User talk:Somesh shandilya

Aerosol

'''This was invented in 1941 by an American. Lyle Goodhue. In fact, there are three sorts of aerosol. The sort used for spraying into a space such as an air freshener puts out particle which are no bigger than one fifty millionth of millimeter in diameter. Canisters for paint prouce a spray with larger sized particles so that they will stick to a surface. Then there are foam shaving creams and so on. The main ingredient is dissolved in alcohol or as in the case of antiperspirants, in a chemical called aluminum chlor-hydroxide. This is measured into the can, the valve is fitted then the propellant which makes it squirt out when you press on the valve is forced into the can through the valve under pressure the propellant can be either a gas or liquid then when you press the valve the pressure forces the contents out again. '''

Zip Fastener
Zip-FastnerWhitcomb L. Judson, Chicago engineer, devised two metal chains, which joined together as a slide passed over them, to take the place of the rows of buttons on high boots in 1893. There were two faults in this invention which the public didn’t like, however. Not only did the device catch on things as people walked past, but it came open too easily without warning. A Swedish engineer, Gideon sandbank, working in Hoboken, New Jersey, USA, in 1913, came up with a simple but brilliant solution to the pro1blem of Judson’s slide fastener. He made his units in pairs, on two parallel tapes on cloth. Each tooth on the zip was really a hook which hooked into an eye under the hook on the same place on the opposite tape. The slide pressed out the teeth as it ran over them and left them hooked together. This is still how a zip fastener works. When America entered the First World War in 1917, the American armed forces ordered the new invention to be fitted on to uniforms, flying clothes, and so on. In Britain, Manufacture began in 1919under the name of the ready fastener, by the firm of Kynoch, of Birmingham. Its real success came, though, when it was demonstrated at the empire exhibition at Webley in 1924. At that exhibition a fastener was zipped and unzipped three million times without breaking down. How it got its modern name happened in 1926, when the writer gilbert franked fiddled with one and said zip!it’s open. Zip! It’s closed. Ever since then it’s been known as the zip-fastener. The first women’s clothes to have zips were designed by Madame Schiaparelli, a famous Parisian clothes designer, in 1930. Until then zips were regarded as improper for women to use on their dresses. That was perhaps a little odd, because the first zips on men’s trousers were not introduced until1935. ''

ANAESTHETIC
''Before anaesthetic were used, if you needed an operation- perhaps to have an arm or a leg amputated first you would be given some alcohol to drink to deaden the pain, then you would be fastened down, so that the surgeon could work very fast to cause as little pain as possiblewhile the knife or the saw was cutting through you. After anaesthetics came into use, a surgeon- or dentist- could at last take more time over operations and so do a much better job. In 1799 sir Humphrey davy, chemist and inventor, suggested using laughing gas for the relif of pain during operations in 1842 William Clark in Rochester, USA, was the first to make a woman unconscious through breathing in the fumes of ether so that she could have a tooth pulled out painlessly. In the same year Dr. Crawford long of Jefferson, Georgia USA made a patient unconscious with ether before he removed a cyst from the patient’s neck and then went on to perform more operations in the same way. he had to stop because the local people were convinced he was using sorcery and threatened to hang him if he didn’t. Four years laer, though, in 1846, ether was being used in a major operation at the Massachusetts general hospital, Boston USAwhen dr. warren removed a tumoour from man’s jaw. and in the sae yeara, at university college hospital, London Dr. liston performed the first painless amputation of a le, also using ether, then sir james simpson of Edinburgh, decided to use chloroform instead of ether because it was thought to be more pleasant and just as effective, both for operations and during childbirth. From then on operations without anesthetic were a thing of the past. ''