Archives January 2013

Louis Renault (1877-1944) is a well-known name in motoring, and in 1902 the French engineer invented the drum brake for cars. Drum brakes work in a similar way to bicycle brakes, using friction to slow and eventually stop a fast moving wheel. In cars, the friction is caused by pads that press against the inside surface of the rotating drum that is connected to the car wheel. The pads provide a wedging action that stops the wheel spinning and thereby stops the car moving. To function correctly, the brake pads need to linger close to the drum without scraping it during normal driving. If the pads are too far away—for example, when the pads wear down from use—then the brake pedal has to be pressed deeper to get a braking action. To avoid this, most drum brakes have an automatic adjuster that regulates the distance between the pads and drum. more...

"If we're serious about our environment, we've got to-get serious about the Segway." Lembit Opik, British politician When the Segway PT (Personal Transporter), produced by Dean Kamen [b. 1951), was finally unveiled in December 2001, there was a sense of disappointment. Rumors had circulated that the Segway was an antigravity device, and influential figures had described it as "maybe bigger than the Internet." In fact, the PT—developed over a decade at a cost of $100 million—is a 5,000-dollar gyroscopic scooter. Standing on a platform between two wheels and holding onto a T-shaped handlebar, its users can reach speeds of up to twelve miles per hour (20 kph). With a range of fifteen miles on a single battery, the PT's originality lies in its array of microprocessors and sensors that register the slightest movements. The eco-friendly electric motors in the wheels instantly act upon these deviations from the norm to attain more...

"Brattain decided to try dunking the entire apparatus into a tub of water. It worked ...a little bit." Ira Flatow, Transistorized! The development of the transistor was one of the true landmark inventions of the twentieth century. Before their existence, almost all electronic circuits made use of cumbersome and unreliable valves. The transistor was developed in the United States at the Bell Telephone Laboratories in New Jersey. Scientists John Bardeen (1908-1991), William Shockley (1910-1989), and Walter Brattain (1902-1987) were researching the behavior and suitability of germanium crystals for use as semiconductors that could replace valve diodes. When this was successfully achieved, the same group turned their attention to the considerably more demanding task of creating a solid-state germanium triode—one that could replace the ubiguitous valve equivalents. Since its development and evolution during the early years of the twentieth century, the valve triode had been at the very heart of every more...

The cow is a very gentle animal. She is kept as a domestic animal. She is regarded as one of the family members. In ancient India, the number of cows showed a man's wealth. The cow has a strong and heavy body with four legs. The body is covered with short hair. She has a pair of homs and a long tail. Her eyes are big and beautiful. The feet are hoofed and the hoofs are split in the middle. Cow-milk is very nutritious and easily digestible. It is very good for people, especially for children, sick people and expectant mothers. This milk can be consumed in many forms. It is also available in powdered and condensed forms. Cows have different colours. They are found everywhere in the world. Their young ones are called calves. The male of a cow is called a bull or an ox. They are used more...

"Healing is a matter of time, but sometimes also a matter of opportunity." Hippocrates, the "Father of Medicine" Our bodies have the capacity to heal themselves, being covered in a remarkable self-healing material—skin. Man-made materials, though, did not have this benefit until American Scott White and his University of Illinois team created self-healing polymers in 2001. Self-healing materials are composites consisting of microcapsules that contain a healing agent and small amounts of a catalyst, which allows the healing agent to repair damage to the material. Usually a material deteriorates over time due to damage from microcracking—faults that ''allow larger cracks to develop. With self-healing materials, microcracks rupture the microcapsules, the healing agent comes into contact with the catalyst, and the fault is filled in, These materials boast a long lifespan and are expected to prove invaluable, particularly for artificial organs and use in the space industry. Self-healing materials have a more...

"Emerson developed a respirator selling for less than $1000 and solved... breathing-rate changes." Charles C. Smith, Jr., Special Air Mission: Polio After working to improve the iron lung in 1931, American biomedical device inventor John Emerson (1906-1997) went on to develop a mechanical ventilator. A ventilator is a machine that automatically moves air into and out of the lungs of a patient who is unable to breathe. Emerson worked on his mechanical assistor with colleagues in the department of anesthesia at Harvard University in 1949. Polio epidemics of the 1940s had increased the demand for such machines, as had an increased use of muscle relaxant drugs during surgery; these would paralyze the patients' respiratory muscles so that they could not breathe. Other models followed Emerson's through the 1950s, such as the Bird ventilator, driven only by gas. In Britain the East Radcliffe and Beaver models were used; the Beaver ventilator more...

There is a good chance you have never heard of Radio Frequency Identification (RFID), but there is every likelihood that you have used it on more than one occasion. Whether it is through a name tag that allows a person to enter a secure part of a building, or a device that monitors library books, RFID has become very much a part of modern society. The concept was first employed in military aircraft and had a single purpose—to broadcast a signal indicating if it was a friendly aircraft or an enemy. A similar rudimentary device was also in use in the security industry, to determine if an object being protected was indeed where it was supposed to be. Mario Cardullo was aware of both systems in 1969, when a chance meeting with an engineer lamenting the difficulties of using bar codes to track railroads caused him to advance RFID dramatically. more...

Punctuality is a necessary habit that must be cultivated by every person. Without it nothing could ever be brought to a conclusion, everything would be in a state of chaos. It is the mark of a civilized society. It has been rightly called 'the soul   of business'. In ordinary living there can be some tolerance of unpunctuality. But it is hard for energetic, quick-minded people to waste time, so they are often tempted to finish a job before setting out to keep an appointment. If no accidents occur on the way, like punctured tyres, diversion of traffic etc. they will be on time. To be on time is a great quality which is unfortunately possessed by a very few. In our daily life, we have to attend to various types of business. This brings us in contact with other people. If we are late, this may cause annoyance and more...

“I was always afraid of dying. It was my fear that... kept me...always alert in the cockpit." Chuck Yeager Supersonic airplanes fly faster than the velocity of sound, this being about 770 miles per hour (1,230 kph) at ground level. During World War II certain fighter planes, such as the Mitsubishi Zero and the Supermarine Spitfire could approach this speed in a dive but the near supersonic air passing over the plane produced disruptive shockwaves and turbulence. The propellers became much less efficient and chaotic effects amplified pressure, perturbations, producing an increase in drag and a loss of lift and control. These effects became known as the "sound barrier," which was "broken" by introducing the much more powerful jet engine and by strengthening the airframes and wings. Fortunately, flight became smooth again when the aircraft moved faster than the speed of sound. There is still a slight controversy over who more...

“... developments start with the desire of the developer to get what he... wants so that he can use it." Dr. Ray Dolby For most of the second half of the twentieth century, magnetic tape was used in the making of most audio recordings, but there was always some background noise present on them. This tape hiss, or "white noise," was most noticeable in quieter musical passages. In 1965 electrical engineer Dr. Ray Dolby (b. 1933) proposed the first magnetic tape noise reduction system. The task was to improve the signal-to-noise ratio of the recording, reducing the level of hiss without affecting the quality of the sound. His approach was to "compand" (compress, then expand) the sound. During recording, an encoding circuit was inserted between the recording source and the tape recorder; this compressed the dynamic range of the recording. During playback, a decoding circuit was inserted between the tape more...