Wednesday, April 25, 2007

Global Positioning System

The Global Positioning System (GPS) is at present the only fully functional Global Navigation Satellite System (GNSS). More than two dozen GPS satellites are in medium Earth orbit, transmitting signals allowing GPS receivers to determine the receiver's location, speed and direction.

Since the first investigational satellite was launched in 1978, GPS has become an indispensable aid to navigation around the world, and an essential tool for map-making and land surveying. GPS also provides a precise time reference used in many applications including scientific study of earthquakes, and synchronization of telecommunications networks.

Developed by the United States Department of Defense, it is authoritatively named NAVSTAR GPS (NAVigation Satellite Timing And Ranging Global Positioning System). The satellite constellation is managed by the United States Air Force 50th Space Wing. The cost of maintaining the system is around US$750 million per year,[1] including the replacement of aging satellites, and research and development. Despite this fact, GPS is free for civilian use as a public good.

Monday, April 02, 2007

Mean sea level pressure

Mean sea level pressure is the pressure at sea level or the station pressure condensed to sea level assuming an isothermal layer at the station temperature. This is the pressure usually given in weather reports on radio, television, and newspapers. When barometers in the home are set to match the local weather reports, they measure pressure condensed to sea level, not the actual local atmospheric pressure. The reduction to sea level means that the usual range of fluctuations in pressure is the same for everyone. The pressures which are measured high pressure or low pressure do not depend on geographical location. This makes isobars on a weather map meaningful and useful tool. The altimeter setting in aviation, set either QNH or QFE, is another atmospheric pressure reduced to sea level, but the method of making this reduction differs slightly.

QNH barometric altimeter setting which will cause the altimeter to read airfield elevation when on the airfield. In ISA temperature conditions the altimeter will read altitude above mean sea level in the vicinity of the airfield.QFE barometric altimeter setting which will cause an altimeter to read zero when at the reference datum of a particular airfield. In ISA temperature conditions the altimeter will read height above the datum in the vicinity of the airfield.

Wednesday, March 21, 2007

Indian Independence movement

The Indian Independence Movement incorporated the efforts by Indians to expel the British, French and Portuguese from their trade-posts in the subcontinent; it involved a wide spectrum of Indian political organizations, philosophies, and rebellions between 1857 and India's emergence as an unified nation-state on August 15, 1947.

The initial Indian Rebellion of 1857 was sparked when soldiers serving in the British East India Company's British Army and Indian kingdoms rebelled against the British. After the revolt was crushed, India developed a class of educated elites whose political organising sought Indian political rights and representation while cleverly allowing the British to go ahead with western-style industrial developments. However, increasing public disenchantment with the presence of the British — their involvement in native civil liberties, political rights, and culture as well as alienation from issues facing common Indians — led to an upsurge in revolutionary activities aimed at overthrowing the non-natives, particularly the British.

Sunday, March 11, 2007

Infrared

Infrared (IR) emission is electromagnetic emission of a wavelength longer than that of noticeable light, but shorter than that of radio waves. The name means "below red", red being the color of detectable light of longest wavelength. Infrared radiation spans three instructions of magnitude and has wavelengths between about 750 nm and 1 mm.

These divisions are suitable by the different human response to this radiation: near infrared is the area closest in wavelength to the radiation detectable by the human eye, mid and far infrared are gradually further from the visible regime. Other definitions follow different physical mechanisms and the newest follow technical reasons .Unfortunately the international standards for these specifications are not currently obtainable.

The boundary between visible and infrared light is not precisely defined. The human eye is markedly less responsive to light above 700 nm wavelength, so longer frequencies make irrelevant contributions to scenes illuminated by common light sources. But particularly strong light (e.g., from lasers, or from bright daylight with the visible light removed by colored gels can be detected up to approximately 780 nm, and will be apparent as red light. The onset of infrared is defined at different values typically between 700 nm and 780 nm.

Monday, March 05, 2007

People mover

A people mover or automated people mover is a completely automated, grade-separated transit system. The term is normally used only to describe systems serving relatively small areas such as airports, downtown districts or theme parks, but is sometimes useful to considerably more complex automated systems. The term does not involve any particular technology, and a people mover may use technologies such as monorail, duorail, automated guide way transit or maglev. Propulsion may engage conventional on-board electric motors, linear motors or cable traction.

A few complex APMs deploy fleets of small vehicles over a track network with off-line stations, and supply near non-stop service to passengers. These taxi-like systems are more frequently referred to as personal rapid transit. Other complex APMs have related characteristics to mass transit systems, and there is no clear cut difference between a complex APM of this type and an automated mass transit system.

Sunday, February 25, 2007

Gold

Gold is a extremely sought-after valuable metal that for many centuries has been used as money, a store of value and in ornaments. The metal occurs as nugget or grains in rocks and in alluvial deposits and is one of the coinage metals. It is a soft, glossy, yellow, dense, malleable, and ductile change metal. Modern manufacturing uses include dentistry and electronics. Gold forms the basis for a financial typical used by the International Monetary Fund and the Bank for International resolution . Its ISO currency code is XAU.

Gold is a tinny element with a trait yellow color, but can also be black or ruby when finely alienated, while colloidal solutions are intensely tinted and often purple. These colors are the effect of gold's plasmon frequency lying in the visible range, which causes red and yellow glow to be reflected, and blue light to be engrossed. Only silver colloids show the same interactions with light, albeit at a shorter occurrence, making silver colloids yellow in color.

Gold is a good conductor of temperature and electricity, and is not precious by air and most reagents. Heat, damp, oxygen, and most corrosive agents have very little chemical effect on gold, making it well-suited for use in coins and jewelry; equally, halogens will chemically alter gold, and aqua regia dissolve it.

Pure gold is too soft for ordinary use and is hard-boiled by alloying with silver, copper, and other metals. Gold and its lots of alloys are most often used in jewelry, coinage and as a typical for monetary exchange in various countries. When promotion it in the form of jewelry, gold is calculated in karats , with pure gold being 24k. However, it is more commonly sold in lower capacity of 22k, 18k, and 14k. A lower "k" indicates a higher percent of copper or silver assorted into the alloy, with copper being the more typically used metal between the two. Fourteen karat gold-copper alloy will be almost identical in color to definite bronze alloys, and both may be used to produce polish and added badges. Eighteen karat gold with a high copper content is establish in some traditional jewelry and will have a distinct, though not dominant copper cast, giving an attractively warm color. A comparable karat weight when alloyed with silvery metals will appear less humid in color, and some low karat white metal alloys may be sold as "white gold", silvery in exterior with a slightly yellow cast but far more resistant to decay than silver or sterling silver. Karat weights of twenty and higher is more general in modern jewelry. Because of its high electrical conductivity and confrontation to decay and other desirable combinations of physical and chemical properties, gold also emerged in the late 20th century as an vital industrial metal, particularly as thin plating on electrical card associates and connectors.





Sunday, February 18, 2007

Rice vinegar

Rice vinegar is vinegar prepared from fermented rice or rice wine in China and Japan. Japanese rice vinegar is very soft and mellow and ranges in colour from colourless to pale yellow. There are two different types of Japanese vinegar: one is made from fermented rice and the other is made by adding rice vinegar to sake. Chinese rice vinegars are stronger than Japanese ones, and range in colour from clear to different shades of red and brown. Chinese and especially Japanese vinegars are very mild and sweet compared to purify and more acidic Western vinegars which, for that reason, are not proper substitutes for rice vinegars. White rice vinegar is colorless to pale yellow liquid, superior in vinegar content and more similar to Western vinegars, but still less acidic and milder in flavor.

Black rice vinegar is popular in southern China. Chinkiang vinegar, which originated in the city of Zhenjiang in the eastern coastal province of Jiangsu, China, is measured the best of the black rice vinegars. Usually black rice vinegar is made with glutinous rice, although millet or sorghum may be used instead. It is dark in colour, and has a deep, almost smoky flavor. In addition to Zhenjiang, it is too produced in Hong Kong.

Red rice vinegar is darker than white rice vinegar, and paler than black rice vinegar, with a typical red colour from Red yeast rice, which is cultivated with the mold Monascus purpureus. This vinegar has a distinctive flavour of its own due to the red mold. In Chinese cookbooks, ½ tablespoon of Western white vinegar is equivalent in strength to 1 tablespoon Chinkiang vinegar. Many Chinese people who grow up with rice vinegars take time to raise accustomed to the strength of Western vinegars when they begin to encounter them. Rice vinegar is also used to make sushi.

Monday, February 12, 2007

Chinese White Dolphin

The Chinese White Dolphin also called Indo-Pacific Humpback Dolphin, is a species of the Humpback dolphin and is one of eighty cetacean species. The adult dolphin is generally white or grey in colour. The population along the Chinese coast is unique in that they display a pink-coloured skin. This colour of the skin is not an effect of colour pigmentation, but is actually from blood vessels used for thermoregulation to avoid overheating during exertion. The adult's body length is about 220 - 250 centimeters and the infant's body length is about 1 meter. The normal weight of an adult is around 150 to 230 kilograms.
The Indo-Pacific dolphins can be found throughout Southeast Asia, and they breed from South Africa to Australia. There are two types, with Sumatra, one of the Indonesian islands, as the dividing line between the Chinese and the Western subspecies, Sousa chinensis plumbea. The two subspecies vary in color and size of their dorsal fin. The subspecies found in Southeast Asia has pinkish white skin and a bigger dorsal fin but lacks the fatty hump of its South African and Australian counterparts.

Monday, February 05, 2007

Jewellery

One universal issue is control over who could wear what jewellery, a point which indicate the powerful symbolism the wearing of jewellery evoked. In ancient Rome, for instance, only convinced ranks could wear rings; later, sumptuary laws dictated who could wear what type of jewellery; again based on rank. Cultural dictate have also played a important role; for example, the wearing of earrings by Western men was considered "effeminate" in the 19th and early 20th centuries. on the other hand, the jewellery industry in the early 20th century launched a crusade to popularize wedding rings for men — which caught on — as well as appointment rings for men , going so far as to make a false history and claim that the practice had Medieval roots. By the mid 1940s, 85% of weddings in the U.S. feature a double-ring ceremony, up from 15% in the 1920s.Religion has also played a role: Islam, for instance, consider the wearing of gold by men as a social taboo,and many religions have edicts against extreme display.

Monday, January 29, 2007

The computer

A computer is a machine for manipulate data according to a list of commands known as a program. Computers are tremendously adaptable. In fact, they are universal information-processing machines. According to the Church–Turing theory, a computer with a positive minimum entrance capability is in principle capable of performing the responsibilities of any other computer. Therefore, computers with capability ranging from those of a personal digital supporter to a supercomputer may all achieve the same tasks, as long as time and memory capacity are not consideration. Therefore, the same computer design may be modified for tasks ranging from doling out company payrolls to controlling unmanned spaceflights. Due to technical progression, modern electronic computers are exponentially more capable than those of preceding generations. Computers take plentiful physical forms. Early electronic computers were the size of a large room, while whole modern embedded computers may be lesser than a deck of playing cards. Even today, huge computing conveniences still exist for focused scientific computation and for the transaction processing necessities of large organizations. Smaller computers designed for personage use are called personal computers. Along with its convenient equivalent, the laptop computer, the personal computer is the ubiquitous in order processing and communication tool, and is typically what is meant by "a computer". However, the most general form of computer in use today is the embedded computer. Embedded computers are usually comparatively simple and physically small computers used to control one more device. They may control equipment from fighter aircraft to industrial robots to digital cameras. in the beginning, the term "computer" referred to a person who performed numerical calculations, frequently with the aid of a mechanical calculating device or analog computer. In 1801, Joseph Marie Jacquard made an improvement to the presented loom designs that used a series of punched paper cards as a program to weave involved patterns. The resulting Jacquard loom is not considered a true computer but it was an essential step in the growth of modern digital computers.
Charles Babbage was the first to conceptualize and design a completely programmable computer as early as 1820, In 1801, Joseph Marie Jacquard made an improvement to the presented loom designs that used a series of punched paper cards as a program to weave involved patterns. The resulting Jacquard loom is not considered a true computer but it was an essential step in the growth of modern digital computers.
but due to a combination of the restrictions of the technology of the time, limited finance, and an incapability to resist tinkering with his design, the device was never really constructed in his lifetime. By the end of the 19th century a number of technologies that would later prove helpful in computing had appeared, out such as the punch card and the vacuum tube, and large-scale automated data giving using punch cards was performed by tabulating equipment designed by Hermann Hollerith.During the first half of the 20th century, many technical computing wants were met by increasingly difficult special-purpose analog computers, which used a direct mechanical or electrical model of the problem as a base for subtraction . Sequence of gradually more powerful and stretchy computing devices were construct in the 1930s and 1940s.