Science & TechnologyS


House

Secret Of Sandcastle Construction Could Help Revive Ancient Building Technique


ScienceDaily
Wed, 03 Jun 2009 08:03 UTC
The secret of a successful sandcastle could aid the revival of an ancient eco-friendly building technique, according to research led by Durham University.

Researchers, led by experts at Durham's School of Engineering, have carried out a study into the strength of rammed earth, which is growing in popularity as a sustainable building method. Just as a sandcastle needs a little water to stand up, the Durham engineers found that the strength of rammed earth was heavily dependent on its water content.

Rammed earth is a manufactured material made up of sand, gravel and clay which is moistened and then compacted between forms to build walls. Sometimes stabilisers such as cement are added but the Durham research focussed on unstabilised materials.
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Rocket

Mars Orbiter Resumes Science Observations


Jet Propulsion Laborator
Wed, 10 Jun 2009 01:08 UTC
Image
© NASA/JPLArtist concept of Mars Reconnaissance Orbiter.
Pasadena, Calif. -- NASA's Mars Reconnaissance Orbiter is examining Mars again with its scientific instruments after successfully transitioning out of a precautionary standby mode triggered by an unexpected June 3 rebooting of its computer.

Engineers brought the spacecraft out of the standby mode on June 6. Cameras and other scientific instruments resumed operation June 9.
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Einstein

Scientists make metal that guides liquids


United Press International
Wed, 10 Jun 2009 01:01 UTC
Rochester, N.Y- U.S. physicists are using an ultra-fast laser to create metal that can attract, repel and guide liquids.

University of Rochester scientists said they are able to create a simple slab of metal that lifts liquid using the same principle as do trees to lift water from the ground -- capillary action -- but at a much faster rate, the researchers said.

Associate Professor Chunlei Guo, who led the study, and researcher Anatoliy Vorobyev, use an ultra-fast burst of femtosecond laser light to change the surface of a metal, forming nanoscale and microscale pits, globules and strands across the metal's surface.
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Robot

IDF developing battlefield robot snake

Dov Lieber
AP/Jerusalem Post Online
Tue, 09 Jun 2009 14:10 UTC

A robot snake, capable of recording video and sound on the battlefield, is the latest addition to the IDF's technological achievements.

According to a Channel 2 report, the spying robot, about two meters long and covered in army camouflage, mimics the movements and appearance of a real snake, slithering around through caves, tunnels, cracks and buildings, sending images and sound back to a soldier controlling the device through a laptop. The snake has a single camera on front end.

Able to bend its joints so well that it can slither through very tight spaces, the new robotic device will be utilized to find people buried under rubble of collapsed buildings. Furthermore, the snake is able to arch its body straight, allowing it to see over obstacles.
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Sherlock

Archeological Evidence of Human Activity Found Beneath Lake Huron, Michigan


PhysOrg
Mon, 08 Jun 2009 21:47 UTC
More than 100 feet deep in Lake Huron, on a wide stoney ridge that 9,000 years ago was a land bridge, University of Michigan researchers have found the first archeological evidence of human activity preserved beneath the Great Lakes.

The researchers located what they believe to be caribou-hunting structures and camps used by the early hunters of the period.

"This is the first time we've identified structures like these on the lake bottom," said John O'Shea, curator of Great Lakes Archaeology in the Museum of Anthropology and professor in the Department of Anthropology. "Scientifically, it's important because the entire ancient landscape has been preserved and has not been modified by farming, or modern development. That has implications for ecology, archaeology and environmental modeling."

A paper about the findings is published in the June 8 issue of Proceedings of the National Academy of Sciences. Co-authors are O'Shea and Guy Meadows, director of the Marine Hydrodynamics Laboratories and a professor in the departments of Naval Architecture and Marine Engineering, and Atmospheric, Oceanic and Space Sciences.
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Magnify

New Antibiotics Could Come From a DNA Binding Compound That Kills Bacteria in 2 Minutes


PhysOrg
Tue, 09 Jun 2009 08:44 UTC
A synthetic DNA binding compound has proved surprisingly effective at binding to the DNA of bacteria and killing all the bacteria it touched within two minutes. The DNA binding properties of the compound were first discovered in the Department of Chemistry at the University of Warwick by Professor Mike Hannon and Professor Alison Rodger (Professor Mike Hannon is now at the University of Birmingham). However the strength of its antibiotic powers have now made it a compound of high interest for University of Warwick researchers working on the development of novel antibiotics.

Dr Adair Richards from the University of Warwick said:

"This research will assist the design of new compounds that can attack bacteria in a highly effective way which gets around the methods bacteria have developed to resist our current antibacterial drugs. As this antibiotic compound operates by targeting DNA, it should avoid all current resistance mechanisms of multi-resistant bacteria such as MRSA."

The compound [Fe2L3]4+ is an iron triple helicate with three organic strands wrapped around two iron centres to give a helix which looks cylindrical in shape and neatly fits within the major groove of a DNA helix. It is about the same size as the parts of a protein that recognise and bind with particular sequences of DNA. The high positive charge of the compound enhances its ability to bind to DNA which is negatively charged.
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Einstein

In Twin Paradox Twist, the Accelerated Twin is Older


PhysOrg
Tue, 09 Jun 2009 08:41 UTC
Time Dilation
© Cetin BalScientists have found that, when twins are orbiting a massive object, time dilation can cause the accelerated twin to be older if that twin is moving slower than the other twin; in this case, velocity is the deciding factor of age, and the twin with the greater velocity is younger.
Just when you thought you were beginning to understand the twin paradox (maybe), scientists have found something new to ponder. In the original version of the famous thought experiment on time dilation, one twin stays on Earth while the other twin takes a rocket at nearly light speed into space, and returns to find that he is younger than his twin on Earth. But a new version of the story now shows that the twin who experiences an acceleration can be older than the twin who doesn't accelerate, under slightly different conditions.

Physicist Marek Abramowicz of Goteborg University in Sweden and astronomer Stanislaw Bajtlik of the Nicolaus Copernicus Astronomical Center in Warszawa, Poland, have proposed the surprising new version of the twin paradox, which at first seems to run contrary to the traditional version. However, the scientists show that the traditional version is actually a specific case of a more general concept.

"In the best known version of the twin paradox, the twin who is accelerated is younger," Abramowicz and Bajtlik told PhysOrg.com. "In the version discussed by us the accelerated twin is older. It is quite surprising. It is almost as to say that 'the older twin is younger.'"
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Magnet

How Mercury retains an Atmosphere

Robert Goodier
Space.com
Tue, 09 Jun 2009 09:08 UTC
Mercury should have trouble hanging on to its atmosphere. It is the closest planet to the sun , its searing daytime temperatures top 800 degrees Fahrenheit (450 degrees Celsius and its gravity is weak, only about 38 percent of Earth's. These conditions don't hold air.

New clues to why Mercury does have a thin atmosphere have been discovered by the MESSENGER spacecraft.

"Mercury's atmosphere is so thin, it would have vanished long ago unless something was replenishing it," James Slavin of NASA's Goddard Space Flight Center, Greenbelt, Md., said in a statement.

That something is the solar wind, charged particles that stream out from the sun and which have a tricky way of skirting the planet's protective magnetic field. The planet has tornado-like magnetic vortices that let charged particles from the sun pour in, Slavin and his colleagues found. The particles kick up atoms at the surface that replenish the planet's thin atmosphere.
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Info

New Technique Improves Estimates Of Pulsar Ages


Space Daily
Tue, 09 Jun 2009 03:14 UTC
Image
© NASA/Dana BerryIsolated pulsars gradually slow their spins, but the opposite happens if the pulsar is joined by a companion star as part of a binary system. Gas accreted from the star can force the pulsar to spin faster, resulting in rotation periods of just a few milliseconds.
Astronomers at the University of California, Santa Cruz, have developed a new technique to determine the ages of millisecond pulsars, the fastest-spinning stars in the universe. The standard method for estimating pulsar ages is known to yield unreliable results, especially for the fast-spinning millisecond pulsars, said Bulent Kiziltan, a graduate student in astronomy and astrophysics at UCSC.

"An accurate determination of pulsar ages is of fundamental importance, because it has ramifications for understanding the formation and evolution of pulsars, the physics of neutron stars, and other areas," he said.

Kiziltan has been working with Stephen Thorsett, professor of astronomy and astrophysics at UCSC, to study the evolution of millisecond pulsars. He will present their new findings at the American Astronomical Society meeting in Pasadena on Monday, June 8.
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Satellite

Japanese probe set to crash into moon

MacGregor Campbell
New Scientist
Tue, 09 Jun 2009 03:03 UTC
Image
© B Foing/B Grieger/ESAKaguya is set to crash into the moon at a lunar latitude of 63° south and longitude of 80° east. Its projected impact site is circled in red in this mosaic of images taken by Europe's SMART-1 spacecraft, which itself smashed into the moon at the end of its mission in 2006
Japan's Kaguya lunar orbiter will end its nearly two-year mission when it collides with the moon at 1830 GMT on Wednesday. Observers may be able to spot a bright flash or plume of dust from the crash, and researchers will study its impact site to watch how radiation and micrometeoroids weather the newly exposed lunar soil over time.

Launched in September 2007, Kaguya, formerly known at SELENE, sought to shed light on the formation and evolution of the moon by studying its composition, gravitational field and surface characteristics.

Kaguya deployed two smaller satellites after reaching lunar orbit that allowed it to relay data to Earth while it was on the moon's far side and to better measure anomalies in the moon's gravitational field (see First gravity map of moon's far side unveiled). It also made the world's first HD video of the lunar surface.
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