Sunday, April 29, 2007

Lighting rod

A lightning rod is a metal narrow piece or rod, typically of copper or similar conductive material, used as part of lightning security to guard tall or isolated structures from lightning damage. Its formal name is lightning finial. Sometimes, the system is informally referred to as:

A lightning conductor,
A lightning arrester, or
A lightning discharger.
However, these terms really refer to lightning guard systems in general or specific mechanism within them.

Lightning rod dissipaters make a structure less nice-looking by which charges can flow to the air around it. This then reduces the voltage between the point and the storm cloud, making a strike less likely. The most common charge dissipaters appear as slightly-blunted metal spikes sticking out in all information from a metal ball. These are mounted on short metal arms at the very top of a radio antenna or tower, the area by far most likely to be struck. These devices diminish, but do not eradicate, the risk of lightning strikes.

Monday, April 23, 2007

American Robin

The American Robin is a migratory songbird of the thrush family.
The American Robin is 25-28 cm (10-11 in) long. It has gray upperparts and head, and orange underparts, typically brighter in the male; the similarity between this coloring and that of the smaller and unrelated European Robin led to its common name. There are seven races, but only T . m. confinus in the southwest is mainly distinctive, with pale gray-brown underparts
During the breeding season, the adult males grow distinctive black feathers on their heads; after the breeding season they lose this eye-catching plumage.
This bird breeds all through Canada and the United States. While Robins infrequently overwinter in the northern part of the United States and southern Canada, most winter in the southern parts of the breeding range and beyond, from the southern USA to Guatemala. Most depart south by the end of August and begin to return north in March. This species is a very rare vagrant to western Europe. In autumn 2003, migration was displaced eastwards leading to massive movements through the eastern USA. most probably this is what led to no less than three American Robins being found in Great Britain, with two attempting to overwinter in 2003-4, one eventually being taken by a Sparrowhawk

Wednesday, April 18, 2007

Auto racing

Auto racing (also known as automobile racing, autosport or motorsport) is a sport involving racing automobiles. Motor racing or motorsport may also mean motorcycle racing, and can comprise motorboat racing and air racing. It is one of the world's most popular spectator sports and perhaps the most thoroughly commercialized.Auto racing began almost immediately after the construction of the first successful petrol-fuelled autos. In 1894, the first contest was organized by Paris magazine Le Petit Journal, a consistency test to determine best performance.A year later the first real race was staged in France, from Paris to Bordeaux. First over the line was Émile Levassor but he was ineligible because his car was not a necessary four-seater.

Monday, April 09, 2007

"Wireless" factories and vacuum tubes

Marconi opened the world's first "wireless" factory in Hall Street, Chelmsford, England in 1898, employing around 50 people. Around 1900, Tesla opened the Wardenclyffe Tower facility and advertised services. By 1903, the tower structure neared completion. Various theories exist on how Tesla planned to achieve the goals of this wireless system. Tesla claimed that Wardenclyffe, as part of a World System of transmitters, would have permitted secure multichannel transceiving of information, universal navigation, time synchronization, and a global location system.
The next great invention was the vacuum tube detector, invented by a team of Westinghouse engineers. On Christmas Eve, 1906, Reginald Fessenden ransmitted the first radio audio broadcast in history from Brant Rock, Massachusetts. Ships at sea heard a broadcast that included Fessenden playing O Holy Night on the violin and reading a passage from the Bible. The world's first radio news program was broadcast August 31, 1920 by station 8MK in Detroit, Michigan. The world's first regular wireless broadcasts for entertainment commenced in 1922 from the Marconi Research Centre at Writtle near Chelmsford, England.

Thursday, April 05, 2007

Space missions

Unmanned space missions are those using remote-controlled spacecraft.
The first such mission was the Sputnik I mission, launched October 4, 1957. Some missions are more appropriate for unmanned missions rather than manned space missions, due to lower cost and lower risk factors.
Since the early 1970s, most unmanned space missions have been based on space probes with built-in mission computers, and as such may be classified as embedded systems.
Most American unmanned missions have been synchronized by the Jet Propulsion Laboratory, and European missions by the European Space Operations Centre, part of ESA (the European Space Agency).
ESA has conducted comparatively few space exploration missions. ESA has, however, launched a variety of spacecraft to carry out astronomy, and is a collaborator with NASA on the Hubble Space Telescope.
There has been a large number of very successful Russian space missions. There were also a few Japanese and Chinese missions.

Sunday, April 01, 2007

Sand Hill Road

Sand Hill Road is a road in Menlo Park, California, prominent for the concentration of venture capital companies there. Its significance as a symbol of private equity in the United States may be compared to that of Wall Street in the stock market. Connecting El Camino Real and Interstate 280, the road provides easy access to Stanford University and Silicon Valley. For several years during the Dotcom boom of the late 1990s, commercial real-estate on Sand Hill Road was more expensive than anywhere else in the U.S. (even Manhattan).Some of the areas Sand Hill Road venture capitalists invest in:Sand Hill Road also serves as home to the Stanford Linear Accelerator.