"If... you had to shift into low gear, the motor scooter would jump about ten yards ahead..." Thomas Fogarty The centrifugal clutch owes its existence to the frustration Thomas Fogarty(b. 1934) experienced With the gears of his motor scooter. A traditional car clutch works via longitudinal mechanical motion, disconnecting the driveshaft for the wheels from the motor by moving a pressure plate away from the clutch disc. The centrifugal clutch works differently, using the rotational motion of the motor to engage and disengage the driveshaft The clutch is cylindrical, with the crankshaft from the engine rotating in its center. Attached to this shaft is a pair of weights that are held in place by springs. The crankshaft and weights rotate together, at the same number of revolutions per minute (rpm) as the engine. When the engine increases in rpm, the revolution speed of the weights also increases and they swing more...

Chinese government official Su Song (1020-1101) was also a naturalist, cartographer, astronomer, horologist, and engineer. His greatest legacy was the clock tower he built in Kaifeng. In 1086 the emperor had ordered the construction of an "armillary clock" to keep time and track celestial bodies. A finished structure was completed in 1094, and consisted of three levels. The upper level contained a rotating armillary sphere that allowed astrological observations through sighting tubes; the middle level had a bronze celestial globe; and the lower level had mechanically timed manikins that would exit doors at fixed times of the day. Perhaps most significant, however, was the clock's innovatory driving system. At the heart of the clock tower was the tian ti, or "celestial ladder." This is the oldest known endless power-transmitting chain drive. The chain transmitted the power from a water wheel to turn the armillary sphere and power the clock. Drive more...

Given its market domination from the moment it first appeared in 1979, many people might imagine that the Sony Walkman was the original personal cassette player. Its iconic status is beyond question—it all but created the vogue for listening to music on the move and is a direct antecedent of today's ubiquitous iPod. And yet seven years earlier, a lone inventor with little expertise in the field of electronics came up with a concept that was almost identical. The story begins in Brazil in 1972 when a German- born former TV executive named Andreas Pavel(b. 1945) sought a way of listening to high-quality music while going about his everyday business. His idea was for a tiny portable cassette player—not that much larger than the cassette itself—that played back audio through a small pair of headphones. He called his novel idea the Stereobelt. Having left Brazil and moved to Switzerland, Pavel more...

Sir Joseph Whitworth (1803-1887) had a life long desire to improve on existing technology. By the time of his death, his interests and efforts had amassed him assets worth more than £150 million.($300 million) in today's money and a large manufacturing complex in Manchester, England. En route, Whitworth had produced pretty much everything from road-sweeping machinery to firearms. Moreover, by absorbing the ideas and philosophies to which he was exposed while working at the renowned Henry Maudslay works at Lambeth Marsh, London, and rejecting the often shoddy standards of the day, this perfectionist had established himself as the father of precision engineering. One Whitworth contribution to the modern world that underpinned so many others, and one that would keep his name on the lips of mechanics and engineers alike for many years, was the Whitworth Thread, which he proposed in 1841. Known subsequently as the British Standard Whitworth (BSW) Thread, more...

"On the whole coast of America there is not another alarm equal to the one spoken of...” Captain Winchester, SS Eastern City, 1860 Before the invention of the foghorn by Scottish-born inventor, civil engineer, and artist Robert Foulis (1796- 1866), harbor towns relied on cannons or bells to guide ships into port in foggy conditions. One such harbor town, Saint John in New Brunswick, Canada, welcomed a new civil engineer when Foulis settled there in 1825. It is likely that Foulis witnessed the 1832 installation of a "warning bell" at Partridge Island, just over half a mile (0.8 km) from Saint John. Partridge Island's new bell, a behemoth at 0.5 tons, helped to bring ships into port, but the need for louder warnings, along with the limitations of bell construction, had mariners crying out for an alternative. Foulis's 1852 offering was a steam-powered automated foghorn with a deep warning sound. more...

"Our scientific power has outrun our spiritual power [with] guided missiles and misguided men." Dr. Martin Luther King, Jr. In 1962 the United States Air Force (USAF) began research into developing a laser-guided weapon that could be used to target stationary targets accurately. During World War II, unguided bombs dropped by aircraft caused immense damage, but many bombs were often required to hit one target successfully. From a military perspective the risk to bomber pilots from antiaircraft fire had been great, and there had been a terrible toll of deaths and injuries among civilians at some distance from the actual targets. By 1967 the USAF had produced the first laser- guided bomb, the BOLT-117, and were able to use it during the Vietnam War the following year. This breakthrough in ordnance capability turned unguided, "dumb" bombs (which simply fall to the ground) into precision guided, "smart" bombs. Laser-guided bombs rely more...

Mountains have always thrown a challenge to the spirit of man and he always accepted it. The loftier a mountain, the  greater is his desire to conquer it, to climb the highest peak and to enjoy the thrill of victory. Nearly all the mountains of the world have now been conquered by the persistence and perseverance of man. Even Mount Everest cannot now claim to be invulnerable, having already been scaled several times, the first time by Hilary, an English man. Several expeditions  were organized to negotiate this highest mountain-peak in the world and at least four of them have been successful-British, Swiss, American and Indian. The Chinese too claim to have conquered Mount Everest from the other side but their claim has not been accepted by many. Life offers challenge to man and some people are fascinated by it. Danger to them is the very essence of life and more...

I live in Delhi. Delhi is the Capital of India. It is the seat of the Central Government. Many government offices are located here. There are embassies, great and beautiful buildings, gardens, lawns, parks, statues and other things of interest. But there are also some places that can be termed as slums and dirty spots. Therefore, there is need to beautify it. First of all, there is urgent need of repairing roads. The roads are in very bad shape and damaged. A person from foreign does not get a good impression of it. Therefore, there is need for repairing and reconstructing roads. Moreover, there are some old and ancient buildings in various parts of the city.  They are in ruins. They not only mar the beauty of the city, but also cause accidents. Therefore, these old building must be repaired. There are many slums. Dirty water and sewage get spread more...

Outline : Qualities, importance, tolerant, broad-minded, law- abiding; works for the cause of nation and society; up-to-date, well- informed of political changes and social evils; a keen civic sense.  An ideal citizen is one who establishes (sets up) his standard in everything. He loves his country more than anything else. He can make any sacrifice for his motherland. He can lay down his life for the honour  of his family, society and clan. He is a true patriot. He is thorough gentleman. He protects the public property at the cost of his own life. He is fully law-abiding. He pays all the taxes honestly and unhesitatingly. He is a true friend of society. He is the saviour of the honour of the fair sex. He swims and the society sinks with him. He is its axis. He is its pivotal point. As far his personal qualities are concerned, he is more...

The autumn season comes after the rainy season. The autumn comprises the months of September and October. At this time, black clouds leave the sky. The sky gets clear and we often enjoy the beauty of moonlight in all its sweetness. Moonlight falls on the green grass. Various flowers like shefali, kash and lotus blossom. This season is very beautiful and nice, and it cannot be compared with any other season. Weather at this time is very cool and pleasant. The autumn season is the festival season. Various festivals, like Dussehra, Diwali and Bhai Duj, are celebrated during this season, causing long vacation in offices, schools, colleges and courts. This season also brings the harvesting season. The farmers are happy with their land full of paddy and other grains. The vast I stretch of luxuriant paddy crops are harvested as the autumn breeze fills the heart of the farmers. Once more...