Minggu, 02 Desember 2012
Minggu, 04 November 2012
Thomas Edison
Thomas Alva Edison (February 11, 1847 – October 18, 1931) was an American inventor and businessman. He developed many devices that greatly influenced life around the world, including the phonograph, the motion picture camera, and a long-lasting, practical electric light bulb. Dubbed "The Wizard of Menlo Park" by a newspaper reporter, he was one of the first inventors to apply the principles of mass production and large-scale teamwork to the process of invention, and because of that, he is often credited with the creation of the first industrial research laboratory.
Edison is the fourth most prolific inventor in history, holding 1,093 US patents in his name, as well as many patents in the United Kingdom, France, and Germany. He is credited with numerous inventions that contributed to mass communication and, in particular, telecommunications. These included a stock ticker, a mechanical vote recorder, a battery for an electric car, electrical power, recorded music and motion pictures.
His advanced work in these fields was an outgrowth of his early career as a telegraph operator. Edison developed a system of electric-power generation and distribution[2] to homes, businesses, and factories – a crucial development in the modern industrialized world. His first power station was on Pearl Street in Manhattan, New York.
Early life
Thomas Edison was born in Milan, Ohio, and grew up in Port Huron, Michigan. He was the seventh and last child of Samuel Ogden Edison, Jr. (1804–96, born in Marshalltown, Nova Scotia, Canada) and Nancy Matthews Elliott (1810–1871, born in Chenango County, New York).[citation needed] His father had to escape from Canada because he took part in the unsuccessful Mackenzie Rebellion of 1837.[citation needed] Edison reported being of Dutch ancestry.In school, the young Edison's mind often wandered, and his teacher, the Reverend Engle, was overheard calling him "addled". This ended Edison's three months of official schooling. Edison recalled later, "My mother was the making of me. She was so true, so sure of me; and I felt I had something to live for, someone I must not disappoint." His mother taught him at home. Much of his education came from reading R.G. Parker's School of Natural Philosophy.
Edison developed hearing problems at an early age. The cause of his deafness has been attributed to a bout of scarlet fever during childhood and recurring untreated middle-ear infections. Around the middle of his career, Edison attributed the hearing impairment to being struck on the ears by a train conductor when his chemical laboratory in a boxcar caught fire and he was thrown off the train in Smiths Creek, Michigan, along with his apparatus and chemicals. In his later years, he modified the story to say the injury occurred when the conductor, in helping him onto a moving train, lifted him by the ears.
Edison's family moved to Port Huron, Michigan, after the railroad bypassed Milan in 1854 and business declined;his life there was bittersweet. He sold candy and newspapers on trains running from Port Huron to Detroit, and he sold vegetables to supplement his income. He also studied qualitative analysis, and conducted chemical experiments on the train until an accident prohibited further work of the kind.
He obtained the exclusive right to sell newspapers on the road, and, with the aid of four assistants, he set in type and printed the Grand Trunk Herald, which he sold with his other papers. This began Edison's long streak of entrepreneurial ventures, as he discovered his talents as a businessman. These talents eventually led him to found 14 companies, including General Electric, which is still one of the largest publicly traded companies in the world.
Telegrapher
Edison became a telegraph operator after he saved three-year-old Jimmie MacKenzie from being struck by a runaway train. Jimmie's father, station agent J.U. MacKenzie of Mount Clemens, Michigan, was so grateful that he trained Edison as a telegraph operator. Edison's first telegraphy job away from Port Huron was at Stratford Junction, Ontario, on the Grand Trunk Railway.In 1866, at the age of 19, Edison moved to Louisville, Kentucky, where, as an employee of Western Union, he worked the Associated Press bureau news wire. Edison requested the night shift, which allowed him plenty of time to spend at his two favorite pastimes—reading and experimenting. Eventually, the latter pre-occupation cost him his job. One night in 1867, he was working with a lead–acid battery when he spilled sulfuric acid onto the floor. It ran between the floorboards and onto his boss's desk below. The next morning Edison was fired.
One of his mentors during those early years was a fellow telegrapher and inventor named Franklin Leonard Pope, who allowed the impoverished youth to live and work in the basement of his Elizabeth, New Jersey home. Some of Edison's earliest inventions were related to telegraphy, including a stock ticker. His first patent was for the electric vote recorder, (U.S. Patent 90,646), which was granted on June 1, 1869.
Minggu, 28 Oktober 2012
VENUS
Venus is the second planet from the Sun, orbiting it every 224.7 Earth days.[11] The planet is named after the Roman goddess of love and beauty. After the Moon, it is the brightest natural object in the night sky, reaching an apparent magnitude of −4.6, bright enough to cast shadows.[13] Because Venus is an inferior planet from Earth, it never appears to venture far from the Sun: its elongation reaches a maximum of 47.8°. Venus reaches its maximum brightness shortly before sunrise or shortly after sunset, for which reason it has been referred to by ancient cultures as the Morning Star or Evening Star.
Venus is classified as a terrestrial planet and is sometimes called Earth's "sister planet" owing to their similar size, gravity, and bulk composition (Venus is both the closest planet to Earth and the planet closest in size to Earth). However, it has been shown to be very different from Earth in other respects. Venus is shrouded by an opaque layer of highly reflective clouds of sulfuric acid, preventing its surface from being seen from space in visible light. It has the densest atmosphere of the four terrestrial planets, consisting mostly of carbon dioxide. The atmospheric pressure at the planet's surface is 92 times that of Earth's. With a mean surface temperature of 735 K (462 °C; 863 °F), Venus is by far the hottest planet in the Solar System. It has no carbon cycle to lock carbon back into rocks and surface features, nor does it seem to have any organic life to absorb it in biomass. Venus is believed to have previously possessed oceans,[14] but these vaporized as the temperature rose due to the runaway greenhouse effect.[15] The water has most probably photodissociated, and, because of the lack of a planetary magnetic field, the free hydrogen has been swept into interplanetary space by the solar wind.[16] Venus's surface is a dry desertscape interspersed with slab-like rocks and periodically refreshed by volcanism.
Physical characteristics
Venus is one of the four solar terrestrial planets, meaning that, like the Earth, it is a rocky body. In size and mass, it is similar to the Earth, and is often described as Earth's "sister" or "twin".[17] The diameter of Venus is 12,092 km (only 650 km less than the Earth's) and its mass is 81.5% of the Earth's. Conditions on the Venusian surface differ radically from those on Earth, owing to its dense carbon dioxide atmosphere. The mass of the atmosphere of Venus is 96.5% carbon dioxide, with most of the remaining 3.5% being nitrogen.[18]Geography
The Venusian surface was a subject of speculation until some of its secrets were revealed by planetary science in the 20th century. It was finally mapped in detail by Project Magellan in 1990–91. The ground shows evidence of extensive volcanism, and the sulfur in the atmosphere may indicate there have been some recent eruptions.[19][20]About 80% of the Venusian surface is covered by smooth, volcanic plains, consisting of 70% plains with wrinkle ridges and 10% smooth or lobate plains.[21] Two highland "continents" make up the rest of its surface area, one lying in the planet's northern hemisphere and the other just south of the equator. The northern continent is called Ishtar Terra, after Ishtar, the Babylonian goddess of love, and is about the size of Australia. Maxwell Montes, the highest mountain on Venus, lies on Ishtar Terra. Its peak is 11 km above the Venusian average surface elevation. The southern continent is called Aphrodite Terra, after the Greek goddess of love, and is the larger of the two highland regions at roughly the size of South America. A network of fractures and faults covers much of this area.[22]
The absence of evidence of lava flow accompanying any of the visible caldera remains an enigma. The planet has few impact craters, demonstrating the surface is relatively young, approximately 300–600 million years old.[23][24] In addition to the impact craters, mountains, and valleys commonly found on rocky planets, Venus has a number of unique surface features. Among these are flat-topped volcanic features called "farra", which look somewhat like pancakes and range in size from 20–50 km across, and 100–1,000 m high; radial, star-like fracture systems called "novae"; features with both radial and concentric fractures resembling spider webs, known as "arachnoids"; and "coronae", circular rings of fractures sometimes surrounded by a depression. These features are volcanic in origin.[25]
Most Venusian surface features are named after historical and mythological women.[26] Exceptions are Maxwell Montes, named after James Clerk Maxwell, and highland regions Alpha Regio, Beta Regio and Ovda Regio. The former three features were named before the current system was adopted by the International Astronomical Union, the body that oversees planetary nomenclature.[27]
The longitudes of physical features on Venus are expressed relative to its prime meridian. The original prime meridian passed through the radar-bright spot at the center of the oval feature Eve, located south of Alpha Regio.[28] After the Venera missions were completed, the prime meridian was redefined to pass through the central peak in the crater Ariadne.[29][30]
Minggu, 14 Oktober 2012
University of Cambridge
The University of Cambridge (informally known as Cambridge University or simply as Cambridge) is a public research university located in Cambridge, United Kingdom. It is the second-oldest university in the English-speaking world (after the University of Oxford), and the seventh-oldest in the world. In post-nominals the university's name is abbreviated as Cantab, a shortened form of Cantabrigiensis (an adjective derived from Cantabrigia, the Latinised form of Cambridge). The university grew out of an association of scholars that was formed in 1209, early records suggest, by scholars leaving Oxford after a dispute with townsfolk.The two "ancient universities" have many common features and are often jointly referred to as Oxbridge. In addition to cultural and practical associations as a historic part of British society, they have a long history of rivalry with each other. Cambridge has performed consistently in various league tables over the years, achieving the top spot in the world according to the QS World University Rankings in both 2010 and 2011;in 2012, the same editors ranked Cambridge second. Other results include a sixth place in the world in the 2011 Times Higher Education World University Rankings, and a fifth position in the world (and first in Europe) in the 2011 Academic Ranking of World Universities. Furthermore, Cambridge regularly contends with Oxford for first place in UK league tables. In the two most recently published rankings of UK universities by The Guardian newspaper, Cambridge was ranked first.In 2011, Cambridge ranked third, after Harvard and MIT, in the Times Higher Education World Reputation Ranking Graduates of the university have won a total of 65 Nobel Prizes, the most of any university in the world. Cambridge is a member of the Coimbra Group, the G5, the International Alliance of Research Universities, the League of European Research Universities and the Russell Group of research-led British universities. It forms part of the 'Golden Triangle' of British universities |
HISTORY
The official founding of Cambridge University is traced to the enhancement, by a charter in 1231 from King Henry III of England, which awarded the ius non trahi extra (a right to discipline its own members) plus some exemption from taxes, and a bull in 1233 from Pope Gregory IX that gave graduates from Cambridge the right to teach "everywhere in Christendom".
After Cambridge was described as a studium generale in a letter by Pope Nicholas IV in 1290,and confirmed as such in a bull by Pope John XXII in 1318, it became common for researchers from other European medieval universities to come and visit Cambridge to study or to give lecture courses.
Libraries and museums
The university has 114 libraries. Cambridge University Library is the central research library, which holds over 8 million volumes and, in contrast with the Bodleian or the British Library, many of its books are available on open shelves, and most books are borrowable. It is a legal deposit library, therefore it is entitled to request a free copy of every book published in the UK and Ireland. It receives around 80,000 books every year, not counting the books donated to the library. In addition to the University Library and its dependent libraries, every faculty has a specialised library, which, on average, holds from 30,000 to 150,000 books; for example the History Faculty's Seeley Historical Library posess more than 100,000 books. Also, every college has a library as well, partially for the purposes of undergraduate teaching, and the older colleges often possess many early books and manuscripts in a separate library. For example Trinity College's Wren Library has more than 200,000 books printed before 1800, while Corpus Christi College's Parker Library possesses one of the greatest collections of medieval manuscripts in the world, with over 600 manuscripts. The total number of books owned by the university is about 12 mil
Student life
Students' Union
Main article: Cambridge University Students' Union
The Cambridge University Students' Union (CUSU) serves to represent all the students within the University which automatically become members upon arrival.It was founded in 1964 as the Students' Representative Council (SRC); the six most important positions in the Union are occupied by Sabbatical officers.Sport
Cambridge maintains a long tradition of student participation in sport and recreation. Rowing is a particularly popular sport at Cambridge, and there are competitions between colleges, notably the bumps races, and against Oxford, the Boat Race. There are also Varsity matches against Oxford in many other sports, ranging from cricket and rugby, to chess and tiddlywinks. Athletes representing the university in certain sports entitle them to apply for a Cambridge Blue at the discretion of the Blues Committee, consisting of the captains of the thirteen most prestigious sports. There is also the self-described "unashamedly elite" Hawks’ Club, which is for men only, whose membership is usually restricted to Cambridge Full Blues and Half Blues.Societies
See also: List of social activities at the University of Cambridge and Category:Clubs and societies of the University of Cambridge
Numerous student-run societies exist in order to encourage people who share a common passion or interest to periodically meet or discuss. As of 2010, there were 751 registered societies.In addition to these, individual colleges often promote their own societies and sports teams.The Cambridge Union serves as a focus for debating. Drama societies notably include the Amateur Dramatic Club (ADC) and the comedy club Footlights, which are known for producing well-known show-business personalities. The Cambridge University Chamber Orchestra explores a range of programmes, from popular symphonies to lesser known works. Membership of the orchestra is composed of students of the university and it has also attracted a variety of conductors and soloists, including Wayne Marshall, Jane Glover, and Nicholas Cleobury.[citation needed]