Vardaman Virtual Forestry Company
FRIDAY REPORT OF 03/23/07
The Most Direct, Frequent Link to Knowledge Workers in the Eastern Forest Economy
“ON SPRING EQUINOX, DAY AND NIGHT EQUAL IN NAME ONLY”
Portions of 03/20/06 article by John Roach for National Geographic News
“In the Northern Hemisphere spring officially begins today, the vernal equinox, at 1:26 p.m. ET…The reverse is true in the Southern Hemisphere. But whether you are entering the season of light or darkness, don’t be fooled into thinking that on the equinox the length of the day is exactly equal to the length of the night. It’s not.
“The day of light and dark equality always happens before the spring and after the fall equinoxes, according to Geoff Chester, a public affairs specialist with the U.S. Naval Observatory in Washington, D.C. ‘Exactly when it happens depends on where you are located on the surface of the Earth,’ he said.
“By the time the center of the sun passes over the Earth’s Equator – the official definition of equinox – the day will be slightly longer than the night everywhere on Earth. The difference is a matter of geometry, atmosphere, and language.
“Chester explains that if the sun was just a tiny point of light and the Earth had no atmosphere, then the day and night of the equinox would each be exactly 12 hours long. But, to begin with, the sun is bigger than a point – it appears as a little fingertip held at arm’s length, or half a degree wide, as seen from Earth. As such, sunrise is defined as the moment the top edge of the sun appears to peek over the horizon, and sunset is when the very last bit of the sun appears to dip below the horizon. The equinox, however, is when the center of the sun crosses the Equator.
“Additionally, the Earth has an atmosphere that bends the light cast by the sun when that light is close to the horizon. The golden orb appears to be a little higher in the sky than it really is. As a result, the sun appears to be above the horizon a few minutes longer than it really is. Therefore, on the equinox, the daylight hours are actually longer than the length of time between when the sun crosses the horizon at dawn and when the sun crosses the horizon at sunset. ‘Those factors all combine to make the day of the equinox not the day when we have 12 hours of light and darkness,’ Chester said.”
“BRIGHT, WHITE FUTURE FOR ‘GREEN’ LEDs, SCIENTIST SAYS”
Portions of 03/15/07 article by John Roach for National Geographic News
“…Mass adoption of LEDs [light-emitting diodes] could cut global electricity use by 10 percent, said George Craford, chief technology officer for Philips Lumileds in San Jose, California. Craford presented a review paper on the latest LED advances last Tuesday during a meeting of the American Physical Society in Denver, Colorado. A switch to LEDs in place of conventional lighting would save ‘a huge amount of electricity and a huge amount of money,’ he told National Geographic News. The energy savings ‘will amount to well over a hundred nuclear power plants worldwide.’
“Materials scientist Steve DenBaars directs a research center at the University of California, Santa Barbara (UCSB), that focuses on energy-efficient lighting and display technologies like LEDs. DenBaars said that Craford’s estimate of energy savings may be a slight overstatement, ‘but it’s on that scale. Twenty-two percent of [U.S.] electrical energy consumption goes into lighting, and we’re talking about taking the efficiency up several factors here and taking that number down to like 3 or 4 percent,’ he said. By that calculation, he said, energy-efficient lighting could save the U.S. the equivalent of the power produced annually by 133 coal-powered plants.
LEDs are tiny devices made of semiconductors – solid devices such as silicon that have varying abilities to conduct electricity. Since the 1960s scientists have known that LEDs made from different semiconductors glow at different colors when voltage is applied. Unlike regular incandescent bulbs, LEDs emit light without a wire filament, so they take longer to burn out, and they produce less heat…
“Perhaps the biggest remaining challenge is to create efficient and economical white-light LEDs, Craford said. LEDs by their nature give off distinct colors – one type of material glows green while another glows blue. [the one on my car key ring glows blue, and the concentrated, directional beam travels a long way.] But white is a combination of colors, Craford explained. To make white light with an LED, scientists most commonly add a yellowish phosphorescent chemical to a blue-emitting diode. The combination of yellow and blue gives an appearance of white to the human eye.
Noah Horowitz is a senior scientist with the nonprofit Natural Resources Defense Council in California. He said through a spokesperson that LEDs that are more efficient than compact fluorescent bulbs are the ‘holy grail’ of lighting, and the environmental group is optimistic about the use of LED technology in the future. But today, he said, ‘they cost a lot more and are not yet widely available for consumer applications.’ Horowitz added that obtaining white light from LEDs that resembles the light of an incandescent remains a challenge, as does spreading the light out from the LED. Currently, Horowitz said, LEDs are good at providing directional lighting as in a spotlight, but not as good for practical uses in things such as table lamps…”
“DEEP SEA, ARCTIC MAY HOLD WORLD’S LARGEST FUEL SUPPLY, EXPERTS SAY”
Portions of article by Richard Lovett in 03/07/07 National Geographic News
“The energy source of the future may lie beneath the ocean floor and under Arctic permafrost, scientists say. Both places are sources of gas hydrates, strange icelike substances that trap methane – the primary component of natural gas. ‘It’s not frozen gas,’ explained Timothy Collett of the U.S. Geological Survey in Denver. ‘It’s [formed] from the interaction of gas and water.’
“The hydrates were discovered in 1983, and no one knows how many of them exist. But there appear to be enough hydrates to represent a larger energy source than all of the world’s gas, oil, and coal combined, Collett said at a meeting of the American Physical Society in Denver, Colorado, on March 5. Twenty-three percent of the Earth’s surface is covered by permafrost and may have hydrates beneath it, he said, and most of the world’s oceans are deep enough for hydrates to exist just under the seabed..
“Because each cubic foot (0.02 cubic meter) of hydrate releases 160 cubic feet (4.5 cubic meters) of natural gas, ‘they’re a very good storage system for methane,’ Collett said. Hydrates are being studied as a fuel source not only in the U.S., which is looking for an alternative to foreign oil, but in India and China, whose burgeoning economies need a new energy source. Japan and Korea are also interested, Collett said…
“Rather than mining solid hydrates, scientists are working on ways to melt the deposits underground. This would free the gas from the ice, allowing the methane to be captured in the same way ordinary gas is collected. More research has to be done to determine how to extract methane safely and efficiently from hydrates’ remote location, scientists say…Other scientists are trying to understand how hydrates might affect the environment. Because methane is a powerful greenhouse gas, some experts wonder if massive methane releases might have contributed to past epochs of global warming…
“Others are concerned that current global warming may heat the oceans enough to melt the hydrates, causing similar methane releases today…Unstable hydrates could also cause underwater landslides, which could damage offshore drilling equipment and possibly create surges large enough to generate tsunamis, according to some models. Earthquakes pose an additional risk, added Riedel, the McGill scientist. At a meeting of the American Geophysical Union last December, he compared the effects of quakes on hydrates to shaking a bottle of soda…”
Visit our partner Wiley.com to save 15% on How
to Make Money Growing Trees and their entire selection of Forestry and Agricultural titles. Your discount will be applied automatically
upon checkout. If you do you not see the discount being applied, please enter
code aff15 in the Promotion Code field and click the Apply Discount button.
|
