Update: Suspicious Packages

by Kelen Tuttle

Two weeks ago, the arrival of a letter containing white powder at Lawrence Berkeley National Laboratory prompted the SLAC directorate to advise all staff to be particularly careful of suspicious or unusual mail. Fortunately, lab tests revealed that the Lawrence Berkeley letter contained nothing more than harmless powder. Nonetheless, SLAC employees and users are encouraged to use caution when opening unexpected packages.

The SLAC directorate has released new guidelines on what to do if you suspect you have opened a package containing harmful substances. Please take a few moments to read these guidelines here.

How do Smoke
Detectors Work?

summarized from How Stuff Works

Daylight Saving Time provides a convenient reminder for people to change the batteries in their smoke detectors. But how do smoke detectors work in the first place?

The most common type of detector contains americium, which slowly releases alpha particles. These particles ionize the oxygen and nitrogen atoms in the air, releasing a free electron and a positively charged atom. Inside the detector, free electrons are attracted to a metal plate with a positive voltage and the positive atoms are attracted to a plate with a negative voltage. Electronics in the detector sense the very small electrical current created by this movement.

When smoke enters the detector, the current disappears as the smoke particles attach to the ions and neutralize them. The detector recognizes this and the alarm goes off.

A second type of detector uses light to detect the smoke. In this case, a beam of light shines across the inside of the detector. When no smoke is present, the photons travel in a straight line, missing a sensor placed to the side. But if smoke enters the detector, the photons bounce off the smoke particles and send light in all directions. This light is then detected by the sensor, and the alarm goes off.

To learn more about the physics of smoke detectors, visit How Stuff Works.

Safety Seconds

by John Cornuelle

In yesterday's edition, I noted that if you look at all the injuries suffered by SLAC staff members, you find at least two common patterns. The first is that almost all were engaged in activities that they understood and were quite familiar with. The second is that the staff member was nearly always not thinking about accident prevention in the seconds before his or her injury.

Stanford Art Gallery Presents "Sliding Scale"

Gail Wight's Supernova
(Click on image for larger version.)

Today, the Stanford Department of Art and Art History is pleased to present the opening of "Sliding Scale: Gail Wight."

With this exhibit, Gail Wight adds her voice to the Imaging Environment: Maps, Models, and Metaphors conference, which brings together scholars from the humanities to consider how the environment shapes the way we study and use it.

In "Sliding Scale," Gail Wight's art playfully resists the dematerialization of objects of scientific investigation. Mice eat through a representation of their genome, butterflies struggle to escape their pins, and beetles tell their stories. Wight's art simultaneously takes on two great flaws of abstract scientific thinking: oversimplification and loss of perspective.

In Crossing, a live mouse plays with a robotic one, and the viewer is left marveling at the incredible complexity of the living being. Recursive Mutations gives a mouse the chance to redesign its own genome through its interaction with the paper it lives on.

With humor, "Sliding Scale" asks the viewer what has been lost in abstracting a mouse to its genes or to a mechanical prototype that replicates only some of its functions. As viewers zoom in and out with The Meaning of Miniscule they find that where they end up is not where they began.

Wight's art prompts viewers to see the objects of scientific research and the larger field of science in a new and different light.

The Thomas Welton Stanford Art Gallery is free and open to the public Tuesday through Friday from 10:00 a.m. until 5:00 p.m. and Saturday and Sunday from 1:00 p.m. until 5:00 p.m. More information...

Events (see all | submit)

November 8: (11:00 a.m.) Lecture: Shared Memory Programming with OpenMP
November 8: (7:00 p.m.) Alternative Energy Presentations

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World-class Radio Telescopes face Closure New Scientist
Learning How Nature Splits Water Fuel Cell Works
Japanese Latecomer Joins Race To Build a Hard X-ray Laser Science

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View online at http://today.slac.stanford.edu/

Update: Suspicious Packages by Kelen Tuttle Two weeks ago, the arrival of a letter containing white powder at Lawrence Berkeley National Laboratory prompted the SLAC directorate to advise all staff to be particularly careful of suspicious or unusual mail. Fortunately, lab tests revealed that the Lawrence Berkeley letter contained nothing more than harmless powder. Nonetheless, SLAC employees and users are encouraged to use caution when opening unexpected packages. The SLAC directorate has released new guidelines on what to do if you suspect you have opened a package containing harmful substances. Please take a few moments to read these guidelines here.

How do Smoke Detectors Work? summarized from How Stuff Works Daylight Saving Time provides a convenient reminder for people to change the batteries in their smoke detectors. But how do smoke detectors work in the first place? The most common type of detector contains americium, which slowly releases alpha particles. These particles ionize the oxygen and nitrogen atoms in the air, releasing a free electron and a positively charged atom. Inside the detector, free electrons are attracted to a metal plate with a positive voltage and the positive atoms are attracted to a plate with a negative voltage. Electronics in the detector sense the very small electrical current created by this movement. When smoke enters the detector, the current disappears as the smoke particles attach to the ions and neutralize them. The detector recognizes this and the alarm goes off. A second type of detector uses light to detect the smoke. In this case, a beam of light shines across the inside of the detector. When no smoke is present, the photons travel in a straight line, missing a sensor placed to the side. But if smoke enters the detector, the photons bounce off the smoke particles and send light in all directions. This light is then detected by the sensor, and the alarm goes off. To learn more about the physics of smoke detectors, visit How Stuff Works. Safety Seconds by John Cornuelle In yesterday's edition, I noted that if you look at all the injuries suffered by SLAC staff members, you find at least two common patterns. The first is that almost all were engaged in activities that they understood and were quite familiar with. The second is that the staff member was nearly always not thinking about accident prevention in the seconds before his or her injury.	Stanford Art Gallery Presents "Sliding Scale" Gail Wight's Supernova (Click on image for larger version.) Today, the Stanford Department of Art and Art History is pleased to present the opening of "Sliding Scale: Gail Wight." With this exhibit, Gail Wight adds her voice to the Imaging Environment: Maps, Models, and Metaphors conference, which brings together scholars from the humanities to consider how the environment shapes the way we study and use it. In "Sliding Scale," Gail Wight's art playfully resists the dematerialization of objects of scientific investigation. Mice eat through a representation of their genome, butterflies struggle to escape their pins, and beetles tell their stories. Wight's art simultaneously takes on two great flaws of abstract scientific thinking: oversimplification and loss of perspective. In Crossing, a live mouse plays with a robotic one, and the viewer is left marveling at the incredible complexity of the living being. Recursive Mutations gives a mouse the chance to redesign its own genome through its interaction with the paper it lives on. With humor, "Sliding Scale" asks the viewer what has been lost in abstracting a mouse to its genes or to a mechanical prototype that replicates only some of its functions. As viewers zoom in and out with The Meaning of Miniscule they find that where they end up is not where they began. Wight's art prompts viewers to see the objects of scientific research and the larger field of science in a new and different light. The Thomas Welton Stanford Art Gallery is free and open to the public Tuesday through Friday from 10:00 a.m. until 5:00 p.m. and Saturday and Sunday from 1:00 p.m. until 5:00 p.m. More information...	Events (see all \| submit) November 8: (11:00 a.m.) Lecture: Shared Memory Programming with OpenMP November 8: (7:00 p.m.) Alternative Energy Presentations Access (see all) Outage - Building 34 Hot Water for Exercise Locker Rooms Power Outages in Research Yard Building 40 Construction Bldg 084 GLAST ISOC Facility Construction Bldg 084 Parking Spaces Closure Alpine Gate & PEP Ring Road Closed Gates 17 & 30 Open 24-7 Research Yard Bisected Announcements (see all \| submit) Lab Announcements Campus Staff Courses for November LCLS Animation Available for Download Register for the GLAST International Science Symposium Community Bulletin Board William Cronon: The Culture of Landscape and the Nature of Politics (Wed., 7 p.m.) 35th Annual SLAC Run & Walk Flu Shot Availability News (see all \| submit) World-class Radio Telescopes face Closure New Scientist Learning How Nature Splits Water Fuel Cell Works Japanese Latecomer Joins Race To Build a Hard X-ray Laser Science
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