Thursday, October 7, 2010
Bulletin Board
A Bulletin Board System, or BBS, is a computer system running software that allows users to connect and log in to the system using a terminal program. Once logged in, a user can perform functions such as uploading and downloading software and data, reading news and bulletins, and exchanging messages with other users, either through electronic mail or in public message boards. Many BBSes also offer on-line games, in which users can compete with each other, and BBSes with multiple phone lines often provide chat rooms, allowing users to interact with each other.
Originally BBSes were accessed only over a phone line using a modem, but by the early 1990s some BBSes allowed access via a Telnet, packet switched network, or packet radio connection.
Ward Christensen coined the term "Bulletin Board System" as a reference to the traditional cork-and-pin bulletin board often found in entrances of supermarkets, schools, libraries or other public areas where people can post messages, advertisements, or community news. By "computerizing" this method of communications, the name of the system was born: CBBS - Computerized Bulletin Board System. See History.
During their heyday from the late 1970s to the mid 1990s, most BBSes were run as a hobby free of charge by the system operator (or "SysOp"), while other BBSes charged their users a subscription fee for access, or were operated by a business as a means of supporting their customers. Bulletin Board Systems were in many ways a precursor to the modern form of the World Wide Web and other aspects of the Internet.
Early BBSes were often a local phenomenon, as one had to dial into a BBS with a phone line and would have to pay additional long distance charges for a BBS out of the local calling area. Thus, many users of a given BBS usually lived in the same area, and activities such as BBS Meets or Get Togethers, where everyone from the board would gather and meet face to face, were common.
As the use of the Internet became more widespread in the mid to late 1990s, traditional BBSes rapidly faded in popularity. Today, Internet forums occupy much of the same social and technological space as BBSes did, and the term BBS is often used to refer to any online forum or message board.
Ward Christensen and the computer that ran the first public Bulletin Board System, CBBS
Although BBSing survives only as a niche hobby in most parts of the world, it is still an extremely popular form of communication for Taiwanese youth (see PTT Bulletin Board System). Most BBSes are now accessible over telnet and typically offer free email accounts, FTP services, IRC and all of the protocols commonly used on the Internet.
Wednesday, October 6, 2010
what do you know about Vespa?
History
Vespa 150 TAP, modified by the French military, that incorporated an anti tank weapon
Post World War II Italy, in light of its agreement to cessation of war activities with the Allies, had its aircraft industry severely restricted in both capability and capacity.
Piaggio emerged from the conflict with its Pontedera fighter plane plant demolished by bombing. Italy's crippled economy and the disastrous state of the roads did not assist in the re-development of the automobile markets. Enrico Piaggio, the son of Piaggio's founder Rinaldo Piaggio, decided to leave the aeronautical field in order to address Italy's urgent need for a modern and affordable mode of transportation for the masses.
Concept
The inspiration for the design of the Vespa dates back to Pre-WWII Cushman scooters made in Nebraska, USA. These olive green scooters were in Italy in large numbers, ordered originally by Washington as field transport for the Paratroops and Marines. The US military had used them to get around Nazi defense tactics of destroying roads and bridges in the Dolomites (a section of the Alps) and the Austrian border areas.
Design
Piaggio MP5 "Paperino", the unloved initial Piaggio prototype
In 1944, Piaggio engineers Renzo Spolti and Vittorio Casini designed a motorcycle with bodywork fully enclosing the drivetrain and forming a tall splash guard at the front. In addition to the bodywork, the design included handlebar-mounted controls, forced air cooling, wheels of small diameter, and a tall central section that had to be straddled. Officially known as the MP5 ("Moto Piaggio no. 5"), the prototype was nicknamed "Paperino".
Enrico Piaggio was displeased with the MP5, especially the tall central section. He contracted aeronautical engineer Corradino D'Ascanio, to redesign the scooter. D'Ascanio, who had earlier been consulted by Ferdinando Innocenti about scooter design and manufacture, made it immediately known that he hated motorcycles, believing them to be bulky, dirty, and unreliable.
D'Ascanio's MP6 prototype had its engine mounted beside the rear wheel. The wheel was driven directly from the transmission, eliminating the drive chain and the oil and dirt associated with it. The prototype had a unit spar frame with stress-bearing steel outer panels. These changes allowed the MP6 to have a step-through design without a centre section like that of the MP5 Paperino. The MP6 design also included a single sided front suspension, interchangeable front and rear wheels mounted on stub axles, and a spare wheel. Other features of the MP6 were similar to those on the Paperino, including the handlebar-mounted controls and the enclosed bodywork with the tall front splash guard.
Upon seeing the MP6 for the first time Enrico Piaggio exclaimed: "Sembra una vespa!" ("It resembles a wasp!") Piaggio effectively named his new scooter on the spot. Vespa is both Latin and Italian for wasp—derived from the vehicle's body shape: the thicker rear part connected to the front part by a narrow waist, and the steering rod resembled antennae. The name also refers to the high-pitched noise of the two-stroke engine.
Product
Glove box on newer Vespa PX
On 23 April 1946, at 12 o'clock in the central office for inventions, models and makes of the Ministry of Industry and Commerce in Florence, Piaggio e C. S.p.A. took out a patent for a "motorcycle of a rational complexity of organs and elements combined with a frame with mudguards and a casing covering the whole mechanical part".
The basic patented design allowed a series of features to be deployed on the spar-frame which would later allow quick development of new models. The original Vespa featured a rear pillion seat for a passenger, or optionally a storage compartment. The original front protection "shield" was a flat piece of aero metal; later this developed in to a twin skin to allow additional storage behind the front shield, similar to the glove compartment in a car. The fuel cap was located underneath the (hinged) seat, which saved the cost of an additional lock on the fuel cap or need for additional metal work on the smooth skin.
The scooter had rigid rear suspension and small 8-inch (200 mm) wheels that allowed a compact design and plenty of room for the rider's legs. The Vespa's enclosed, horizontally-mounted two-stroke 98 cc engine acted directly on the rear drive wheel through a three-speed transmission. The twistgrip-controlled gear change involved a system of rods. The early engine had no cooling, but fan blades were soon attached to the flywheel (otherwise known as the magneto, which houses the points and generates electricity for the bike and for the engine's spark) to push air over the cylinder's cooling fins. The modern Vespa engine is still cooled this way. The mixture of two-stroke oil in the fuel produced high amounts of smoke, and the engine made a high buzzing sound like a wasp.
The MP6 prototype had large grilles on the front and rear of the rear fender covering the engine. This was done to allow air in to cool the engine, as the prototype did not have fan cooling. A cooling fan similar to that used on the MP5 "Paperino" prototype was included in the design of the production Vespa, and the grilles were removed from the fender.
Launch
Piaggio filed a patent for the Vespa scooter design in April 1946. The application documents referred to a "model of a practical nature" for a "motorcycle with rationally placed parts and elements with a frame combining with mudguards and engine-cowling covering all working parts", of which "the whole constitutes a rational, comfortable motorcycle offering protection from mud and dust without jeopardizing requirements of appearance and elegance". The patent was approved the following December.
The first 13 examples appeared in spring 1946, and reveal their aeronautical background. In the first examples, one can recognize the typical aircraft technology. Attention to aerodynamics is evident in all the design, in particular on the tail. It was also one of the first vehicles to use monocoque construction (where the body is an integral part of the chassis).
The company was aiming to manufacture the new Vespa in large numbers, and their longstanding industrial experience led to an efficient Ford-style volume production line. The scooter was presented to the press at Rome Golf Club, where journalists were apparently mystified by the strange, pastel coloured, toy-like object on display. But the road tests were encouraging, and even with no rear suspension the machine was more manoeuvrable and comfortable to ride than a traditional motorcycle.
Following its public debut at the 1946 Milan Fair, the first fifty sold slowly—then with the introduction of payment by installments, sales took off.
Chocolate creates world
Chocolate comprises a number of raw and processed foods produced from the seed of the tropical Theobroma cacao tree. Cacao has been cultivated for at least three millennia in Mexico, Central and South America, with its earliest documented use around 1100 BC. The majority of the Mesoamerican people made chocolate beverages, including the Aztecs, who made it into a beverage known as xocolātl, a Nahuatl word meaning "bitter water". The seeds of the cacao tree have an intense bitter taste, and must be fermented to develop the flavor.
After fermentation, the beans are dried, then cleaned, and then roasted, and the shell is removed to produce cacao nibs. The nibs are then ground to cocoa mass, pure chocolate in rough form. Because this cocoa mass usually is liquefied then molded with or without other ingredients, it is called chocolate liquor. The liquor also may be processed into two components: cocoa solids and cocoa butter. Unsweetened baking chocolate (bitter chocolate) contains primarily cocoa solids and cocoa butter in varying proportions. Much of the chocolate consumed today is in the form of sweet chocolate, combining cocoa solids, cocoa butter or other fat, and sugar. Milk chocolate is sweet chocolate that additionally contains milk powder or condensed milk. White chocolate contains cocoa butter, sugar, and milk but no cocoa solids.
Cocoa solids contain alkaloids such as theobromine and phenethylamine, which have physiological effects on the body. It has been linked to serotonin levels in the brain. Some research found that chocolate, eaten in moderation, can lower blood pressure. The presence of theobromine renders it toxic to some animals, especially dogs and cats.Chocolate has become one of the most popular food types and flavors in the world. Gifts of chocolate molded into different shapes have become traditional on certain holidays: chocolate bunnies and eggs are popular on Easter, chocolate coins on Hanukkah, Santa Claus and other holiday symbols on Christmas, and chocolate hearts or chocolate in heart-shaped boxes on Valentine's Day. Chocolate is also used in cold and hot beverages, to produce chocolate milk and hot chocolate.
Around three quarters of the world's cacao bean production takes place in West Africa
Tuesday, October 5, 2010
Proxima Centauri
Proxima Centauri is a red dwarf star approximately 4.2 light-years (3.97 × 1013 km) distant in the constellation of Centaurus. The star is the nearest star to the Sun and is only 0.24 ly (15,000 ± 700 astronomical units) away from the binary star system Alpha Centauri. Proxima Centauri's diameter is one-seventh that of the Sun; its mass is about an eighth of the Sun's, and its average density is about 40 times that of the Sun. Although it has a very low average luminosity, Proxima Centauri is a flare star that undergoes random increases in brightness because of magnetic activity; during a flare the star generates a total X-ray emission similar to that produced by the Sun. The star's relatively low energy production rate means that it will be a main-sequence star for another four trillion years, or nearly 300 times the current age of the universe. Searches for companions orbiting Proxima Centauri have been unsuccessful; the detection of smaller objects will require the use of new instruments, such as the proposed James Webb Space Telescope. Whether a planet orbiting this star could support life is disputed. Because of the star's proximity, it has been proposed as a destination for interstellar travel.
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