Archives July 2013

Samuel Alderson developed the first working model of an electrically powered artificial arm, which appeared in 1949. Designed for factory workers who had suffered amputation, the device was very bulky and was plugged into an external power source. Reinhold Reiter, a physics student at Munich University, patented the first myoelectric prosthetic arm. Also requiring an external power source, it used muscle-contraction signals from the remaining biceps to control the opening and closing of the hand. It was bulky and used vacuum tubes. The transistor would have made the technology more feasible, but this was not invented until 1948. By then the German currency was revalued, and the project lost its funding. In 1958 a Russian team led by A. E. Kobrinski had developed a myoelectric hand controlled by signals from surviving wrist muscles. Both Otto Bock Orthopaedic Industry in Germany and Viennatone in Austria marketed versions of the "Russian hand." more...

"[Scientists] should return to the plainness... of Observations on material and obvious things." Robert Hooke, Micrographia (1664) In a mercury thermometer, mercury in a small glass bulb expands into an evacuated, linear, uniform cross- section glass tube; the amount of expansion is used to measure the temperature of the bulb. Dante Gabriel Fahrenheit (1686-1736) left Gdansk, Poland, and eventually became a glassblower and scientific instrument maker in the Netherlands. His first glass thermometer (1709) used alcohol as the expanding fluid, but this has a limited temperature difference between its freezing and boiling points. In 1714 Fahrenheit turned to mercury, a liquid metal that expands uniformly over normal temperature ranges. Fahrenheit insisted that thermometer results should be universally reproducible, and similar temperatures should be represented by the same number. To this end he introduced, in 1724, three "fixed" points and eight graduations on his thermometer tube. Zero degrees was the lowest more...

Her voice was once described as sounding like two robot tobacco auctioneers fighting over a cigar butt. However, Audrey's synthesized speech was state-of- the-art back in 1952. A clumsy acronym for Automatic Digit Recognition, Audrey was an analog computer at Bell Laboratories. But it was not her primitive voice that she was renowned for. Scientists at Bell Laboratories had tried for many years to devise a technology that could recognize human speech and Audrey was their first working solution. The potential applications for a computer that could convert words spoken by humans directly into digital text were obvious. However, the sheer number of variations in the qualities of people's voices, along with their different intonations and pronunciations, means that foolproof speech recognition is a huge task. Audrey could only recognize spoken numbers from one to ten, and used flashing lights to illustrate what she had heard—or thought she had heard. more...

"A table, a chair, a bowl of fruit, and a violin; what else does a man need to be happy?" Albert Einstein In 2006 Microsoft announced a new way in which a human can interact with a computer. The mouse and keyboard are thrown away and replaced with a tabletop containing an embedded rear-projection touch screen. Behind the screen, inside the table, are five cameras with overlapping fields of view. These can look through the screen and be programmed to recognize or read items that are placed on the screen. These cameras can also recognize physical objects, track hand gestures and the movement of pens and brushes, and read credit cards and "loyalty" cards. The software supports a multitude of touch points so many people can use the computer at once. A single user can also multitask. For example, if a digital camera is placed on the computer table, the more...

"Zillah bore Tubal-Cain; he was the forger of all instruments of bronze and iron." Genesis 4:22 Metallurgy is one of the most ancient fields of technology and also one of the most important. The use of metals has been so essential to humankind that long periods of history—the Bronze Age and the Iron Age—have been named after the metals that were used most predominantly in those times. Being able to join pieces of metal together has always been essential in making metal artifacts. The joining can be done in a number of different ways, including welding, brazing, and soldering. Metal items to be joined by welding must themselves be partly melted before the joining can take place. Brazing or soldering—which are sometimes called "hard" and "soft" soldering respectively, with brazing carried out at a higher temperature—are processes whereby pieces of metal are joined together by the introduction of a metal more...

The birthday of first Prime Minister Sh. Jawahar Lal Nehru, 14th November, is celebrated as Children's Day throughout the country. He was reciprocated as "Chacha Nehru" by the children for his immense love towards children. This year also the Children's Day was celebrated in our school with great zeal and enthusiasm. The children themselves organized the whole function. The compound of the school was beautifully decorated with multicolored buntings. Balloons were also hanging in large number. A good seating arrangement was made for the teachers and the students. The Principal was the honourable guest at the function. After the arrival of the Principal a well organized programme started. The first item was 'Vande Matram' the National Song. Then there was an item of the "Mangal Gaan". A girl student was in leading role of "Bharat Mata". She was looking very pretty in her white dress and crown on her head. more...

"A vacuum is a hell of a lot better than some of the stuff that nature replaces it with." Tennessee Williams, Cat on a Hot Tin Roof (1955) A vacuum is an empty space containing nothing, not even air. Anything containing a vacuum has a much lower pressure on its inside than its outside, and this creates a tremendous force. Otto von Guericke (1602- 1686), a German scientist, was the first to experiment with the power of the vacuum. In his experiments, he filled containers with water and then used a suction pump to remove the water while trying to avoid letting in any air. Wood was useless for this as it leaked air, so he used glass or metal containers. To minimize air intake, Guericke put his container in another layer of water as it was easier to stop water leakage than air leakage. The inward pressure on the more...