Sunday, May 27, 2007

Uses for chain

Exact uses for chain include: Bicycle chain, chain that transfers power from the wheel to the
drive-wheel of a bicycle thus propelling it Chain drive, the main feature which differentiated the safety bicycle Chain gun, type of machine gun that utilizes a chain, driven by an external power source, to actuate the mechanism rather than using recoil Chain pumps, type of water pump where an endless chain has positioned on it circular discs Chain-linked Lewis, lifting device made from two curved steel legs Chainsaw, portable mechanical, motorized saw Curb chain, used on curb bits when riding a horse Keychain, a small chain that connects a small item to a key ring Lead shank, used on difficult horses that are misbehaving O-ring chain,

a specialized type of roller chain Roller chain, the type of chain most commonly used for transmission of mechanical power on bicycles, motorcycles, and in industrial and agricultural .machinery Snow chains, used to improve traction in snow Timing chain, used to regulate the valve and ignition timing on an internal combustion engine Ball and chain, phrase that can refer to either the actual restraint device that was used to slow down prisoners, or a derogatory description of a person's significant other Bicycle lock, lockable chain.

Saturday, May 19, 2007

Content Management System

A Content Management System is a software system intended for content management. This includes computer files, image media, audio files, electronic documents and web content. The idea behind a Content Management System is to make these files available inter-office, as well as over the web. A Content Management System would most often be used as archival as well. Many companies use a Content Management System to store files in a non-proprietary form. Companies using a Content Management System file share with ease, as most systems use server based software, even further broadening file availability. As shown below, many Content Management Systems include a feature for Web Content, and some have a feature for a "workflow process."

"Workflow" is the idea of moving an electronic document along for either approval, or for adding content. Some Content Management Systems will simply facilitate this process with email notification, and automated routing. This is ideally a mutual creation of documents. A Content Management System facilitates the organization, control, and publication of a large body of documents and other content, such as images and multimedia resources.

Monday, May 14, 2007


Biography is a type of literature and further forms of media such as film, based on the written accounts of individual lives. While a biography may focus on a subject of fiction or non-fiction, the term is frequently in reference to non-fiction. Pat Shipman however, says "I think a good biographer has to write fiction some of the time to make apparent a significant event in someone's life." This is sometimes debated. As opposed to a profile or curriculum vitae, a biography develops a complex analysis of personality, highlighting different aspects of it and including intimate details of experiences. A biography is more than a list of distant facts like birth, education, work, relationships and death. It also delves into the emotions of experiencing such events.

Ancient Greeks developed the biographical tradition which we have inherited, although until the 5th century AD, when the word 'biographia' first appears, in Damascus' Life of Isodorus, biographical pieces were called simply "lives" . It is quite likely that the Greeks were drawing on a pre-existing eastern tradition; certainly Herodotus' Histories contains more exhaustive biographical information on Persian kings and subjects than on anyone else, implying he had a Persian source for it.

Wednesday, May 09, 2007

History of bridges

The initial bridges were spans made of made of wood logs or planks and eventually stones, using a easy support and crossbeam arrangement. Most of these early bridges were very poorly built and could not often support heavy weights. It was this insufficiency which led to the development of better bridges. The arch was first used by the Roman Empire for bridges and aqueducts, some of which still situate today. These arch based bridges could stand in circumstances that would previously have swept any bridge away. An example is the Alcantara Bridge, built over the river Tagus.
Earlier bridges would have been swept away by the strong current. The Romans also used cement, which reduced the difference of strength found in natural stone. One type of cement, called pozzolana, consisted of water, lime, sand, and volcanic rock. Brick and mortar bridges were built after the Roman era, as the skill for cement was lost then later rediscovered. Rope bridges, a simple type of suspension bridge, were used by the Inca civilization in the Andes Mountains of South America, just prior to European colonization in the 1500s.During the 18th century there were many innovations in the design of timber bridges by Hans Ulrich, Johannes Grubenmann, and others. The first engineering book on building bridges was written by Hubert Gautier in 1716.

With the Industrial Revolution in the 19th century, truss systems of shaped iron were developed for larger bridges, but iron did not have the tensile strength to support large loads. With the advent of steel, which has a high tensile strength, much larger bridges were built, many using the ideas of Gustave Eiffel.