Cotton Water Filters

September 8, 2010

A recent article at the New Scientist reports on some nanotechnology research that might provide a new, inexpensive method of purifying water in remote areas.  A team at Stanford University, led by Li Cui, developed the filtering material by adding carbon nanotubes and silver nanowires to ordinary cotton fabric.

The fabric is easy to produce, says lead researcher Yi Cui at Stanford University in California. Cui’s team simply dip a piece of cotton into a solution of CNTs and then pipette droplets containing silver nanowires onto the cotton.

The carbon adheres to individual fibers in the cotton, and the silver then forms a grid between them.  This allows the fabric to conduct electricity.  Only a weak electric current is used; but, in combination with the anti-bacterial properties of the silver, it is apparently enough to kill many bacteria.  In a test reported [abstract] in Nano Letters, published by the ACS, the researchers found that a single pass through the filter material removed 89% of E. coli bacteria; three passes removed more than 98%.   They calculate a gravity-fed device could filter 100,000 liters/hour per square meter of filter area.  Because it does not require mechanical pumps, the filter uses only about 20% of the energy of conventional filters.

This is preliminary research; the team still needs to test the material with other microorganisms, and needs to make sure that the filter does not shed material, particularly the carbon nanotubes, into the filtered water.  Still, this is potentially a very promising development.  For a sizable chunk of the world’s population, getting clean water is a serious challenge.  Anything that could make it easier and more economically feasible would be a significant step forward.


Adobe Acrobat/Reader Flaw Being Exploited

September 8, 2010

The Internet Storm Center at the SANS Institute has posted a diary entry about a newly discovered security vulnerability in Adobe’s Reader and Acrobat software, which is apparently being actively exploited.  Adobe has issued a Security Advisory, but they have not provided much in the way of details so far.  The flaw is apparently triggered by a maliciously-crafted PDF file; so far, it has been seen as an attachment to a phishing E-mail, hawking a method to improve your golf score: “David Leadbetter’s One Point Lesson”.   This particular example of the exploit apparently causes Acrobat or Reader to crash, and then opens a dummy file.  The vulnerability apparently exists on all versions of the software, including 9.3.4, the most current, on all platforms (MAC OS X, Windows, and UNIX/Linux).

Adobe says they are “evaluating the schedule for an update to resolve this vulnerability”.   The only mitigation step I’m aware of now is one that should be standard procedure: don’t open PDF files from untrusted sources.  I don’t know enough about the exploit to know whether disabling JavaScript (under Edit / Preferences from the main menu) will help, but it probably can’t hurt.   At present, only a minority of anti-virus programs appear to be able to detect this exploit.

I will post updated information here as I learn of it.


Mozilla Updates Thunderbird

September 8, 2010

Those folks over at the Mozilla organization have been busy,  In addition to the Firefox update yesterday, they also released a new version of the Thunderbird E-mail client, version 3.1.3, for Linux, Mac OS X, and Windows.  The new version incorporates bug fixes for the user interface, as well as stability and security updates.   (Not surprisingly, many of the security updates are for the same flaws that were patched in Firefox — the two products share a considerable code base.)   Further details are in the Release Notes.

I recommend installing this update as soon as you conveniently can.   You can get it via the built-in update mechanism (Main menu: Help / Check for Updates), or you can download versions for all platforms and languages here.

Update Thursday, 9 September, 11:18 EDT

Like the recent Firefox 3.6.9 update, this update to Thunderbird fixes the “DLL Hijacking” vulnerability in Windows.


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