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Sunday, April 29, 2007

Bonneville Dam

100 Bonneville Lock and Dam consists of a number of dam structures that together whole a span of the Columbia River between the US states of Oregon and Washington at River Mile 146.1. The dam is situated 40 miles east of Portland, Oregon, in what is now the Columbia River Gorge National Scenic Area. The main functions of Bonneville Lock and Dam are those of electrical power generation and river navigation. The dam was built and is managed by the US Army Corps of Engineers. Electrical power generated at Bonneville is spread by the Bonneville Power Administration. Bonneville Lock and Dam are named for Army Capt. Benjamin Bonneville, an early explorer endorsed with charting much of the Oregon Trail. The name is marked BAH-nee-vill.

History
The unusual structures: a lock and powerhouse constructed on the south side of Bradford Island and a spillway on the north side were built by the Army Corps of Engineers during the New Deal—started in 1933 and finished in 1937. Prior to this damming of the river, a set of locks that were opened in 1896 moved ships around Cascades Rapids, situated several miles upstream of Bonneville. Both the cascades and the old lock structure were submerged by Lake Bonneville, the tank that formed behind the dam. The original navigation lock at Bonneville was opened in 1938 and was, at that time, the biggest single-lift lock in the world.

Dimensions and statistics

Aerial view of spillway flanked by powerhouses, Bonneville Lock and Lake Bonneville beyond First Powerhouse – Constructed in 1933-37; 313 m long; 10 generators with an output capacity of 526,700 kW.
Spillway – Constructed 1933-37; 18 gates over a length of 442 m; maintains the reservoir usually 18 m above the river on the downstream side;
Second Powerhouse – Constructed 1974-81; 300.5 m long; 8 generators with a total generating capacity of 558,200 kW.
Bonneville Lock – Constructed in 1993 at a cost of $341 million; 26 m wide, 206 m long; transit time is approx. 30 minutes.
Lake Bonneville – 77 km long reservoir on the Columbia River created by Bonneville Dam; part of the Columbia-Snake Inland Waterway.

Monday, April 23, 2007

Longleaf Pine

The Longleaf Pine (Pinus palustris) is a pine native to the southeast United States, found along the coastal plain from eastern Texas to southeast Virginia.
It reaches a height of 30-35 m (100-115 ft) and a diameter of 0.7 m (28"). In the past, they reportedly grew to 47 m (154 ft) with a diameter of 1.2 m (47").
The bark is thick, reddish-brown, and scaly. The dark green, needle-like leaves occur in bundles of three. They are often twisted and are remarkably long 20-45 cm (8-18") in length. It is one of the two southern pines with long needles, the other being Slash Pine.
The cones, both male (catkins) and female (cones), are initiated during the growing season before buds emerge. Male cones begin forming in their buds in July, while female conelets are shaped during a relatively short period of time in August. Pollination occurs early the next spring, with the male cones 3-8 cm (1-3") long. The female (seed) cones mature in about 20 months from pollination; when grown-up they are yellow-brown in color, 15-25 cm long, 5-7 cm broad opening to 12 cm (6-10" long, 2-2½" broad opening to 5" broad), and have a small but sharp downward-pointing spine on the middle of each scale. The seeds are 7-9 mm long, with a 25-40 mm wing (1/3" long, with a 1 - 1¾" wing).
Longleaf Pine takes 100 to 150 years to turn out to be full size and can live to 300 years old. When young, they grow a long taproot, which is frequently 2-3 m (6-10 ft) long; by maturity they have a wide spreading lateral root system with several deep 'sinker' roots. It grows on well-drained, regularly sandy soil, often in pure stands. The scientific name meaning "of marshes" is a misunderstanding on the part of Philip Miller who described the species, from seeing Longleaf Pine forests with temporary winter flooding.Longleaf Pine is also known as Southern Yellow Pine or Longleaf Yellow Pine, and in the past as Pitch Pine (dropped as it caused confusion with Pitch Pine, Pinus rigida). Long leaf pines are found in the upland pine forest habitat

Wednesday, April 18, 2007

Airliner

Definition and description

An airliner is a great fixed-wing aircraft whose key function is for the carry of paying passenger. Airliners are typically operated by an airline company which owns or leases the aircraft.
An Airbus A340 airliner operated by Air Jamaica. The description of an airliner can differ from country to country, but typically, 20 or more traveler seats or an unfilled weight above 50,000 lb qualifies an aircraft as an airliner.
Passenger aircraft with fewer than 20 passenger places are called commuter aircraft or air taxis, depending on their size, engines and seating configurations.
While piston engines were common on prop liners like the Douglas DC-3 until the opening of the jet age, nearly all modern airliners are powered by turbine engines, either turbofans or turboprops, since they work resourcefully at much higher altitudes, are far more dependable than piston engines, and provide a ride with less shaking and noise for the passengers.
There may be variants of an airliner that are residential for moving freight or for luxury corporate use. Many airliners have also been adapted for government use as "VIP" transports and for various unarmed functions such as airborne, air ambulance, reconnaissance as well as the more obvious troop-carrying roles.

Monday, April 09, 2007

Magnetic recording

Magnetic recording was established in principle as early as 1898 by Valdemar Poulsen in his telegraphone. Magnetic wire recording, and its successor, magnetic tape recording, involve the use of a magnetizable medium which moves with a constant speed past a recording head. An electrical signal, which is analogous to the sound that is to be recorded, is fed to the recording head, inducing a pattern of magnetization like to the signal. A playback head can then pick up the changes in magnetic field from the tape and convert it into an electrical signal.

Thursday, April 05, 2007

Irish pound coin

The Irish pound coin was introduced on June 20, 1990 using the design of a red deer, by the Irish artist Tom Ryan. The 2000 Millennium was used to subject a commemorative coin, the design was based on the "Broighter Boat" in the National Museum of Ireland; the coins design was by Alan Ardiff and Garrett Stokes and were issued on November 29, 1999. The coin featured a milled edge - unique in Irish coinage.
The "Broighter Boat" issue for 2000.The Irish pound coin, which was introduced in 1990, remains the largest Irish coin introduced since decimalisation at 3.11 centimetres diameter and was 10 grams weight. The coin was almost the same in dimensions to the old penny coin that circulated before 1971, and was quite similar in diameter to, but thinner, than the half-crown coin.
During the early circulation of the coin, many payphone and vending machines which had been changed to accept the pound coin also accepted the old penny because of the similar size, the latter coin which was no longer legal tender and had little value to collectors. As a result losses accrued to vending machine operators due to the substitution of the penny coin and further costs were associated with updating the machines so they would no longer accept the penny.

Sunday, April 01, 2007

Banksia

Banksia is a genus of around 80 species in the plant family Proteaceae. They are native to Australia, happening in all but the most arid areas. Easily recognised by their characteristic flower spikes and fruiting "cones", Banksia are a well-known Australian wildflower and a popular garden plant. They grow in forms changeable from prostrate woody shrubs to trees up to 25 metres tall. They are generally known as Banksias or Australian Honeysuckle Trees.
Banksias grow as trees or woody shrubs. The largest trees, the Coast Banksia, B. integrifolia, and the River Banksia, B. seminuda, often grow over 15 metres tall, and may be up to 25 metres tall. Banksia species that grow as shrubs are typically erect, but there are several species that are prostrate, with branches that grow on or below the soil.