Tuesday, March 27, 2007


Sunglasses are a kind of visual correction aid, variously termed spectacles or glasses, which feature lenses that are coloured or darkened to screen out strong light from the eyes.
Many people find direct sunlight too bright to be comfortable, particularly when reading from paper on which the sun directly shines. In outdoor activities like skiing and flying, the eye can receive more light than usual. It has been recommended to wear these kind of glasses on sunny days to protect the eyes from ultraviolet radiation, which can lead to the development of a cataract. Sunglasses have also been linked with celebrities and film actors mainly due to the desire to mask identity, but in part due to the lighting involved in production being typically stronger than natural light and uncomfortable to the naked eye.
Augusto Pinochet sits with sunglasses in the front of the Chilean JuntaContents

Thursday, March 22, 2007

Aircraft carrier

An aircraft carrier is a warship whose main role is to deploy and recover aircraft—in effect acting as a sea-going airbase. Aircraft carriers thuo depend on local bases for land-based aircraft. Modern navies, who work such ships, treat aircraft carriers as the centerpiece of the fleet, a role before played by the battleship. The change, part of the growth of air power as a significant part of warfare, took place during World War II. Unescorted carriers are careful vulnerable to attack by other ships, aircraft, submarines or missiles and so travel as part of a carrier battle group.
Flight deck configuration
Aircraft carriers have a flat-top deck, the flight deck that serves as a take-off and landing area for aircraft. Aircraft take off to the front, into the wind, and land from the rear. The carrier steams at up to 35 knots (65 km/h) straight into the wind throughout take-off in order to increase the apparent wind speed, thereby reducing the necessary speed of the aircraft relative to the ship. A steam-powered catapult is used to propel the aircraft forward assisting the power of its engines and allowing it to take off in a shorter distance than would otherwise be necessary, even with the headwind effect of the ship's course. on the other hand, when landing on a carrier, aircraft rely upon a tailhook that catches on arrestor wires stretched across the deck to bring them to a stop in a shorter distance than normal. Since the end of WWII it has been ordinary to direct the landing recovery area off to port at an angle to the line of the ship. This allows launching of aircraft at the same time as others land.
The above deck areas of the warship are intense to the starboard side of the deck in a comparatively small area called an "island". Only a very few carriers have ever been intended or built without an island and such a configuration has not been seen in a fleet sized carrier.
A more recent configuration, used by the Royal Navy, has a 'ski-jump' ramp at the front end of the flat deck. This was developed to help launch VTOL (or STOVL) aircraft (aircraft that are able to take off and land with little or no forward movement) such as the Sea Harrier. Though the aircraft are capable of flying vertically off the deck, using the ramp is more fuel efficient. As catapults and arrestor cables are unnecessary, carriers with this arrangement reduce weight, complexity, and space wanted for equipment.

Friday, March 16, 2007


Gliders are aircraft with no internal powerplant. Model gliders are generally hand-launched or catapult-launched (using an elastic bungee.) The newer "discus" style of wingtip handlaunching has mostly supplanted the earlier "javelin" type of launch. Other launch methods include ground based power winches, hand-towing, and towing aloft using a second powered aircraft. As gliders are unpowered, flight must be sustained throughout exploitation of the natural wind in the environment. A hill or slope will often produce updrafts of air which will sustain the flight of a glider. This is called slope soaring, and when piloted skillfully, R/C gliders can stay airborne for as long as the updraft prevails. Another means of attaining height in a glider is exploitation of thermals, which are bubbles or columns of warm rising air created by hot spots on the ground. As with a powered aircraft, lift is obtained by the action of the wings as the aircraft moves through the air, but in a glider, height can only be gained by flying through air that is rising faster than the aircraft is sinking relative to the airflow.
Sailplanes are flown using available thermal lift. As thermals can only be indirectly experiential through the reaction of the aircraft to the invisible rising air currents, pilots find sailplane flying challenging yet rewarding.

Monday, March 12, 2007


An igloo ,translated sometimes as snowhouse, is a shelter constructed from blocks of snow, normally in the form of a dome. Although igloos are regularly associated with all Inuit, they were mostly constructed by people of Canada's Central Arctic and Greenlands Thule area. Other Inuit people tended to use snow to insulate their houses which consisted of whalebone and hides. The use of snow is due to the fact that snow is an insulator (due to its low density). On the outside, temperatures may be as low as -45 °C (-49 °F), but on the inside the temperature may range from -7 °C (19 °F) to 16 °C (61 °F) when warmed by body heat alone

Wednesday, March 07, 2007


Cheese is a solid food prepared from the milk of cows, goats, sheep, and other mammals. Cheese is made by curdling milk using a mixture of rennet (or rennet substitutes) and acidification. Bacteria acidify the milk and play a role in essential the texture and flavor of most cheeses. Some cheeses also feature molds, either on the outer rind or all through.
There are hundreds of types of cheese produced all over the world. Different styles and flavors of cheese are the result of using milk from various mammals or with different butterfat contents, employing particular species of bacteria and molds, and varying the length of aging and other dealing out treatments. Other factors contain animal diet and the addition of flavoring agents such as herbs, spices, or wood smoke. Whether the milk is pasteurized may also affect the flavor. The yellow to red coloring of many cheeses is a result of adding annatto. Cheeses are eaten both on their own and cooked as part of a variety of dishes; most cheeses melt when heated.
For a few cheeses, the milk is curdled by adding together acids such as vinegar or lemon juice. Most cheeses, however, are acidified to a lesser degree by bacteria, which turn milk sugars into lactic acid, followed by the addition of rennet to complete the curdling. Rennet is an enzyme mixture conventionally obtained from the stomach lining of young cattle, but now also laboratory created. Vegetarian alternatives to rennet are available; most are formed by fermentation of the fungus Mucor miehei, but others have been extracted from a variety of species of the Cynara thistle family.

Friday, March 02, 2007

Random access memory

Random access memory (usually known by its acronym, RAM) is a kind of data storage used in computers. It takes the figure of integrated circuits that allow the stored data to be accessed in any order — that is, at random and without the physical group of the storage medium or a physical reading head.
The word "random" refers to the fact that any piece of data can be returned rapidly, and in a constant time, inspite of its physical location and whether or not it is linked to the previous piece of data. This contrasts with storage mechanisms such as tapes, magnetic disks and optical disks, which rely on the physical movement of the recording medium or a analysis head. In these devices, the movement takes longer than the data transfer, and the retrieval time varies depending on the physical location of the next item.