January 10, 2006, 7:14 PM CT

ESA Warns Asthma Sufferers By Mobile Phone

We all wonder what is in the air for 2006-but for people with asthma and other breathing problems, advance knowledge of air pollution levels is very important. An ESA-backed project is forecasting daily forecasts via text message to selected individuals in parts of London and the London borough of Croydon.

As the video above recounts, the service anticipated particularly high levels of air pollution during late June 2005, when a concentrated air pollution mass formed over central Europe. The winds carried that pollution to England, with ozone reaching harmful levels in London on 24 to 26 June.

However as part of a portfolio of services called PROMOTE, this development was predicted by the sophisticated French air quality modeling service PREV'AIR. Another PROMOTE service, YourAir, then included these inputs when modeling local air quality in the London borough of Croydon. Then, through a trial system called AirTEXT, a warning was sent via SMS text messages to around a thousand people with asthma or other vulnerable conditions, one day in advance of the elevated ozone levels.

The YourAir service combines regional air quality forecasts from PROMOTE partners with information on local road traffic patterns. The regional air quality information is important because not all pollution affecting a city actually originates there-studies show that up to half may originate elsewhere.........

Posted by: Kevin      Permalink


January 8, 2006, 11:52 AM CT

Supersolid Matter In Making

The scientists at the university of the State of Pennsylvania announce the possible discovery of an entirely new matter phase: a ultra-cold, forms "supersolid" of helium-4.

Writing in a January issue of the nature, the physicist Moise H. W Chan and his graduated student, Eun-Seong Kim of state of Penn, explain why their material is a solid in the sense that all its atoms helium-4 are cold in a rigid crystal trellis, just like the atoms and the molecules in a normal solid such as the ice. The difference is that "frozen," in this case, does not mean "stationary." Since the trellis helium-4 is so much very cold, less than one tenth of a degree above absolute zero, the laws of the uncertainty of quantum succeeds. Indeed, the helium atoms start to behave as if they were solid and fluid in the the same time. In the good circumstances, in fact, a certain fraction of the helium atoms can start to move by the trellis like a substance known under the name of "superfluid": a liquid which moves without friction some. Thus the "named supersolid".........

Posted by: Sarah      Permalink


January 4, 2006, 10:41 PM CT

Radiation studies key to nuclear reactor life

Two UW-Madison projects to study advanced materials and fuels for current and future nuclear reactors received roughly $1 million this month under the Department of Energy Nuclear Energy Research Initiative (NERI).

The NERI program supports research and development under three Department of Energy nuclear initiatives: Generation IV nuclear energy systems, advanced fuel cycles and nuclear hydrogen.

In one three-year project, UW-Madison nuclear engineers will study the resistance to radiation damage of oxide, carbide and nitride nuclear fuel "matrix" materials-the vessels that contain nuclear fuel. A second project will exploit recent advances in computational power and technique to develop computer models of how a reactor's structural materials behave as a result of long-term radiation exposure.

The projects were among 24 selected across the country; UW-Madison was among five universities to receive funding for multiple projects.

Matrix materials are a key element of future fast-spectrum reactors, which are capable of safely and efficiently recycling spent nuclear fuel. The nuclear fission process produces high-energy radioactive neutrons, called "fast" because of their great energy. Current thermal reactors use a moderator to reduce the neutrons' velocity, making them capable of sustaining the nuclear fission reaction using simpler fuel.........

Posted by: Jaison      Permalink


December 30, 2005, 4:52 PM CT

Most detailed image of the Crab Nebula

A new Hubble image - among the largest ever produced with the Earth-orbiting observatory - gives the most detailed view so far of the entire Crab Nebula. The Crab is arguably the single most interesting object, as well as one of the most studied, in all of astronomy. The image is the largest ever taken with Hubble's WFPC2 workhorse camera.

The Crab Nebula is one of the most intricately structured and highly dynamical objects ever observed. The new Hubble image of the Crab was assembled from 24 individual exposures taken with the NASA/ESA Hubble Space Telescope's Wide Field and Planetary Camera 2 (WPFC2) and is the highest resolution image of the entire Crab Nebula ever made.

The Crab Nebula is a six-light-year-wide expanding remnant of a star's supernova explosion. Japanese and Chinese astronomers witnessed this violent event nearly 1,000 years ago in 1054.

The filaments are the tattered remains of the star and consist mostly of hydrogen. The rapidly spinning neutron star embedded in the centre of the nebula, only barely visible in this Hubble image, is the dynamo powering the nebula's eerie interior bluish glow. The blue light comes from electrons whirling at nearly the speed of light around magnetic field lines from the neutron star. The neutron star, like a lighthouse, ejects twin beams of radiation that appear to pulse 30 times a second due to the neutron star's rotation. A neutron star is the crushed ultra-dense core of the exploded star.........

Posted by: Brooke      Permalink


December 29, 2005, 0:02 AM CT

Black Hole Swallowing Neutron Star

Scientists using the NASA Swift satellite have found evidence of a black hole swallowing a neutron star. The discovery is reported in the December 15 issue of the journal Nature.

This rare event, seen on 24 July 2005, created a gamma-ray burst that lasted only for a few milliseconds. Observations of the lingering afterglow, however, provided evidence of what could have been the bizarre demise of a neutron star orbiting a black hole. The black hole may have first stretched the dense neutron star into a crescent, breaking off crumbs in the process. The black hole then could have swallowed the star largely in one gulp, feeding on the crumbs in the minutes and hours that followed. Such a black hole would grow more massive, like a python that downs a wild boar.

"For billions of years this black hole and neutron star orbited each other in a gravitational tug-of-war," said Scott Barthelmy of NASA Goddard Space Flight Center in Greenbelt, Maryland, lead author on one of three the Nature articles on the subject. "The neutron star lost."

In recent months the Swift team has reported that "short" gamma-ray bursts arise from a merger either between two neutron stars or a neutron star and black hole. The specific scenario was not clear. This latest analysis of a July burst, although not definitive, is the best evidence of a black hole-neutron star merger, Barthelmy said.........

Posted by: Brooke      Permalink


December 28, 2005, 11:55 PM CT

Additives May Save Energy for Cooling

A National Institute of Standards and Technology (NIST) researcher has come up with a method designed to improve the energy efficiency of water chillers that cool the nation's large commercial buildings. The NIST method, if confirmed through experiments with full-scale chiller systems, could save as much as 1 percent of the 320 billion kWh of electricity used annually by chillers or an equivalent 5.5 million barrels of oil per year, according to Mark Kedzierski, the NIST mechanical engineer who developed the technique.

The advance builds on past NIST research designed to optimize mixtures of chiller refrigerants with lubricants. The scientists discovered that some lubricants, when injected in small amounts, can significantly enhance evaporator heat transfer, increasing the efficiency of chillers. When they studied the process more closely they found the most efficient heat transfer occurred when the added oil's surface tension, viscosity, composition and chemical characteristics complemented those of the chiller's base lubricant.

In a recent paper* describing the method, Kedzierski describes how the right additive forms a very thin covering on an evaporator surface, which produces enhanced bubbling during boiling. The improved conversion of the refrigerant molecules into vapor molecules increases the chiller's cooling capacity similar to a heat pump.........

Posted by: Jaison      Permalink


December 28, 2005, 11:52 PM CT

Copper Ridges and X-ray Sensor Performance

A series of copper ridges nearly doubles the resolution of experimental X-ray sensors, enabling more precise identification of the X-ray "fingerprints" of different atoms, scientists at the National Institute of Standards and Technology (NIST) report. The sensors are expected to be powerful tools for astronomy, such as in determining the temperature and motion of matter in space, and for semiconductor materials analysis, helping to differentiate between nanoscale contaminant particles on silicon wafers.

The new design, described in the Nov. 7 issue of Applied Physics Letters,* can measure X-ray energies with an uncertainty of only 2.4 electron volts (eV), breaking through a long-standing 4.5 eV plateau in the performance of superconducting "transition edge" sensors (TES). The cryogenic sensors absorb individual X-rays and measure the energy based on the resulting rise in temperature. The temperature is measured with a bilayer of normal metal (copper) and superconducting metal (molybdenum) that changes resistance in response to the heat from the radiation. The new TES design performs about 40 times better than conventional X-ray sensors made of silicon and lithium.

The primary design change was the addition of five copper ridges patterned on the sensor, perpendicular to the current flow, which blunts or softens the change in resistance from superconducting to normal. NIST holds a patent on the sensor design concept.** The gentler transition reduces unexplained "noise" that degrades measurement precision. A second change was a reduction in device size from 400 to 250 micrometers square, which increases the rise in temperature caused by the X-rays, to better match the broader temperature range of the change in resistance.........

Posted by: Jaison      Permalink


December 26, 2005, 10:30 PM CT

First Gamma-ray Bursts Detected By New Nasa Satellite

Cosmic gamma-ray bursts produce more energy in the blink of an eye, than the Sun will release in its entire lifetime. These short-lived explosions appear to be the death throes of massive stars, and, a number of researchers believe, mark the birth of black holes. Testing these ideas has been difficult, however, because the bursts fade so quickly and rapid action is required. Now a team of Carnegie and Caltech astronomers, led by Carnegie-Princeton and Hubble fellow Edo Berger, has made crucial strides toward answering these cosmic quandaries. The team was able to discover and study burst afterglows thanks to the exquisite performance of NASA's new Swift satellite and rapid follow-up with telescopes in both the southern and northern hemispheres.

"I'm thrilled," said Berger. "We've shown that we can chase the Swift bursts at a moment's notice, even right before Christmas! This is a great sign of exciting advances down the road." The discoveries herald a new era in the study of gamma-ray bursts, hundreds of which are expected to be discovered and scrutinized in the next several years.

The Swift satellite detected the first of the four bursts on December 23, 2004, in the constellation Puppis, and Carnegie astronomers used telescopes at the Las Campanas Observatory in Chile to pinpoint the visual afterglow within several hours. This was the first burst detected solely by the new Swift satellite to be pinpointed with sufficient accuracy to study the remains. The next three bursts came in quick succession between January 17 and 26 and were immediately pinpointed by a team of Carnegie and Caltech astronomers using the Palomar Mountain 200-inch Hale telescope in California and the Keck Observatory 10-meter telescopes in Hawaii.........

Posted by: Brooke      Permalink


December 26, 2005, 5:08 PM CT

Vortex In Engineered Superconductor

They look like tiny swirling dust devils on the surface of the superconductor: "vortices" that appear where magnetic fields interact with the material. Unlike harmless dust devils, however, vortices can sap a superconductor's ability to transmit current without resistance.

Knowing how the vortices move and arrange themselves under various temperatures and magnetic fields, as well as how they are influenced by the physical properties of the material, is critical in maintaining supercurrent flow.

As part of Argonne's intense focus on superconductors, a team of researchers in the laboratory's Materials Science Division (MSD) has obtained, for the first time, detailed images of the interaction of magnetic vortices with artificial, nanoscale engineered defects in a superconductor. Understanding this interaction could help researchers reduce the vortices' current-sapping effects - or lead to fundamentally new superconductor designs for transmitting DC and AC electric power, and quantum logic devices based on vortex manipulation.

High-temperature superconductors, discovered in 1986, have attracted intense interest due to their ability to conduct electricity without resistance when cooled with liquid nitrogen. Previously, superconductivity was only known in metals cooled with liquid helium, which is much more difficult and expensive to produce and handle. High-temperature superconductors are now used in a number of applications, including RF filters for mobile telephone networks, magnetic resonance imaging (MRI) machines and particle accelerators.

A critical factor limiting applications for these superconductors is their response to magnetic fields, such as in electric motors. Magnetic fields reduce the amount of current a superconducting material can carry. The fields create swirling tubes of electrical current - vortices - in the superconducting material. Superconductivity is completely suppressed within these structures. (The individual structure of vortices and their arrangement were predicted by Alexei Abrikosov of Argonne's Materials Science Division, who won the 2003 Nobel Prize in physics for his work on superconductors.) And as current flows through the superconductor, the vortices are pushed at right angles to the current flow by the Lorentz force. The vortex movement inside the material dissipates energy and produces resistance.........

Posted by: Jaison      Permalink


December 26, 2005, 4:48 PM CT

Keys To Improving Commercial Magnet Technology

Permanent magnets are important in a broad variety of commercial technologies, from car starters to alternators for wind power generation to computer hard drives. Scientists at the U.S. Department of Energy's Argonne National Laboratory have found new clues to making those magnets longer-lasting and more powerful.

Using the Western Hemisphere's most powerful X-rays at the Advanced Photon Source at Argonne, the scientists were able to see new details of rare-earth ions, a critical component of permanent magnets. The examination of the ions, probing their magnetism with unprecedented resolution, revealed that the presence of rare-earth ions in more than one atomic environment reduces the magnetic stability of the best-performing permanent magnets to date. This knowledge will enable manufacturers to manipulate the rare-earth ion atomic structure for optimization of future magnets.

The research is published this week in Physical Review Letters.

Rare-earth ions come from metallic elements that share similar chemical properties; they are not particularly rare, but they are used sparingly because of the high cost in preparation of the materials. Rare-earth ions play an important role in determining magnetic stability against demagnetizing fields, and therefore in magnet performance.

"The research found that rare-earth ions in dissimilar crystalline environments compete with one another, and undermine the magnetic performance of the highest performance magnets," said Argonne scientist Daniel Haskel, who led the research team. "These findings point to the need for specialized atomic engineering of the material - manipulating the rare-earth local atomic structure to fully utilize the rare-earth contribution in next generations of magnets".........

Posted by: Jaison      Permalink