Archives February 2013

"Publishing [verse] is like dropping a rose petal down the Grand Canyon and waiting for the echo." Don Marquis, U.S. humorist, journalist, and author Sonar (which started as an acronym for sound navigation and ranging) is a technique widely used in shipping to detect nearby vessels and underwater obstructions. The word was coined by the Americans during World War II. The British also call Sonar, ASDIC, which has been daimed to stand for Anti-Submarine Detection Investigation Committee. There are two major kinds of sonar, active and passive. Active sonar produces a sound "ping"' and then measures how long it takes a reflected pulse to return to the ship. The sound source and receiver are continually rotated, so that the direction of the echoing body can be found. Lower frequencies are used if the reflector is a long way off. Passive sonars listen without transmitting. The first Sonar devices were passive more...

While studying for his degree, Herbert Henry Dow (1866-1930) became interested in developing more economical ways of extracting bromine from the underground brine reservoirs of Michigan in the United States. Dow, a man with a business acumen that matched his intellect, recognized that the use of bromine in medicine and the photographic industry meant there was a potential for massive profits. By 1889 he received his first patent for a new extraction process and immediately set up his own company, which went bankrupt within the year. Undeterred, Dow continued his investigations and by 1891 had patented the Dow Process. If a current is run through the brine, a process known as electrolysis, the negative bromide ions collect at the positive electrode, from where they can be collected. Dow knew that he had to compete in the European market, where prices were controlled by a cartel of German companies called the more...

"We've run these bulbs almost 10,000 hours in test cases, and there's no wear and tear." Michael Dry One of the goals of good lighting is to produce a radiation that has an energy distribution very similar to the sensitivity of the human eye. Michael Dry and Charles Wood decided that the ideal radiator would be ionized molecular sulfur (82), which produces a continuous spectrum as opposed to a line spectrum. About 73 percent of the light emission is in the visual spectrum, with only 1 percent in the ultraviolet. Sulfur plasma is extremely corrosive so normal tungsten electrodes could not be used. Dry and Wood decided to use a magnetron power source rather like those used in microwave ovens, the sulfur being contained in a golf ball-sized quartz bulb. However, the sulfur inside the bulb gets extremely hot and the bulb has to be continually rotated and cooled by more...

"When I talked to people about it, they said it couldn't be done..." Dr. Patricia Bath In nearly all circumstances, pointing a laser at your eye is a bad thing, but if you have cataracts it may just restore your sight. Cataracts are a leading cause of blindness. The disorder occurs when the part of the eye that focuses light—known, not surprisingly, as the lens—turns cloudy. This is a process that occurs in almost all of us if we live long enough. Unfortunately, currently there is no viable way to make a cloudy lens transparent again, and so ophthalmologists are forced to resort to other means to alleviate the problem. The current method of dealing with a cataract is to remove the lens of the eye. One problem is that taking out the lens in its entirety requires a rather large incision into the eye in order to remove it. more...

Despite the continuing secrecy surrounding the development of the atomic bomb, it is public knowledge that Edward Teller (1908-2003), a Hungarian physicist, worked on the Manhattan Project to produce the first atomic bomb based on uranium fission. Teller had long been interested in a hydrogen fusion bomb, but secrecy and the lack of access to computers contributed to slow progress. Stanislaw Ulam (1909-1984),a Polish mathematician, realized that a fission bomb could be used as a trigger for a fusion reaction. It is believed that Teller seized on this for what became, in T951, the "Teller-Ulam" design. Most sources agree that the H-bomb works in a series of stages, occurring in microseconds, one after the other. A narrow metal case houses two nuclear devices separated by polystyrene foam. One is ball shaped; the other is cylindrical. The ball is essentially a standard atomic fission bomb. When this is detonated, high-energy radiation more...

"It was fearsome looking stuff, this barbed wire ...the barbs looked....like miniature daggers...” Cameron Judd, Devil Wire Barbed wire is unusual among inventions because it appears to have been created on several separate occasions at roughly the same time in history. Frenchman Leonce Eugene Grassin-Baledans made the first attempt in 1860, with twisted strands of sheet metal. Another Frenchman, Louis Jannin, came up with what would become known as barbed wire in 1865. In 1867 several Americans followed in hisfootsteps with different yet fairly ineffective designs, using single-stranded wire. The final contribution in this flurry of inventiveness came from American Joseph Glidden (1813-1906), whose 1874 patented wire machine created practical, cheap, mass-produced barbed wire, leading to its widespread adoption. The reason for this simultaneous outbreak of ingenuity was due in part to a need for cheap fencing after the 1862 Homestead Act allowed any resident outside of the thirteen original more...

On 1 February 2003, India's first spacewoman Kalpana Chawla along with the other six crew members perished when the Columbia space shuttle disintegrated just minutes before it was to land. The whole world was shocked at this tragic Incident. It was her second space mission.  Kalpana Chawla was born in Karnal, a small town in Haryana in 1961. She got her primary education in a local school where she was just an average student. She had a great fascination for aeroplanes from very beginning. She wanted to fly in the open sky like birds. Hence she joined Punjab Engineering College to study in aerospace engineering. There she was the first woman in this field. Luckily, she got top rank and then she went to the US for doctorate which she completed in 1988. Kalpana was a genius. She wanted to do more and more. She joined NASA. NASA selected her more...