[FPSPACE] Some data recovered from Columbia STS-107

[LARRY KLAES]

>From: physnews at aip.org
>Reply-To: physnews at aip.org
>To: ljk4 at MSN.COM
>Subject: Physics News Update 864
>Date: Mon, 19 May 2008 11:45:31 -0400
>
>PHYSICS NEWS UPDATE
>The American Institute of Physics Bulletin of Physics News
>Number 864 May 19, 2008      www.aip.org/pnu
>by Phillip F. Schewe and Jason S. Bardi
>
>XENON KETCHUP
>Using data recovered from a damaged computer hard-drive that was
>aboard the ill-fated Space Shuttle Columbia in 2003, scientists have
>learned more about why the act of shaking a material can quickly
>transform it into something completely different.
>One of the best examples of this phenomenon is ordinary ketchup.
>Shake the bottle and the semi-solid paste becomes a runny liquid.
>Food scientists do the shaking in a controlled way by putting
>ketchup (and other processed foods) into a rheometer (rheo, meaning
>“flow”) to see how its viscosity -- the scientific word for
>stickiness -- decreases when shaken.
>Robert Berg and his colleagues at the National Institute of
>Standards and Technology in Gaithersburg, MD., wanted to do more
>than measure viscosity.  They wanted to know why the changes happen
>through "shear thinning," a phenomenon in which a force which cuts
>across weak attachments among atoms or molecules can be enhanced by
>agitation.  Understanding shear thinning is a big deal in the
>industrial world of processed foods, polymers, and paints.   For
>instance, motor oil’s viscosity can be degraded by the movement of
>engine parts, and the application of paint to a surface can be easy
>or hard depending on the manner of the brushstroke.
>To better understand the microscopic relation between viscosity and
>shear thinning, the NIST scientists looked at how the thinning works
>in an unusual fluid -- in the noble gas Xenon.  The trick is,
>xenon’s own weight-as light as it is-still can compress the sample
>of the gas enough to throw off the delicate measurements that were
>needed.  To do a proper study, the experiment needed a zero-gravity
>environment.  And so up it went in Columbia.
>But Columbia’s mission ended when insulation tiles on the leading
>edge of the left wing, damaged during launch, failed upon reentry.
>The craft burned up and disintegrated, killing the seven astronauts
>on board.  Some of the data from the Xenon experiment had been
>down-linked before the shuttle was destroyed, but the rest were
>stuck on the hard drive that fell to earth along with Columbia.
>Fortunately, NASA's recovery team found the hard drive among the
>debris that was scattered for hundreds of miles across Texas and
>Louisiana.  The data on the disk were retrieved by a company that
>specializes in recovering information from the kind of disk crashes
>that happen every day here on Earth.
>The package in which the experiment itself took place was also found
>(see figures at http://www.aip.org/png/2008/301.htm ).  It was at
>the heart of a series of concentric apparatus shells, the outermost
>of which had burned up.  The cell containing the xenon atoms,
>however, was intact.  None of the atoms had escaped.
>Xenon is one of those atoms that doesn’t like to associate or react
>with other atoms.  The researchers set up the Columbia experiment to
>look at how Xenon behaves when, under exact conditions of pressure
>and temperature, it exists midway between two fluid states.
>Why go to the trouble of getting xenon atoms into just the right
>pressure conditions?  Xenon is a gas, whereas ketchup and most
>interesting fluids consist of liquids and pastes.  The answer is
>that the shear thinning process becomes possible for even simple
>fluids like pressurized Xenon at the special critical point. What is
>learned from the simple fluid might also apply to ketchup.
>While in orbit aboard Columbia, the xenon was gently stirred by a
>fine mesh, a sort of tiny tennis racket.  The experiment was a
>success.  Stirring harder decreased the viscosity, confirming a
>decades-long theory about the relation between shear thinning and
>stirring.  (The results were published in the April 2008 issue of
>Physical Review)
>
>***********
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