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February 21, 2011

New batteries fix themselves

WASHINGTON — A newly created lithium-ion battery that can heal itself may improve the life span and safety of today’s energy-storage technologies, researchers report.

Rechargeable lithium-ion batteries power cell phones, laptops and other portable electronics. But, like any batteries, they tend to break down over time.

"There are many different types of degradation that happen, and fixing this degradation could help us make longer-lasting batteries," said Scott White, a materials engineer at the University of Illinois at Urbana-Champaign who reported the details of the battery February 20 at a meeting of the American Association for the Advancement of Science.

One site of damage is the anode, a battery’s negatively charged terminal. As a battery charges and discharges, the anode swells and shrinks. Over time, this cycling causes damage, creating cracks that can interfere with the flow of current and, ultimately, kill the battery.

To counteract this cracking, White embedded tiny microspheres inside the graphite of an anode. As cracks formed in the anode, they tore open the plastic shells, releasing the contents within: a material called indium gallium arsenide. This liquid metal alloy seeped out of the spheres and filled the cracks in the anode, restoring the flow of electricity.

Damage to a battery — or a short circuit between its components — can cause problems other than a shorter life span. Out-of-control electrical currents have been known to create hot spots that grow into a raging fire.

“It’s not a common occurrence, but when it happens, the consequences are severe,” White said. Battery fires have prompted laptop recalls by Dell and Hewlett-Packard, and the U.S. Department of Transportation has proposed stricter rules for cargo planes that transport large quantities of lithium-ion batteries.

To safeguard against this type of failure, White developed a second kind of microsphere made of solid polyethylene, an inexpensive and widely available plastic. A small quantity of these spheres embedded in the anode and other battery components can function as a safety cutoff switch. If the temperature inside the battery rises above 105° Celsius, the spheres melt into a thin layer of insulating material that shuts off the flow of electricity, preventing a conflagration.

“We’ve tested this in real batteries,” said White, whose research is funded by the U.S. Department of Energy. “It works beautifully.” This safety feature, he said, could be useful for the electric cars emerging on the market.

"Lithium-ion batteries will continue to be the technology used for the next 10 to 15 years in electric cars," said Kristin Persson of Lawrence Berkeley National Laboratory in California, who is looking for new battery materials that not only have better energy storage but also avoid some of the pitfalls of traditional batteries. "It will take at least that amount of time to develop new materials."

Science News

February 8, 2011

Need Forgiveness? - There is an app for that!


The Catholic Church has approved an iPhone app that helps guide worshippers through confession.

The Confession program has gone on sale through iTunes for £1.19 ($1.99).

Described as "the perfect aid for every penitent", it offers users tips and guidelines to help them with the sacrament.

Now senior church officials in both the UK and US have given it their seal of approval, in what is thought to be a first.

The app takes users through the sacrament - in which Catholics admit their wrongdoings - and allows them to keep track of their sins.

It also allows them to examine their conscience based on personalised factors such as age, sex and marital status - but it is not intended to replace traditional confession entirely.

Instead, it encourages users to understand their actions and then visit their priest for absolution.

A spokesperson from the Catholic Bishops' Conference of England and Wales told BBC News the app was a "useful tool to help people prepare for the Sacrament of Reconciliation".

"The Church believes in embracing new technology and this creative app will hopefully help people to make a good confession."

It is thought to be the first time the church has approved a mobile phone application, although it is not entirely unfamiliar with the digital world.


Source <www.bbc.co.uk>

February 2, 2011

Are aliens here? Shining white 'UFO' spotted over Jerusalem shrine

A shining ball of light has been filmed hovering above a Jerusalem shrine, in footage which UFO enthusiasts say could finally prove aliens exist.
The clips show the pulsating orb descend and hover above the Dome of the Rock, an ancient Islamic shrine, before shooting up into the night sky. It then descends again and disappears.
Unusually, the sighting has been filmed from different viewpoints, meaning it has been more difficult to dismiss than most.
Object: The 'UFO' (ringed) has been filmed from several perspectives, making the sighting more difficult to dismiss than most

UFO?: The white light hovers over the Dome of the Rock
G-Force: The 'UFO' shoots up into the sky at a rate 'no living thing could survive' according to UFO expert Nick Pope


Highlighted: The mystery blob can be clearly seen in the night sky above the city

The footage was taken in Jerusalem at 1am on Saturday morning and has spread like wildfire on the internet.
It has been viewed by hundreds of thousands of people and prompted fierce debate among UFO enthusiasts and skeptics.

Former Ministry of Defence UFO investigator Nick Pope told The Sun: 'If these are real, they are some of the most incredible videos ever shot.
'If they are not, then this is a very well-planned and coordinated hoax designed to eliminate elements of doubt.'
He said the way the object shoots up suggests it is unmanned: 'We know the Israeli army has some very high-tech drones at its disposal.
'If this is one, it is one of the most advanced pieces of technology created by man.'

Source Daily Mail



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