Tanks were a great problem for infantry during the first years of World War II. The thick armor was proof against small arms, and grenades powerful enough to penetrate it had to be placed directly on the tank. Three Americans addressed this problem by combining a shaped-charge hand grenade with an electrically fired rocket launcher. Dr. Clarence Hickman had worked with Robert Goddard on tube-fired rockets during World War I. Starting in 1940, he helped U.S. Army officers Edward Uhl and Leslie Skinner to develop an electrically fired rocket launcher. When the user pulled the trigger, a battery in the stock sent a charge to ignite the rocket, which then fired through a steel tube. The first fielded version was officially called the M1 Rocket Launcher, but it was soon nicknamed the bazooka because it resembled a musical instrument of the same name. By the end of 1942 U.S. troops more...

“I never understood what people did with them—who's buying all these?" Diane Smahlik, daughter of Ettore Steccone Italian immigrant Ettore Steccone (1896-1984) liked to keep windows clean. When he moved across the Atlantic in 1922, window cleaners were using heavy, cumbersome tools, but he was about to change all that. In 1936 the patent for Steccone's squeegee was filed, and in 1938 it was published. But he was viewed as an uneducated Italian immigrant, and his attempts to sell his invention to dealers proved fruitless. Instead he approached fellow window cleaners, offering them the chance to try his tool for one day Its simplicity and ergonomic design made it an instant hit and the Steccone family made a great deal of money. The squeegee has been making the lives of window cleaners easier ever since, and the design has hardly changed in the process. The key lies in the rubber, more...

"I made 5,127 prototypes of my vacuum... There were 5,126 failures. But I learned from each one." James Dyson, Fast Company magazine (May 2007) In 1978, designer James Dyson (b. 1947) noticed that the suction of his vacuum cleaner diminished as the bag started to fill with dust. He realized that a system in which dust is siphoned into a bin, rather than retained by a filter, would maintain the suction of the appliance. Five years and some 5,127 prototypes later, Dyson had invented the technology that would be the cornerstone of the iconic Dyson vacuum cleaner. James Dyson studied at the Royal College of Art, where he began a career in design that would lead him to develop many unique ideas. However, his big breakthrough came seven years after he began his research into developing filtering processes for vacuum cleaners. The cleaning power of a Dyson vacuum cleaner lies more...

Good manners make a full man. They are very essential for human civilization. Without good manners, man is like a purse without money though it is very attractive from outside. They are the outcome of good breeding. A person who has been brought up in a good environment must have good manners. You may call them the flowers of mankind's garden.  Never hate anyone at all. It is clear that if we hate others, we congratulate ourselves over the misfortunes and failings of others, as It Is bad reasoning and makes us enemies of half the world. With he help of good manners, we can find entry into the heart of a I person and can therefore earn his love. Good manners are the best recommendations of a man. One should be sympathetic towards the weak and old. Whenever we see an old person in need of a seat while more...

A television system, by definition, transmits and receives live, moving half-tone images. Early versions, such as those invented by John Logie Baird in the 1920s, used crude, electromechanical, spinning, perforated, scanning discs to record and subsequently produce the images. The first transatlantic images were transmitted with this system in 1928. Television relies on the fact that the human brain can convert a sequence of slightly different still images into a moving picture if more than fifteen frames are received every second. As soon as the number drops below fifteen, the motion looks jerky. Today's televisions are a product of the invention of the cathode ray tube. This is coated with a phosphor that glows when an electron beam hits it. Behind the phosphor is a shadow mask that divides the image into picture elements (pixels). Television sets typically have 525 lines down the screen and these are raster scanned every more...

The relationship between atmospheric pressure and height above sea level was known by Blaise Pascal and Edmond Halley in the mid-seventeenth century: one can be used to measure the other. In 1862 James Glaisher used an aneroid barometer as a height instrument on a 7-mile (11 km) high balloon flight. The barometric (or pressure) altimeter uses an aneroid barometer to register pressure change. The higher you go, the less air there is above pressing down on the instrument. Near sea level, under normal conditions, the pressure changes by one millibar (0.03 inches of mercury) for every 27 feet (8 m) of altitude. Alas, the pressure also changes with the weather and the temperature. In addition, the pressure-height relationship is not truly linear but exponential. Paul Kollsman (1900-1982), a German mechanical engineer, emigrated to the United States in 1923. His watchword was "accuracy." Previous altimeters determined airplane heights to a few more...

"It's going to be a pump war out there.... [Pump dispensers are] a real trend—not a fad." Jack Saizman, industry analyst It is hard to believe that U.S. patent number 49,561 took more than a century to become widespread, but that is exactly what happened with liquid soap. It was New Yorker William Shepphard who discovered in 1865 that, by mixing large amounts of ammonium bicarbonate with normal soap, he could produce a soap that had the consistency of treacle. Although his invention slowly began to appear in dispensers in public, it was not until 1980 that the U.S. Minnetonka Corporation began selling it widely to the general public. Under the brand name "Softsoap*," the liquid hand cleaner was an instant success, partially due to the way it was dispensed. On the top of its^ bottle was a small plastic pump that, when depressed, issued a fixed quantity of soap more...

Introduction. The original name of Indian American astronaut Sunita Williams is Sunita Pandya. She is also known by Suni Williams. She is the greatest woman astronaut in the history of space shuttle mission. Her mother's name is Bonnie Pandya and father Dr. Deepak Pandya is a famous Neuroanatomist. She was bom at Euclid, Ohio in America. Education. Sunita Williams got her elementary education from Ncedham High School, Massachusetts in 1983. She passed her graduation In B.S. (Physical Science) from U.S. Naval Academy in 1987. After that, ihe completed her M.S. (Engineering Management) from Florida Institute Of Technology in 1995. Sunita Pandya was married to Michael J. Williams. Organizations. After completing her education, Sunita Williams Joined the Society of Experimental Test Pilot Organization and Society of Plight Test Engineers. She also served some time in American Helicopter Association. Then she was designated as Commander, USN. Selection in NASA. Taking into account more...

Dr. W. T. Green, a pediatric orthopedist at Children's Hospital in Boston, Massachusetts, made one of the first attempts at tissue engineering. He tried to grow cartilage in laboratory mice. Although unsuccessful, his work set the stage for later attempts by suggesting that, once suitable materials were invented, cells would grow on configured scaffolds. Joseph Vacanti, a transplant surgeon, and Robert Langer (b. 1948), an engineer, created an engineered, biosynthetic, biodegradable scaffold in 1987. The scaffolds they developed provided access to nutrients as well as waste removal for the growing cells. The final structure can resemble a natural organ. A famous development was the "auriculosaurus," a mouse with a human-shaped ear growing on its back. The "ear" was a biodegradable scaffold seeded with bovine cartilage cells. The mouse was a nude animal specifically bred not to reject foreign proteins. The auriculosaurus, filmed by a BBC video crew, became the image more...

It is said when examinations are approaching, students suffer from examination fever. And rightly examinations are regarded as a curse by students. The approach of examinations means the beginning of fear in the mind of a student. As a matter of fact, examinations are the only hurdles in an otherwise happy and carefree life of a student. The bugbear of an examination interrupts the smooth course of a student's life; games, musical concerts, debates and activities are all stopped when examinations are nearing. Students are not to be found at the cinema houses, restaurants and other places of entertainment during those days. Examinations are held to test student's ability, to cheek up the work they have done during a term, to judge what progress they have made and to determine whether they have been utilizing or wasting their time. If there were no examinations, the merits of the various students more...