Tuesday, July 27, 2004
World Year of Physics/Einstein Year 2005
Did you remember that 1905 was the year that Einstein published 3 groundbreaking papers in Physics? IOP, AIP, APS, and others are all sponsoring activities to commemorate. In fact, they're calling 2005 the World Year of Physics and working to get a UN resolution on it. The two main sites with events, facts, activities are: http://www.physics2005.org (primarily US), http://www.einsteinyear.org (British)
Monday, July 26, 2004
ABCNEWS.com : Ship-Sinking Monster Waves Are Widespread -- ESA
(warning: Pop-ups galore)
7/24/04 Found via Topix
"Rogue waves that rise as high as 10-story buildings and can sink large ships are far more common than previously thought, imagery from European Space Agency (ESA) satellites has shown."
This is a little disconcerting. I've spent many a day on the ocean and have never seen a wave like this (even in hurricane sorties, thank goodness). If you read the press release from the ESA you can learn a little more about this. Susanne Lehner from the University of Miami is working this so we'll look out for more from her.
7/24/04 Found via Topix
"Rogue waves that rise as high as 10-story buildings and can sink large ships are far more common than previously thought, imagery from European Space Agency (ESA) satellites has shown."
This is a little disconcerting. I've spent many a day on the ocean and have never seen a wave like this (even in hurricane sorties, thank goodness). If you read the press release from the ESA you can learn a little more about this. Susanne Lehner from the University of Miami is working this so we'll look out for more from her.
Friday, July 23, 2004
Hawking and Black Holes
Brief background: Stephen Hawking, the famous physicist from Cambridge and author of A Brief History of Time among others, contacted the organizers of a conference to submit a paper at the last minute. Why so important? Apparently he now has reversed his theory on black holes and information and lost a bet. In the past he maintained that black holes sucked in everything around them without so much as a thank you. Now he says some of the information about the creation of the black hole actually hangs out near the event horizon and can influence radiation emitted by the black hole. Listen to Sean Carroll and Juan Maldacena discuss it here (real required).
There are plenty of articles on this in the media (like
About Those Fearsome Black Holes? Never Mind by Dennis Overbye, NY Times 7/22/04) and many scientific bloggers have weighed in (here and here)
The problem is that just because Hawking says it doesn't make it a done deal. Physics is rarely revolutionary (or at least as much as people think); instead, it's evolutionary. Good scientists who have carefully studied this subject disagree and it isn't proven -- there are only thought experiments. I do think that it's great that Hawking can generate this much media attention and I look forward to more discussion.
There are plenty of articles on this in the media (like
About Those Fearsome Black Holes? Never Mind by Dennis Overbye, NY Times 7/22/04) and many scientific bloggers have weighed in (here and here)
The problem is that just because Hawking says it doesn't make it a done deal. Physics is rarely revolutionary (or at least as much as people think); instead, it's evolutionary. Good scientists who have carefully studied this subject disagree and it isn't proven -- there are only thought experiments. I do think that it's great that Hawking can generate this much media attention and I look forward to more discussion.
Thursday, July 22, 2004
The New York Times > Technology > Circuits > What's Next: For Doctored Photos, a New Flavor of Digital Truth Serum
7/22/04 by Noah Schachtman
Another article discussing issues around doctoring of digital photographs. Dr. Farid, who is cited in this article, had a nice article in New Scientist (v. 179 no. 2411 (9/6/2003): 38, here for Academic Search Premier subscribers) on this same subject. You can read his other academic papers on his Dartmouth site.
Another article discussing issues around doctoring of digital photographs. Dr. Farid, who is cited in this article, had a nice article in New Scientist (v. 179 no. 2411 (9/6/2003): 38, here for Academic Search Premier subscribers) on this same subject. You can read his other academic papers on his Dartmouth site.
An Intuitive Explanation of Bayesian Reasoning
Pointed out on Furl as one of Today's Popular Items
"Bayes' Theorem for the curious and bewildered; an excruciatingly gentle introduction. By Eliezer Yudkowsky"
If you, like me, kind of get Bayesian Reasoning but wonder why everybody's so excited about it... read through this lengthy explanation. Ok, so I'm still not excited but now I remember how to read p(X|A). It's a nice resource either way.
"Bayes' Theorem for the curious and bewildered; an excruciatingly gentle introduction. By Eliezer Yudkowsky"
If you, like me, kind of get Bayesian Reasoning but wonder why everybody's so excited about it... read through this lengthy explanation. Ok, so I'm still not excited but now I remember how to read p(X|A). It's a nice resource either way.
Thursday, July 15, 2004
e4engineering.com > Revolutionary Steel
7/8/2004
"Scientists at the University of Virginia have announced the discovery of a non-magnetic amorphous material that is three times stronger than conventional steel and has superior anti-corrosion properties." The scientists say it's somewhat brittle right now but they're working on that. Apparently it can be molded and shaped like plastic.
See V. Ponnambalam, S. Joseph Poon, and Gary J. Shiflet. "Fe-based bulk metallic glasses with diameter thickness larger than one centimeter" Journal of Materials Research v19 no5 (May 2004): 1320-1323. (DOI: 10.1557/JMR.2004.0176, PDF for subscribers).
"Scientists at the University of Virginia have announced the discovery of a non-magnetic amorphous material that is three times stronger than conventional steel and has superior anti-corrosion properties." The scientists say it's somewhat brittle right now but they're working on that. Apparently it can be molded and shaped like plastic.
See V. Ponnambalam, S. Joseph Poon, and Gary J. Shiflet. "Fe-based bulk metallic glasses with diameter thickness larger than one centimeter" Journal of Materials Research v19 no5 (May 2004): 1320-1323. (DOI: 10.1557/JMR.2004.0176, PDF for subscribers).
Wednesday, July 14, 2004
e4engineering.com> High society (engineering of new skyscrapers)
7/9/2004By Christopher Sell
"Once complete, Burj Dubai will claim the title of the world's tallest building. At over 2,000ft it will be almost twice as high as the Empire State Building and over 500ft taller than the current record holder, the Petronas Towers in Kuala Lumpur, Malaysia. But to reach such dizzying heights, unique engineering design challenges have presented themselves." Innovation had a really neat episode on the engineering of new skyscrapers. Most observers won't realize how much these buildings move. You can get sea sick! The article linked above discusses how the engineers for the Dubai building went back to wind tunnels and other standard approaches because the computer models doen't adequately predict the microscale wind turbulence. It also discusses vortex shedding (see Tacoma Narrows Bridge). The article also mentions the materials to be used which are much stiffer than older materials. The Innovation episode also discusses the change in attitude or lack of real change in attitude toward skyscrapers since 2001.
Update: NYT has a nice article on an exhibit of skyscrapers. It's more on the art than the engineering but still worth a visit. (Herbert Muschamp, "Skyscraping Around the Urban World" July 16, 2004, free registration required or contact your library to find out how to get access through their databases) (7/16/04)
"Once complete, Burj Dubai will claim the title of the world's tallest building. At over 2,000ft it will be almost twice as high as the Empire State Building and over 500ft taller than the current record holder, the Petronas Towers in Kuala Lumpur, Malaysia. But to reach such dizzying heights, unique engineering design challenges have presented themselves." Innovation had a really neat episode on the engineering of new skyscrapers. Most observers won't realize how much these buildings move. You can get sea sick! The article linked above discusses how the engineers for the Dubai building went back to wind tunnels and other standard approaches because the computer models doen't adequately predict the microscale wind turbulence. It also discusses vortex shedding (see Tacoma Narrows Bridge). The article also mentions the materials to be used which are much stiffer than older materials. The Innovation episode also discusses the change in attitude or lack of real change in attitude toward skyscrapers since 2001.
Update: NYT has a nice article on an exhibit of skyscrapers. It's more on the art than the engineering but still worth a visit. (Herbert Muschamp, "Skyscraping Around the Urban World" July 16, 2004, free registration required or contact your library to find out how to get access through their databases) (7/16/04)
Thursday, July 08, 2004
Slate: Science as Metaphor: Where does Brian Greene stand in the pantheon of physicists?
7/6/04 by Amanda Schaffer
"His celebrity can be attributed to a widespread popular appetite for avant-garde science dressed in neat metaphorical packages: The universe is elegant; the cosmos is like a string symphony. Yet there is plenty to be suspicious of in Greene's unself-conscious romanticism—his unnuanced use of terms like elegance and beauty—and his teleological approach to the history of physics. Where, exactly, does he stand in the pantheon of physicists?"
Sean Carroll points out and discusses this article on his blog, Preposterous Universe. He also points to several other people who are commenting on this article.
I have my own opinion. First, a disclaimer: I only have a BS in physics so am not the one to really poke holes in the actual theory. My opinion: The best physics and math is elegant, simple, and yes, beautiful. Mathematics is beautiful. The power to describe the world in terms of equations is amazing. I've tried to explain this to people who got turned off of math and science by high school teachers who couldn't actually explain their subjects. I like Brian Greene and I like what he's trying to do. I think he does a good job of making this information more accessible to the public. For all of you doing government funded research, this is important! Greene also gives some disclaimers and problems of the theory, but maybe he doesn't go far enough. I think he does. I had a middle school age kid come up to me at a public library and ask for a copy of Fabric. I asked him and he read, understood, and enjoyed Elegant and he wants to be a physicist. That's what I'm talking about.
So, to answer the question, where does Brian Greene stand? He's respected in his field. He is respected and liked outside of his field.
"His celebrity can be attributed to a widespread popular appetite for avant-garde science dressed in neat metaphorical packages: The universe is elegant; the cosmos is like a string symphony. Yet there is plenty to be suspicious of in Greene's unself-conscious romanticism—his unnuanced use of terms like elegance and beauty—and his teleological approach to the history of physics. Where, exactly, does he stand in the pantheon of physicists?"
Sean Carroll points out and discusses this article on his blog, Preposterous Universe. He also points to several other people who are commenting on this article.
I have my own opinion. First, a disclaimer: I only have a BS in physics so am not the one to really poke holes in the actual theory. My opinion: The best physics and math is elegant, simple, and yes, beautiful. Mathematics is beautiful. The power to describe the world in terms of equations is amazing. I've tried to explain this to people who got turned off of math and science by high school teachers who couldn't actually explain their subjects. I like Brian Greene and I like what he's trying to do. I think he does a good job of making this information more accessible to the public. For all of you doing government funded research, this is important! Greene also gives some disclaimers and problems of the theory, but maybe he doesn't go far enough. I think he does. I had a middle school age kid come up to me at a public library and ask for a copy of Fabric. I asked him and he read, understood, and enjoyed Elegant and he wants to be a physicist. That's what I'm talking about.
So, to answer the question, where does Brian Greene stand? He's respected in his field. He is respected and liked outside of his field.
Tuesday, July 06, 2004
e4engineering.com: New twist on fibre optics
by Josh Chamot, 6/2/2004
"By twisting fibre optic strands into helical shapes, researchers have created unique structures that can precisely filter, polarise or scatter light. Compatible with standard fibre optic lines, these hair-like structures may replace bulky components in sensors, gyroscopes and other devices.
While researchers are still probing the unusual properties of the new fibres, tests show the strands impart a chiral, or 'handed,' character to light by polarising photons according to certain physical properties." The author discusses an article originally published in Science (DOI: 10.1126/science.1097631). This is a pretty cool way to do this plus it's pretty simple... elegant even. For a really nice explanation of how fiber optics work, see the PBS Innovation episode "Light Speed". These scientists use a rectangular internal core, pop it into an oven, and give it a twist. The amount of twist decides if the photons of the same handedness are reflected backward, trapped in the cladding, or escape the cladding into space.
"By twisting fibre optic strands into helical shapes, researchers have created unique structures that can precisely filter, polarise or scatter light. Compatible with standard fibre optic lines, these hair-like structures may replace bulky components in sensors, gyroscopes and other devices.
While researchers are still probing the unusual properties of the new fibres, tests show the strands impart a chiral, or 'handed,' character to light by polarising photons according to certain physical properties." The author discusses an article originally published in Science (DOI: 10.1126/science.1097631). This is a pretty cool way to do this plus it's pretty simple... elegant even. For a really nice explanation of how fiber optics work, see the PBS Innovation episode "Light Speed". These scientists use a rectangular internal core, pop it into an oven, and give it a twist. The amount of twist decides if the photons of the same handedness are reflected backward, trapped in the cladding, or escape the cladding into space.
Wednesday, June 30, 2004
IEE Communications Engineer: Designing Buildings for the Wireless Age
Apparently this isn't online yet. Full citation: Alan Newbold, "Designing Buildings for the Wireless Age," IEE Communications Engineer v.2 no.3 (Jun/Jul 2004): 18-21.
I mentioned on my other blog about jamming or installing screening material to block mobile phone signals in libraries, theaters, etc. As emergency workers and "essential employees" go to their hiding spaces in buildings outside of the beltway, they have been planning on use mobile phones to maintain communications. Unfortunately, almost all buildings were not designed to take wireless communications into account. If I want to use my cell phone, do I have to go outside to get a signal? Some buildings have been retrofitted with repeaters.
On the other hand, internal wireless data networks can be snooped from across the street.
This articles discusses using frequency selective surfaces (fss) in building design to tackle these problems. Some of these surfaces are films for windows and reflecting material for walls that consists of a pattern of conductors on a dielectric substrate. If the walls have this dielectric substrate, low-pass filters can be installed to allow emergency communications frequencies through. Makes sense, but I wonder how many architects are taking RF into account? Also, what frequency band will we be using in 5 years?
I mentioned on my other blog about jamming or installing screening material to block mobile phone signals in libraries, theaters, etc. As emergency workers and "essential employees" go to their hiding spaces in buildings outside of the beltway, they have been planning on use mobile phones to maintain communications. Unfortunately, almost all buildings were not designed to take wireless communications into account. If I want to use my cell phone, do I have to go outside to get a signal? Some buildings have been retrofitted with repeaters.
On the other hand, internal wireless data networks can be snooped from across the street.
This articles discusses using frequency selective surfaces (fss) in building design to tackle these problems. Some of these surfaces are films for windows and reflecting material for walls that consists of a pattern of conductors on a dielectric substrate. If the walls have this dielectric substrate, low-pass filters can be installed to allow emergency communications frequencies through. Makes sense, but I wonder how many architects are taking RF into account? Also, what frequency band will we be using in 5 years?
optics.org - News - Fiber gratings give abrasion alert
6/24/04
Andrew Gillooly has developed a wear sensor that uses a chirped fiber Bragg grating (CFBG). CFBGs have been used for temperature measurement and other sensor applications, but this is an inexpensive way to do wear sensing.The full article is from Measurement Science and Technology (TOC, PDF for subscribers)
Andrew Gillooly has developed a wear sensor that uses a chirped fiber Bragg grating (CFBG). CFBGs have been used for temperature measurement and other sensor applications, but this is an inexpensive way to do wear sensing.The full article is from Measurement Science and Technology (TOC, PDF for subscribers)
Monday, June 21, 2004
Physical Review Focus: The Computer Minds the Commuter
6/18/04
"The model gives virtual drivers the option of cruising cautiously or speeding forward optimistically based on what they think the car ahead is about to do. Previous models haven't accounted for driver psychology in such a direct way. "
Another use of stat. mech. outside of physics: to model traffic. As you see above, this model improves on similar previous models because it doesn't have instantaneous acceleration and also models the "overreaction" of drivers. Does it model the complete jerks on the DC beltway, though? That's what I'd like to know.
Original article: Hyun Keun Lee, Robert Barlovic, Michael Schreckenberg, and Doochul Kim. "Mechanical Restriction Versus Human Overreaction Triggering Congested Traffic States" Phys. Rev. Lett. 92, 238702.
"The model gives virtual drivers the option of cruising cautiously or speeding forward optimistically based on what they think the car ahead is about to do. Previous models haven't accounted for driver psychology in such a direct way. "
Another use of stat. mech. outside of physics: to model traffic. As you see above, this model improves on similar previous models because it doesn't have instantaneous acceleration and also models the "overreaction" of drivers. Does it model the complete jerks on the DC beltway, though? That's what I'd like to know.
Original article: Hyun Keun Lee, Robert Barlovic, Michael Schreckenberg, and Doochul Kim. "Mechanical Restriction Versus Human Overreaction Triggering Congested Traffic States" Phys. Rev. Lett. 92, 238702.
Tuesday, June 15, 2004
PhysicsWeb - Nanobulbs make their debut
6/4/04
"...physicists in China have now made a light bulb in which the conventional tungsten filament is replaced by carbon nanotubes. The new design has several advantages over traditional light bulbs and could be available in less than five years (J Wei et al. 2004 Appl. Phys. Lett. 84 4869)."
Finally a real, practical use for carbon nanotubes. These lightbulbs burn brighter with lower applied voltage and will probably last longer.
"...physicists in China have now made a light bulb in which the conventional tungsten filament is replaced by carbon nanotubes. The new design has several advantages over traditional light bulbs and could be available in less than five years (J Wei et al. 2004 Appl. Phys. Lett. 84 4869)."
Finally a real, practical use for carbon nanotubes. These lightbulbs burn brighter with lower applied voltage and will probably last longer.
optics.org - News - Sensor takes the drag out of flying (June 2004)
6/11/04
"Airspeed measurements are currently made using a number of finger-sized pitot tubes that protrude from the aircraft. They measure airspeed (the speed of the aircraft relative to the surrounding air) by sensing the impact pressure, the difference between static and total pressure. But this well established technology comes at a price. The probes cause drag and with aircraft operating lifetimes estimated at between 20 - 25 years, the associated fuel cost to the airline industry is huge"
It uses doppler shift (like lidar). Unlike other applications, they are trying to increase backscatter. To me, though, SOG (speed over ground) is a little more important and I assume they're using GPS for that. Ships use a pit sword which also creates drag. At the speed they're going, though, perhaps it isn't so important.
(I'm obviously using my new feeds from IOP, thanks guys)
"Airspeed measurements are currently made using a number of finger-sized pitot tubes that protrude from the aircraft. They measure airspeed (the speed of the aircraft relative to the surrounding air) by sensing the impact pressure, the difference between static and total pressure. But this well established technology comes at a price. The probes cause drag and with aircraft operating lifetimes estimated at between 20 - 25 years, the associated fuel cost to the airline industry is huge"
It uses doppler shift (like lidar). Unlike other applications, they are trying to increase backscatter. To me, though, SOG (speed over ground) is a little more important and I assume they're using GPS for that. Ships use a pit sword which also creates drag. At the speed they're going, though, perhaps it isn't so important.
(I'm obviously using my new feeds from IOP, thanks guys)
optics.org - News - Tiny projectors set for 2005 debut (June 2004)
6/15/04
"Pocket-sized projectors being developed by a Finnish company will make their commercial debut next year.
Upstream Engineering of Finland plans to release a pocket-sized color video projector onto the market next year. What's more, Upstream believes it can shrink the product down to the size of a matchbox within three years. These developments could pave the way for miniature projectors to be used in everything from mobile phones to laptop computers. "
Soon we'll have Power Point presentations going from our mobile phones/PDAs/cameras. This is definitely a better way to share information and will save the backs of many presenters.
"Pocket-sized projectors being developed by a Finnish company will make their commercial debut next year.
Upstream Engineering of Finland plans to release a pocket-sized color video projector onto the market next year. What's more, Upstream believes it can shrink the product down to the size of a matchbox within three years. These developments could pave the way for miniature projectors to be used in everything from mobile phones to laptop computers. "
Soon we'll have Power Point presentations going from our mobile phones/PDAs/cameras. This is definitely a better way to share information and will save the backs of many presenters.
Monday, June 07, 2004
IOP now has even more feeds
Use this page to find all of the IOP feeds on jobs, features, news, and magazine and journal tables of contents. Sort by category or look at recently updated feeds.
Thursday, June 03, 2004
(Wireless) Sensor Networks
There are sensors in just about everything: from biomedical devices to bridges. The in-style thing right now is Wireless Sensor Networks. After all, if we can all be wireless with tiny little devices, why can't the sensors. An easy way to see how mainstream this is is to scan the shelves of your local science library. The covers of two journals this month feature sensor network article(s):
Communications of the ACM, v47 n6 (June 2004). (link for subscribers)
Scientific American, v290 n6 (June 2004).(free preview, click here if you have Academic Search Premier).
These networks have been enabled by the miniaturization of the sensor and communications technologies, decreased power consumption, increased durability, and decreased cost.
Privacy activists worry that Big Brother will look more like the little computers in Crichton's Prey(Harper Collins, 2002). The "motes" are very simple, how do you guarantee they only tell you what they are sensing, not anyone with a receiver?
(updated to correct typos)
Communications of the ACM, v47 n6 (June 2004). (link for subscribers)
Scientific American, v290 n6 (June 2004).(free preview, click here if you have Academic Search Premier).
These networks have been enabled by the miniaturization of the sensor and communications technologies, decreased power consumption, increased durability, and decreased cost.
Privacy activists worry that Big Brother will look more like the little computers in Crichton's Prey(Harper Collins, 2002). The "motes" are very simple, how do you guarantee they only tell you what they are sensing, not anyone with a receiver?
(updated to correct typos)
Science Daily: 17th Century Solar Oddity Believed Linked To Global Cooling Is Rare Among Nearby Stars
6/3/04 UC Berkeley-
"For 70 years, from 1645 until 1714, early astronomers reported almost no sunspot activity. The number of sunspots - cooler areas on the sun that appear dark against the brighter surroundings - dropped a thousandfold, according to some estimates. Though activity on the sun ebbs and flows today in an 11-year cycle, it has not been that quiet since. "
Sunspots are pretty important because of the potential impact they have on our climate, space missions, communications satellites, etc. There have been a few recent press releases about sunspots because of the Denver meeting of American Astronomical Society (AAS).
Another interesting one: "Groundbreaking Research To Improve Forecasts Of Sunspot Cycle" Science Daily, 6/1/04.
"Using a new computer model of the Sun, scientists have begun work on a groundbreaking forecast of the next cycle of sunspots. Mausumi Dikpati of the National Center for Atmospheric Research (NCAR) announced new research leading to an improved forecast of cycle 24"
"For 70 years, from 1645 until 1714, early astronomers reported almost no sunspot activity. The number of sunspots - cooler areas on the sun that appear dark against the brighter surroundings - dropped a thousandfold, according to some estimates. Though activity on the sun ebbs and flows today in an 11-year cycle, it has not been that quiet since. "
Sunspots are pretty important because of the potential impact they have on our climate, space missions, communications satellites, etc. There have been a few recent press releases about sunspots because of the Denver meeting of American Astronomical Society (AAS).
Another interesting one: "Groundbreaking Research To Improve Forecasts Of Sunspot Cycle" Science Daily, 6/1/04.
"Using a new computer model of the Sun, scientists have begun work on a groundbreaking forecast of the next cycle of sunspots. Mausumi Dikpati of the National Center for Atmospheric Research (NCAR) announced new research leading to an improved forecast of cycle 24"
Science -- NetWatch {28 May 2004; 304 (5675)}: Watching the Transit of Venus
This week Science points to several sites that will offer webcasts of the transit of Venus on 8 June. Venus will pass between Earth and the sun. You'll have to get up early, it starts at 1 a.m. Eastern!
Wednesday, June 02, 2004
Associated Press: Scientists Dig into Chesapeake Bay Impact Crater
6/1/04 (found via Topix)
"CAPE CHARLES, Va. (AP) _ Geologists drilling half a mile below Virginia's Eastern Shore say they have uncovered more signs of a space rock's impact 35 million years ago."
With all the talk of Bedout and Chicxulub, it's good that they're looking at our very own impact crater (the 6th largest in the world). The USGS press release is here. According to a recent workshop proceedings report (PDF, text), they are drilling to study:
"CAPE CHARLES, Va. (AP) _ Geologists drilling half a mile below Virginia's Eastern Shore say they have uncovered more signs of a space rock's impact 35 million years ago."
With all the talk of Bedout and Chicxulub, it's good that they're looking at our very own impact crater (the 6th largest in the world). The USGS press release is here. According to a recent workshop proceedings report (PDF, text), they are drilling to study:
- Crater Structure and Morphology
- Crater Materials
- Impact - Postimpact Transition and Postimpact Events
- Modern Deep Biosphere
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