System for Thermal Management on Aging Military Aircraft

by John McHale Military & Aerospace Electronics, December 2005 Engineers at ISR in Liberty Lake, Wash., are developing next-generation common thermal-management systems for the U.S. Air Force current and future aircraft. Read more

High-Speed Recording Needs More Than Just Storage Capacity

by Ben Ames Military & Aerospace Electronics, December 2005 Applications in airborne intelligence, surveillance, and reconnaissance have always demanded that recording systems capture large amounts of data. Engineers have sought ways to use ruggedized rotating media to replace the more expensive and inflexible solid-state flash memory data-recording systems. Read more

Military Storage Designers Call for Hard Drives

by by Ben Ames Military & Aerospace Electronics, December 2005 Flash memory is getting cheaper, disk drive growth is slowing, but magnetic media is still the best choice for most military and aerospace recording jobs. Read more

Conference Seeks Papers on Diversity in Telecommunications

The 17th Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications has announced a call for papers concerning "diversity in telecommunications." Papers must be submitted by 1 March 2006 and can focus on a broad range of topics, from air-interface technologies to advances in wireless systems and regulation. The conference, one of the premier conferences in wireless research, will take place next September in Helsinki, Finland. Read more

How AWPP Will Make Mesh Networks Easier to Deploy

by Neal Castagnoli Wireless Net DesignLine, 5 Dec 2005 Wireless routing is a key technology enabling the deployment of large wireless mesh networks that expand broadband wireless connectivity from hot “spots" to hot "zones." A new protocol for wireless mesh networks, called the Adaptive Wireless Path Protocol, is expected to play a central role in the building of reliable wireless mesh networks, making them easy to manage and deploy. Read more

Computer-Aided Guidance System Simplifies the Surgical Treatment for Movement Disorders

News-Medical.Net, 21 Nov 2005 Tens of thousands of people who experience movement disorders associated with Parkinson's and a variety of other neurological conditions stand to benefit from a new guidance system that uses computerized brain-mapping techniques to significantly improve an increasingly popular procedure called deep brain stimulation. Read more

The Science of Pseudoscience

by David Kushner IEEE Spectrum Online, December 2005 Hollywood has always been interested in science -- and has employed consultants to get it right throughout most of its history. It's a relationship, though, that has been controversial at times, and in this article we look at how technical advisors resolve the tension between accurate science and dramatic storytelling. Read more

Machine Learning Conference Seeks Papers

Paper submissions to the 2006 IEEE International Workshop on Machine Learning for Signal Processing are due 31 March. The workshop, formerly known as Neural Networks for Signal Processing, seeks papers featuring the latest innovations and newest concepts in signal processing. Authors may focus on an array of signal processing issues, whether pattern recognition and classification, or image and video processing applications. The conference, sponsored by the IEEE Signal Processing Society, will take place this September in Ireland. Read more

Building a Better Snail: Lubrication and Adhesive Locomotion

by Brian Chan, N. J. Balmforth, & A. E. Hosoi Physics of Fluids, November 2005 Many gastropods, such as slugs and snails, crawl via an unusual mechanism known as adhesive locomotion. We investigate this method of propulsion using two mathematical models: one for direct waves and one for retrograde waves. We then test the effectiveness of both proposed mechanisms by constructing two mechanical crawlers. Each crawler uses a different mechanical strategy to move on a thin layer of viscous fluid. The first uses a flexible flapping sheet to generate lubrication pressures in a Newtonian fluid, which in turn propel the mechanical snail. The second generates a wave of compression on a layer of Laponite, a non-Newtonian, finite-yield stress fluid with characteristics similar to those of snail mucus. This second design can climb smooth vertical walls and perform an inverted traverse. Read more

DARPA Eyes Smart, Agile Nets

by Patrick Mannion EE Times, 19 Dec 2005 In an effort to provide reliable and highly available battlefield communications at low system cost, the Defense Advanced Research Projects Agency has launched a program based on the premise that low-cost handsets or nodes can be effective if combined with intelligent, adaptive networks. Read more

Memories Look to New Materials Set

by David Lammers EE Times, 19 Dec 2005 Over the last five years, changes to logic devices have grabbed much of the industry's attention, as copper, low-k dielectrics and strained silicon were introduced to keep scaling on track. Now, memories are set to undergo an equally dramatic series of materials and design changes, ranging from new dielectrics in DRAM and flash to SRAMs with eight transistors per cell. Read more

"Going Back to Our Roots": Second Generation Biocomputing

by Jon Timmis et al. arXiv.org E-orint Archive, 6 Dec 2005 Researchers in the field of biocomputing have, for many years, successfully "harvested and exploited" the natural world for inspiration in developing systems that are robust, adaptable and capable of generating novel and even "creative" solutions to human-defined problems. However, in this position paper we argue that the time has now come for a reassessment of how we exploit biology to generate new computational systems. Previous solutions (the "first generation" of biocomputing techniques), whilst reasonably effective, are crude analogues of actual biological systems. We believe that a new, inherently inter-disciplinary approach is needed for the development of the emerging "second generation" of bio-inspired methods. This new modus operandi will require much closer interaction between the engineering and life sciences communities, as well as a bidirectional flow of concepts, applications and expertise. We support our argument by examining, in this new light, three existing areas of biocomputing (genetic programming, artificial immune systems and evolvable hardware), as well as an emerging area (natural genetic engineering) which may provide useful pointers as to the way forward. Read more

The Hydrogen Gold Rush Is On

by Dan Orzech Wired News, 14 Dec 2005 Move over, Ben Franklin. Todd Livingstone has a plan to solve the energy crisis by capturing huge amounts of energy from lightning. The idea itself is not new. But Livingstone, an inventor and electronics technician from Boston -- the town where Benjamin Franklin was born 300 years ago next month -- has added a unique twist. Using lasers to capture lightning bolts, he wants to channel them through a large tank of water, producing near-limitless amounts of hydrogen. Read more

Honda to Mass Produce Next-Generation Thin Film Solar Cell

PhysOrg.com, 19 Dec 2005 Honda announced its plan to begin mass production in 2007, of an independently developed thin film solar cell composed of non-silicon compound materials, which requires 50% less energy, and thus generate 50% less CO2, during production compared to a conventional solar cell. Read more

Measurement-Induced Entanglement for Excitation Stored in Remote Atomic Ensembles

by C. W. Chou et al. Nature, 8 Dec 2005 A critical requirement for diverse applications in quantum information science is the capability to disseminate quantum resources over complex quantum networks. For example, the coherent distribution of entangled quantum states together with quantum memory (for storing the states) can enable scalable architectures for quantum computation, communication and metrology. Here we report observations of entanglement between two atomic ensembles located in distinct, spatially separated set-ups. Quantum interference in the detection of a photon emitted by one of the samples projects the otherwise independent ensembles into an entangled state with one joint excitation stored remotely in 105 atoms at each site. After a programmable delay, we confirm entanglement by mapping the state of the atoms to optical fields and measuring mutual coherences and photon statistics for these fields. We thereby determine a quantitative lower bound for the entanglement of the joint state of the ensembles. Our observations represent significant progress in the ability to distribute and store entangled quantum states. Read more

Storage and Retrieval of Single Photons Transmitted between Remote Quantum Memories

by T. Chanelière et al. Nature, 8 Dec 2005 An elementary quantum network operation involves storing a qubit state in an atomic quantum memory node, and then retrieving and transporting the information through a single photon excitation to a remote quantum memory node for further storage or analysis. Implementations of quantum network operations are thus conditioned on the ability to realize matter-to-light and/or light-to-matter quantum state mappings. Here we report the generation, transmission, storage and retrieval of single quanta using two remote atomic ensembles. A single photon is generated from a cold atomic ensemble at one site, and is directed to another site through 100 metres of optical fibre. The photon is then converted into a single collective atomic excitation using a dark-state polariton approach. After a programmable storage time, the atomic excitation is converted back into a single photon. This is demonstrated experimentally, for a storage time of 0.5 microseconds, by measurement of an anti-correlation parameter. Storage times exceeding ten microseconds are observed by intensity cross-correlation measurements. This storage period is two orders of magnitude longer than the time required to achieve conversion between photonic and atomic quanta. The controlled transfer of single quanta between remote quantum memories constitutes an important step towards distributed quantum networks. Read more

Natural Polysaccharides as Electroactive Polymers

by Victoria L. Finkenstadt Applied Microbiology and Biotechnology, June 2005 Electroactive polymers (EAPs), a new class of materials, have the potential to be used for applications like biosensors, environmentally sensitive membranes, artificial muscles, actuators, corrosion protection, electronic shielding, visual displays, solar materials, and components in high-energy batteries. The commercialization of synthetic EAPs, however, has so far been severely limited. Biological polymers offer a degree of functionality not available in most synthetic EAPs. Carbohydrate polymers are produced with great frequency in nature. Starch, cellulose, and chitin are some of the most abundant natural polymers on earth. Biopolymers are a renewable resource and have a wide range of uses in nature, functioning as energy storage, transport, signaling, and structural components. In general, electroactive materials with polysaccharide matrices reach conductance levels comparable with synthetic ion-conducting EAPs. This review gives a brief history of EAPs, including terminology, describes evaluation methods, and reports on the current progress of incorporating polysaccharides as matrices for doped, blended, and grafted electroactive materials. Read more

Optimized Interactions for Targeted Self-Assembly: Application to a Honeycomb Lattice

by Mikael C. Rechtsman, Frank H. Stillinger, & Salvatore Torquato Physical Review Letters, 25 Nov 2005 We devise an inverse statistical-mechanical methodology to find optimized interaction potentials that lead spontaneously to a target many-particle configuration. Target structures can possess varying degrees of disorder, thus extending the traditional idea of self-assembly to incorporate both amorphous and crystalline structures as well as quasicrystals. For illustration purposes, our computational technique is applied to yield an optimized isotropic (nondirectional) pair potential that spontaneously yields the three-coordinated honeycomb lattice as the ground state structure in two dimensions. This target choice is motivated by its three-dimensional analog, the diamond lattice, which is known to possess desirable photonic band gap properties. Read more

Rapid Chiral Assembly of Rigid DNA Building Blocks for Molecular Nanofabrication

by R. P. Goodman et al. Science, 9 Dec 2005 Practical components for three-dimensional molecular nanofabrication must be simple to produce, stereopure, rigid, and adaptable. We report a family of DNA tetrahedra, less than 10 nanometers on a side, that can self-assemble in seconds with near-quantitative yield of one diastereomer. They can be connected by programmable DNA linkers. Their triangulated architecture confers structural stability; by compressing a DNA tetrahedron with an atomic force microscope, we have measured the axial compressibility of DNA and observed the buckling of the double helix under high loads. Read more

Fabrication of Three-Dimensional Structures by Three-Photon Polymerization

by M. Farsari, G. Filippidis, & C. Fotakis Optics Letters, 1 Dec 2005 We report the fabrication of three-dimensional structures of submicrometer resolution by three-photon polymerization. This resolution has been achieved by polymerizing ORMOCER, a UV photocurable organic-inorganic hybrid material, with an ultrafast laser irradiation at 1028 nm. To our knowledge, this is the first demonstration of three-photon polymerization, a process that may allow the fabrication of components of very high resolution. Read more

Generating Highly Ordered DNA Nanostrand Arrays

by Jingjiao Guan & L. James Lee Proceedings of the National Academy of Sciences, 20 Dec 2005 Highly ordered arrays of stretched DNA molecules were generated over the millimeter scale by using a modified molecular combing method and soft lithography. Topological micropatterning on polydimethyl siloxane stamps was used to mediate the dynamic assembly of DNA molecules into arranged nonostrand arrays. These arrays consisted of either short nanostrands of several micrometers with fixed length and orientation or long nanostrands up to several hundred micrometers in length. The nanostrand arrays were transferred onto flat solid surfaces by contact printing, allowing for the creation of more complex patterns. This technique has potential applications for the construction of next-generation DNA chips and functional circuits of DNA-based 1D nanostructures. Read more

Routers Bring MPLS into the Access Layer

by Tami Freeman fibers.org News, 29 Nov 2005 Service providers are eagerly deploying MultiProtocol Label Switching (MPLS) in the core and aggregation layers of their optical networks, but its high price-point means that it is often ruled out as an option for the cost-sensitive access arena. That's unfortunate, because settling for traditional Ethernet technologies, such as virtual local-area networks, means the access layer misses out on the resiliency, reliability and scalability that MPLS can bring to Ethernet-based networks. Read more

NPUs Give Flexibility to Carrier Ethernet Design

by Stephen Hardy fibers.org News, 5 Dec 2005 Network processors offer a flexible way to perform a variety of packet-processing functions, including classification, queuing, modification, management and control. But have they got what it takes to become the prevalent choice for the next generation of Carrier Ethernet designs? Read more

GPON vs EPON: The Battle Lines Are Drawn

by Roy Rubenstein fibers.org News, 19 Dec 2005 Carriers looking to deliver the latest broadband services over fibre access have a choice of passive optical network (PON) technologies. Gigabit PON offers greater bandwidth and functionality, but Ethernet PON benefits from maturity. Read more

New Microchip Technology for Medical Imaging Biomarkers of Disease

University of California - Los Angeles UCLA News (online), 15 Dec 2005 A collaboration between scientists at UCLA, Caltech, Stanford, Siemens and Fluidigm have developed a new technology using integrated microfluidics chips for simplifying, lowering the cost and diversifying the types of molecules used to image the biology of disease with the medical imaging technology, Positron Emission Tomography (PET). These molecules are used with PET to diagnostically search throughout the body to look for the molecular errors of disease and to guide the development of new molecular therapeutics. Read more

Direct Observation of Nanocrystallite Buckling in Carbon Fibers under Bending Load

by D. Loidl et al. Physical Review Letters, 25 Nov 2005 Single carbon fibers are deformed in bending by forming loops with varying radius. Position-resolved x-ray diffraction patterns from the bent fibers are collected from the tension to the compression region with a synchrotron radiation nanobeam of 100 nm size from a waveguide structure. A strain redistribution with a shift of the neutral axis is observed. A significant increase of the misorientation of the graphene sheets in the compression region shows that intense buckling of the nanosized carbon crystallites is the physical origin of different tensile and compressive properties. Read more

Organic LEDs Look Forward to a Bright, White Future

by Robert F. Service Science, 16 Dec 2005 If you want to save the world, you might start by getting rid of the light bulb. In the United States alone, lighting sucks up more than 6 quadrillion BTUs of energy every year, 17% of all the energy used in buildings. Incandescent bulbs turn about 90% of that energy into not light but heat. Fluorescents do better, converting 70% of the energy they use into light. But researchers have spent decades working to create novel semiconductor-based light-emitting diodes (LEDs) that do even better. Red LEDs and other colors made from inorganic compounds are already in widespread use in traffic lights, car taillights, and other niche applications. Inorganic white LEDs are also on the market. But so far, all of them remain too costly for general lighting use. Now a new competitor is coming on strong. Read more

Fuel Up With Banana Peels

by Cyrus Farivar Wired News, 2 Dec 2005 Mad scientist Doc Brown powers his time machine by feeding coffee grounds and other biowaste into the DeLorean in "Back to the Future." While time travel is still in the realm of science fiction, carbon-based fuel cells are about to become science fact -- rendering a similar scenario all the more possible. SRI announced in November that it has developed direct carbon fuel-cell technology. Read more

Call for Papers: Robot and Human Interactive Communication

Abstracts for the IEEE International Symposium on Robot and Human Interactive Communication are due by 15 February 2006. Papers can focus on a diversity of Robotics technologies spanning academic, public, and governmental initiatives. For instance, will robots one day be used as assistants to human beings? What future technologies may allow engineers to design such complicated machines? Topics may range from innovative robot designs to ethical issues in human-robot interaction research. The conference will take place next September in Hertfordshire, U.K. Read more

Two RSS Feeds Every IEEE Member Should Know

What's New @ IEEE in Circuits, December 2005 All active IEEE members have full-text access to the contents of IEEE Spectrum and IEEE Potentials magazines through the IEEE Xplore digital library. One way which members can make sure they don't miss an issue of these titles is to subscribe to RSS feeds announcing their latest contents. The feeds can be found at: IEEE Spectrum: http://ieeexplore.ieee.org/rss/TOC6.XML IEEE Potentials: http://ieeexplore.ieee.org/rss/TOC45.XML

Research Firm Claims Optical Silicon Progress

by John Walko EE Times, 28 Nov 2005 Translucent Inc. has demonstrated electroluminescence at telecommunications wavelengths and at room temperature. The company claims this is a ‘major breakthrough’ since it shows advanced photonic devices can be made to work at room temperature in a form of silicon that is compatible with today's mass-produced chips, and more importantly, future silicon electronics technology nodes. Read more

Nodal Quasiparticle in Pseudogapped Colossal Magnetoresistive Manganites

by N. Mannella et al. Nature, 24 Nov 2005 A characteristic feature of the copper oxide high-temperature superconductors is the dichotomy between the electronic excitations along the nodal and antinodal directions in momentum space, generally assumed to be linked to the 'd-wave' symmetry of the superconducting state. Angle-resolved photoemission measurements in the superconducting state have revealed a quasiparticle spectrum with a d-wave gap structure that exhibits a maximum along the antinodal direction and vanishes along the nodal direction. Subsequent measurements have shown that, at low doping levels, this gap structure persists even in the high-temperature metallic state, although the nodal points of the superconducting state spread out in finite 'Fermi arcs'. This is the so-called pseudogap phase, and it has been assumed that it is closely linked to the superconducting state, either by assigning it to fluctuating superconductivity or by invoking orders which are natural competitors of d-wave superconductors. Here we report experimental evidence that a very similar pseudogap state with a nodal–antinodal dichotomous character exists in a system that is markedly different from a superconductor: the ferromagnetic metallic groundstate of the colossal magnetoresistive bilayer manganite La_1.2Sr_1.8Mn₂O₇. Our findings therefore cast doubt on the assumption that the pseudogap state in the copper oxides and the nodal-antinodal dichotomy are hallmarks of the superconductivity state. Read more

Organize Tours to Technical Facilities

by Kathy Kowalenko The Institute, December 2005 Engineers are an inquisitive lot; they like to know how things work. The IEEE’s local organizations can help feed that curiosity by arranging tours of nearby technical facilities, such as manufacturing and electric power plants, satellite ground stations, and telecommunications facilities. Members -- and nonmembers, who are also welcome to come along -- learn about equipment they may have wondered about, and they may also have the opportunity to meet with an organization’s top management, which sometimes can even lead to a new job. Read more

Adding Ethics to Engineering Education

by Willie D. Jones The Institute, December 2005 Imagine this scenario: you’ve just joined a company competing for a government contract to build a military bomber. But the plane would have to fly so fast that it pushes its envelope of safety. The project manager of your engineering team quits because he believes the design is not safe. The company asks you to take over his job. Knowing that your company’s financial future depends on getting this contract, would you give the project the green light or refuse the promotion? In handling such an ethical dilemma, engineers can’t rely on instinct alone. They need training that can help them balance considerations such as the health, safety, and welfare of the public with technical concerns. Read more

When Chaos Meets Computers

by Shujun Li arXiv.org E-print Archive, 12 Dec 2005 This paper focuses on an interesting phenomenon when chaos meets computers. It is found that digital computers are absolutely incapable of showing true long-time dynamics of some chaotic systems, including the tent map, the Bernoulli shift map and their analogues, even in a high-precision floating-point arithmetic. Although the results cannot directly generalized to most chaotic systems, the risk of using digital computers to numerically study continuous dynamical systems is shown clearly. As a result, we reach the old saying that "it is impossible to do everything with computers only." Read more

The Role of Quantum Interference in Quantum Computing

by A.Y. Shiekh arXiv.org E-print Archive, 11 Dec 2005 Quantum interference is proposed as a tool to augment Quantum Computation. Read more

Capacity of Differential Versus Non-Differential Unitary Space-Time Modulation for MIMO Channels

by Aris L. Moustakas, Steven H. Simon, & Thomas L. Marzetta arXiv.org E-print Archive, 12 Dec 2005 Differential Unitary Space-Time Modulation (DUSTM) and its earlier nondifferential counterpart, USTM, permit high-throughput MIMO communication entirely without the possession of channel state information (CSI) by either the transmitter or the receiver. For an isotropically random unitary input we obtain the exact closed-form expression for the probability density of the DUSTM received signal, which permits the straightforward Monte Carlo evaluation of its mutual information. We compare the performance of DUSTM and USTM through both numerical computations of mutual information and through the analysis of low- and high-SNR asymptotic expressions. In our comparisons the symbol durations of the equivalent unitary space-time signals are both equal to T, as are the number of receive antennas N. For DUSTM the number of transmit antennas is constrained by the scheme to be M = T/2, while USTM has no such constraint. If DUSTM and USTM utilize the same number of transmit antennas at high SNR's the normalized mutual information of the differential and the nondifferential schemes expressed in bits/sec/Hz are asymptotically equal, with the differential scheme performing somewhat better, while at low SNR's the normalized mutual information of DUSTM is asymptotically twice the normalized mutual information of USTM. If, instead, USTM utilizes the optimum number of transmit antennas then USTM can outperform DUSTM at sufficiently low SNR's. Read more

Mobile WiMAX Gets Seal of Approval from IEEE

Compound Semiconductor News, 13 Dec 2005 In a move that should help the development of broadband wireless access (BWA) systems across the globe, the IEEE has approved the 802.16e WiMAX standard. RF chipmakers will welcome the move, which extends the existing 802.16 standard to include combined fixed and mobile BWA subscriber stations moving at speeds typical of car travel. Mobile WiMAX will operate in licensed bands below 6 GHz. Read more

Robot Chopper Documents Katrina's Power

by Marsha Walton CNN.com, 9 Dec 2005 Kevin Pratt communicated with the other members of the helicopter flight team to shoot the best angles of video of two Katrina damaged structures. What was unique about this flight? The four-person crew was on the ground, while the camera-carrying, 10-pound robotic aircraft flew around the buildings. Read more

Femtosecond Imaging of Surface Plasmon Dynamics

by Atsushi Kubo et al.

SPIE Nanotechnology E-Newsletter, December 2005

Light interacting with nanostructured metals excites collective charge-density fluctuations known as surface plasmons (SP). Through excitation of SP eigenmodes, incident light is trapped on nanometer spatial and femtosecond temporal scales and its field is enhanced. Excitation of SP resonances leads to extraordinary physical phenomena including the anomalous transmission of light through sub-wavelength aperture arrays and the enhancement of nonlinear optical processes. Recently, the prospect of plasmonic devices has stimulated considerable effort to understand the fundamental dynamics of SPs and to develop practical applications such as ultra-sensitive chemical sensors and sub-wavelength optics. Read more

Supercritical Fluid Deposition of Nanowire Building Blocks

by Donna C. Arnold & Justin D. Holmes SPIE Nanotechnology E-Newsletter, December 2005

Moore’s Law is the beating heart at the centre of this industry, driving business growth through the technological realization of new process technologies that double the number of transistors on a chip about every two years. However, as the semiconductor industry continues to miniaturize in following Moore’s Law, there are some real challenges ahead, particularly in moving deeper and deeper into the nano-length scale. Sustaining the traditional logic MOSFET (metal-oxidesemiconductor field-effect transistor) structure, design, and material composition will be especially difficult beyond 22nm. The next technology standard is a 9nm physical gate length, predicted to be reached in 2016 according to the International Technology Roadmap for Semiconductors, and as early as 2011 according to some company roadmaps. There is even the question of how far silicon charge-based logic MOSFET transistor devices can be scaled. The semiconductor sector of the ICT industry is therefore actively chasing solutions that can fulfill the Moore criteria. Read more

Getting a Grip on the Grid

by Vahid Mahani & Damir Novosel IEEE Spectrum, December 2005 Arguably, the most complex and tightly coupled systems ever constructed for use in daily life are those making up the interconnected electric power grid, which is by its nature vulnerable to system accidents. When such accidents are rife, they must be regarded as the symptom of inadequate grid design and management, itself a product of a bad system of incentives. Tellingly, expert groups investigating Italy’s nationwide blackout of 28 September 2003 and the northeastern North American blackout of 14 August 2003 reached very similar conclusions about their underlying causes. What is more, if recommendations made following the three major western North American blackouts between 1994 and 1996 had been followed, the effects of the 2003 outages would have been far less severe. Read more

Earthquake Alarm

by Tom Bleier & Friedemann Freund IEEE Spectrum, December 2005 It seems that earthquakes should be predictable. After all, we can predict hurricanes and floods using detailed satellite imagery and sophisticated computer models. Using advanced Doppler radar, we can even tell minutes ahead of time that a tornado will form. Accurate earthquake warnings are, at last, within reach. They will come not from the mechanical phenomena -- measurements of the movement of the earth’s crust -- that have been the focus of decades of study, but, rather, from electromagnetic phenomena. And, remarkably, these predictions will come from signals gathered not only at the earth’s surface but also far above it, in the ionosphere. Read more

The Chemistry of Deformation: How Solutes Soften Pure Metals

by Dallas R. Trinkle & Christopher Woodward Science, 9 Dec 2005 Solutes have been added to strengthen elemental metals, generating usable materials for millennia; in the 1960s, solutes were found to also soften metals. Despite the empirical correlation between the "electron number" of the solute and the change in strength of the material to which it is added, the mechanism responsible for softening is poorly understood. Using state-of-the-art quantum-mechanical methods, we studied the direct interaction of transition-metal solutes with dislocations in molybdenum. The interaction increases dramatically with increasing electron number and strongly influences the mechanisms responsible for plasticity in these materials. Our quantitative model explains solution softening of metals by using changes in energy and stress scales of plasticity from solutes. Read more

Mach-Zehnder Interferometry in a Strongly Driven Superconducting Qubit

by William D. Oliver et al. Science, 9 Dec 2005 We demonstrate Mach-Zehnder–type interferometry in a superconducting flux qubit. The qubit is a tunable artificial atom, the ground and excited states of which exhibit an avoided crossing. Strongly driving the qubit with harmonic excitation sweeps it through the avoided crossing two times per period. Because the induced Landau-Zener transitions act as coherent beamsplitters, the accumulated phase between transitions, which varies with microwave amplitude, results in quantum interference fringes for n = 1 to 20 photon transitions. The generalization of optical Mach-Zehnder interferometry, performed in qubit phase space, provides an alternative means to manipulate and characterize the qubit in the strongly driven regime. Read more

IBM, AMD Further Cut Chip Power Consumption

by Michael Kanellos ZDNet News, 6 Dec 2005 IBM and Advanced Micro Devices are stressing out their chips. The companies, allies in developing semiconductor manufacturing technology, will present two papers at a chip conference this week outlining how they have reduced power consumption on chips made on the 65-nanometer process. Read more

Sun Powers Pontoon Boat

by Stephen Leahy Wired News, 2 Dec 2005 The Gisborne family got a free ride, energy-wise, on a recent six-day boating cruise along Ontario's scenic Trent-Severn Waterway. Their eight-seat pontoon boat called The Loon is solar-electric. On overcast days, eight 6-volt batteries kept them clipping along all day at 5 knots (6 mph). At night, The Loon was plugged into standard electrical outlets at local marinas to recharge its batteries. Read more

Fido's First Cell Phone

by Jenn Shreve Wired News, 6 Dec 2005 Lost dog? As of next March, pet owners will be able to drop the photocopier and staple gun and pick up the phone instead. That's when PetCell, the first cell phone for dogs, is due to hit pet-store shelves. Read more

Processing Techniques for Deoxyribonucleic Acid: Biopolymer for Photonics Applications

by Emily M. Heckman et al. Applied Physics Letters, 21 Nov 2005 Marine-based deoxyribonucleic acid (DNA), purified from waste products of the Japanese fishing industry, has recently become a material of interest in photonics applications. Using highly purified DNA, unique processing techniques developed specifically to transform the purified DNA into a biopolymer suitable for optical device fabrication are reported. Read more

Myriad Mirrors Turn Desert into Energy Farm

New Scientist, 26 Nov 2005 Giant mirrors will blanket thousands of hectares of desert in California as part of the two largest solar farms in the world. The farms will use 11-metre-wide dishes coated with an array of glass mirrors. Made by Stirling Energy Systems in Phoenix, Arizona, each dish will focus the sun's rays onto a 750-kilogram engine containing metal piston cylinders filled with hydrogen. As the gas heats to 720 °C, it expands, driving the piston before flowing out as the piston drops down and cool gas flows in. This drives a generator, converting solar energy to electricity at around 30 per cent efficiency. The farms are due to join the grid by 2009. A 20,000- dish array in the desert near Los Angeles will produce 500 megawatts, while a smaller array near San Diego will generate 300 Mw.

Cave Mapping

by Barry Fox NewScientist.com, 29 Nov 2005 Pursuing a suspect through an underground tunnel or cave is dangerous work for the police or military. But a system being developed at the University of Denver could make their lives a whole lot easier. Revealed in a recent patent finding, the system uses faint sound resonances to build a map of a hidden chamber and locate anyone hiding inside. Low frequency noise -- between 1 and 200 hertz -- is fed into the tunnel from a loudspeaker placed at its mouth. The cavity will then resonate at different strengths and frequencies depending on its shape. A microphone detects these resonances and a connected computer converts the audio information into a map showing the size and shape of the chamber on a screen. If anyone is hiding inside, their movement should alter the reflection pattern and thus changes the resonant spectrum. Tests show that the system works even when the person hiding is just 1/500th of the volume of the entire chamber. And the system should get more accurate with the creation of a database of resonant patterns relating to different cavity shapes. Read the cave mapping patent

Hot-Air Plane

by Barry Fox NewScientist.com, 29 Nov 2005 A drone aircraft powered by a 200-year-old engine design is the latest concept under wraps at Lawrence Livermore National Laboratory in California. The Stirling engine uses temperature difference to activate its gas-filed pistons. The engine is efficient at generating mechanical power, although slow. But the lab thinks it could be ideal for use in a solar-powered aircraft that needs to fly throughout the night on stored energy. Instead of using solar cells to convert sunlight to electricity, and storing this in rechargeable batteries, the new plane will use a thermal battery that stores heat in order to drive its Stirling engine. During the day, sunlight will be used to heat a mix of lithium and lithium hydride and a moving parabolic mirror will keep track of the Sun to focus its rays on the thermal store. While the Sun's rays will provide heat for the engine's gas, the cold air outside the plane will provide an ideal way of lowering its temperature. Read the hot-air plane patent

Robots Aim to Explore and Build on Other Worlds

by Maggie McKee NewScientist.com, 2 Dec 2005 NASA is offering two new $250,000 prizes to stimulate advances in the use of robots in planetary exploration and automated construction. Read more

Quantum Bubbles Are the Key

by Marcus Chown New Scientist, 26 Nov 2005 As futuristic as quantum computers seem, what with all those qubits and entangled atoms, here is an idea that promises to make atom-based quantum computers look passé even before anyone has built a full-sized version. It seems that bubbles of electrons lined up in ultracold liquid helium could be used to build a quantum computer capable of carrying out a staggering 1030 simultaneous calculations. Read more

A Cool Way to Soup Up a Supercomputer

by Celeste Biever New Scientist, 26 Nov 2005 A slender card that slides into a PC will more than double the speed of the world's fastest supercomputing PC cluster while only fractionally increasing its power consumption. The 30-centimetre booster card, called Advance, can also be used with high-end graphics or scientific PCs to quadruple their speed at certain heavy-duty calculations. Read more

Origin of the Metallic Properties of Heavily Boron-Doped Superconducting Diamond

by T. Yokoya et al. Nature, 1 Dec 2005 The physical properties of lightly doped semiconductors are well described by electronic band-structure calculations and impurity energy levels. Such properties form the basis of present-day semiconductor technology. If the doping concentration n exceeds a critical value n_c, the system passes through an insulator-to-metal transition and exhibits metallic behaviour; this is widely accepted to occur as a consequence of the impurity levels merging to form energy bands. However, the electronic structure of semiconductors doped beyond n_c have not been explored in detail. Therefore, the recent observation of superconductivity emerging near the insulator-to-metal transition in heavily boron-doped diamond has stimulated a discussion on the fundamental origin of the metallic states responsible for the superconductivity. Two approaches have been adopted for describing this metallic state: the introduction of charge carriers into either the impurity bands or the intrinsic diamond bands. Here we show experimentally that the doping-dependent occupied electronic structures are consistent with the diamond bands, indicating that holes in the diamond bands play an essential part in determining the metallic nature of the heavily boron-doped diamond superconductor. This supports the diamond band approach and related predictions, including the possibility of achieving dopant-induced superconductivity in silicon and germanium. It should also provide a foundation for the possible development of diamond-based devices. Read more

NPUs Give Flexibility to Carrier Ethernet Design

by Stephen Hardy fibers.org News, 5 Dec 2005 Network processors offer a flexible way to perform a variety of packet-processing functions, including classification, queuing, modification, management and control. But have they got what it takes to become the prevalent choice for the next generation of Carrier Ethernet designs? Read more

Saving Soldiers

Georgia Tech Research News, 6 Dec 2005 Professor Robert Speyer and his research team have created a new boron carbide formation process. The method yields higher relative densities -- thus better ballistic performance -- than currently available boron carbide armor. Read more

Distributed and Multithreaded Neural Event-Driven Simulation Framework

by Anthony Mouraud, Didier Puzenat, & Hélène Paugam-Moisy arXiv.org E-print Archive, 5 Dec 2005 In a Spiking Neural Networks (SNN), spike emissions are sparsely and irregularly distributed both in time and in the network architecture. Since a current feature of SNNs is a low average activity, efficient implementations of SNNs are usually based on an Event-Driven Simulation (EDS). On the other hand, simulations of large scale neural networks can take advantage of distributing the neurons on a set of processors (either workstation cluster or parallel computer). This article presents a large scale SNN simulation framework able to gather the benefits of EDS and parallel computing. Two levels of parallelism are combined: Distributed mapping of the neural topology, at the network level, and local multithreaded allocation of resources for simultaneous processing of events, at the neuron level. Based on the causality of events, a distributed solution is proposed for solving the complex problem of scheduling without synchronization barrier. Read more

A Practical Approach to Joint Network-Source Coding

by Nima Sarshar & Xiaolin Wu arXiv.org E-print Archive, 5 Dec 2005 We are interested in how to best communicate a real valued source to a number of destinations (sinks) over a network with capacity constraints in a collective fidelity metric over all the sinks, a problem which we call joint network-source coding. It is demonstrated that multiple description codes along with proper diversity routing provide a powerful solution to joint network-source coding. A systematic optimization approach is proposed. It consists of optimizing the network routing given a multiple description code and designing optimal multiple description code for the corresponding optimized routes. Read more

A Game-Theoretic Approach to Energy-Efficient Power Control in Multi-Carrier CDMA Systems

by Farhad Meshkati et al. arXiv.org E-print Archive, 3 Dec 2005 A game-theoretic model for studying power control in multi-carrier CDMA systems is proposed. Power control is modeled as a non-cooperative game in which each user decides how much power to transmit over each carrier to maximize its own utility. The utility function considered here measures the number of reliable bits transmitted over all the carriers per Joule of energy consumed and is particularly suitable for networks where energy efficiency is important. The multi-dimensional nature of users' strategies and the non-quasiconcavity of the utility function make the multi-carrier problem much more challenging than the single-carrier or throughput-based-utility case. It is shown that, for all linear receivers including the matched filter, the decorrelator, and the minimum-mean-square-error detector, a user's utility is maximized when the user transmits only on its "best" carrier. This is the carrier that requires the least amount of power to achieve a particular target signal-to-interference-plus-noise ratio at the output of the receiver. The existence and uniqueness of Nash equilibrium for the proposed power control game are studied. In particular, conditions are given that must be satisfied by the channel gains for a Nash equilibrium to exist, and the distribution of the users among the carriers at equilibrium is also characterized. In addition, an iterative and distributed algorithm for reaching the equilibrium (when it exists) is presented. It is shown that the proposed approach results in significant improvements in the total utility achieved at equilibrium compared to a single-carrier system and also to a multi-carrier system in which each user maximizes its utility over each carrier independently. Read more

Has Tallest Tower Caused More Quakes?

CNN.com, 3 Dec 2005 Seismic activity in Taipei has increased since the world's tallest building, Taipei 101, was built, raising questions over whether the Taiwan capital has become more vulnerable to earthquakes, a geologist said on Friday. According to Lin Cheng-horng, a geologist at the Institute of Earth Sciences at Taiwan's most prestigious think tank, the Academia Sinica, "There is a distinct possibility of earthquakes being triggered by the recent construction of the world's highest building, the imposing Taipei 101." Read more

NSF Says Science and Engineering Doctorates Are Up for Second Year in a Row

According to new survey results, the number of Ph.D. degrees granted in science and engineering fields has increased for the second year in a row. Despite the gains, the 26,275 Ph.D. degrees earned in the 2004 academic year -- the period the survey covers -- are still shy of the 1998 peak of 27,278. Read more

String Theory Meets Practice as Violinmakers Rethink Their Craft

by Adrian Cho Science, 2 Dec 2005 A little thin down low, the sound of the violin blossoms as Bach's unaccompanied sonata in C major wends into the upper registers. Close your eyes, and you can almost see the instrument making the bright, crystalline sound, its classic form curving as gracefully as the music, its amber finish enriched with nicks and scrapes accumulated over the centuries, its compact body resonating with the very emotion of the soloist. It may be best to keep your eyes closed, however. The instrument looks less like a violin than a model airplane gone horribly wrong, and it's hard to reconcile the beauty of the sound with the device's homely appearance. Read more

Electrowetting in Carbon Nanotubes

by J. Y. Chen et al. Science, 2 Dec 2005 We demonstrate reversible wetting and filling of open single-wall carbon nanotubes with mercury by means of electrocapillary pressure originating from the application of a potential across an individual nanotube in contact with a mercury drop. Wetting improves the conductance in both metallic and semiconducting nanotube probes by decreasing contact resistance and forming a mercury nanowire inside the nanotube. Molecular dynamics simulations corroborate the electrocapillarity-driven filling process and provide estimates for the imbibition speed and electrocapillary pressure. Read more

Strength in Numbers

by Gene Klager oemagazine, November/December 2005

High-quality situational awareness is critical to the continued existence of a medium-weight force that cannot depend on extensive armor for survival. Current reconnaissance, surveillance, and target-acquisition (RSTA) capabilities are not sufficient to cover intelligence gaps or provide the beyond-line-of-sight (BLOS) targeting and ambush avoidance that are necessary for combat forces operating in complex terrain and urban areas near enemy forces. Networked Sensors for the Future Force is a U.S. Army program designed to develop and demonstrate a new generation of networked, low-cost, distributed unmanned sensor systems. The goal of the program is to extend the eyes and ears of the RSTA element to provide BLOS situational understanding and targeting information.

Read more