Archives May 2013

Russell Ohl (1898-1987) was a precocious talent who by the age of sixteen had already entered Pennsylvania State University After a period in the Army Signal Corps and a brief career as a teacher, OhI finally took a research position in U.S. industry. Early radios were only able to receive low- frequency transmissions. At Bell Labs in Holmdel, New Jersey, Ohl worked to create an improved radio receiver for high frequencies. Here he experimented with semiconductor materials that he thought would outperform the electron tubes used in existing receivers. An expert in the behavior of crystals, Ohl investigated different materials for semiconductors, such as germanium and silicon. The crystals were heated, and when cool would be sliced for use. In 1939 Ohl was working with a silicon sample that he noticed had a crack down the middle. When he tested the electrical resistance of the sample he noted that when more...

"An antibiotic for all seasons, it's used for a dozen reasons... there is no proxy, for our antibiotic doxy." James McCallum, from the poem "Doxycycline" The world existed for a long time without antibiotics, but as soon as they were discovered, the race was on to find more. Penicillin and streptomycin had both been isolated from some form of fungus, and the search continued for products that came from naturally occurring bacteria. Research groups looked everywhere but one of the more promising avenues of investigation began to emerge from groups studying certain fungi that lived in soil—organisms known as actinomycetes. Lederle Laboratories found the now forgotten antibiotic aureomycin in dirt samples. Pfizer soon followed suit with the equally obscure antibiotic terramycin. Both aureomycin and terramycin functioned as broad-spectrum antibiotics, covering a range of both gram- positive and gram-negative bacteria. This sparked a great deal of interest in figuring out how more...

"The Space Shuttle is the most effective device known to man for destroying dollar bills." Dana Rohrabacher, U.S. Congressman Booster rockets—such as the Saturn V that launched the Apollo astronauts toward the Moon—are extremely wasteful. They can fly only once, parts are thrown away after use, and 97 percent of the mass is Consumed in the first few minutes. Clearly, what was really needed for advanced and economic space exploitation was a spacecraft that could take off and return, to be reused time after time. In 1972 NASA-.in the United States decided to build the Space Shuttle. Rockets were to be used to assist the launch. Crew facilities were to be provided for up to eight people, and the huge cargo bay would be used to take satellites and sections of the International Space Station (ISS) into orbit. New instruments would also be taken up to existing spacecraft, and In-orbit more...

In 1952 Gregory Pincus (1903-1967), a biologist working at the Worcester Foundation for Experimental Biology in the United States, demonstrated that a synthetic form of the hormone progesterone, known as norethidrone, inhibited ovulation in rabbits and rats. Norethidrone had been developed a year earlier by Carl DJerassi, a chemist working at the Syntex company in Mexico City. It had initially been created with the aim of producing high concentrations of progesterone to treat menstrual disorders. It had the advantage of being more active than the human hormone, and also of being effective when taken orally. Margaret Sanger, founder of the American Birth Control League, saw the potential of Pincus's work. She enlisted the help of heiress Katharine McCormick, who agreed to fund research to develop a contraceptive pill. Pincus developed a pill with the aid of gynecologist John Rock (1890-1984), a devout Catholic aiming to improve conception among infertile couples. more...

"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...