Your Guide to Physics

Sunday, April 09, 2006

NASA - Magnetic Moondust

Thirty-plus years ago on the moon, Apollo astronauts made an important discovery: Moondust can be a major nuisance. The fine powdery grit was everywhere and had a curious way of getting into things. Moondust plugged bolt holes, fouled tools, coated astronauts' visors and abraded their gloves. Very often while working on the surface, they had to stop what they were doing to clean their cameras and equipment using large--and mostly ineffective--brushes.

Dealing with "the dust problem" is going to be a priority for the next generation of NASA explorers. But how? Professor Larry Taylor, director of the Planetary Geosciences Institute at the University of Tennessee, believes he has an answer: "Magnets".

Thursday, April 06, 2006

Black Bodies and Quantum Cats - Jennifer Ouellette talks to NPR about her new physics book

Weekend Edition Sunday, April 2, 2006 · Jennifer Ouellette is a self-described "physics phobe" who couldn't tell a quark from a cathode ray. But after successfully avoiding the subject for more than 25 years, she stumbled into science writing as a freelance journalist. That led her to explore the fundamentals of physics from a cultural and historical perspective.

Ouellette's new book is Black Bodies and Quantum Cats, subtitled "Tales from the Annals of Physics." The author tells Liane Hansen she hopes readers will see that physics is more than a cold, hard discipline: it has emotional content

Sunday, April 02, 2006

Black Hole Merger Movie and A Submersible Holographic Microscope

BLACK HOLE MERGER MOVIE. Accurate calculations of the gravitational waveforms emitted during the collision of black holes can now be made. A new computer study of how a pair of black holes, circling each other, disturbs the surrounding space and sends huge gusts of
gravitational waves outwards, should greatly benefit the experimental search for those waves with detectors like LIGO and LISA. The relative difficulty of computer modeling of complicated physical behavior depends partly on the system in question and on the equations that describe the forces at work. To describe the complicated configuration of charges and currents, one uses Maxwell's equations to determine the forces at work. In the case of black-hole binaries, the equations are those from Albert Einstein's theory of general relativity. Black holes encapsulate the ultimate in gravitational forces, and this presents difficulties for
computations attempting to model behavior nearby. Nevertheless, some physicists at the University of Texas at Brownsville have now derived an algorithm that not only produces accurate estimates of the gravity waves of the inspiraling black holes, even over the short time intervals leading up to the final merger, but also is
easily implemented on computers (see figures and movie at www.aip.org/png/2006/256.htm ). "The importance of this work," says
Carlos Lousto, one of the authors of the new study, "is that it gives an accurate prediction to the gravitational wave observatories, such as LIGO, of what they are going to observe." The new results are part of a larger study of numerical relativity carried out at the University of Texas, work referred to as the
Lazarus Project (http://www.phys.utb.edu/numrel/research_dir/lazarus.html ).
(Campanelli, Lousto, Marronetti, and Zlochower; Physical Review Letters, 24 March 2006; contact information, lousto@phys.utb.edu, 956-882-6651)

A SUBMERSIBLE HOLOGRAPHIC MICROSCOPE. A new device allows scientists to form 3D images of tiny marine organisms at depths as great as 100 m. The device allows the recording of behavioral characteristics of zooplankton and other marine organisms in their natural environment without having to bring specimens to the surface for examination. Scientists at Dalhousie University in Halifax, Canada, used the hologram arrangement originally invented by Denis Gabor: light from a laser is focused on a pinhole that acts as a point source of light if the size of the hole is comparable to the wavelength of light. The spherical waves that emanate from the
pinhole illuminate a sample of sea water. Waves scattered by objects in the sea water then combine at the chip of a CCD camera with un-scattered waves (the reference wave) from the pin hole to form a digitized interference pattern or hologram. The digital holograms are then sent to a computer where they are digitally
reconstructed with specially developed software to provide images of the objects. The Dalhousie researchers packaged their holography apparatus in such a way that the laser and digital camera parts are in separate watertight containers, while the object plane is left open (see figure at http://www.aip.org/png/2006/255.htm ). One
difficulty was to get container windows of optical quality that are thin enough for high resolution imaging but thick enough to resist sea pressure. The new submersible microscope can also record the trajectories of organisms in the sample volume so that movies of the swimming characteristics of micron size marine organisms can easily be produced. Holograms with1024 x 1024 pixels can be recorded at 7
to 10 frames/s. This requires a large bandwidth for data transmission to a surface vessel and was accomplished with water tight Ethernet cables. Imaging volumes can be several cubic centimeters depending on the desired resolution. The Gabor geometry
allowed the Dalhousie researchers to design a very simple instrument capable of wavelength limited resolution of marine organisms in their natural environment. Past generations of submersible holographic microscopes had lower resolution, weighed several tons, had to be deployed from large ships, and used high-resolution film
as the hologram recording medium. This meant that only a small number of holograms could be recorded. In contrast, the Dalhousie instrument only weighs 20 kg, can be deployed from small boats or even pleasure vessels, and can record thousands of holograms in a few minutes so that the motion of aquatic organisms can be captured
in detail. (Jericho et al., Review of Scientific Instruments, upcoming article; contact M.H. Jericho, Dalhousie University, jericho@fizz.phys.dal.ca, and also the Universidad Nacional de Columbia)

The American Institute of Physics Bulletin of Physics News
Number 771   March 29, 2006  by Phillip F. Schewe, Ben Stein, and
Davide Castelvecchi

NIST TECHBEAT

March 30, 2006
a biweekly tip sheet for journalists from the National Institute of Standards and Technology

Quantum Dot Method Rapidly Identifies Bacteria
A rapid method for detecting and identifying very small numbers of diverse bacteria, from anthrax to E. coli, has been developed by scientists from the National Cancer Institute and NIST. Described in the March 28 issue of Proceedings of the National Academy of Sciences, the work could lead to the development of handheld devices for accelerated identification of biological weapons and antibiotic-resistant or virulent strains of bacteria-situations where speed is essential.

RFID Tags to Assist in Tracking First Responders
Radio Frequency Identification (RFID) technology has been around for many years and is widely used to identify, track and communicate information about items, products and even animals. An interdisciplinary team of NIST researchers is studying whether RFID technology can be used as a low cost, reliable means to track firefighters and other first responders inside buildings and help them navigate under hazardous conditions.

NIST /ORNL Dedicate New Nuclear Medicine Lab
NIST is establishing a satellite facility at Oak Ridge National Laboratory in Oak Ridge, Tenn., to promote measurement accuracy for nuclear medicine imaging. In a dedication ceremony at the new laboratory today (March 30), NIST Director William Jeffrey and ORNL Director Jeff Wadsworth described the program, which is a pilot test for a planned series of such sites around the country.

Quality Standards Issued For Testing Herbal Products
NIST has issued the first suite of Standard Reference Materials (SRMs) in a planned series of reference materials for botanical dietary supplements. Manufacturers can use these materials for quality control, and researchers can use them to ensure that their laboratory analyses of supplements are accurate.

Measuring Electrical Arcs At the Micrometer Scale
A new device and technique have been developed by NIST researchers for measuring “breakdown” voltage-the voltage required to produce electrical arcs when electrodes are 400 nanometers to 45 micrometers apart. The advance could be useful in microelectronics, such as in the design of microelectro-mechanical systems (MEMS), in which arcing could cause device failure.

Bytes by the Quintillion For Today and Tomorrow
Engineers and information specialists from government, industry and academia agreed this month at a NIST workshop that immediate action is needed to keep vast amounts of digital knowledge from disappearing into cyberspace or becoming in 200, or even 20 years, as incomprehensible as the markings on Babylonian cuneiform tablets.

“March Madness” Effects Observed in Ultracold Gases
Physicists at Harvard University, George Mason University and NIST have discovered new quantum effects in ultracold gases that may lead to improved understanding of electrical conductivity in metals. In work presented at the March meeting of the American Physical Society in Baltimore, Md., the researchers calculated the properties of an “artificial crystal” of ultracold atoms in a lattice formed by intersecting laser beams.

Quick Links

NIST Proposes Updating Digital Signature Standard
To keep current with changing technology, NIST is proposing several changes to the Digital Signature Standard (DSS). The draft Federal Information Processing Standard (FIPS) 186-3 allows the use of 1024, 2048, and 3072-bit encryption keys.

Rescue Robots Test Skills At ‘Disaster City’ Event
Ground, aerial and aquatic emergency response robots from across the country will face real-life challenges April 4-6 in tests of their life-saving skills at Texas A&M University’s "Disaster City" in College Park, TX. The event, hosted by Texas A&M Engineering Extension Service and the local Federal Emergency Management Agency Task Force, is the second in a series of evaluation exercises conducted by NIST for urban search-and-rescue robots.

IT Meeting to Help Agencies With Security Assessments
NIST will host a workshop at its headquarters in Gaithersburg, Md., on April 26 to help federal agencies comply with FISMA (Federal Information Security Management Act) through the development of uniform requirements for security assessment service providers.

Chenok Set To Chair IT Security Advisory Board
NIST Director William Jeffrey has appointed Daniel J. Chenok, a prominent leader in the information technology industry, as the new chair of the Information Security and Privacy Advisory Board. The Board advises NIST on emerging managerial, technical, administration, and physical safeguard issues related to information security and privacy issues.

Collins Named to Head NIST Technology Services
Belinda L. Collins, an expert in both the technical and policy related aspects of standards development, has been promoted to director of NIST's Technology Services.

Saturday, April 01, 2006

Virtual Swimmer to Speed Up Australia's Pool Times

Related Resources
Fluid

Elsewhere on the Web
Physics of Swimming
The Physics of Sport

CSIRO and the Australian Institute of Sport are using mathematics in a bid to speed up our top swimmers by testing changes to swimming strokes.

The research will make use of the same software CSIRO uses for other fluid simulations such as animating water for movies and modelling volcanoes and tsunamis. Researchers are hoping to see some practical results in time to implement improvements for the London Olympics in 2012.

Bullet-shaped scramjet put to the test

Elsewhere on the Web
UQ Press Release
Bullet-Shaped SCRAMjet put to the Test - ABC Space and Astromony News
Scramjet Clocks Nearly Mach 10

The HyShot team from UQ have tested a new version of their SCRAMjet engine (an engine designed to burn fuel passing through it at supersonic speeds). This test flight is believed to have reached speeds of Mach 7.

March 30th 2006: The HyShot™ IV experimental scramjet test has been conducted today at the Woomera range, 500km north of Adelaide, South Australia at about 1.10pm local time (CDT).

“The rocket launch looked as expected. We had another clean liftoff,” Associate Professor Michael Smart of the UQ HyShot team said.

Quantum Mechanics and Quantum Physics

In the words of Niels Bohr "anybody who thinks they understand quantum physics is wrong." Quantum mechanics describes how the very small particles like electrons and atoms behave in ways contrary to most intuition. Discover the weirdness of quantum mechanics and how it is changing the way we make computers and secret codes through quantum computing and cryptography. Learn about the Heisenberg Uncertainty Principle and how it constrains how much we can know about a particle.

The 2005 Nobel Prize in Physics
The 2005 Nobel Prize in Physics is devoted to optics, with half of the prize going to Roy J. Glauber of Harvard University for his quantum theory of optical coherence, and one-quarter each going to John L. Hall and Theodor W. Hänsch, for their development of ultra-high-precision measurements of light.

1927 Solvay Conference Film
One of the most famous photos in the history of physics captures the illustrious participants at the fifth Solvay Conference in Brussels, October 1927. 29 physicists, the main quantum theorists of the day, came together, 17 of the 29 attendees were or became Nobel Prize winners. This is a home movie shot by Irving Langmuir, (1932 Nobel Prize winner). Twenty-one of the 29 attendees are on the film. The film includes shots of Erwin Schrödinger, Albert Einstein, Marie Curie, Dirac and Niels Bohr.

The Quantum Computer
By exploiting the unusual properties of Quantum Physics, physicists hope to make a computer that is, in many ways, better and faster than any computer that can ever possibly be built using the techniques of “classical” electronics.

Visual Quantum Mechanics
Instructional units that introduce quantum physics to high school and college students who do not have a background in modern physics or higher level math using interactive computer programs and digital multimedia in an activity based environment

What is Quantum Physics
Brief description of Quantum Physics, from Jim Tucek.

New Scientist's Guide to The Quantum World
An general level summary of the basic concepts and latest developments in Quantum Mechanics and Quantum Physics, from New Scientist.

Quantum Physics Online Course
A Java based course in quantum mechanics and quantum phsyics suitable for intermediate undergraduate university students.

Bell's theorem and Einstein-Podolsky-Rosen Paradox FAQ
Bell's Theorem and the EPR paradox have important ramifications on possible communication faster than the speed of light. An introduction to the problem of measurement of quantum entangled particles from the Usenet newsgroups.

Bell Experiment with Independent Observers
An excellent description of experimental investigations of Bell's theorem, which investigate fundamental philosophical issues of Quantum Physics