September 7, 2006, 5:11 AM CT

Laser Nanoantenna

Engineers and applied researchers from Harvard University have demonstrated a new photonic device with a wide range of potential commercial applications, including dramatically higher capacity for optical data storage. Termed a plasmonic laser antenna, the design consists of a metallic nanostructure, known as an optical antenna, integrated onto the facet of a commercial semiconductor laser.

Spearheaded by two research groups led by Ken Crozier, assistant professor of electrical engineering, and Federico Capasso, Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering, the findings appear in the journal Applied Physics Letters. The scientists have also filed for U.S. patents covering this new class of photonic devices.

"The optical antenna collects light from the laser and concentrates it to an intense spot measuring tens of nanometers, or about one-thousandth the width of a single human hair," says Crozier. "The device could be integrated into optical data storage platforms and used to write bits far smaller than what's now possible with conventional methods. This could lead to vastly increased storage capacities in the terabyte range (a thousand gigabytes)".

Writable CDs and DVDs are a popular means for storing and backing up data, but the storage density is limited by the resolution limit of conventional optics. The optical antenna offers a substantial improvement in spatial resolution, which in turn leads to increased storage density. While optical antennas are similar to conventional antennas used for wireless communications (Wi-Fi), they are much smaller in scale -- only a few hundred nanometers across. Moreover, optical antennas operate in the visible and infrared portion of the electromagnetic spectrum; these wavelengths are far smaller than the wavelengths used in Wi-Fi.........

Posted by: Kevin      Permalink         Source

September 6, 2006, 9:56 PM CT

No Proof For Dark Matter Proof

When Douglas Clowe of the University of Arizona in Tucson announced on 21 August that his team had "direct proof of dark matter's existence", it seemed the issue had been settled. Now proponents of the so-called modified theories of gravity, who explain the motion of stars and galaxies without resorting to dark matter, have hit back and are suggesting that Clowe's team has jumped the gun.

"One should not draw premature conclusions about the existence of dark matter without a careful analysis of alternative gravity theories," writes John Moffat, of the University of Waterloo in Ontario, Canada, who pioneered an alternative theory of gravity known as MOG (www.arxiv.org/astro-ph/0608675).

The controversy centres on the pattern of gravitational lensing, or the bending of light, around the Bullet cluster of galaxies, which formed from the collision of two clusters. While most of the Bullet cluster's visible mass lies in a pool of hot gas near the centre, galaxies can also be seen on either side. Clowe's study of lensing indicates that most of the mass is contained in the two lobes, rather than in the pool of gas. The team says this is evidence of dark matter surrounding the galaxies.

Moffat claims that his MOG theory can explain the Bullet cluster without an ounce of dark matter. In MOG, gravity acts as predicted by Newton's inverse square law up to a certain distance from the gravitating mass, after which it gets a little stronger. In the Bullet cluster, the complex arrangement of galaxies and hot gas combines to make gravity strongest in the lobes, so that is where the lensing would be most apparent. Moffat has worked this out for the Bullet cluster using a.........

Posted by: Kevin      Permalink         Source

September 6, 2006, 5:11 AM CT

Tiny Ion Pump Sets New Standards

University of Washington scientists have succeeded in building a cooling device tiny enough to fit on a computer chip that could work reliably and efficiently with the smallest microelectronic components.

The device, which uses an electrical charge to create a cooling air jet right at the surface of the chip, could be critical to advancing computer technology because future chips will be smaller, more tightly packed and are likely to run hotter than today's chips. As a result, tomorrow's computers will need cooling systems far more efficient than the fans and heat sinks that are used today.

"With this pump, we are able to integrate the entire cooling system right onto a chip," said Alexander Mamishev, associate professor of electrical engineering and principal investigator on the project. "That allows for cooling in applications and spaces where it just wasn't realistic to do before."

The micro-pump also represents the first time that anyone has built a working device at this scale that uses this method, Mamishev added.

"The idea has been around for several years," he said. "But until now it hasn't been physically demonstrated in terms of a working prototype."

Mamishev and doctoral students Nels Jewell-Larsen and Chi-Peng Hsu presented a paper on the device at the American Institute of Aeronautics and Astronautics/American Society of Mechanical Engineers Joint Thermophysics and Heat Transfer Conference earlier this summer and are scheduled to give an additional presentation this fall. In addition, the UW scientists and collaborators with Kronos Advanced Technologies and Intel Corp. have been awarded a $100,000 grant from the Seattle-based Washington Technology Center for the second phase of the project.........

Posted by: Kevin      Permalink         Source

September 5, 2006, 7:31 PM CT

Guide For Removing Data From Computers

Before ditching or donating that used computer, CD or other data-storage media, sensitive or personal information should be properly "sanitized," according to a new guide from the National Institute of Standards and Technology (NIST). Information systems store information using a wide variety of media, including "hard" copy, such as paper printouts and facsimile ribbons, and electronic media, including cell phones, CDs or DVDs, and hard drives. Even if stored data supposedly has been deleted, in many cases residual data can be retrieved and reconstructed.

The NIST guide, Guidelines for Media Sanitization (NIST Special Publication 800-88), provides information on techniques to remove data from a wide variety of media types and a decision matrix to determine which technique is best. The guide recommends that organizations first determine the confidentiality of the information and then decide how to dispose of the media.

The guide describes the three most common methods of sanitizing media:

• Clearing using software or hardware products to overwrite storage space on the media with non-sensitive data.
• Purging magnetic media through degaussing, exposure to a strong magnetic field to disrupt the magnetically encoded information.
• Destroying the media through a variety of methods ranging from shredding to melting and incineration.
........

Posted by: Kevin      Permalink         Source




September 5, 2006, 7:20 PM CT


Gold Nanoparticles Are Hot Stuff


Gold nanoparticles are highly efficient and sensitive "handles" for biological molecules being manipulated and tracked by lasers, but they also can heat up fast-by tens of degrees in just a few nanoseconds-which could either damage the molecules or help study them, as per researchers at JILA, a joint institute of the National Institute of Standards and Technology (NIST) and University of Colorado at Boulder.

Biophysicists often study nanoscale and even picoscale mechanics by using lasers to both apply force to and track the position of fragile biomolecules such as DNA or protein by manipulating a tiny sphere-typically polystyrene-attached to the molecule. The JILA team would like to find new microsphere materials that can be trapped by laser radiation pressure more efficiently, which would enable faster measurements and detection of smaller motions at the same laser power. As described in the Aug. 15 issue of Optics Letters,* the JILA team demonstrated that 100-nanometer-wide gold beads, as expected because of their metallic nature, can be trapped and detected six times more easily than polystyrene particles of a similar size.

However, the researchers also observed that gold absorbs light and heats up quickly, by a remarkable 266 degrees (Celsius) per watt of laser power, at the wavelength most often used in optical traps. Unless very low laser power is used, the heat could damage the molecules under study. Thus, gold beads would not be useful for temperature-sensitive experiments or applying force to molecules. But the heating effect could be useful in raising local temperatures in certain experiments, such as heating a protein just enough to allow researchers to watch it unfold, the paper suggests.........

Posted by: Sarah      Permalink         Source




September 5, 2006, 6:50 PM CT


Secrets of the Atomic Switch


Researchers at the Commerce Department's National Institute of Standards and Technology (NIST) have used a beam of electrons to move a single atom in a small molecule back and forth between two positions on a crystal surface, a significant step toward learning how to build an "atomic switch" that turns electrical signals on and off in nanoscale devices.

The results, described in the Aug. 18, 2006, issue of Science,* are the first would be published about work at NIST's new Center for Nanoscale Science and Technology (www.nist.gov/public_affairs/releases/cnst.htm).

"It's still futuristic to talk about a real atomic switch but we're getting closer," says physicist Joseph Stroscio, lead author of the paper. In addition, by applying the findings to nanoscale fabrication on semiconductors and insulating thin films, it may be possible to develop new classes of electronic and magnetic devices constructed atom by atom.

In the work described in Science, NIST physicists used a custom-built, cryogenic scanning tunneling microscope (STM)-which provides a voltage and beam of electrons at its needle-like tip-to perform several different types of atomic scale measurements and manipulations. NIST theorists performed calculations of the atoms' electronic structure, which confirmed the experimental results.........

Posted by: Sarah      Permalink         Source




September 3, 2006, 6:42 AM CT


Genomics solve world hunger


Genomic technologies may have the potential to alleviate food insecurity and food shortages around the world. Scientists think that biotechnology has the potential to improve the nutritional content of food crops and, crucially, resistance to insects and disease. This could lead to improved yields of food crops for both human and animal consumption. Scientists are also working on 'molecular farming' production of pharmaceutical products in plants, with the potential to revolutionise vaccination procedures. However, these technologies are only likely to impact on world hunger if there is effective and efficient exchange of knowledge and experience through partnerships.

A keynote speaker at the ESRC Innogen Centre's Annual Conference to be held on 5th-6th September at Regent's College, London warns of a caveat to this enthusiasm for the introduction of genomic technologies. Dr Simon Best, Chairman of the Board of the International Crops Research Institute for the Semi-Arid tropics (ICRISAT) highlights the need for greater and more efficient collaboration between the public and private sectors involved in this research. The Director of Development Partnerships for the International Potato Centre (CIP), Dr. Roger Cortbaoui, echoes these arguments saying there is a need to construct, "useful partnerships and networks including with the private sector" in an industry where basic research is dominated by public funded research centres.........

Posted by: Kevin      Permalink         Source




August 31, 2006, 4:11 PM CT


eMachines Model T6536


eMachines have rolled out a new model called T6536 that seems good when comparing quality and price, it's not the great beast better than any computer but it does have some kind of attraction style. Features an AMD Athlon 64 3800+ processor with 1GB of RAM memory, an EIDE hard-drive with a capacity of 250GB, dual-layer DVD burner and on the graphics card there is a nVidia GeForce 6100. It already comes with Microsoft Windows XP Media Center Edition 2005 installed which might not be the best solution, so one of the positive aspects is being compatible with Vista requirements, and the other is the price: $590*.

Full review is available at PCMag site.........

Posted by: Kevin      Permalink         Source




August 29, 2006, 6:42 PM CT


Your Bathroom TV Set


If you can't afford to give your bathroom the luxury of a waterproof TV set, but, you wish you could! Then we have a wonderful option for you that is affordable too, the IP Rated Bathroom TV. The waterproof TV is designed to fit into a wall space approximately the size of a tile. The chrome-finished panel features Sharp's LCD TFT 5-inch screen (diagonal).

The TV comes with a standard 3 pin mains plug, a waterproof remote control, aeriel connection, A/V leads to connect to a DVD/Video etc. The TV features a contrast ratio of 300:1 and it sells for just pounds169.99.........

Posted by: Gina      Permalink         Source


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