Archives March 2013

A river is a large stream of water. A river generally receives its water by the melting snow on the mountains. Sometimes it is fed by rainwater. The river is a great use to us. It helps us in many ways. It flows through many countries. It makes them fertile. Prosperous cities are situated on the banks of rivers. Ancient civilizations grew in some river valleys. A river is very helpful to farmers. In some countries, many types of crops grow in plenty because of the presence of rivers. A river supplies us with drinking water. The water works of the municipalities generally get their supply of water from rivers. We use this water for many purposes in our houses, industries and fields. A river helps in our trade and commerce. Big ports grow on their banks. Formerly there were no railways. Roads also were very few. Almost all inland more...

William Cowper, the famous English Poet, wrote, "God made the country and man made the town." This famous statement represents the natural difference between town life and country (village) life. In a village, we see things as God made them—wide open sky above, the green fields, beautiful flowers and murmuring stream. But the town is the product of man's labour and cuts us off from the direct contact with nature. Both town life and country life have their advantages and disadvantages. A village has no good roads making transport difficult, no electricity, no proper intellectual atmosphere and no recreational facilities. Generally good doctors and teachers avoid villages on account of hard life. The shops cannot always supply all the needs of modern life. So people have to run to nearby town. But the village life has its bright side also. It is free from most of the evils of town more...

Stanislas Baudry (1780-1830) was the proprietor of a Parisian bathhouse; he was also a bus operator who provided clients with transportation to his spa. Baudry did not invent the horsedrawn bus—horsedrawn carriages of various kinds had long been in existence—but in 1826 he instigated the use of the term "omnibus," and he is therefore credited with inventing the omnibus as a concept. His inspiration came from the name of a hat-maker's shop (Omnes Omnibus, Latin for Everything for Everyone) that he regularly passed on his way to the baths. Baudry's concept of a means of transport available to all, regardless of social class, spread across the globe and evolved into various forms with varying numbers of horses, alternative seating configurations within the vehicle, and, no doubt, different tariffs depending on their clientele. The buses survived the test of time and eventually the horses were replaced by diesel engines. Latter-day concerns more...

"All work and no play makes one dull," so goes the saying. Holidays are a must in our life. Holidays refresh our minds and give us relief. Oxford dictionary describes holiday as a day of rest from work. But do we have rest ? Well, to some holiday means a change from the routine. Thus holidays are essential. Life becomes dull and dreary without them, Human body is like a machine. It wears down like machine by constant and regular work. As machine needs rest, oiling and sometimes over-hauling so that it may work efficiently again, a human body needs rest to recoup its lost energy. A tired mind requires rest to regain its sharpness and speed. Every now and then our mind longs for leisure. It is the holidays that give us time to take care of our health and spirit.  Continuous dull and routine work makes our spirits more...

Conrad Rontgen (1845-1923) was the first person to take X-ray photographs of a person, winning the first Nobel Prize in Physics in 1901. X-ray films are sometimes referred to as Rontgenograms in his honor. For the first time, surgeons could see shrapnel and bullets contained within the body. However, X-rays were two-dimensional. In order to see how deep an object was, a second X-ray picture, usually perpendicular to the first , had to be taken. X-rays also fail to image the body's soft tissues very well. Many techniques had been tried to improve the images produced by X-rays, but it was not until computer-assisted tomography (CAT) was developed that these problems were solved. Godfrey Hounsfield (1919-2004) devised the CAT scan in 1968, and by 1971 a prototype scanner was installed at Atkinson Morley's Hospital, Wimbledon, England, for use in clinical trials. In computer-assisted tomography, the X-ray tube is moved so more...

"We... believe that a hypersonic airplane could be a reality in the not too distant future." Dr. Steven Walker, DARPA Tactical Technology Office In the twenty-first century, speed seems to be of paramount importance. As well as improving the simple but inefficient turbine-based engine systems that drive rockets and planes, scientists have developed Supersonic Combustion Ramjet engines (scramjet) to allow much faster travel. Scramjets improve on ordinary engines by eliminating the need to carry a fuel oxidant. Instead, they use oxygen from the atmosphere to burn the onboard fuel, making them lighter, more efficient, and extremely fast. Scramjets have long been a theoretical possibility, but in 2002 scientists at the University of Queensland, Australia, and at the U.K. defense company QinetiQ successfully completed the first flight of a scramjet vehicle. Although the test simply demonstrated the technology and not a practical engine system, the vehicle reached Mach 7, which is more...

British mathematician and physicist James" Clerk Maxwell (1831-1879) was a giant of nineteenth- century science. Best known for his Maxwell equations, which were the best insight into electromagnetism of their day, his interests also included Saturn's rings and the human perception of color. It was this latter interest that led to the first color photograph in 1861. In the manner of a true showman, Maxwell revealed his photograph of a tartan ribbon at the Royal Institution in London. His studies of human vision, including the condition of color blindness, had led him to conclude that color images were possible using a "trichromatic process." He had arranged for his tartan ribbon to be shot by professional photographer Thomas Sutton, the inventor of the single-lens reflex camera. The images were black and white, but, critically, Maxwell had three such images taken through red, green, and blue filters, respectively. Having turned the images more...

"... chain mail makers, slowly going mad [while] they clipped together chain mail rings..." Ursula K. Le Guin, Tehanu(1990) Chain mail was originally called Just mail or chain in England and maille in France (the French word maille means "meshy" or "netted"). It was not until the 1700s that chain mail became its common English name. Mail is constructed from a series of links made from wire. These are bent into circles around a forming cylinder, and the finished links are welded or riveted into the form of a shirt. The result is a sturdy piece of armor that affords very effective protection from most cutting blows while at the same time being relatively lightweight and flexible. Chain mail alone could not protect against crushing injuries, however, and warriors therefore combined it with a gambeson, which was worn underneath the mail. This was a padded jacket made from layers of more...

The lithotripter gave the world a new, noninvasive way to treat kidney stones with little to no pain. Discoveries in aerospace engineering and research on shock waves in the 1970s led to the technology's birth. Early studies at the Dornier research group (founded by German engineer Claude Dornier) focused on aerospace technology. One- new phenomenon noted by Dornier scientists was the pitting effect that occurred in airplanes as they approached the speed' of sound. It was discovered that this was caused by shock waves created in front of droplets of moisture. This finding in 1974 was the beginning of a collaboration between Dornier engineers and hospitals, and led to the invention of clinical extracorporeal shock wave lithotripsy (ESWL). In 1980 this new technology was used to treat its first patient, using the Dornier HM1 lithotripter. The treatment of kidney stones begins with an X-ray to identify the localization of the more...

The name of Robert Hooke (1635-1703) pops up frequently in the late seventeenth century. This was a time when a small number of scientists led the whole world in new discoveries across various scientific fields, and of this distinguished group Hooke was one of the most accomplished. The English polymath discovered the laws of physics that govern elasticity and now bear his name. He was the first person to use the word "cell" to describe the basic building blocks that made up living things. In addition, Hooke was also a top architect— even collaborating on projects with Sir Christopher Wren. But among all of his achievements it was his often overlooked invention of the universal joint that opened up whole new possibilities to the world of applied mechanics. Like many inventions, the universal joint evolved as the solution to a problem that the inventor had encountered personally. Hooke was a more...