Search This Blog

Thursday, November 1, 2007

Scientists Discover New Way To Make Water


Scientists Discover New Way To Make Water


In a familiar high-school chemistry demonstration, an instructor first uses electricity to split liquid water into its constituent gases, hydrogen and oxygen. Then, by combining the two gases and igniting them with a spark, the instructor changes the gases back into water with a loud pop.


Scientists at the University of Illinois have discovered a new way to make water, and without the pop. Not only can they make water from unlikely starting materials, such as alcohols, their work could also lead to better catalysts and less expensive fuel cells.


"We found that unconventional metal hydrides can be used for a chemical process called oxygen reduction, which is an essential part of the process of making water," said Zachariah Heiden, a doctoral student and lead author of a paper accepted for publication in the Journal of the American Chemical Society, and posted on its Web site.


A water molecule (formally known as dihydrogen monoxide) is composed of two hydrogen atoms and one oxygen atom. But you can't simply take two hydrogen atoms and stick them onto an oxygen atom. The actual reaction to make water is a bit more complicated: 2H2 + O2 = 2H2O + Energy.


In English, the equation says: To produce two molecules of water (H2O), two molecules of diatomic hydrogen (H2) must be combined with one molecule of diatomic oxygen (O2). Energy will be released in the process.


"This reaction (2H2 + O2 = 2H2O + Energy) has been known for two centuries, but until now no one has made it work in a homogeneous solution," said Thomas Rauchfuss, a U. of I. professor of chemistry and the paper's corresponding author.


The well-known reaction also describes what happens inside a hydrogen fuel cell.


In a typical fuel cell, the diatomic hydrogen gas enters one side of the cell, diatomic oxygen gas enters the other side. The hydrogen molecules lose their electrons and become positively charged through a process called oxidation, while the oxygen molecules gain four electrons and become negatively charged through a process called reduction. The negatively charged oxygen ions combine with positively charged hydrogen ions to form water and release electrical energy.


The "difficult side" of the fuel cell is the oxygen reduction reaction, not the hydrogen oxidation reaction, Rauchfuss said. "We found, however, that new catalysts for oxygen reduction could also lead to new chemical means for hydrogen oxidation."


Rauchfuss and Heiden recently investigated a relatively new generation of transfer hydrogenation catalysts for use as unconventional metal hydrides for oxygen reduction.


In their JACS paper, the researchers focus exclusively on the oxidative reactivity of iridium-based transfer hydogenation catalysts in a homogenous, non-aqueous solution. They found the iridium complex effects both the oxidation of alcohols, and the reduction of the oxygen.


"Most compounds react with either hydrogen or oxygen, but this catalyst reacts with both," Heiden said. "It reacts with hydrogen to form a hydride, and then reacts with oxygen to make water; and it does this in a homogeneous, non-aqueous solvent."


The new catalysts could lead to eventual development of more efficient hydrogen fuel cells, substantially lowering their cost, Heiden said.


The work was funded by the U.S. Department of Energy.




Technorati : , , , ,

New mathematical model predicts more virulent microbes


New mathematical model predicts more virulent microbes


Microbes and humans interact in myriad ways, sharing a long history. Many of the most successful microbes are those that inhabit but do not kill their host. Cheaters lose. Tuberculosis settles into the lungs. Helicobacter pylori, the microbe causing ulcers, burrows into the stomach where it thrives on acids. And Salmonella typhi takes up residence in the gallbladder. All of these organisms can persist in our bodies for decades. What explains their success?


A new mathematical model, devised by a microbiologist renowned for his study of H. pylori and a mathematician, provides the framework for understanding how persistent microbes obtain equilibrium with their human hosts. The multi-scale model, published in the October 18, 2007, issue of the journal Nature, is based on the idea that certain microbes and humans evolved together and along the way established complex strategies that enabled them to co-exist. These strategies are contingent in part on human population size.


The model helps explain the rules that govern the transmission of microbes and how they have operated in human history, says Martin J. Blaser, M.D., the Frederick King Professor and Chair of the Department of Medicine, and Professor of Microbiology at New York University School of Medicine. He and Denise Kirschner of the University of Michigan Medical School, Ann Arbor, are authors of the study. The model uses game theory, developed by Nobel prize-winning mathematician John Nash, the subject of the book and movie A Beautiful Mind, to describe a particular type of equilibrium.


The model can be used to better understand microbial responses to a changing human world, says Dr. Blaser. Based on their formulations, our biological future will probably be filled with some "pretty bad epidemics," says Dr. Blaser. "Our model predicts that as effective population size increases and as immunodeficiency increases due to the spread of HIV infection, and an aging population, there will be more virulent organisms. This is bad news for us."


Through the course of human evolution, Drs. Blaser and Kirschner propose that three classes of persistent microbes have evolved, each employing a different biological strategy to avoid being eliminated quickly by their human hosts. TB, H. pylori, and Salmonella are an example of each class. Any microbe that was "cheating" the system, in other words, tried to expand its territory in the body, wouldn't survive because it would likely kill its host.


According to their theory, small populations select for certain kinds of microbial agents. More than 50,000 years ago, when humans lived as hunter-gatherers in small, isolated groups, the majority of microbes were transmitted within families or were those that would emerge late in life. Microbes that were not lethal were favored because there wasn't a large reservoir of people to infect. Any microbe that killed off its hosts, wouldn't have survived itself. H. pylori evolved during this time.


As population size increased and humans became less isolated, organisms that had perfected ways to hide in the body for decades, such as TB and Salmonella typhi, and then suddenly reactivate or get transmitted, evolved. These organisms could afford to induce more disease early in life because they had mechanisms to sustain themselves in human populations.


As even larger societies developed, more virulent organisms, such as measles, emerged because the population could permit the virus to spread. Our most recent epidemics, including influenza in the early 20th century and AIDS today, involve organisms that can kill millions because these highly virulent organisms have a huge pool of people to infect, and still be transmitted.


"We did not make the laws of nature," says Dr. Blaser. "Even though we may not like them, we need to understand them to better control infectious diseases."




Technorati : , , , , ,

Intel Unveils Seven New Itanium Processors


Intel Unveils Seven New Itanium Processors


Underscoring strong momentum and industry support, Intel Corporation today unveiled Dual-Core Intel Itanium Processor 9100 series processors. Built for managing high-end applications and armed with advanced features that improve reliability and reduce power consumption, the 9100 series accentuates the ongoing shift from proprietary RISC products to the choice offered by Itanium-based servers. The 9100 series represents the sixth generation of Itanium chips, with three future generations under development.


The Itanium platform's mission-critical support is strengthened by a new feature called Core Level Lock-Step that improves the data integrity and reliability of applications by eliminating undetected errors in the core. Core Level Lock-Step joins existing Socket Level Lock-Step technology to deliver greater reliability, availability and serviceability (RAS) by guaranteeing that calculation results are consistent among the cores and sockets.


Another new feature, Demand Based Switching (DBS), reduces server power consumption during low utilization periods, which can result in energy cost savings.


The 9100 series features clock speed of up to 1.66 GHz and 667 MHz Front Side Bus (FSB) within a 104W power envelope. A three-load bus - two processors and a chipset on the same bus - provides increased bandwidth for enterprise and high-performance computing tasks.


"The Itanium ecosystem continues to grow as customers choose industry standard platforms supported by leading system OEMs that provide them with the broadest choice of applications." said Pat Gelsinger, senior vice president and general manager, Intel's Digital Enterprise Group.


Unlike products from the remaining RISC vendors, the 9100 series continues to offer end-user freedom through a broad choice of software with more than 12,000 applications in production, and flexibility to support multiple operating systems, including Linux, Windows, HP-UX, HP NonStop, HP OpenVMS, z/OS and Solaris/SPARC.


"Microsoft continues to be a committed supporter of the Itanium architecture, and with the 9100 series our enterprise customers can run even more highly scalable and reliable databases and business applications," said Bill Laing, general manager, Windows Server Division at Microsoft. "Supporting the Demand-Based Switching feature on Microsoft Windows Server 2008 for Itanium-Based Systems will help businesses better manage power consumption and improve the efficiency of their enterprise operations."


"Red Hat is excited about the launch of Intel's latest Itanium processor-based platforms," said Paul Cormier, Red Hat's executive vice president of Worldwide Engineering. "We have worked closely with Intel in an effort to ensure that our upcoming release of Red Hat Enterprise Linux 5.1 fully supports the latest RAS and virtualization features that Intel delivers with this platform. By working closely together, we are able to deliver the industry-leading 64-bit platform our customers are asking for, presenting them with an opportunity to significantly drive down their total cost of ownership in the datacenter."


Customers in industries that rely on real-time decision-making based on large amounts of data, such as energy, financial services, healthcare, manufacturing and telecommunications, are taking advantage of Itanium's open architecture, advanced parallelism, and extreme scalability and flexibility.


All server-maker members of the Itanium Solutions Alliance (ISA) will launch new Dual-Core Intel Itanium Processor 9100 series-based products, including Bull, Fujitsu, Fujitsu Siemens Computers, HP, Hitachi, Intel, NEC, SGI and Unisys.


The 9100 series, with its extensive virtualization partitioning features, is the premier platform for RISC and mainframe migration. Itanium offers a single platform for virtualization of diverse OS environments such zOS, legacy Unix, Linux and Windows; allowing for the consolidation of applications from old proprietary platforms. The 9100 series has also garnered virtualization support from key developers, including Transitive and SWsoft.


"SWsoft Virtuozzo 4.0 on the new Itanium processor will enhance operating-system level virtualization support for Windows and Linux server infrastructure," said SWsoft CEO Serguei Beloussov. "The combination of scalability in Itanium platforms and the proven density and performance characteristics of Virtuozzo virtualization make an ideal platform for consolidation of mission-critical applications."


"Transitive is releasing its QuickTransit for Solaris/Sparc-to-Linux/Itanium solution today." said Transitive President and CEO Bob Wiederhold. "The combination of QuickTransit with servers equipped with Itanium processors provides datacenter operators with the ability to run legacy Solaris/SPARC applications on standards-based platforms without porting or recompilation, thereby allowing them greater efficiency, flexibility and return on investment."


Six Intel dual-core and a single-core Itanium 9100 series processors are shipping today, with prices ranging from $696 to $3,692 depending on order volume, features and performance. Parts supporting Core level Lock-Step will begin shipping in the first quarter of 2008.




Technorati : , , , , ,

Researchers Uncover Physics of Coiling Ropes


Researchers Uncover Physics of Coiling Ropes


When a mountain climber drops a rope, it often forms a series of coils on the ground. Not only thick ropes, but also sewing thread and even cooked spaghetti behave in a similar way. Recently, scientists have carried out the first controlled laboratory experiments on the peculiar phenomenon of coiling ropes, revealing the surprising dynamics behind it.


Researchers Mehdi Habibi, Neil Ribe, and Daniel Bonn, together representing the Institute for Advanced Studies in Basic Sciences in Iran, the École Normale Supérieure and the Institut de Physique du Globe in Paris, and the University of Amsterdam, have published their results on the coiling of elastic ropes in a recent issue of Physical Review Letters.


"With the results of this work, we -- finally -- are able to understand such a widespread phenomenon as rope coiling," Bonn told PhysOrg.com. "Understanding coiling is important, for instance, in the food industry, where one needs to fill jars with visco-elastic materials such as yogurt or mayonnaise. Coiling has also been used to make pottery."


The scientists used two experimental setups to investigate the different conditions under which coiling occurs. In the first setup, they wound sewing thread onto a wheel, which was rotated by an electric motor to feed the thread down through a hole at a fixed rate (with tests from 0.3 - 200 cm/sec-1) onto a flat surface 2 - 200 cm below. In the second setup, they softened long pieces of spaghetti in water, and used a syringe or a rod to eject the noodles downward from a vertical glass tube.


By comparing their laboratory measurements with the predictions of a numerical model, the group developed a phase diagram showing the different styles of coiling that occur depending on the fall height and velocity. Depending on these variables, there are three basic regimes where coiling can occur.


"For the lowest fall heights and velocities, the coil frequency and radius are dictated by the geometry: the coiling frequency, for instance follows simply from the fall height and rope velocity," Bonn explained. "For intermediate heights and velocities, there is a balance between the gravity force and the rope's elasticity that uniquely determines the frequency and radius of coiling. For very high velocities and heights, it's mainly the inertia of the rope that dictates its behavior, but the elasticity of the rope remains important: this is the inertial regime."


Habibi, Ribe and Bonn found that the inertial regime in particular is surprisingly complex. First, they observed that a thin thread fed at very high velocities becomes unstable to form a "figure of eight" pattern that persists for the length of the thread.


Second, they found that coiling in the inertial regime can occur with different frequencies for a given feed rate and fall height. The different frequencies correspond to resonant oscillations of the nearly vertical upper part of the rope, which can vibrate either as a weak "string" or as a stiff "shaft" depending on the feed rate and the fall height. These oscillations are excited when their natural frequencies happen to match the basic "inertial regime" frequency dictated by the coiled part of the rope just above the ground.


The scientists noted that other examples of coiling "elastic rods" include phenomena such as the kinking of telephone cables on the ocean floor, the coiled tendrils of climbing plants exhibiting handedness reversal, and the supercoiling of DNA strands. The coiling of liquid ropes, such as a thread of honey falling onto toast, has also received recent attention, and shares some similarities with the coiling of elastic ropes.




Technorati : , , , ,

Google Gets More Social With New Network


Google Gets More Social With New Network


Google Inc. is setting up a distribution network for social networking applications, adding a new twist in the Internet search leader's brewing rivalry with rapidly maturing startup Facebook Inc.


Google hopes to build a one-stop shop for software developers who create tools that make it easier to share music, pictures, video and other personal interests on social networking sites like Facebook and News Corp.'s MySpace.com.


The popularity of these applications, also known as "widgets," has grown dramatically since Facebook opened its Web site to accommodate outside developers five months ago.


Facebook now hosts more than 8,000 widgets, helping to boost its worldwide audience to about 50 million users and elevate its market value to $15 billion after Microsoft Corp. paid $240 million for a 1.6 percent stake in the Palo Alto-based company last week.


Microsoft trumped Google in the bidding for a piece of Facebook. Google's bigger social networking ambition is believed to be one of the reasons Facebook decided to deepen its partnership with Microsoft instead.


Google now hopes to attract many of the same applications thriving on Facebook to its own network, dubbed "OpenSocial."


The system is set up so the participating software developers will only have to code their applications once. Google will then ensure they are compatible with all the Web sites in its network.


The early participants in OpenSocial include social networking destinations like LinkedIn, hi5.com, Friendster and Ning, as well as the Web sites of business software specialists Salesforce.com Inc. and Oracle Corp.


Google also will feature the applications on its own social network, Orkut, which hasn't attracted much traffic outside South America.


OpenSocial's combined audience will exceed 100 million users, according to Google.


The list of developers feeding applications to Google include three of Facebook's most popular Widget suppliers - Slide, RockYou and iLike.


Mountain View-based Google won't try to make money from the OpenSocial network right away but hasn't ruled out the possibility of eventually inserting ads into the applications.


"There is no question Google will benefit from this," Joe Kraus, a Google product manager, said in a Tuesday interview. "Google's role is highly intertwined with the Web, so anything that makes the Web a better experience tends to help Google."


While Google muscles into the social networking scene, Facebook appears to be gearing up to grab some of the advertising revenue that has been pouring into Google. Facebook is expected to discuss its plans for its own advertising network during a Nov. 6 event scheduled in New York.




Technorati : , , ,

Magnetic fields may stop young stars self-destructing


Magnetic fields may stop young stars self-destructing


UNLIKE human infants, newborn stars seem to have a way to stop themselves getting too hyper for their own good. When stars form from a spinning disc of gas and dust, they should spin ever faster as gravity pulls this matter in towards the centre - just as pirouetting ice skaters spin faster as they retract their arms - and so throw material back out. Yet for some reason this doesn't happen.
Now researchers have shown that a young star's magnetic field could slow the disc's overall spin by helping to get rid of the fastest-spinning material, removing it in giant perpendicular plumes. "Lots of people have seen these jets moving rapidly away from forming stars, but we never understood why they were so well-formed," says Philip Lucas at the University of Hertfordshire. The team's computer model suggests spiral-shaped magnetic fields are the most likely to form plumes



The Magnetic Fields


Magnetic fields are produced by electric currents, which can be macroscopic currents in wires, or microscopic currents associated with electrons in atomic orbits. The magnetic field B is defined in terms of force on moving charge in the Lorentz force law. The interaction of magnetic field with charge leads to many practical applications. Magnetic field sources are essentially dipolar in nature, having a north and south magnetic pole. The SI unit for magnetic field is the Tesla, which can be seen from the magnetic part of the Lorentz force law Fmagnetic = qvB to be composed of (Newton x second)/(Coulomb x meter). A smaller magnetic field unit is the Gauss (1 Tesla = 10,000 Gauss).






Technorati : , , , ,

NASA postpones spacewalk until Friday


NASA postpones spacewalk until Friday


NASA has postponed for one day a spacewalk by two crew members from the Discovery space shuttle, pushing it back from Thursday to Friday, US space officials said.
They said the spacewalk, the fourth of this current mission, will focus on repairing a panel torn Tuesday on one wing of a solar array.


"The flight control team has just informed the crew that the mission's fourth spacewalk is now targeted for Friday," the US space agency said in a statement Wednesday. "The spacewalk will be focused on the solar array wing."


The solar panel on the International Space Station ripped as the antenna was deployed Tuesday.


The solar antenna, which has wings measuring 76 meters (249 feet) when unfurled, was repositioned after astronauts earlier successfully installed a massive truss that is used to rotate the energy-generating solar arrays.


NASA estimated the tear in the panel to be about 90 centimeters (35 inches), but said the solar antenna nevertheless has been providing about 97 percent of the energy it supplies to the space station.


The solar array is critical to providing power for the European Laboratory scheduled for delivery in December.


Another solar array is crippled by a malfunctioning rotary mechanism which was supposed to have been inspected during the spacewalk originally scheduled for Thursday.


Officials had planned to examine the rotary joint after having found small metal shavings and unusual wear in the joint in a space walk on Sunday.


All three solar arrays have to be fully operational before a Japanese laboratory can be delivered to the ISS next spring.


The shuttle, which blasted off on October 23, now is scheduled to return to Earth on November 7, after NASA earlier this week extended the mission by one day.






Technorati : , , ,

Find here

Home II Large Hadron Cillider News