|Ken Novak's Weblog
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Wednesday, March 10, 2004
Broadband overtaking dial-up in major cities:
"Broadband is rapidly becoming the preferred way residents of major U.S. metropolitan areas are accessing the Internet, according to a study released Wednesday. San Diego currently has the highest broadband penetration rate in the nation, with 52% of its residents connecting to the Internet using a high-speed service, according to online measurement firm ComScore Networks. Boston ranks second with an even split between broadband and narrowband customers. New York City is in third place with 49%. The San Francisco Bay Area and Los Angeles rank ninth and tenth with 44% broadband penetration each.
Despite gains in certain major cities, dial-up services remain the preferred choice for Americans to go online. 64% percent of all online Americans still use a dial-up services such as America Online, MSN and EarthLink. AOL still holds the lead, counting 28% of the U.S. Internet population as subscribers. " 12:21:04 PM
Ocean Power Delivery Limited: "Ocean Power Delivery Ltd has developed a novel offshore wave energy converter called Pelamis. Building on technology developed for the offshore industry, the Pelamis has a similar output to a modern wind turbine... It is anticipated that future `wave farm' projects would consist of an arrangement of interlinked multi-machines connected to shore by a single subsea cable. A typical 30MW installation would occupy a square kilometre of ocean .. " The final full-scale prototype machine is built and being prepared for initial sea trials which will begin at the beginning of March.
Animation available. News story summarizes operation: "The 750 kW Pelamis machine measures 120m long by 3.5m wide (about the size of four train carriages) .. [It] is a semi-submerged, articulated structure composed of cylindrical sections linked by hinged joints. The wave-induced motion of these joints is resisted by hydraulic rams, which pump high-pressure oil through hydraulic motors via smoothing accumulators. The hydraulic motors drive electrical generators to produce electricity. Power from all the joints is fed down a single umbilical cable to a junction on the sea bed. Several devices can be connected together and linked to shore through a single seabed cable. A novel joint configuration is used to induce a tuneable, cross-coupled resonant response, which greatly increases power capture in small seas..
The machine is held in position by a mooring system, for which a patent has been applied for, comprising of a combination of floats and weights which prevent the mooring cables becoming taut .. Ideally the Pelamis would be moored in waters approximately 50-60m in depth (often 5-10km from the shore). This would allow access to the great potential of the larger swell waves but it would avoid the costs involved in a longer submarine cable .. the prototype design [meets] (DNV) offshore codes and standards." 12:09:42 PM
Sorcerer II sails the world finding new species and new energy genes: "Using precise mathematical algorithms previously used to assemble sequence results from single species, the researchers were able to assemble whole genomes and major sections of genomes from the diverse microbial community found in the ocean. The paper describes a minimum of 1,800 new species identified in the Sargasso Sea. As well, there were 1,214,207 new genes identified by the researchers, which is a significant increase over the number currently in public databases. ..
One of the most important single discoveries from the Sargasso Sea environmental shotgun sequencing study is the 782 new rhodopsin-like photoreceptor genes. Only a few dozen photoreceptors have been characterized in microorganisms to date and less than 200 photoreceptors have been discovered from all species, including human where they are responsible for our vision. Therefore, this discovery represents a substantial increase in the total number of this family of proteins. One interpretation of this finding is that at least 50% of the new species discovered use some type of photobiology and could explain the diversity of species in such a low nutrient environment. Better understanding of these photoreceptor genes could be very important to IBEA researchers as they explore the mechanisms of photosynthesis as a means to efficiently and economically produce hydrogen as a fuel source. ..
Dr. Venter also announced the official launch of the Sorcerer II Expedition, a scientific expedition of discovery that will circumnavigate the globe under sail, surveying marine and terrestrial microbial populations. The Expedition has the potential to uncover tens of thousands of new microbial species and tens of millions of new genes. The voyage and sample collection are being funded by the J. Craig Venter Science Foundation and by the Discovery Channel Quest Program. The Sorcerer II Expedition is the subject of a Discovery Channel documentary film slated to air in 2005. In addition to the DOE Office of Science grant previously announced, the Expedition has received an important new grant from the Gordon and Betty Moore Foundation for $4.25 million which will be used to sequence the DNA collected along the coast of North America." The site has pictures and flash presentations. 10:42:59 AM
Researchers Report Bubble Fusion Results Replicated: "The research team used a standing ultrasonic wave to help form and then implode the cavitation bubbles of deuterated acetone vapor. The oscillating sound waves caused the bubbles to expand and then violently collapse, creating strong compression shock waves around and inside the bubbles. Moving at about the speed of sound, the internal shock waves impacted at the center of the bubbles causing very high compression and accompanying temperatures of about 100 million Kelvin.
These new data were taken with an upgraded instrumentation system .. . According to the new data, the observed neutron emission was several orders of magnitude greater than background and had extremely high statistical accuracy. Tritium, which also is produced during the fusion reactions, was measured and the amount produced was found to be consistent with the observed neutron production rate. Earlier test data, which were reported in Science (Vol. 295, March 2002), indicated that nuclear fusion had occurred, but these data were questioned because they were taken with less precise instrumentation. .. [Unlike laser or plasma fusion,] spherical compression of the plasma was achieved due to the inertia of the liquid surrounding the imploding bubbles. ..
[Rensselaer professor Richard] Lahey explained that, unlike fission reactors, fusion does not produce a significant amount of radioactive waste products or decay heat. Tritium gas, a radioactive by-product of deuterium-deuterium bubble fusion, is actually a part of the fuel, which can be consumed in deuterium-tritium fusion reactions."
Several theoretical results are presented consistent with the observed data. Not everyone agrees. PhysicsWeb reports: "Michael Saltmarsh of Oak Ridge says he is "intrigued but sceptical" about the new work. "Unlike their Science paper, most of the background notes and supporting information seem to be correct but there are still some puzzling inconsistencies. In particular, the estimated neutron detection efficiency is still an order of magnitude too low. While better than the Science article, the difference would produce a mismatch between the reported neutron and tritium yields."
"Thermonuclear sono-fusion may not be impossible," says Willy Moss of the Lawrence Livermore National Lab, "but more tests need to done." .. Aaron Galonsky of Michigan State University [says] "Taleyarkhan and co-workers have not done .. enough for me to be able to say whether they have seen nuclear fusion in a bottle of acetone. With two million 14 MeV neutrons per second injected into the room where the experiment was performed, there are opportunities for error in detecting the much rarer, lower-energy sonoluminescent neutrons."" 9:41:05 AM