The Impact Of Computers Essays - E-commerce, Free Essays

The Impact Of Computers Essays - E-commerce, Free Essays The Impact Of Computers THE IMPACT OF COMPUTERS Computer technology not only has solved problems but also has created some, including a certain amount of culture shock as individuals attempt to deal with the new technology. A major role of computer science has been to alleviate such problems, mainly by making computer systems cheaper, faster, more reliable, easier to use. Computers are forever present in the workplace. Word processors-computer software packages that simplify the creational and modification of documents-have largely replaced the typewriter. Electronic mail has made it easy to send messages worldwide via computer communication networks. Office automation has become the term for linking workstations, printers, database system, and other tools by means of a local-area network. An eventual goal of office automation has been termed the paperless office. Although such changes ultimately make office work much more efficient, they have not been without cost in terms of purchasing and frequently upgrading the necessary hardware and software and of training workers to use the new technology. Computer integrated manufacturing is a relatively new technology arising from the application of many computer science sub disciplines to support the manufacturing enterprise. The technology of CIM emphasizes that all aspects of manufacturing should be not only computerized as much as possible but also linked together via a computer communication network into an integrated whole. In short, CIM has the potential to enable manufacturers to build cheaper, higher-quality products and thus improve their competitiveness. Making a telephone call no longer should conjure up visions of operators connecting cables by hand or even of electrical signals causing relays to click into place and effect connections during dialing. The telephone system now is just a multilevel computer network with software switches in the network nodes to route calls get through much more quickly and reliably than they did in the past. A disadvantage is the potential for dramatic and widespread failures; for as has happened. The downside of this technology is the potential for security problems. Intruders can see packets traveling on a network and can perhaps interpret them to obtain confidential information. Computer technology has had a significant impact on retail stores. All but the smallest shops have replaced the old-fashioned cash register with a terminal linked to a computer system. The terminal may require that the clerk type in the code for the item; but more and more frequently the checkout counter include a bar-code scanner, a device that directly reads into the computer the UPC printed on each package. Cash-register receipts can then include brief descriptions of the items purchased, and the purchase information is also relayed back to the computer to cause and immediate adjustment in the inventory data. The inventory system can easily alert the manager when the supply of some item drops below a specified threshold. In the case of retail chains linked by networks, the order for a new supply of an item may be automatically generated and sent electronically to the supply warehouse. In a less extensively automated arrangement, the manager can send in the order electronically by a dial-up link to the suppliers computer. These developments have made shopping much more convenient. The checkout process is faster; checkout lines shorter; and the desired item are more likely to be in stock. Computer technology has been incorporated into automobiles. Computers are involved (CAD systems) not only the design of cars but also in the manufacturing and testing process, perhaps making use of CIM technology. Todays automobiles themselves include numerous computer chips that analyze sensor data and alert the driver to actual and potential malfunctions. Although increased reliability has been achieved by implementing such computerization, a drawback is that only automotive repair shops with a large investment in high-tech interfaces and diagnostic tools for these computerized systems can handle any but the simplest repairs

An Introduction to Combustion (Burning) Reactions

An Introduction to Combustion (Burning) Reactions A combustion reaction is a major class of chemical reactions, commonly referred to as burning. Combustion usually occurs when a hydrocarbon reacts with oxygen to produce carbon dioxide and water. In the more general sense, combustion involves a reaction between any combustible material and an oxidizer to form an oxidized product. Combustion is an exothermic reaction, so it releases heat, but sometimes the reaction proceeds so slowly that a temperature change is not noticeable. Good signs that you are dealing with a combustion reaction include the presence of oxygen as a reactant and carbon dioxide, water, and heat as products. Inorganic combustion reactions might not form all of the products but are recognizable by the reaction of oxygen. Combustion doesnt always result in fire, but when it does, a flame is a characteristic indicator of the reaction. While the activation energy must be overcome to initiate combustion (i.e.:Â  using a lit match to light a fire), the heat from a flame may provide enough energy to make the reaction self-sustaining. General Form of a Combustion Reaction hydrocarbon oxygen → carbon dioxide water Examples of Combustion Reactions Here are several examples of balanced equations for combustion reactions. Its important to remember that combustion reactions are easy to recognize because the products always contain carbon dioxide and water. In these examples, oxygen gas is present as a reactant, but trickier examples of the reaction exist where the oxygen comes from another reactant. combustion of methaneCH4(g) 2 O2(g) → CO2(g) 2 H2O(g)burning of naphthaleneC10H8 12 O2 → 10 CO2 4 H2Ocombustion of ethane2 C2H6 7 O2 → 4 CO2 6 H2Ocombustion of butane (commonly found in lighters)2C4H10(g) 13O2(g) → 8CO2(g) 10H2O(g)combustion of methanol (also known as wood alcohol)2CH3OH(g) 3O2(g) → 2CO2(g) 4H2O(g)combustion of propane (used in gas grills and fireplaces)2C3H8(g) 7O2(g) → 6CO2(g) 8H2O(g) Complete Versus Incomplete Combustion Combustion, like all chemical reactions, does not always proceed with 100% efficiency. It is prone to limiting reactants the same as other processes. So, there are two types of combustion you are likely to encounter: Complete Combustion - Also called clean combustion, clean combustion is oxidation of a hydrocarbon that produces only carbon dioxide and water. An example of clean combustion is burning of candle wax, where the heat from the wick vaporizes wax (a hydrocarbon), which reacts with oxygen in the air to release carbon dioxide and water. Ideally, all the wax burns so nothing remains once the candle is consumed. The water vapor and carbon dioxide dissipate into air.Incomplete Combustion - Also called dirty combustion, incomplete combustion is hydrocarbon oxidation that produces carbon monoxide and/or carbon (soot) in addition to carbon dioxide. An example of incomplete combustion would be burning coal, where a lot of soot and carbon monoxide is released. Many of the fossil fuels burn incompletely, releasing waste products.