The center node takes you to the work of Timothy Wei, professor and acting dean of Rensselaer’s School of Engineering, to see how he has solved Gray’s Paradox using his new state-of-the-art water flow diagnostic technology — Digital Particle Image Velocimetry DPIV — that measures the force a dolphin generates with its tail. Other nodes are about DPIV, how the US Navy trains dolphins (a retired Navy dolphin stars in the Rensselear video), general dolphin information (from the San Diego Zoo), and open courseware from Tufts University School of Veterinary Medicine on marine mammal medicine including care of dolphins, who are cetaceans.

In this learn node the 2008 discovery of how the dolphin kicks with huge power is spotlighted at Rensselaer Polytechnic Institute where the discovery was made. For decades, scientists have puzzled over the sea mammal’s speed, since “Gray’s Paradox” was described, as the Rensselaer website explains:

There was something peculiar about dolphins that stumped prolific British zoologist Sir James Gray in 1936. He had observed the sea mammals swimming at a swift rate of more than 20 miles per hour, but his studies had concluded that the muscles of dolphins simply weren’t strong enough to support those kinds of speeds. The conundrum came to be known as “Gray’s Paradox.”

Timothy Wei, professor and acting dean of Rensselaer’s School of Engineering, has solved Gray’s Paradox using his new state-of-the-art water flow diagnostic technology that measures the force a dolphin generates with its tail. The image above is from a video that captures the action of the dolphin by using Digital Particle Image Velocimetry (DPIV). The dolphin performing in the video is Primo, who is retired from the U.S. Navy.

For background on these subjects, the San Diego Zoo has an excellent online dolphin section and the University of California Irvine School of Biological Sciences explains DPIV in great detail.

This learn node links out to “The story of steam power [that] stretches from attempts to harness atmospheric pressure in the 1600s to the steam turbines we depend upon today.” (Science Museum Energy Hall, source of the flywheel image above.) A steam industry source, spiraxsarco, provides an excellent steam overview. A US Department of Energy Best Practices page for Steam provides extensive practical information and explains:

Over 45% of all the fuel burned by U.S. manufacturers is consumed to raise steam. Steam is used to heat raw materials and treat semi-finished products. It is also a power source for equipment, as well as for building heat and electricity generation. Many manufacturing facilities can recapture energy through the installation of more efficient steam equipment and processes.

An interesting page on nuclear warfare at Notre Dame Open Courseware includes the mention that military tanks were tried with steam power, but it was the internal combustion engine that made tanks successful.

The image above is the Hurricane Ike Interactive Map from NOAA. When you go to the page you can click into the boxes to locate and study satellite photos of damage. StormWatch is part of the work of the Johns Hopkins University/ Applied Physics Laboratory.

Remote sensing imagery and study materials abound on the internet. An excellent cluster of information can be found at the Atmospheric Radiation Measurement (ARM) Program which “is a multi-laboratory, interagency program, and is a key contributor to national and international research efforts related to global climate change. A primary objective of the program is improved scientific understanding of the fundamental physics related to interactions between clouds and radiative feedback processes in the atmosphere. ARM focuses on obtaining continuous field measurements and providing data products that promote the advancement of climate models.”

To learn scientific and technical background for the field MIT offers open couseware on Atmospheric Radiation that is “an introduction to the physics of atmospheric radiation and remote sensing including use of computer codes. Subjects covered include: radiative transfer equation including emission and scattering, spectroscopy, Mie theory, and numerical solutions. We examine the solution of inverse problems in remote sensing of atmospheric temperature and composition.”

A NASA- based Remote Sensing Tutorial provides further introduction to the field.

Phoenix Mars Lander is the topic of a magnificent learn node in the New York Science times today. Like any quality learn node, this one in the Times focuses on a small hunk of a subject: the scheduled landing of the vehicle this week on Mars. The node has internal links to superb supporting materials such as the graphic from which a piece is shown at the top of this post – although the graphic regretfully does not have a url of its own. Other internal links do, such as the slide show.

The node aspects are stunted here because there are not links beyond the NY Times to related material, such as The University of Arizona’’s Phoenix Mars Mission home webpage and NASA’s Phoenix Mars Lander homepage. The great news is that the New York Times no longer posts its science materials for free and then a few days later closes them behind a paid subscription. Since it will remain open online, this Phoenix Mars Lander node will remain available to link into other networks of space exploration and related subjects.

The above image combines a map from the USGS Earthquake Hazards Program with a formula from a Connexions module by Sunil Kumar Singh that teaches forced oscillation. The map was captured as a screenshot from the USGS website 2 days after the Sichuan Earthquake began, and as the large squares on the map indicate, the aftershocks were continuing.

The Connexions module text accompanying the formula explains:

The resonance is an interesting feature of oscillation. This phenomenon attracts interest as it makes possible to achieve extra-ordinary result (material failure of large structure) with small force! Resonance also explains why earthquake causes differentiating result to different structures – most devastating where resonance occurs! The condition for maximum amplitude is obtained by differentiating amplitude function with respect to applied frequency as [the illustrated formula sets out.]

Thomas L. Pratt, who teaches research geophysicists at the University of Washington, provides a webpage that explains frequencies, periods, and resonance in which he includes this simple explanation: “Resonance is when motion at a given frequency is amplified by waves of that same frequency. For example, when a child is being pushed on a swing, the swinging is increased by a push being applied at the right time (at the correct frequency) during each swing.”

At Science Fair Central you can follow instructions for a simple experiment with 2 paper circles and a piece of cardboard to show why earthquakes shake some buildings more than others.

Science and art devoted to the anticipation, recognition, evaluation, and control of those workplace environmental factors which may cause sickness, impaired health and well-being, or significant discomfort and inefficiency among workers or among citizens of the community.

If you have time to listen to the complete brief video, you will get a preview on LED lighting, which this expert predicts as the future of lighting. You can also copy the code by clicking the icon on the video, and embed it in teaching, learning or other bright idea online locations.

The triangle of information shown in this learn node is a phase diagram thermodynamic calculation for solder Bi-Pb-Sn. So who care about something like that? In the advancing complexity of metallurgy, depth of detail is important. This is the explanation of the NIST host of the diagram, whose Web site explains the mission:

The NIST Metallurgy Division is working closely with materials suppliers and users to develop the measurement and standards infrastructure needed in diverse technological areas – from steelmaking to the fabrication of nanostructured multilayers for magnetic recording heads. . . .

Learning about solder might seem more likely to involve technique, like that offered in the PDF which contains the illustration of “Tinning the soldering iron” from About Soldering—making Clip Leads—CLK from MIT’s Open Courseware. A sample of third sort of soldering knowledge available online is this popular Soldering Guide, a tutorial supported by Google ads.

Within the open Internet, patterns of related ideas for the subject of solder can be an amalgam from diverse sources.

More learn nodes at: learnodes.com

• 100-year life span
• 10 lanes of traffic, five in each direction—two lanes wider than the former bridge
• 189 feet wide—the previous bridge was 113 feet wide
• 13 foot wide right shoulders and 14 foot wide left shoulders, the previous bridge had no shoulders
• Light Rail Transport-ready which may help accommodate future transportation needs
• Design-build project complete in 437 days.
• Designed to be aesthetically pleasing and fit in with its environment

Another bridge disaster that is very famous is the Tacoma Narrows Bridge collapse. A Web exhibit at the University of Washington Library offers this invitation:

The Tacoma Narrows Bridge opened in 1940 with the third longest suspension span in the world. Four months after traffic began crossing the bridge it collapsed. On the webpages here the University of Washington Library interfaces the story of the bridge with narrative and images from its historic collections. Engineering students can visit these pages to virtually live a professional nightmare.

This Google Sightseeing map views the replacement bridge that crosses the Tacoma Narrow today