Understanding Widely Scattered Traffic Flows, the Capacity Drop, Platoons, and Times-to-Collision as Effects of Variance-Driven Time Gaps

by Martin Treiber, Arne Kesting, & Dirk Helbing arxiv.org E-print Archive, 30 Aug 2005 We investigate the adaptation of the time headways in car-following models as a function of the local velocity variance, which is a measure of the inhomogeneity of traffic flow. We apply this mechanism to several car-following models and simulate traffic breakdowns in open systems with an on-ramp as bottleneck. Single-vehicle data generated by several 'virtual detectors' show a semi-quantitative agreement with microscopic data from the Dutch freeway A9. This includes the observed distributions of the net time headways and times-to-collision for free and congested traffic. While the times-to-collision show a nearly universal distribution in free and congested traffic, the modal value of the time headway distribution is shifted by a factor of about two in congested conditions. Macroscopically, this corresponds to the 'capacity drop' at the transition from free to congested traffic. Finally, we explain the wide scattering of one-minute flow-density data by a self-organized variance-driven process that leads to the spontaneous formation and decay of long-lived platoons even for deterministic dynamics on a single lane. Read more

On the Origin of Non-Gaussian Statistics in Hydrodynamic Turbulence

by C. Meneveau & Y. Li arxiv.org E-print Archive, 29 Aug 2005 Turbulent flows are notoriously difficult to describe and understand based on first principles. One reason is that turbulence contains highly intermittent bursts of vorticity and strain-rate with highly non-Gaussian statistics. Quantitatively, intermittency is manifested in highly elongated tails in the probability density functions of the velocity increments between pairs of points. A long-standing open issue has been to predict the origins of intermittency and non-Gaussian statistics from the Navier-Stokes equations. Here we derive, from the Navier-Stokes equations, a simple nonlinear dynamical system for the Lagrangian evolution of longitudinal and transverse velocity increments. From this system we are able to show that the ubiquitous non-Gaussian tails in turbulence have their origin in the inherent self-amplification of longitudinal velocity increments, and cross amplification of the transverse velocity increments. Read more

Breakthrough in Development of Quantum Computers

PhysOrg.com, 31 Aug 2005 Hitachi Europe Ltd. announced today that a Hitachi-Cambridge team has developed a new silicon device for quantum computing: a quantum-dot charge qubit. This structure, based on years of work on single-electronics, is the first step in the development of a quantum computer based on conventional silicon technology. Read more

Adaptive Scanning Optical Microscope: A Multidisciplinary Optical Microscope Design for Large Field of View and High Resolution Imaging

by Benjamin Potsaid, Yves Bellouard, & John T. Wen Optics Express, 22 Aug 2005 From micro-assembly to biological observation, the optical microscope remains one of the most important tools for observing below the threshold of the naked human eye. However, in its conventional form, it suffers from a trade-off between resolution and field of view. This paper presents a new optical microscope design that combines a high speed steering mirror, a custom designed scanner lens, a MEMS deformable mirror, and additional imaging optics to enlarge the field of view while preserving resolving power and operating at a high image acquisition rate. We describe the theory of operation and our design methodology, present a preliminary simulated design, and compare to existing technologies. A reduced functionality experimental prototype demonstrates both micro-assembly and biological observation tasks. Read more

A Doll That Can Recognize Voices, Identify Objects and Show Emotion

by Michel Marriott New York Times, 25 Aug 2005 Judy Shackelford, who has been in the toy industry for more than 40 years, has seen a lot of dolls. But none, she says, like her latest creation, a marvel of digital technologies, including speech-recognition and memory chips, radio frequency tags and scanners, and facial robotics. She and her team have christened it Amazing Amanda. Read more

Scale Buildings in a Single Bound

by David Cohen NewScientist.com, 26 Aug 2005 Spiderman does it, so does James Bond. Now a gadget has been developed to allow US marines to zip up the sides of buildings or ships with virtually no effort. All you do is fire a rope to the top of the structure using a harpoon gun or grappling hook, and then fit the rope into the device, called PowerQuick, which attaches to your climbing harness. Then just sit back and squeeze a lever. Read more

Drivers to Get Perfect View in the Wet

New Scientist, 3 Sep 2005 A nanoparticle silica coating could prevent car windows fogging up, making driving safer. Windows fog up when water droplets condense onto glass, forming tiny beads that scatter light. For obvious reasons this can make driving hazardous. "Our coating is made up of super-water-loving particles," says developer Michael Rubner of MIT. "These suck in the water, forcing the droplets to flatten over the surface as a sheet, so they no longer scatter light." The transparent coating should permanently prevent fogging, says Rubner. And at only 100 nanometres thick, it uses very little material and so should be cheap, he adds. The coating, which should be available in two to five years, can also be engineered to maximise the amount of light passing through -- an effect that could be used in solar panels.

Robotic Spy-Planes Use Shape-Shifting Wings

by Duncan Graham-Rowe NewScientist.com , 25 Aug 2005 Small robotic spy-planes have been developed that use shape-shifting wings to switch from being stable gliders to ultra-manoeuvrable fliers. The articulated wings -- with a span of 60 centimetres -- were inspired by the way seagulls alter their wing-shape during flight. Read more

Quantum Computing Switches Wavelengths

New Scientist, 3 Sep 2005 Future networks of quantum computers will have to both store quantum information and move it from place to place. Doing both at once may be easier now that physicists have learned how to transfer information between photons that have different wavelengths. Researchers already know how to store bits of quantum information -- or "qubits" -- in the states of atoms. Information can be recorded by making an atom absorb a photon, and this works best for photons of wavelength roughly 800 nanometres. But unfortunately, this wavelength isn't very useful for transmitting information: standard fibre-optic cables work best with wavelengths of roughly 1300 nm. Now physicist Sébastien Tanzilli and colleagues at the University of Geneva in Switzerland have now found a way to overcome this mismatch, by showing how to transfer a qubit between photons of different wavelengths. Using a nonlinear crystal that forces photons of different wavelengths to interact, the team showed that they can make an incoming photon of wavelength about 1300 nm transfer its information to another photon of about 710 nm.

Nanorings Hook Up

by Rosamund Daw Nature Materials Update, 25 August 2005 Scientists have dreamed up a complex carbon nanostructure -- resembling chainmail -- and have tested its properties using molecular dynamics simulations. Although clearly difficult to construct, if achieved, such materials could remove the necessity for adhesive resins of composites, which may compromise the potential weight and strength benefits predicted using nanostructures. Read more

A Photonic Quantum Information Interface

by S. Tanzilli et al. Nature, 1 Sep 2005 Quantum communication requires the transfer of quantum states, or quantum bits of information (qubits), from one place to another. From a fundamental perspective, this allows the distribution of entanglement and the demonstration of quantum non-locality over significant distances. Within the context of applications, quantum cryptography offers a provably secure way to establish a confidential key between distant partners. Photons represent the natural flying qubit carriers for quantum communication, and the presence of telecommunications optical fibres makes the wavelengths of 1,310 nm and 1,550 nm particularly suitable for distribution over long distances. However, qubits encoded into alkaline atoms that absorb and emit at wavelengths around 800 nm have been considered for the storage and processing of quantum information. Hence, future quantum information networks made of telecommunications channels and alkaline memories will require interfaces that enable qubit transfers between these useful wavelengths, while preserving quantum coherence and entanglement. Here we report a demonstration of qubit transfer between photons of wavelength 1,310 nm and 710 nm. The mechanism is a nonlinear up-conversion process, with a success probability of greater than 5 per cent. In the event of a successful qubit transfer, we observe strong two-photon interference between the 710 nm photon and a third photon at 1,550 nm, initially entangled with the 1,310 nm photon, although they never directly interacted. The corresponding fidelity is higher than 98 per cent. Read more

A General Strategy for Nanocrystal Synthesis

by Xun Wang et al. Nature, 1 Sep 2005 New strategies for materials fabrication are of fundamental importance in the advancement of science and technology. Organometallic and other organic solution phase synthetic routes have enabled the synthesis of functional inorganic quantum dots or nanocrystals. These nanomaterials form the building blocks for new bottom-up approaches to materials assembly for a range of uses; such materials also receive attention because of their intrinsic size-dependent properties and resulting applications. Here we report a unified approach to the synthesis of a large variety of nanocrystals with different chemistries and properties and with low dispersity; these include noble metal, magnetic/dielectric, semiconducting, rare-earth fluorescent, biomedical, organic optoelectronic semiconducting and conducting polymer nanoparticles. This strategy is based on a general phase transfer and separation mechanism occurring at the interfaces of the liquid, solid and solution phases present during the synthesis. We believe our methodology provides a simple and convenient route to a variety of building blocks for assembling materials with novel structure and function in nanotechnology. Read more

Aggregated Diamond Nanorods, the Densest and Least Compressible Form of Carbon

by Natalia Dubrovinskaia et al. Applied Physics Letters, 22 Aug 2005 We report the synthesis of aggregated diamond nanorods (ADNRs) from fullerene C₆₀ at 20(1) GPa and 2200 °C using a multianvil apparatus. Individual diamond nanoroads are of 5–20 nm in diameter and longer than 1 µm. The x-ray and measured density of ADNRs is ~0.2%–0.4% higher than that of usual diamond. The extremely high isothermal bulk modulus K_T=491(3) GPa was obtained by in situ x-ray diffraction study. Thus, ADNRs is the densest among all carbon materials and it has the lowest so far experimentally determined compressibility. Read more

Hydrogen Production from Hydrolytic Oxidation of Organosilanes Using a Cationic Oxorhenium Catalyst

by Elon A. Ison, Rex A. Corbin, & Mahdi M. Abu-Omar Journal of the American Chemical Society, 5 Aug 2005 (web release) We describe herein the novel application of a transition metal oxo complex, a cationic oxorhenium(V) oxazoline, in the production of molecular hydrogen (H₂) from the catalytic hydrolytic oxidation of organosilanes. The main highlights of the reaction are quantitative hydrogen yields, low catalyst loading, ambient conditions, high selectivity for silanols, water as the only co-reagent, and no solvent requirement. The amount of hydrogen produced is proportional to the water stoichiometry. Thus, reaction mixtures of polysilyl organics such as HC(SiH₃)₃ and water contain potentially >6 wt % hydrogen. Kinetic and isotope labeling experiments have revealed a new mechanistic paradigm for the activation of Si-H bonds by oxometalates. Read more

Why Most Published Research Findings Are False

by John P. A. Ioannidis PLoS Medicine, August 2005 There is increasing concern that most current published research findings are false. The probability that a research claim is true may depend on study power and bias, the number of other studies on the same question, and, importantly, the ratio of true to no relationships among the relationships probed in each scientific field. In this framework, a research finding is less likely to be true when the studies conducted in a field are smaller; when effect sizes are smaller; when there is a greater number and lesser preselection of tested relationships; where there is greater flexibility in designs, definitions, outcomes, and analytical modes; when there is greater financial and other interest and prejudice; and when more teams are involved in a scientific field in chase of statistical significance. Simulations show that for most study designs and settings, it is more likely for a research claim to be false than true. Moreover, for many current scientific fields, claimed research findings may often be simply accurate measures of the prevailing bias. Read more

Intel-Led Alliance Stirs Angst over Future Wireless Spec

by Patrick Mannion EE Times, 31 Aug 2005 Intel has convinced fellow chip makers Broadcom, Atheros and Marvell to join forces outside of an IEEE wireless LAN group to develop an interoperable physical and media access control layer scheduled to be presented for IEEE acceptance by November. By working independently of the IEEE's 802.11n next-generation task group, Intel has angered task group members who accuse the Intel-led alliance of everything from co-opting the IEEE process to outright antitrust violations that could draw Federal Trade Commission scrutiny. Read more

WiMax Ready for Prime Time -- Almost

CNN.com, 29 Aug 2005 On a stormy day at an Argentine agricultural school, Maria del Carmen Villar stood in front of a camera that streamed her image over the Internet to a conference here -- more than 6,500 miles away. Such an event is hardly unusual in this era of broadband and webcams, but it was a milestone for the Instituto Agropecuario de Monte, a rural school that until recently had only slow dial-up connections that were bogged down by text, let alone video. The school in San Miguel del Monte, 90 miles outside Buenos Aires, is one of the first test sites for a wireless broadband technology called WiMax. Now, the school's 250 students use the Internet for research in classrooms and in the fields. They've even collaborated online with schools as far away as Paris. Read more

New Era of 'Smart' Lighting

CNN.com, 30 Aug 2005 Scientists have been taking a closer look at the lighting in our homes, offices and vehicles, and they're seeing potential for a way to improve health and a new means of electronic communication. Read more

'Penguin' Could Hop around Lunar Surface

CNN.com, 31 Aug 2005 A robotic Lunar Penguin explorer could be hopping around on the moon by 2009, maker Raytheon Co. said on Tuesday as it unveiled the concept lander at an aerospace conference. The unmanned lunar device, in development for two years, is 3 feet tall and weighs approximately 230 pounds. It "hops" by reigniting small propulsion engines. The Penguin can make a single jump of about six-tenths of a mile and could be adapted to make additional jumps, possibly over greater distances. Read more

High Frictional Anisotropy of Periodic and Aperiodic Directions on a Quasicrystal Surface

by Jeong Young Park et al. Science, 26 Aug 2005 Strong friction anisotropy is found when the twofold surface of an atomically clean aluminum-nickel-cobalt quasicrystal slides against a thiol-passivated titanium-nitride tip. Friction along the aperiodic direction is one-eighth as much as that along the periodic direction. This anisotropy, which is about three times as large as the highest value observed in anisotropic crystalline surfaces, disappears after the surface is oxidized in air. These results reveal a strong connection between interface atomic structure and the mechanisms by which energy is dissipated, which likely include electronic or phononic contributions, or both. Read more

Early Look at Research Project to Re-engineer the Internet

by John Markoff New York Times, 29 Aug 2005 The National Science Foundation is planning an effort to fundamentally re-engineer the Internet and overcome its shortcomings, creating a network more suited to the computerized world of the next decade. The new project, the Global Environment for Networking Investigations, was described for the first time by researchers and foundation officials at a technical meeting held in Philadelphia last week. Read more

Tapping America’s Potential: The Education for Innovation Initiative

Speaking for fifteen major business organizations such as the US Chamber of Commerce, the Business Roundtable, the National Association of Manufacturers, the Semiconductor Industry Association, the Business-Higher Education Forum, the Minority Business Roundtable and the National Defense Industrial Association, this report states that the United States must make a major effort to educate more scientists and engineers or risk falling behind other nations which are making stronger efforts to educate their people. While acknowledging the importance of primary and secondary education, the report calls for additional sustained effort at the college and university level to increase the number of baccalaureate-level citizens prepared to create and innovate. Read the report

Science Foundation Adds $150-Million to Its Support for TeraGrid Computing Network

by Vincent Kiernan The Chronicle of Higher Education, 19 Aug 2005 The National Science Foundation will spend almost $150-million over five years to operate its TeraGrid high-performance computing network, the agency announced on Wednesday. The contract award was not an extension of the science foundation's previous financial support of TeraGrid but rather is addition to $98-million that the agency already has spent on TeraGrid. Read more

Overview of Nanotechnology and Its Applicability to the Department of Defense

by A. Hernandez, R. C. Stevens, & K. J. Thorson Proceedings of SPIE, August 2005 Advances in a wide variety of nanotechnologies are expected to substantially benefit future military weapon systems. The technology development cycle for military platforms requires a given technology to reach a defined state of maturity before its use in a deployable system. Nanotechnologies such as quantum dots and carbon nanotubes, while showing great promise of performance benefits, are still considered too immature for immediate use. Defense contractors are in active research of applications of nanoscale engineered materials and devices and are beginning to engage nanotechnology suppliers for future military platforms. Read more

Branching Is Key to Carbon Nanotube Transistors

by Sarah Graham ScientificAmerican.com, 15 Aug 2005 Scientists have long been intrigued by the electrical properties of carbon nanotubes, those tiny straws of pure carbon measuring less than a hair's width across. Now one research team has unveiled an improved design for transistors based on the minuscule tubes, one that could substantially reduce the lower limit on transistor size. Read more

IEEE/OSA Journal of Display Technology

IEEE/OSA Journal of Display Technologies is sponsored by seven IEEE societies and the Optical Society of America. It covers the theory, design, fabrication, manufacturing and application of information displays and aspects of display technology that emphasize the progress in device engineering, device design, materials, electronics, physics and reliability aspects of displays and the application of displays. The first issue contains nearly 20 papers, covering key display technologies such as liquid crystal displays, plasma displays, organic light-emitting diodes, polymer LEDs, three-dimensional displays, projection displays, and lighting technology. Table of contents

Nanomaterials to Mimic Cells

PhysOrg.com, 23 Aug 2005 Mimicking a real living cell by combining artificial membranes and nanomaterials in one construction is the aim of a new research grant at UC Davis. The Nanoscale Integrated Research Team grant, funded by the National Science Foundation with $1.6 million over four years, will study membranes mounted on aerogels, solid materials riddled with so many tiny pores that they are mostly empty. Read more

Optical Chip Senses Multiple Gases

by Oliver Graydon optics.org News, 18 Aug 2005 Environmental monitoring and the analysis of food packaging could benefit from a new type of optical sensor that can detect the presence of several gases simultaneously. Read more

Regulators Propose Rules for Stronger Vehicle Roofs

by Danny Hakim New York Times, 20 Aug 2005 Federal regulators proposed new rules yesterday to bolster car and truck roofs, an area of increasing concern because of the rising number of deaths in vehicle rollovers. But the proposal appears to fall short of requirements in recently passed highway legislation and is far less than what many safety advocates had hoped for. The proposed rules would subject large sport utility vehicles, pickup trucks and vans to roof integrity regulations for the first time. And they would bolster current testing procedures. Read more

Stored Summer Heat De-Ices Winter Roads

New Scientist, 20 Aug 2005 In a UK trial, sunshine will heat water in pipes under the road which is then stored in ultra-insulated tanks until needed to combat surface frost. Read more

Conformable, Flexible, Large-Area Networks of Pressure and Thermal Sensors with Organic Transistor Active Matrixes

by Takao Someya et al. Proceedings of the National Academy of Sciences, 30 Aug 2005 Skin-like sensitivity, or the capability to recognize tactile information, will be an essential feature of future generations of robots, enabling them to operate in unstructured environments. Recently developed large-area pressure sensors made with organic transistors have been proposed for electronic artificial skin (E-skin) applications. These sensors are bendable down to a 2-mm radius, a size that is sufficiently small for the fabrication of human-sized robot fingers. Natural human skin, however, is far more complex than the transistor-based imitations demonstrated so far. It performs other functions, including thermal sensing. Furthermore, without conformability, the application of E-skin on three-dimensional surfaces is impossible. We have successfully developed conformable, flexible, large-area networks of thermal and pressure sensors based on an organic semiconductor. A plastic film with organic transistor-based electronic circuits is processed to form a net-shaped structure, which allows the E-skin films to be extended by 25%. The net-shaped pressure sensor matrix was attached to the surface of an egg, and pressure images were successfully obtained in this configuration. Then, a similar network of thermal sensors was developed with organic semiconductors. Next, the possible implementation of both pressure and thermal sensors on the surfaces is presented, and, by means of laminated sensor networks, the distributions of pressure and temperature are simultaneously obtained. Read more

'Singing' Wings Help Prevent Small-Plane Stalls

by Emma Young NewScientist.com, 18 Aug 2005 "Singing" wings could reduce the number of fatal small plane crashes, Australian research suggests, and may even lead to a new generation of smaller-winged, more fuel-efficient aircraft. The new technology uses a sound-emitting plastic coating to help control the flow of air over the wings, reducing the chance of the aircraft stalling -- experiencing a sudden loss of lift -- in mid-air. Read more

Rock ‘n’ Roll Robot Regains Its Feet

by Will Knight NewScientist.com, 19 Aug 2005 A humanoid robot with an exceptionally nimble knack for getting back on its feet after a fall has been developed by researchers in Japan. Named R Daneel, the robot kicks up its legs and rolls back onto its shoulders to gain the momentum it needs to rock up onto its feet and into a crouching position. This might be fairly easy for a human to do, but for the 60-kilogram bot, it requires a relaxed attitude to body control. Read more

Photovoltaic Effect in Ideal Carbon Nanotube Diodes

by Ji Ung Lee Applied Physics Letters, 15 Aug 2005 We demonstrate that individual single-walled carbon nanotubes (SWNTs) can form ideal p-n junction diodes. An ideal behavior is the theoretical limit of performance for any diode, a highly sought after goal in all electronic materials development. We further elaborate on their properties by examining photovoltaic effects, an application where its performance is intimately related to the quality of the diode. Under illumination, SWNT diodes show significant power conversion efficiencies owing to enhanced properties of an ideal diode. Read more

SFPs Challenge Tunable Lasers in Metro Sparing

by Meghan Fuller fibers.org News, 22 Aug 2005 Tunable lasers have long promised dynamic reconfigurability and on-the-fly provisioning, but these applications have yet to materialize. In the interim, sparing remains the key driver for tunable-laser use in the metro. Yet, tunable lasers come with a considerable price tag, prompting carriers to consider small-form-factor-pluggable transceivers to perform the same function at a much lower price point. Read more

Microdisplacement Printing

by A. A. Dameron et al. Nano Letters, 19 Aug 2005 (web release) We describe a new patterning technique that employs microcontact printing to replace preformed labile self-assembled monolayers (SAMs) selectively; we call this "microdisplacement printing." We demonstrate that this technique results in ordered molecular regions of both the patterning ("displacing") molecule as well as the remnant labile film, here 1-adamantanethiolate. The existence of the 1-adamantanethiolate SAM before patterning hinders lateral surface diffusion of the patterning molecules, and therefore permits the use of molecules that are otherwise too mobile to pattern by other methods. Read more

Experimental Measurement of the Photonic Properties of Icosahedral Quasicrystals

by Weining Man et al. Nature, 18 Aug 2005 Quasicrystalline structures may have optical bandgap properties -- frequency ranges in which the propagation of light is forbidden -- that make them well-suited to the scientific and technological applications for which photonic crystals are normally considered. Such quasicrystals can be constructed from two or more types of dielectric material arranged in a quasiperiodic pattern whose rotational symmetry is forbidden for periodic crystals (such as five-fold symmetry in the plane and icosahedral symmetry in three dimensions). Because quasicrystals have higher point group symmetry than ordinary crystals, their gap centre frequencies are closer and the gaps widths are more uniform -- optimal conditions for forming a complete bandgap that is more closely spherically symmetric. Although previous studies have focused on one-dimensional and two-dimensional quasicrystals, where exact (one-dimensional) or approximate (two-dimensional) band structures can be calculated numerically, analogous calculations for the three-dimensional case are computationally challenging and have not yet been performed. Here we circumvent the computational problem by doing an experiment. Using stereolithography, we construct a photonic quasicrystal with centimetre-scale cells and perform microwave transmission measurements. We show that three-dimensional icosahedral quasicrystals exhibit sizeable stop gaps and, despite their quasiperiodicity, yield uncomplicated spectra that allow us to experimentally determine the faces of their effective Brillouin zones. Our studies confirm that they are excellent candidates for photonic bandgap materials. Read more

Optically Controlled Slow and Fast Light in Optical Fibers Using Stimulated Brillouin Scattering

by Miguel González-Herráez, Kwang-Yong Song, & Luc Thévenaz Applied Physics Letters, 22 Aug 2005 We demonstrate a method to achieve an extremely wide and flexible external control of the group velocity of signals as they propagate along an optical fiber. This control is achieved by means of the gain and loss mechanisms of stimulated Brillouin scattering in the fiber itself. Our experiments show that group velocities below 71 000 km/s on one hand, well exceeding the speed of light in vacuum on the other hand and even negative group velocities can readily be obtained with a simple benchtop experimental setup. We believe that the fact that slow and fast light can be achieved in a standard single-mode fiber, in normal environmental conditions and using off-the-shelf instrumentation, is very promising for a future use in real applications. ©2005 American Institute of Physics Read more

All the World's a Computer

by Yoshiko Hara EE Times, 22 Aug 2005 Ken Sakamura has been talking pervasive computing since before the term was invented. The University of Tokyo professor, easily the most famous computer architect in Japan, first proposed the idea of networked, ubiquitous computing back in 1984, when he devised the open architecture known as TRON (The Real-time Operating System Nucleus). Since then, Sakamura has led the TRON project and several spin-offs in developing core technologies for an environment in which every object incorporates a computer and is linked to a network. His latest invention is the Micro Ubiquitous Communicator, a personal identification device the size of a matchbox that works as a door key, electronic money and PC authentication. Read more

'Silent Aircraft' Design Launched

BBC News, 17 Aug 2005 Plans for the world's first completely silent aircraft have been unveiled by Cambridge University engineers. Environmental campaigners and people living on flight paths have already welcomed the campaign to build the jet. Read more

Strong, Transparent, Multifunctional, Carbon Nanotube Sheets

by Mei Zhang et al. Science, 19 Aug 2005 Individual carbon nanotubes are like minute bits of string, and many trillions of these invisible strings must be assembled to make useful macroscopic articles. We demonstrated such assembly at rates above 7 meters per minute by cooperatively rotating carbon nanotubes in vertically oriented nanotube arrays (forests) and made 5-centimeter-wide, meter-long transparent sheets. These self-supporting nanotube sheets are initially formed as a highly anisotropic electronically conducting aerogel that can be densified into strong sheets that are as thin as 50 nanometers. The measured gravimetric strength of orthogonally oriented sheet arrays exceeds that of sheets of high-strength steel. These nanotube sheets have been used in laboratory demonstrations for the microwave bonding of plastics and for making transparent, highly elastomeric electrodes; planar sources of polarized broad-band radiation; conducting appliqués; and flexible organic light-emitting diodes. Read more

AeroVironment Test-Flies Liquid-Hydrogen-Powered UAV

by John McHale Military & Aerospace Electronics, 17 Aug 2005 The Global Observer, a liquid-hydrogen-powered unmanned aerial vehicle, has completed flight tests. Officials at AeroVironment in Monrovia, Calif., made the announcement regarding their High-Altitude Long-Endurance (HALE) system earlier this summer. AeroVironment’s Global Observer HALE aircraft will be able to operate at altitudes as high as 65,000 feet for more than a week without refueling and with a flexible payload-carrying capacity of as much as 1,000 pounds, AeroVironment officials say. Read more

Navy Looks into How To Control Next-Generation Autonomous Unmanned Aircraft

by John Keller Military & Aerospace Electronics, 17 Aug 2005 U.S. Navy experts are redesigning the unmanned aerial vehicle control station of the future, not only to accommodate new technologies and futuristic pilotless aircraft, but also to reduce military manning levels by introducing more machine autonomy. Read more

NASA Technology Helps Smooth Bumpy Airline Rides

National Aeronautics and Space Administration Press Release, 19 Jul 2005 Most airline passengers and flight crews have one thing in common: they don't like turbulence. Researchers at NASA's Langley Research Center in Hampton, Va., and AeroTech Research, Inc., Newport News, Va., have developed an automatic turbulence reporting system. Read more

Predicting the Lifetime of Extreme UV Optics

NIST Tech Beat, 13 Jul 2005 Extreme ultraviolet lithography (EUVL) may be the next-generation patterning technique used to produce smaller and faster microchips with feature sizes of 32 nanometers and below. However, durable projection optics must be developed before this laboratory technique can become commercially viable. As part of its long-standing effort to develop EUVL metrology and calibration services, the National Institute of Standards and Technology is creating a measurement system for accelerated lifetime testing of the mirrors used in EUVL. Read more

Academia's Quest for the Ultimate Search Tool

by Stefanie Olsen New York Times, 15 Aug 2005 The University of California at Berkeley is creating an interdisciplinary center for advanced search technologies and is in talks with search giants including Google to join the project. The project is one of many efforts at U.S. universities designed to address the explosive growth of Internet search and the complex issues that have arisen in the field. Read more

DOE Funding Opportunity - Solid State Lighting Core Technologies

The Department of Energy National Energy Technology Laboratory, on behalf of the Office of Energy Efficiency and Renewable Energy’s Building Technologies Program, is seeking applications for applied research in the Solid-State Lighting Core Technologies Program. There are four separate Areas of Interest to which an application can be submitted:

• LED High-Efficiency Semiconductor Materials
• LED Device Approaches, Structures, and Systems
• OLED Materials Issues
• OLED Packaging, Encapsulation, and Fabrication

Read more

‘Dirty Silicon’ To Enable Cheaper Solar Cells

by Mark LaPedus EE Times, 16 Aug 2005 Researchers at the University of California at Berkeley have developed a new technique based on "dirty silicon" that could reduce the cost of solar cells. Read more

Nanotubes May Heal Broken Bones

by Aaron Dalton Wired News. 15 Aug 2005 Human bones can shatter in accidents, or they can disintegrate when ravaged by disease and time. But scientists may have a new weapon in the battle against forces that damage the human skeleton. Carbon nanotubes, incredibly strong molecules just billionths of a meter wide, can function as scaffolds for bone regrowth, according to researchers led by Robert Haddon at the University of California at Riverside. They have found a way to create a stronger and safer frame than the artificial bone scaffolds currently in use. Read more

Atomic-Scale Sources and Mechanism of Nanoscale Electronic Disorder in Bi2Sr2CaCu2O8+{delta}

by K. McElroy et al. Science, 12 Aug 2005 The randomness of dopant atom distributions in cuprate high-critical temperature superconductors has long been suspected to cause nanoscale electronic disorder. In the superconductor Bi2Sr2CaCu2O8+, we identified populations of atomic-scale impurity states whose spatial densities follow closely those of the oxygen dopant atoms. We found that the impurity-state locations are strongly correlated with all manifestations of the nanoscale electronic disorder. This disorder occurs via an unanticipated mechanism exhibiting high-energy spectral weight shifts, with associated strong superconducting coherence peak suppression but very weak scattering of low-energy quasi-particles. Read more

An Index to Quantify an Individual’s Scientific Output

by J. E. Hirsch arXiv.org e-Print archive, 10 Aug 2005 The publication record of an individual and the citation record are clearly data that contain useful information. That information includes the number of papers published over n years, the number of citations for each paper, the journals where the papers were published and their impact parameter, etc. This is a large amount of information that will be evaluated with different criteria by different people. Here I would like to propose a single number, the "h-index," as a particularly simple and useful way to characterize the scientific output of a researcher. Read more

Patent Highlights, 11 Aug 2005

optics.org News, 11 Aug 2005 The pick of this week's patents including a mirrorball-based laser device that deters birds from landing. • Lithography system using a programmable electro-wetting mask • Method and apparatus for increasing a perceived resolution of a display • Method and device providing an easy way to deter birds from landing Read more

US Shoots Ahead in Stun Gun Design

by David Hambling NewScientist.com, 15 Aug 2005 Weapons designed to fire "electric bullets" into crowds are being developed for police and border protection agencies in the U.S. The Homeland Security Advanced Research Projects Agency, the domestic equivalent of the defence agency DARPA, has launched an "innovative less-lethal devices for law enforcement" programme to radically expand the capabilities of electric shock weapons. Read more

Urine-Activated Paper Batteries for Biosystems

by Ki Bang Lee Journal of Micromechanics and Microengineering, September 2005 The first urine-activated laminated paper batteries have been demonstrated and reported in this paper. A simple and cheap fabrication process for the paper batteries has been developed which is compatible with the existing plastic laminating technologies or plastic molding technologies. In this battery, a magnesium (Mg) layer and copper chloride (CuCl) in the filter paper are used as the anode and the cathode, respectively. A stack consisting of a Mg layer, CuCl-doped filter paper and a copper (Cu) layer sandwiched between two plastic layers is laminated into the paper batteries by passing through the heating roller at 120 °C. The paper battery is tested and it can deliver a power greater than 1.5 mW. In addition, these urine-activated laminated paper batteries could be integrated with bioMEMS devices such as home-based health test kits providing a power source for the electronic circuit. Read more

Nanotech Transistor Powers Up

by Mark Peplow news@nature.com, 14 Aug 2005 The first electrical switch made entirely from carbon nanotubes has been unveiled. Its inventors hope that it could help to replace silicon chips with faster, cheaper, smaller components. Read more

Dynamic Devices

by Charlene Lobo Nature Materials Update, 11 Aug 2005 High-resolution electron microscopy has traditionally been viewed as a static structural characterization tool, rather than a means of studying the dynamic properties of nanoscale materials and devices. However, placing a scanning tunnelling microscope probe inside a high-resolution transmission electron microscope has enabled researchers to simultaneously perform atomic-scale imaging and electrical transport measurements. Read more

Nanotubes Get a Better Grip

by Philip Ball Nature Materials Update, 11 Aug 2005 Re-usable adhesives that mimic the sticky surfaces of gecko feet while increasing the adhesive forces 200-fold have been made by researchers in the U.S. The sticky material might find applications in robotics, microelectronics and space engineering. Read more

The Optical Control Plane Will Rewrite the Rulebook

by Volkmar Kaufmann fibers.org News, 15 Aug 2005 Fundamental dislocation is under way in the optical network. As a matter of priority, service providers are looking beyond today's clunky service-delivery model, with its reliance on manual provisioning and long-term bandwidth allocation, to a next-generation network architecture capable of intelligent capacity utilization, automated delivery of value-added services and on-demand circuit provisioning. Underpinning that vision is the realization of a unified optical control plane that will enable service providers to create, manage and troubleshoot optical services end-to-end. Read more

Bluetooth Device to Save Stroke Victims

CNN.com, 16 Aug 2005 A British computer scientist is developing a portable brain scanner that could help prevent people from suffering brain damage after they have a stroke. The wireless scanner will use Bluetooth technology and will be linked to a computer on board an ambulance. Paramedics will use the device to scan patients who are suffering a suspected stroke before they arrive at hospital, meaning life-saving treatment may be given immediately. Read more

250 Miles Per Gallon? They're Doing It

CNN.com, 16 Aug 2005 Politicians and automakers say a car that can both reduce greenhouse gases and free America from its reliance on foreign oil is years or even decades away. Ron Gremban says such a car is parked in his garage. It looks like a typical Toyota Prius hybrid, but in the trunk sits an 80-miles-per-gallon secret -- a stack of 18 brick-sized batteries that boosts the car's high mileage with an extra electrical charge so it can burn even less fuel. Read more

Thin Skin Will Help Robots 'Feel'

BBC News, 15 Aug 2005 Japanese researchers have developed a flexible artificial skin that could give robots a humanlike sense of touch. The team manufactured a type of "skin" capable of sensing pressure and another capable of sensing temperature. These are supple enough to wrap around robot fingers and relatively cheap to make, the researchers have claimed. Read more

A Digital Signal Processing Teaching Methodology Using Concept-Mapping Techniques

by M.R. Martinez-Torres et al. IEEE Transactions on Education, August 2005 The main goal of this study is to develop a scientific method for designing a teaching methodology used in a basic digital signal processing (DSP) course. The proposed method is based on concept-mapping techniques, which applies multivariate statistic analysis to summarize the experience and knowledge of teachers involved in basic DSP teaching. As a result, a set of teaching methodologies is obtained. This result, as well as other information obtained related to the relative importance of the concepts to be covered, has been used to program the course. Moreover, different teaching tools have been developed to implement the proposed teaching methodology. Finally, the reliability of the method has been compared with similar studies to validate the proposed methodology. Read more

An Electronic Instrumentation Design Project for Computer Engineering Students

by F.J.F. Martin et al. IEEE Transactions on Education, August 2005 Ongoing technological progress in electronic instrumentation triggered the development of an innovative, hands-on teaching program to help students toward a fuller understanding of recent changes in the field. This paper describes the different stages of a design project to teach electronic instrumentation to computer engineering students in Spain. The project involves designing a weather station to measure the main meteorological variables and then displaying this information on a computer screen. Although this course is intended for nonspecialist students of electronics, it could easily be adapted to other syllabuses with minimum modification of the specifications. The course provides not only enhanced academic training but also increased student motivation, as students participate actively in all course activities and work in a team within which each student has specific responsibilities. Read more

ABET 2000 Challenges in Curricular Compression: Fluids and Circuits - A Pilot $2+1+1$ Approach

by C.K. Skokan et al. IEEE Transactions on Education, August 2005 In response to a call from the National Science Foundation for curriculum reform and elimination of legacy materials in engineering curricula, the faculty at the Colorado School of Mines, Golden, has developed and offered a combined set of course modules in fluids and circuits. These modules consist of a two-credit interdisciplinary course in fundamentals, followed by two one-credit modules focusing on applications in fluids and in circuits, respectively. The course set reduces the overall number of credits from six to four through the $2+1+1$ format. The fundamentals course, consisting of two credits, is based on conservation and accounting principles for the concepts of mass, momentum, energy, and charge. Two applications modules, each of one credit, develop these ideas in the respective disciplines. During the study, four challenges to implementation were uncovered: faculty and administrative buy-in, textbook selection, logistics, and stakeholders' acceptance. Read more

Air Force Solicitation - Advanced Structures Initiative

The Manufacturing Technology Division of the AFRL Materials and Manufacturing Directorate is developing plans for a new initiative to develop designs and manufacturing technologies for advanced aircraft structures. The Government is specifically interested in white papers for programs that address technologies that help attack barriers to transition of advanced structures and programs that address structures technologies to enable next generation airframes. These structures are not limited to a single material class, such as composite or metal. The areas are listed in no particular order of importance. The Government is interested in responses from across the aerospace industry, including prime contractors, parts fabricators, material suppliers, and other subtier suppliers as appropriate. Read more

DARPA Solicitation - Mobile Networked Multiple Input-Multiple Output Technology

Recent developments show Multiple Input-Multiple Output (MIMO) technology to be immensely promising in a wide range of military applications. DARPA seeks to convert the potential demonstrated in the first phase of the current DARPA MNM program into practical military systems that exploit the adaptability of MIMO capable systems for both vehicular and handheld applications. Toward that end, DARPA seeks to identify technologies that will result in a system of communications devices and software that are built from the ground-up to support the requirements and potential flexibility of a MNM enabled network. The system should be able to intelligently adapt all of its radio and processing resources to support the user's communications needs. These adaptations should include, but are not limited to: spatial diversity for higher data rates, spatial diversity for low power spectral density, spatial diversity to increase range, frequency agility, bandwidth agility, interference suppression, beam forming, and multiple simultaneous beams. Additionally, the system must support a tactically relevant network implementation that can also adapt as the environment and mission change. DARPA also seeks to explore the synergy of MNM technologies with advanced spectrum access and management approaches such as those being researched in the DARPA Next Generation Communications Program. Read more

Hybrid-Electric . . . Bicycle

WorldChanging, 18 Jul 2005 Why is it that so many microcars have cutesy names? The two-seat Tango? The ultra-skinny Naro? The Smart? The G-Wiz?!?! Add the "Twike" to the list, albeit with a disclaimer: while it sounds like an all-too-precious version of "trike" (an impression supported by its three wheels), the word has not heard in the same way in Switzerland and Germany, its point of origin. Instead, Twike comes from "twin bike" -- and it's a much more intriguing concept than it might initially appear. Read more

Feds Fund VoIP Tapping Research

by Declan McCullagh CNET News.com, 9 Aug 2005 The federal government is funding the development of a prototype surveillance tool by George Mason University researchers who have discovered a novel way to trace Internet phone conversations. Their project is designed to let police identify whether suspects under surveillance have been communicating through voice over Internet Protocol -- information that would be unavailable today if people choose to communicate surreptitiously. Read more

Help Needed to Evaluate College Engineering Programs

The Institute, 5 Aug 2005 The IEEE Educational Activities Board needs volunteers willing to roll up their sleeves and get out into the field to evaluate the quality of engineering and engineering technology programs at U.S. colleges. The goal is to have the programs accredited by the Engineering Accreditation Commission and the Technology Accreditation Commission of ABET. The ABET commissions carry out the accreditation procedures and decide whether the programs deserve to be accredited. The deadline to apply for members interested in being evaluators is 15 November 2005. Read more

Kryder's Law

by Chip Walter Scientific American, August 2005 Over the years there has been a lot of talk about Moore's Law and the way that doubling the power and memory of computer semiconductors every 18 months has driven technological advance. But from where Mark Kryder sits, another force is at least as powerful, perhaps more: the cramming of as many bits as possible onto shrinking magnetic hard drives. Read more

Startup Claims Breakthrough in PC Clocking

by Mark LaPedus EE Times, 10 Aug 2005 Startup TimeLab Corp. next week is expected to roll out a technology that could revolutionize PC clocks, according to an e-mail newsletter from Semico Research Corp. Read more

Scientists Use Plastic to Make Steel

Reuters CNN.com, 10 Aug 2005 Australian scientists have developed a technique to use waste plastic in steel making, a process that could have implications for recycling scrap metal that accounts for 40 percent of steel production. Professor Veena Sahajwalla of the University of New South Wales has won a prestigious Australian science award for what she calls "the hottest research in town", which she hopes will turn an environmental headache into a valuable resource. Read more

Coherent Locomotion as an Attracting State for a Free Flapping Body

by Silas Alben & Michael Shelley Proceedings of the National Academy of Science, 9 Aug 2005 A recent experiment has shown that an axle-mounted blade can spontaneously rotate when oscillated (or "flapped") above a critical frequency in a fluid. To understand the nature of flapping locomotion we study numerically the dynamics of a simple body, flapped up and down within a viscous fluid and free to move horizontally. We show here that, at sufficiently large "frequency Reynolds number," unidirectional locomotion emerges as an attracting state for an initially nonlocomoting body. Locomotion is generated in two stages: first, the fluid field loses symmetry by an instability similar to the classical von Kármán instability; and second, precipitous interactions with previously shed vortical structures "push" the body into locomotion. Body mass and slenderness play central and unexpected roles in each stage. Conceptually, this work demonstrates how locomotion can be transduced from the simple oscillations of a body through an interaction with its fluid environment. Read more

Superlens Breaks Optical Barrier

by David Smith Physics World, August 2005 One of the best known properties of light is that it diffracts, bending or spreading around objects that lie in its path. A familiar example is when a collimated beam of light passes through a small aperture in an opaque barrier. If the aperture is large, the light emerges as a beam with the same radius as that of the aperture. But if the size of the aperture is similar to the wavelength of the incident light, the emerging light flares out from the aperture and forms a diffraction pattern whereby the intensity of the transmitted light has a broad central peak. Read more

Gold Based Bulk Metallic Glass

by Jan Schroers et al. Applied Physics Letters, 8 Aug 2005 Gold-based bulk metallic glass alloys based on Au–Cu–Si are introduced. The alloys exhibit a gold content comparable to 18-karat gold. They show very low liquidus temperature, large supercooled liquid region, and good processibility. The maximum casting thickness exceeds 5 mm in the best glassformer. Au₄₉Ag_5.5Pd_2.3Cu_26.9Si_16.3 has a liquidus temperature of 644 K, a glass transition temperature of 401 K, and a supercooled liquid region of 58 K. The Vickers hardness of the alloys in this system is ~350 Hv, twice that of conventional 18-karat crystalline gold alloys. This combination of properties makes the alloys attractive for many applications including electronic, medical, dental, surface coating, and jewelry. Read more

Optical Vibration Sensor Fabricated by Femtosecond Laser Micromachining

by Masanao Kamata et al. Applied Physics Letters, 1 Aug 2005 We fabricated an optical vibration sensor using a high-repetition rate femtosecond laser oscillator. The sensor consists of a single straight waveguide written across a series of three pieces of glass. The central piece is mounted on a suspended beam to make it sensitive to mechanical vibration, acceleration, or external forces. Displacement of the central piece is detected by measuring the change in optical transmission through the waveguide. The resulting sensor is small, simple, and requires no alignment. The sensor has a linear response over the frequency range 20 Hz–2 kHz, can detect accelerations as small as 0.01 m/s², and is nearly temperature independent. Read more

Robots Find Their Feet with Help of Sonar

by Paul Marks New Scientist, 6 Aug 2005 Two-legged robots like Sony's diminutive Qrio and Honda's child-size Asimo might give the impression that they've got the problems of locomotion licked. But the robots are always put through their paces in carefully controlled environments with surfaces on which their creators know the bots won't slip. Read more

Robot Catcher Grabs High Speed Projectiles

by Will Knight NewScientist.com, 4 Aug 2005 If robots are to inherit the Earth, then they should at least be able to catch. So say the researchers behind a bot that can match the most skilled human baseball player faced with a hurtling ball. The robotic catcher, developed by scientists at the University of Tokyo, can comfortably grab a ball careering through the air at 300 kilometres per hour, or 83 metres per second, its creators say. And, of course, the robot never gets tired of doing so. Read more

Guessing Game Gives Machines Clearer Vision

by Will Knight NewScientist.com, 9 Aug 2005 A guessing game that lets players idle away a few minutes online could also teach computers how to recognise the world around them. The game, called Peekaboom, was devised by researchers at Carnegie Mellon University. It harnesses the brain power of online players to train a set of powerful vision recognition algorithms. This could eventually enable computers to recognise images in a similar way to humans -- by focusing on the most relevant features. Read more

Pocket-Sized Computer 'Soul' Developed

by Will Knight NewScientist.com, 10 Aug 2005 Personal computers could soon fit entirely on a key ring. Researchers at IBM in New York, US, have developed a way to carry a powerful, personalised virtual computer from one PC to the next, without losing the user’s work. The trick is to store the virtual computer on a USB key, or any portable device with substantial storage space, like an MP3 player. Read more

Remote-Controlled Humans Enhance Immersive Games

by Will Knight NewScientist.com, 10 Aug 2005 Remote controlled humans might sound a bizarre and nightmarish prospect, but Japanese researchers hope to harness the trick for computer gaming. By remotely stimulating a person's vestibular system -- the fluid-filled tubes in the inner ear that guide their sense of balance -- with electrodes placed on the skin just below the ear, researchers at NTT's research laboratories in Kanagawa have found a way to turn humans into oversized radio controlled vehicles. Read more

Spotting the Bots with Brains

New Scientist, 13 Aug 2005 How do you tell just how smart your robot is? Simple: give it a universal IQ test. Traditional measures of human intelligence often won't be appropriate for systems that have senses, environments and cognitive capacities very different from our own. So Shane Legg and Marcus Hutter at the Swiss Institute for Artificial Intelligence in Manno-Lugano have drafted an alternative test that will allow the intelligence of vision systems, robots, natural language processing programs or trading agents to be compared and contrasted despite their broad and disparate functions. Although there is no consensus on what exactly human intelligence is, most views appear to cluster around the idea that it hinges on a general ability to achieve goals in a wide range of environments, says Legg. The same can be applied to an AI system, by measuring its ability to carry out complex tasks within its particular environment, compared with all other environments. "But there is a problem," he says. Before putting this theory into practice the AI community will have to thrash out an agreement on just how complex each environment is. And that won't be easy. Under his definition, chess-playing computer Deep Blue would come out worse than a generalist learning algorithm, as it is only designed to carry out a very specific task.

Gradient Chemical Micropatterns: A Reference Substrate for Surface Nanometrology

by Duangrut Julthongpiput et al. Nano Letters, 8 Jul 2005 (web release) We present fabrication routes for a new type of surface specimen that exhibits a micropattern with a gradient in chemical contrast between the pattern domains. Design elements in the specimen allow chemical contrast in the micropattern to be related to well-established surface characterization data, such as contact angle measurements. These gradient specimens represent a reference tool for calibrating image contrast in chemically sensitive scanning probe microscopy techniques and a platform for the high-throughput analysis of polymer thin film behavior. Read more

Nanotube Forests Take Off the Heat

by Philip Ball Nature Materials Update, 28 Jul 2005 A composite material made from carbon nanotubes embedded in a polymer matrix can whisk away heat, Chinese researchers have shown. They say that their heat-sink material might help with the problem of thermal management on silicon chips. Read more

Triangular and Fibonacci Number Patterns Driven by Stress on Core/Shell Microstructures

by Chaorong Li, Xiaona Zhang, & Zexian Cao Science, 5 Aug 2005 Fibonacci number patterns and triangular patterns with intrinsic defects occur frequently on nonplanar surfaces in nature, particularly in plants. By controlling the geometry and the stress upon cooling, these patterns can be reproduced on the surface of microstructures about 10 micrometers in diameter. Spherules of the Ag core/SiO_x shell structure, possessing markedly uniform size and shape, self-assembled into the Fibonacci number patterns (5 by 8 and 13 by 21) or the triangular pattern, depending on the geometry of the primary supporting surface. Under proper geometrical constraints, the patterns developed through self-assembly in order to minimize the total strain energy. This demonstrates that highly ordered microstructures can be prepared simultaneously across large areas by stress engineering. Read more

Monodisperse Face-Centred Tetragonal FePt Nanoparticles with Giant Coercivity

by Kevin Elkins et al. Journal of Physics D, 1 Jul 2005 Monodisperse face-centred tetragonal (fct) FePt nanoparticles with high magnetic anisotropy and, therefore, high coercivity have been prepared via a new heat treatment route. The as-synthesized face-centred cubic FePt nanoparticles were mixed with salt powders and annealed at 700°C. The salts were then removed from the particles by washing the samples in water. Monodisperse fct FePt particles were recovered with the particle size and shape being retained. Coercivity of the isolated particles up to 30 kOe at room temperature has been obtained. Read more

Anisotropy of Sheared Carbon-Nanotube Suspensions

by D. Fry et al. Physical Review Letters, 15 Jul 2005 We measure the anisotropy of sheared carbon-nanotube suspensions for a broad range of concentration, aspect ratio, and strain rate using a variety of methods. Our measurements highlight the importance of excluded-volume interactions in the semidilute regime, with scaling in terms of a dimensionless shear rate. Our results also suggest that such interactions might be exploited to fractionate carbon nanotubes by length in simple shear flow. Read more

Reclaimed Wastewater

Texas A&M University Press Release, 9 Aug 2005 As water becomes ever more scarce, quenching thirsty crops with wastewater may be OK if done right, researchers at the Texas Agricultural Experiment Station say. Read more

Droplet Control for Microfluidics

by Mathieu Joanicot & Armand Ajdari Science, 5 Aug 2005 Future applications of microfluidic technology -- in which nanoliter quantities of chemicals are processed and reacted, perhaps on an integrated chip -- would immensely benefit from exquisite control of small droplets. Joanicot and Ajdari discuss recent developments in droplet creation and management within microfluidic devices. New methods for microscale control, combined with better theoretical understanding, will result in precise handling of chemical processes at the single-droplet level and engineering of new materials. Read more

An Experimental Approach to the Percolation of Sticky Nanotubes

by B. Vigolo et al. Science, 5 Aug 2005 Percolation is a statistical concept that describes the formation of an infinite cluster of connected particles or pathways. Lowering the percolation threshold is a critical issue to achieve light and low-cost conductive composites made of an insulating matrix loaded with conductive particles. This has interest for applications where charge dissipation and electrical conductivity are sought in films, coatings, paints, or composite materials. One route to decreasing the loading required for percolation is to use rod-like particles. Theoretical predictions indicate that this may also be achieved by altering the interaction potential between the particles. Although percolation may not always respond monotonically to interactions, the use of adhesive rods can be expected to be an ideal combination. By using a system made of carbon nanotubes in an aqueous surfactant solution, we find that very small attraction can markedly lower the percolation threshold. The strength of this effect can thereby have direct technological interest and explain the large variability of experimental results in the literature dealing with the electrical behavior of composites loaded with conducting rods. Read more

A Crossover in the Mechanical Response of Nanocrystalline Ceramics

by Izabela Szlufarska, Aiichiro Nakano, & Priya Vashishta Science, 5 Aug 2005 Multimillion-atom molecular dynamics simulation of indentation of nanocrystalline silicon carbide reveals unusual deformation mechanisms in brittle nanophase materials, resulting from the coexistence of brittle grains and soft amorphous grain boundary phases. Simulations predict a crossover from intergranular continuous deformation to intragrain discrete deformation at a critical indentation depth. The crossover arises from the interplay between cooperative grain sliding, grain rotations, and intergranular dislocation formation similar to stick-slip behavior. The crossover is also manifested in switching from deformation dominated by indentation-induced crystallization to deformation dominated by disordering, leading to amorphization. This interplay between deformation mechanisms is critical for the design of ceramics with superior mechanical properties. Read more

DoD Funding Opportunity - Applying Information Technology to Command, Control, Communications, Computer and Intelligence Systems

The Information Directorate, Command and Control Engineering Branch of the Air Force Research Laboratory, Rome Research Site, is soliciting white papers under this announcement for innovative technologies to support Command, Control, Communications, Computers, and Intelligence applications. Of particular interest are technologies that can significantly reduce the time between information technology availability and its employment into the research and development programs that support legacy and new military electronic systems. Also of interest are commercial technologies that can improve the functionality, performance, reliability, longevity, and usability of these new and legacy military electronic systems. Read more

New Solutions in Optomechanics

by Daniel Vukobratovich oemagazine, August 2005 The growth of optomechanics was at least partially fostered by the publications, conferences, and short courses of SPIE. In particular, SPIE helped publicize and provide forums for discussing two important concepts in optomechanics: sub-cell lens mounting and the use of alternative materials such as silicon carbide. The technology associated with sub-cell mounting moved from idea to standard practice in high-performance aerospace applications in less than 15 years. Silicon carbide technology for mirror substrates is at the same stage of development as sub-cell mounting was three decades ago. Designers are applying it in some systems, but it is not yet standard practice. As time passes, however, that should change. Read more

Optical Engineering

by Winn Hardin oemagazine, August 2005 The introduction of high-brightness LEDs in everything from automobiles to signage to hand-held torches, and a need for end-to-end design, illumination, and propagation packages, is helping to drive optical engineering environments to new levels of integration. Read more

Is Cooling the Central Design Issue of Our Time?

by John Keller Military & Aerospace Electronics, July 2005 For years now we’ve lived with the assumption that computer processing power -- and hence systems capability -- doubles about every couple of years. This is the essence of Moore’s Law, which has been an electronics maxim for the past four decades. Few principles in the electronics business have been so constant, dependable, and predictable as Moore’s Law, but a sea change in its guidance may be in the offing. The problem is heat. Fast electronics and tightly integrated packaging that are typical in embedded systems in military and aerospace applications generate substantial amounts of excess heat, and the pace of improvements in integrated circuitry is outstripping our ability to remove the unwanted heat. Read more

Lead-Free Processing Involves Several Board Issues

by Keith Gurnett & Tom Adams Military & Aerospace Electronics, July 2005 As worldwide electronics manufacturing moves slowly and unevenly into lead-free materials and processes, most attention goes to components and the bonding of those components to the printed wiring board-especially to the effects of the relatively high reflow temperatures on components and joints. Read more

The Interplanetary Internet

by Joab Jackson IEEE Spectrum, August 2005 Here’s an idea: why doesn’t NASA put a network in the sky, with each orbiter, rover, space-borne telescope, and any other skyward-launched device working as a node? Why not internetwork space? In fact, why not use the existing Internet? Read more

Shedding Light on Organic Transistors

by Justin Mullins IEEE Spectrum, August 2005 The first single-crystal organic transistor that can be switched on and off by light is giving physicists a unique peek into the way photons interact with organic semiconductors. The new device could have a major impact on the way organic light-emitting displays are manufactured and may lead to a new generation of highquality flexible color displays. Read more

Advanced Bridge Materials’ Efficacy Tested at NC State University

PhysOrg, 3 Aug 2005 Engineers at North Carolina State University are now utilizing full-scale tests on two materials to gauge their effectiveness in making bridges stronger and safer, as well as reducing the costs and duration of repairs to this critical infrastructure. Read more

High Performing Rope Takes Weight Off

CNN.com, 29 Jul 2005 High-tech is not a word often used to describe a piece of rope, but add a data sensor to its fibers and you have what its creators call electronic rope technology. This rope is able to sense its own load and signal any weakness, sending the information to a handheld device well before it frays and gives way. Read more

Virginia Tech Electrical Engineers Invent Wireless Internet Connection

PhysOrg, 3 Aug 2005 A new unlicensed, wireless Internet connection, WiFi, is providing new freedom to the World Wide Web addict. An antenna for WiFi, invented by Warren Stutzman of Virginia Tech's Bradley Department of Electrical and Computer Engineering and his Ph.D. post-graduate researcher Michael Barts, allows users to receive signals in remote locations such as airports and hotels to log on to the Web. Read more

Smart Fridges Could Ease Burden on Energy Supply

by Gaia Vince New Scientist, 30 Jul 2005 'Dynamic device control' could allow fridges and other appliances to reduce their energy use at peak hours, reducing a country's CO₂ emissions. Read more

Quick Change for Super Sponge

by Mark Peplow news@nature.com, 20 Jul 2005 Just a little heat is enough to turn a waterproof block of foam into a sponge, a group of scientists reports. Neil Shirtcliffe and his colleagues from Nottingham Trent University, UK, don't quite know what their nifty materials could be used for. The waterproof-sponge hybrids have been made to perform their trick at 400 °C or less, so the most likely application might be as a temperature sensor in an oven, they suggest. Regardless of use, the materials are an interesting chemical oddity. Read more

Nanotube Forests Take Off the Heat

by Philip Ball Nature Materials Update, 28 Jul 2005 A composite material made from carbon nanotubes embedded in a polymer matrix can whisk away heat, Chinese researchers have shown. They say that their heat-sink material might help with the problem of thermal management on silicon chips. Read more

Quantum Optics: Crystal-Clear Images

by Claude Fabre Nature, 28 Jul 2005 Randomness lies at the root of many quantum effects: in the arrival times of the photons on a detector, for example; or, if the intensity is such that the photons cannot be distinguished individually, in the temporal fluctuations of the current generated in the detector by those photons. In the past two decades, physicists have found ways to tame this 'quantum noise', and to master, at least in some instances, the temporal distribution of photons. Two papers now show that it is also pos-sible to control photons' spatial distribution. Read more

Ion Beams Enhance Optoelectronic Durability

by Oliver Graydon fibers.org News, 3 Aug 2005 A small Swedish firm believes that it has found a way to fabricate semiconductor lasers that can be driven at much higher temperatures and output powers than ever before, without failing. If the claim of Stockholm-based Comlase turns out to be true, it could have dramatic consequences in fields ranging from data storage and telecoms, to fibre pumping and laser welding. Read more

'Smart' Bio-Nanotubes May Help in Drug Delivery

University of California - Santa Barbara Press Release, 2 Aug 2005 Materials scientists working with biologists at the University of California, Santa Barbara have developed "smart" bio-nanotubes -- with open or closed ends -- that could be developed for drug or gene delivery applications. The nanotubes are "smart" because in the future they could be designed to encapsulate and then open up to deliver a drug or gene in a particular location in the body. Read more

A New Spin on Silicon

Stanford University Press Release, 2 Aug 2005 For about 40 years, the semiconductor industry has been able to continually shrink the electronic components on silicon chips, packing ever more performance into computers. Now, fundamental physical limits to current technology have the industry scouring the research world for an alternative. In a paper published in the Aug. 1 Physical Review Letters, Stanford University physicists present ''orbitronics,'' an alternative to conventional electronics that could someday allow engineers to skirt a daunting limit while still using cheap, familiar silicon. Read more

Electrical Exercise System Gives Paralysis Sufferers Power To Recover Strength

Engineering and Physical Sciences Research Council Press Release, 2 Aug 2005 People affected by paralysis could enjoy more independence, better health and a higher quality of life thanks to an innovative system designed to improve fitness and increase arm strength. This breakthrough is the result of a collaborative project undertaken by University of Glasgow engineers and Glasgow's Queen Elizabeth National Spinal Injuries Unit with funding from the Engineering and Physical Sciences Research Council. The areas covered range from information technology to structural engineering, and mathematics to materials science. Read more

Emissions-Free, Petroleum-Free Vehicles

National Academies Press Release, 2 Aug 2005 A public-private effort to develop more fuel-efficient automobiles and eventually introduce hydrogen as a transportation fuel is well-planned and identifies all major hurdles the program will face, says a new report from the National Academies' National Research Council. Many technical barriers must be overcome and new inventions will be needed, but the program, which was launched three years ago, has already made an excellent start, said the committee that wrote the report. Read more

Optoelectronics To Increase the Broadband Flow

Press Release, 3 Aug 2005 The broadband boom is creating an ever-increasing demand for more capacity and higher rates of data transfer on both fixed-line and wireless networks. Helping to meet that demand, without the need to lay costly new infrastructure, is the LABELS project. Read more

Optoelectronic Integration Overcoming Processor Bottlenecks

Press Release, 3 Aug 2005 One of the biggest obstacles facing computer systems today is the problem of memory latency, the time a computer must wait to access the data stored in memory despite faster processor speeds. Two demonstrators reveal that optoelectronics may offer solutions. Read more

'Eternal Planes' To Watch Over Us

by Jo Twist BBC News, 2 Aug 2005 Unmanned Aerial Vehicles patrol innocuous-looking skies and silently report back streams of strategically important data, video, and images from locations around the world. They are the ultimate Earth watchers. Read more