of the plugs. When the bullet breaks through the ceramics a split second later it hits the free plug, which wraps round its sharp tip. The bullet then has a wide, soft tip that is easily trapped by the nylon below. In testing, the vest could trap armour-piercing bullets fired at point blank range from a rifle at 850 metres per second. View patent application

Sound Blaster Cleans Contaminated Soil

by Tom Simonite NewScientist.com, 6 Sep 2006 Soil polluted by organic toxins can be blasted clean with ultrasound, say researchers in Australia. The method may prove to be more effective at cleaning up contamination from oil refineries, power stations and aluminium factories than existing methods. The new clean-up method was inspired by the mining industry, which uses ultrasound to process some minerals. Read more

Cooling a Nanomechanical Resonator with Quantum Back-Action

by A. Naik et al. Nature, 14 Sep 2006 Quantum mechanics demands that the act of measurement must affect the measured object. When a linear amplifier is used to continuously monitor the position of an object, the Heisenberg uncertainty relationship requires that the object be driven by force impulses, called back-action. Here we measure the back-action of a superconducting single-electron transistor (SSET) on a radio-frequency nanomechanical resonator. The conductance of the SSET, which is capacitively coupled to the resonator, provides a sensitive probe of the latter's position; back-action effects manifest themselves as an effective thermal bath, the properties of which depend sensitively on SSET bias conditions. Surprisingly, when the SSET is biased near a transport resonance, we observe cooling of the nanomechanical mode from 550 mK to 300 mK -- an effect that is analogous to laser cooling in atomic physics. Our measurements have implications for nanomechanical readout of quantum information devices and the limits of ultrasensitive force microscopy. Furthermore, we anticipate the use of these back-action effects to prepare ultracold and quantum states of mechanical structures, which would not be accessible with existing technology. Read more

Finite Lifetime of Turbulence in Shear Flows

by Björn Hof et al. Nature, 7 Sep 2006 Generally, the motion of fluids is smooth and laminar at low speeds but becomes highly disordered and turbulent as the velocity increases. The transition from laminar to turbulent flow can involve a sequence of instabilities in which the system realizes progressively more complicated states, or it can occur suddenly. Once the transition has taken place, it is generally assumed that, under steady conditions, the turbulent state will persist indefinitely. The flow of a fluid down a straight pipe provides a ubiquitous example of a shear flow undergoing a sudden transition from laminar to turbulent motion. Extensive calculations and experimental studies have shown that, at relatively low flow rates, turbulence in pipes is transient, and is characterized by an exponential distribution of lifetimes. They also suggest that for Reynolds numbers exceeding a critical value the lifetime diverges, marking a change from transient to persistent turbulence. Here we present experimental data and numerical calculations covering more than two decades of lifetimes, showing that the lifetime does not in fact diverge but rather increases exponentially with the Reynolds number. This implies that turbulence in pipes is only a transient event, and that the turbulent and laminar states remain dynamically connected, suggesting avenues for turbulence control. Read more

Industry Contemplates WDM-PON Technology

by Meghan Fuller fibers.org News, 11 Sep 2006 Wavelength-division-multiplexed passive optical networks (WDM-PONs), which offer point-to-point delivery of one wavelength per customer, may eventually supply an optimal fibre-to-the-home architecture. WDM-PON has been positioned as a possible successor to Ethernet/gigabit PON fibre-to-the-home implementations. Though technically feasible, it is still considered too expensive for widespread residential deployment. Some wonder if, at least in the near term, the technology is better suited for commercial service delivery. And one analyst even suggests that WDM-PON might be most suitable for applications typically served by coarse wavelength division multiplexing. Read more

Tiny Fuel Cell Might Replace Batteries in Computers and Electronics

American Chemical Society Press Release, 12 Sep 2006 If you're frustrated by frequently losing battery power in your laptop computer, digital camera or portable music player, then take heart: A better source of "juice" is in the works. Chemists at Arizona State University in Tempe have created a tiny hydrogen-gas generator that they say can be developed into a compact fuel cell package that can power these and other electronic devices -- from three to five times longer than conventional batteries of the same size and weight. Read more

Researchers Simulate Jet Colliding with World Trade Center

Purdue, University News, 11 Sep 2006 Researchers at Purdue University have created a simulation that uses scientific principles to study in detail what likely happened when a commercial airliner crashed into the World Trade Center's North Tower on Sept. 11, 2001. The simulation could be used to better understand which elements in the building's structural core were affected, how they responded to the initial shock of the aircraft collision, and how the tower later collapsed from the ensuing fire fed by an estimated 10,000 gallons of jet fuel. Read more

New Catalyst Removes Perchlorate from Groundwater

University of Illinois at Urbana-Champaign Press Release, 11 Sep 2006 Found in solid-rocket fuel, roadside flares and fireworks, perchlorate is a dangerous contaminant that can disrupt thyroid function by interfering with the uptake of iodine. Infants and fetuses are believed to be particularly at risk from the effects of perchlorate exposure. Because perchlorate is readily soluble in water, it can be transported vast distances in groundwater or rivers. Scientists at the University of Illinois at Urbana-Champaign have developed a new chemical catalyst that uses hydrogen gas to efficiently remove and destroy harmful perchlorate in contaminated groundwater. Read more

Artificial Cornea Is in Sight

by Dawn Levy Stanford Report, 13 Sep 2006 If eyes are "the windows of the soul," corneas are the panes in those windows. They shield the eye from dust and germs. They also act as the eye's outermost lens, contributing up to 75 percent of the eye's focusing power. On Sept. 11 in San Francisco at the annual meeting of the American Chemical Society, chemical engineer Curtis W. Frank presented a novel biomimetic material that's finding its way into artificial corneas. It's a hydrogel, or polymer that holds a lot of water. That material may promise a new view for at least 10 million people worldwide who are blind due to damaged or diseased corneas or many millions more who are nearsighted or farsighted due to misshapen corneas. Read more

University Research Aims at More Secure Wi-Fi

by Jack Shandle EE Times, 1 Sep 2006 Researchers at Carleton University, Ottawa, Canada, have reported positive results for a novel means of securing Wi-Fi and other wireless networks from hackers and other unauthorized intrusion. The technology depends on the RF signal "fingerprints" or profiles that make every wireless transceiver in the world virtually unique. The RF fingerprints are the result of variations in the silicon and other electronic components that comprise the transceiver. Read more

Material Could Help Curb Polysilicon Shortage

by Dylan McGrath EE Times, 5 Sep 2006 Moving to offset the polysilicon shortage increasingly handicapping the semiconductor and solar industries, Dow Corning Corp. introduced a new material designed to enable polysilicon suppliers to squeeze more solar-grade material from existing production lines. PV 1101, derived from metallurgical silicon that exhibits good solar cell performance characteristics when blended with traditional polysilicon feedstock, is the first commercially available feedstock produced from such technology using large scale manufacturing processes. Read more

Topology Control and Network Lifetime in Three-Dimensional Wireless Sensor Networks

by S. M. Nazrul Alam & Zygmunt J. Haas arXiv.org E-print Archive, 11 Sep 2006 Coverage and connectivity issues of three-dimensional (3D) networks are often addressed with the assumption that a node can be placed at any arbitrary location. In this work, we drop that assumption and rather assume that nodes are uniformly and densely deployed in a 3D space. We want to devise a mechanism that keeps some nodes active and puts other nodes into sleep so that the number of active nodes at a time is minimized, while maintaining full coverage and connectivity. One simple way to do that is to partition the 3D space into cells, and only one node in each cell remains active at a time. Our results show that the number of active nodes can be minimized if the shape of each cell is a truncated octahedron. It requires the sensing range to be at least 0.542326 times the transmission radius. This value is 0.5, 0.53452 and 0.5 for cube, hexagonal prism, and rhombic dodecahedron, respectively. However, at a time the number of active nodes for cube, hexagonal prism and rhombic dodecahedron model is respectively 2.372239, 1.82615 and 1.49468 times of that of truncated octahedron model. So clearly truncated octahedron model has the highest network lifetime. We also provide a distributed topology control algorithm that can be used by each sensor node to determine its cell id using a constant number of local arithmetic operations provided that the sensor node knows its location. We also validate our results by simulation. Read more

On Performance of Event-to-Sink Transport in Transmit-Only Sensor Networks

by Bartlomiej Bartek Blaszczyszyn & Bozidar Radunovic arXiv.org E-print Archive, 8 Sep 2006 We consider a hybrid wireless sensor network with regular and transmit-only sensors. The transmit-only sensors do not have receiver circuit, hence are cheaper and less energy consuming, but their transmissions cannot be coordinated. Regular sensors, also called cluster-heads, are responsible for receiving information from transmit-only sensors and forwarding it to sinks. The main goal of such a hybrid network is to reduce the cost of deployment while achieving some performance constraints. In this paper we are interested in the communication between transmit-only sensors and cluster-heads. We develop a detailed analytical model of the physical and MAC layer using tools from queuing theory and stochastic geometry. We give an explicit formula for the frequency of successful packet reception by a cluster-head, given sensors' locations. We further define packet admission policies at a cluster-head, and we calculate the optimal policies for different performance criteria. Finally we show that the proposed hybrid network, using the optimal policies, can achieve substantial cost savings as compared to conventional architectures. Read more

Application Layer Definition and Analyses of Controller Area Network Bus for Wire Harness Assembly Machine

by Hui Guo & Ying Jiang arXiv.org E-print Archive, 31 Aug 2006 With the feature of multi-master bus access, nondestructive contention-based arbitration and flexible configuration, Controller Area Network (CAN) bus is applied into the control system of Wire Harness Assembly Machine (WHAM). To accomplish desired goal, the specific features of the CAN bus is analyzed by compared with other field buses and the functional performances in the CAN bus system of WHAM is discussed. Then the application layer planning of CAN bus for dynamic priority is presented. The critical issue for the use of CAN bus system in WHAM is the data transfer rate between different nodes. So processing efficient model is introduced to assist analyzing data transfer procedure. Through the model, it is convenient to verify the real time feature of the CAN bus system in WHAM. Read more

OSS-Based Grid Computing

by A. Mani arXiv.org E-print Archive, 11 Sep 2006 In this expository paper we will be primarily concerned with core aspects of Grids and Grid computing using open-source software with some emphasis on utility computing. It is based on a technical report entitled 'Grid-Computing Using Linux' by the present author. Read more

GaN/AlGaN Ultraviolet/Infrared Dual-Band Detector

by G. Ariyawansa et al. Applied Physics Letters, 28 Aug 2006 Group III-V wide band gap materials are widely used in developing solar blind, radiation-hard, high speed optoelectronic devices. A device detecting both ultraviolet (UV) and infrared (IR) simultaneously will be an important tool in fire fighting and for military and other applications. Here a heterojunction UV/IR dual-band detector, where the UV/IR detection is due to interband/intraband transitions in the Al_0.026Ga_0.974N barrier and GaN emitter, respectively, is reported. The UV threshold observed at 360 nm corresponds to the band gap of the Al_0.026Ga_0.974N barrier, and the IR response obtained in the range of 8–14 µm is in good agreement with the free carrier absorption model. Read more

Scientists Walk on Tech Pavement

By Elli Leadbeater BBC News, 12 Sep 2006 A giant pavement built in an old warehouse may make frustrating Saturday shopping crushes a thing of the past. Scientists are using the computer-controlled surface to recreate all sorts of pedestrian nightmares. They hope that their hi-tech sidewalk will help to identify what makes for user-friendly surfaces and streets. Read more

Fastest Supercomputer to Be Built

BBC News, 7 Sep 2006 Computer giant IBM will build the world's most powerful supercomputer at a government laboratory. The machine, codenamed Roadrunner, could be four times more potent than the current fastest machine, BlueGene/L, also built by IBM. The new computer is a "hybrid" design, using both conventional supercomputer processors and the new "cell" chip designed for Sony's PlayStation 3. Roadrunner will be installed at the Los Alamos National Laboratory, New Mexico. Read more

There Is No "I" in "Robot"

by Christopher Grau IEEE Intelligent Systems, July/August 2006 In this article, I use the 2004 film "I, Robot" as a philosophical resource for exploring several issues relating to machine ethics. Though I don't consider the film particularly successful as a work of art, it offers a fascinating (and perhaps disturbing) conception of machine morality and raises questions that are well worth pursuing. Through a consideration of the film's plot, I examine the feasibility of robot utilitarians, the moral responsibilities that come with creating ethical robots, and the possibility of a distinct ethic for robot-to-robot interaction as opposed to robot-to-human interaction. Read more

Hydrogen on Track

by Willie Jones IEEE Spectrum Online, accessed 8 Sep 2006 Hydrogen is routinely dismissed as a "decades away" fuel technology for vehicle propulsion. But while much attention has been focused on fuel-cell-powered passenger cars, a little-noticed but promising development has been taking place in rail transportation and heavy industry, where experiments with hydrogen-fuel-cell propulsion are well under way. Read more

New Publication - IEEE Vehicular Technology Magazine

This publication covers theoretical, experimental, application and operational aspects of electrical and electronic engineering relevant to motor vehicles and associated land transportation infrastructure, including mobile radio (technologies appropriate to terrestrial mobile vehicular services), motor vehicles (components, systems and auxiliary functions), land transportation (components and systems used in both automated and non-automated facets of ground transport technology, especially as they relate to vehicular systems). Read more

All-Optical Networks Provide Flexibility for Platforms on the Global Information Grid

by Ketan Patel, Peter Guilfoyle, & Julian Cheng SPIE Newsroom, accessed 8 Sep 2006 The advent of network-centric operations and the Global Information Grid (GIG) -- which provides information storage, management, processing and transport for U.S. defense and security functions -- have highlighted the need for ultra-wide bandwidth networks to efficiently and securely route multigigabit data streams among air, space, and ground platforms. Fiber optics (FO) plays an important role in the GIG: beyond the inherently higher bandwidth as compared to copper cables, the electromagnetic interference immunity and reduced weight of FO will be crucial. Conventional FO-based networks use a star topology in which all transmissions go through a central node and electronic switches dynamically route information based on header information embedded in the data streams. A decentralized network, however, enhances the GIG by enabling asymmetric links as well as broadcast and point-to-point high rate data communication links. These are particularly useful when latency must be managed for mission critical links. Read more

Powerful Nodes Enhance Mobile Network Connectivity

by Xiyu Shi, Christopher Adams, & Ahmet Kondoz SPIE Newsroom, accessed 8 Sep 2006 A mobile ad hoc network (MANET) is a temporary collection of wireless nodes communicating without the benefit of infrastructure. A connection between two nodes may involve several others in what is known as multi-hop routing. MANET can be used in situations in which, for example, soldiers relay and share information on a battlefield or relief workers coordinate efforts during an emergency. Read more

Video-Based Spatial-Optical System for Wireless Communication

by Xin Lin & Hideo Itoh SPIE Newsroom, accessed 8 Sep 2006 Radio and ray are complementary transmission media, and different applications favor the use of one medium or the other. Radio is favored for applications in which user mobility must be maximized or where transmission though walls or over long range is required. For indoor and wireless local-area networks, however, spatial optical communication is an attractive, safe alternative. A number of indoor wireless communications systems using infrared radiation have been proposed. Read more

Military Gigabit Ethernet: A TOE-to-TOE Comparison

by Steve Rood Goldman Military & Aerospace Electronics, August 2006 Ethernet's widespread use and longevity has resulted in an abundance of commercial-off-the-shelf hardware and network application software for military use. Fast Ethernet has been deployed for years and now Gigabit Ethernet is being designed into system upgrades and new weapon systems. The switch to Gigabit Ethernet presents new challenges to achieve the benefits of increased throughput. Read more

Fueling the Future

by Courtney E. Howard Military & Aerospace Electronics, August 2006 The parties involved in the Future Combat Systems (FCS) program -- including the U.S. Army, the Defense Advanced Research Projects Agency (DARPA), and various technology vendors and systems integrators -- are focused on inventing the future. The U.S. Army, with the help of DARPA, is undergoing a significant, structured transformation-which will involve substantial innovations in power-electronics technologies to help fuel the nation's growing appetite for lightweight electronics on the emerging digital battlefield. A123 Systems has worked with the Natick Soldier Center to produce a lithium-ion battery for the Future Force Warrior program. Read more

Eliminating Multipath Fading Improves Wireless Signal Reception

by George W. Webb, Igor Minin, & Oleg Minin SPIE Newsroom, accessed 7 Sep 2006 Dropped mobile phone connections, missing wireless data packets, and lost radio reception at traffic lights are all examples of the problems that can result from multipath fading (MPF). This phenomenon can also produce 'ghost' images in analog television and impair the accuracy of Global Positioning System receivers. Previous attempts to eliminate it have not been completely successful, so we developed a new technique that can drastically reduce MPF and improve signal power by a factor of more than 10³. Read more

Sandia Package to Be Part of NASA Space Station Experiment

Sandia National Laboratories

Press Release, 8 Aug 2006

For the past three years a Sandia research team headed by Mat Celina has been investigating the performance of various piezoelectric polymer films that might one day serve as ultra-light mirrors in space telescopes. In 2007 the research will go one step further when a Labs' experimental package of promising polymers will be part of a NASA experiment on the upcoming Materials International Space Station Experiment to be launched into low Earth orbit. Read more

Improving Thin-Film Solar Cells through Optical Modeling

by Janez Krc, Franc Smole, & Marko Topic SPIE Newsroom, accessed 7 Sep 2006 Thin-film solar cells convert solar energy into electrical energy, but require less material and lower temperatures than their conventional counterparts. Typically, thin-film solar cells comprise semi-transparent layers with thicknesses measured in microns and nanometers. Also, they have textured interfaces that scatter incoming light, prolonging the optical path. This improves light trapping and optical absorption by the layers, ultimately increasing the overall efficiency of solar-to-electric energy conversion. Read more

Humidity Sensors Using Nanofilms Deposited on Hollow Core Fibers

by Ignacio R. Matias et al. SPIE Newsroom, accessed 7 Sep 2006 Hollow core fibers (HCFs), transmit light through a central air hole. Recent developments make HCF technology suitable for detecting moisture, and we are using it to develop relative humidity sensors. HCFs are especially attractive because one can deposit on them nanofilms that make it possible to modulate the so-called evanescent -- that is, highly localized -- electromagnetic field as a function of the external medium. In our work, we coat the fibers with a humidity-sensitive nanofilm whose thickness is the same order of magnitude as that of the evanescent field penetration length. Read more

Simplifying Hybrid Semiconductor-Nanodevice Circuits

by Konstantin Likharev SPIE Newsroom, accessed 7 Sep 2006 The current revolution in information technology arose from exponential progress in integrated circuits thanks largely to miniaturization. Over the next decade, however, that progress looks set to slow, for the following reason. The workhorse device of integrated circuits is the silicon field-effect transistor, which requires accurate lithographic creation of several dimensions, including the length and width of its conducting channel. As these devices are scaled down, quantum-mechanical effects demand increasingly precise lithography, which is much more expensive. At some point, scaling will bring diminishing returns. Unfortunately, alternative electronic devices either run into similar fabrication problems, have lower functionality, or both. Read more

Monitoring the Health of Aeronautical Structures

by Igor Bovio SPIE Newsroom, accessed 7 Sep 2006 Traditional non-destructive tests (NDTs) for assessing damage to aeronautical structures typically include ultrasonic waves or x-rays. These techniques have the disadvantage that they require the disassembly of the part to be tested, expensive equipment, and expert operators. A new NDT, based on vibrational measurements, avoids these drawbacks. Read more

Malicious Nodes Seriously Affect the Performance of Mobile Ad Hoc Networks

by Fanzhi Li & Sabah Jassim SPIE Newsroom, accessed 7 Sep 2006 Wireless ad hoc networks are rapidly gaining popularity as a mode of communication, especially among highly mobile sectors of society. A mobile ad hoc network is formed with wireless mobile devices without the need for existing network infrastructure. As a result, such networks are relatively easy to deploy and use for a very short time, for example, in both personal and business applications. Read more

Carnegie Mellon, General Motors Will Compete in 2007 DARPA Urban Challenge

Carnegie Mellon University Press Release, 31 Aug 2006 Carnegie Mellon University will partner with General Motors Corp. to form Tartan Racing, a team that will enter a driverless Chevy Tahoe in the $2 million Defense Advanced Research Projects Agency Urban Challenge scheduled for November 2007. The race will require autonomous vehicles to travel 60 miles of streets in a mock urban setting. To succeed, vehicles must drive completely on their own -- without drivers or remote control -- and finish the course within six hours. Cars must stay in their lanes, negotiate intersections, drive in traffic and follow rules of the road with only computers at the wheel. Read more

Electrical Measurement of Spin-Wave Interactions of Proximate Spin Transfer Nanooscillators

by M. R. Pufall, W. H. Rippard, & S. E. Russek Physical Review Letters, 23 Aug 2006 We have investigated the interaction mechanism between two nanocontact spin transfer oscillators made on the same magnetic spin valve multilayer. The oscillators phase lock when their precession frequencies are made similar, and a giant magnetoresistance signal is detectable at one contact due to precession at the other. Cutting the magnetic mesa between the contacts with a focused-ion beam modifies the contact outputs, eliminates the phase locking, and strongly attenuates the magnetoresistance coupling, which indicates that spin waves rather than magnetic fields are the primary interaction mechanism. Read more

Polymers Show Promise for Lab-on-a-Chip Technology

University of Alberta Press Release, 30 Aug 2006 Researchers are touting the use of liquid crystalline polymers (LCP) as a viable tool for use in devices such as the sought-after lab-on-a-chip technology. University of Alberta researchers, collaborating with colleagues at the Eindhoven University of Technology and Phillips Research Laboratories in the Netherlands, have shown that LCP, when formed into a thin film on a glass backing, can be fabricated and patterned on a microscale. Read more

High-Performance Steel Used in New Bridge

Northwestern University Press Release, 30 Aug 2006 The Illinois Department of Transportation (IDOT) today announced the completion of a new bridge in Lake Villa, Lake County, IL, constructed with a groundbreaking type of high-performance steel developed by engineering researchers at Northwestern University. About 500 tons of the copper alloy steel, known as ASTM A710 Grade B high-performance structural steel, was used in constructing the 430-foot span that carries IL Rt. 83 over the Canadian National Railroad tracks. Read more

NSF Funding Opportunity - Biomaterials

The focus of the Biomaterials Program is the study of biologically related materials and phenomena, including biological pathways to new materials. The materials and systems of interest include biomolecules, biomolecular assemblies (systems of strongly interacting biomolecules), biomolecular systems (vesicles, membranes, and various other assemblies and networks of biomolecules), and biomimetic, bioinspired, or biocompatible materials. The methods of materials research may be applied to biological systems to discover or understand phenomena and to create or optimize materials. Consistent with DMR’s mission, awards will be in the general areas of biological condensed matter physics and chemistry, and biologically related materials science. Materials-focused proposals for research and education in these areas are encouraged. Read more

Research Grant Available to Promote Technological Literacy

The IEEE Foundation is accepting applications for grants supporting new and innovative projects that seek to improve the worldwide technological literacy of society from childhood through adulthood. The goal of these grants is to motivate middle and high school students to pursue technology related careers, draw attention to the critical need for excellence and diligence in scientific research, and bring together researchers, professionals and students to discuss and identify technological solutions for the needs of the world. Applications submitted before the 16 September deadline will be examined at the November 2006 IEEE Foundation Meeting. Read more

Ethics for Engineers Falls in an Unstructured Gray Zone

by J. Watson IEEE Potentials, July-August 2006 Because engineering is a profession, engineers must consider the impact of ethics in their behavior. The design and application of technology include the responsibility to provide quality products and services. Professional engineering includes the responsibility of creating a positive impact on society and the quality of life. Read more