Archives May 2013

In 1835, shortly after the American Joseph Henry (1797-1878) became a professor at Princeton University, he passed crude on/off messages from his laboratory to his nearby home on campus using an electromagnetic relay and a current-carrying wire. In the early relays, switching an electrical current on or off magnetized the relay's electromagnet core, and this magnetic field attracted a pivoting iron armature, which itself operated a set of contacts that made or broke an electrical circuit. One of the advantages of such relays was that the current through the electromagnet could be very small, and the switched-circuit current could be much larger. Relays formed the basis of the telegraph system and were at the heart of telephone exchanges. In modern industry, electromagnetic relays are used to control electric motors and are a vital component of automated systems of machine manufacture. Great advances have been made in relay design, mainly to more...

"We waste our lights in vain, like lamps by day..." William Shakespeare, Romeo and Juliet George Carwardine's (1887-1948) company was a car manufacturing factory and it was there that he came up with the idea of arranging springs on a metal arm that could be adjusted in orientation and yet stay in place when released. The design mimicked the. movement of the human arm and was inspired by the constant tension principle. He patented the design in 1931, but it was not until the year after that the idea came to him to use it to angle temporarily the direction of a lamp. To the moveable sprung arm, he attached a heavy base and a directional lamp, which allowed the lamp to be moved to face any direction but remain rigid in position. Carwardine found the lamps useful in his factory for illuminating the assembly process, but he soon realized more...

Chlorofluorocarbons (CFCs) were for decades commonly used in the cooling systems of refrigerators and in aerosol cans. However, when these usually inert compounds get zapped by radiation in the upper atmosphere, they are energized and produce chlorine radicals that react with ozone. This has led to a significant depletion in the ozone layer, notably at the North and South Poles. The world was on the brink of losing its natural protection from harmful ultraviolet (UV) rays, mostly thanks to a household appliance used worldwide. Ironically, CFCs started out as savior compounds, replacing nasty substances such as ammonia and sulfur dioxide in refrigeration equipment. Faulty units would cause unpleasant illnesses and even deaths. The American Thomas Midgley (1889-1944) first proposed CFCs as refrigerants in 1928, demonstrating their suitability with theatrical flourish—he proved their lack of reactivity and toxicity by inhaling the gas and then exhaling onto a lit candle. Developed with more...

The backhoe loader, or JCB®, was invented by Joseph Cyril Bamford (1916-2001) of Staffordshire, England. In 1945, using only scrap metal, war surplus Jeep axles, and a cheap welding kit, he produced an hydraulically operated tipping trailer that he later sold for £45 ($180 at the time). With the dump truck-like tipping trailer created, Bamford's business grew steadily as he designed and built new machines using hydraulic power. When the backhoe loader was created in 1953, the JCB®  logo was used for the first time, based on its inventor's initials. Typical backhoe loaders are made up of three components: a tractor, a loader, and a backhoe. The tractor enables the backhoe loader to traverse difficult terrain of all sorts. At the front of the tractor, the loader can scoop, smooth, and push great quantities of material. Meanwhile, the back of the tractor sports a backhoe, which is a large maneuverable more...

Patriotism in its simplest term means love for one's country. It is a natural instinct in us. In the early days families clung together to save themselves from wild animals. Thus many families joined together to make a tribe. Tribes  made  the nation. We show our love to our country in many ways. We wave our national flag on special occasions. We cheer the speeches of our national leaders. True patriotism is more than just raising slogans. It is to identify ourselves with nation. People everywhere do great things for their country. Joan of Arc liberated France from the British. Bhagat Singh, Chandra Shekhar and Subhash Chandra  Bose made supreme sacrifices for the sake of their country. Such men can never be forgotten. In Africa Mandela fought against 'racism' for years and ultimately won. He is a great leader of his country. Genuine patriotism is a sentiment of which we more...

There are some people in society who talk much more than they should. They are always ready to offer suggestions, advice and recommendations even when they are not asked to. No one wants to listen to them yet they continue to bore people with their never-ending chatter. Such people do not think before they speak and often land themselves into unnecessary trouble. They love to indulge in talking all day and never getting down to doing any work at all. The practical examples are our present-day political leaders. They make a lot of promises during election time but hardly keep them when they return to power. In fact one must do great things without promising them. A man is required to do more work than talking because life passes by too fast and one has to accomplish a lot in one's life. There have been men like Mahatma Gandhi, Nehruji, more...

We live in a three-room flat on the ground floor. It is in a big and modern colony of the city. There is a large drawing- cum-dining hall, two bed rooms, kitchen and toilets. There is also a big varanda. My father bought it ten years ago. Then, I was just four-year-old. It is large enough for all of us. We are just four persons in the family. I have one sister only. My parents believe in having  a very small family. My house is built of bricks, iron, tiles and marbles. It has got  all the modem amenities of life. The bath room is also large, airy and tiled. It has a shower. The floor of my house is fully marbled. The kitchen of my house is large and comfortable. It is near the living room. One of its doors opens in a large balcony, rrom there we have more...

The Internet? Television? The internal combustion engine? All of these things are important, but they pale in significance next to arguably the most important invention of all time—the toilet. Archeological research indicates that toilets flushed by water have existed since about 2500 B.C.E. Inhabitants of the Indus Valley developed a sophisticated system of toilets and accompanying plumbing; each house had a toilet with a seat, the waste being borne away by water in a sewer system covered with dry-clay bricks. This system was used in India for most of the existence of the Indus Valley Civilization, which ran from about 3000 to 1700 B.C.E. Ancient Egypt also developed a similar system that removed waste through the use of running water. The ancient Romans were so fastidious that .they constructed a toilet for use when they were traveling. Their sewerage systems were sophisticate and public toilets were common. After some lamentably more...

Our Principal sent an order to the classes that the Inspector of Schools would pay a visit on 15th of December. The teachers and the students became serious. Great preparations were started few days before the day of inspection. The broken panes were removed. The school building was white-washed and furniture was painted. The compound was cleaned of bits of paper. The carpenter repaired the broken furniture. The drawing teachers prepared pictures, maps, diagrams and charts for drawing room, history room and geography room. On the day of inspection we were in our best of clothes. The teachers were in their best suits. At 10 a.m. the Inspector and his staff arrived in their car. The Principal gave them a warm reception. With the Principal the Inspector took round of the whole building. He inspected each class. He put questions regarding the school to some boys. He checked whether the more...

In 1791 the English inventor John Barber (1734-1801) patented "an Engine for using Inflammable Air for the Purpose of procuring Motion." We now know his invention as the gas turbine, a mechanism that was simultaneously 150 years before its time and based on an idea more than 1,700 years old. A turbine is a machine that turns the energy of moving gas or liquid into rotational energy During the first century, the Greek inventor Hero of Alexandria developed the first steam turbine. His device drove steam from boiling water through curved nozzles to rotate a cylinder. John Barber's engine, while based on similar principles, included features not present in its ancient predecessor. A gas turbine engine such as Barber's has three main components: a compressor to increase the pressure of the air, a combustion chamber in which the air is combined with fuel to produce an explosion, and a turbine more...