Steam Engine Essays - Piston Engines, Steam Engines, Compound Engine

Steam Engine The steam engine was an engine powered by steam. It provided an important source of power independently. The steam engine played a major role in manufacturing and transportation during the Industrial Revolution. The challenge of improving the steam engine was the beginning of the science of thermodynamics. The steam engine was a very important invention. ?Steam can be made at any time simply by boiling water, so it is more dependable than wind or water energy? (Norbeck 34-36). The heating and cooling of steam in cylinder causes pistons to move up and down. The simplest of a steam engine is used as a boiler. This was a common household heating system. The efficiency of the steam engine was very low; there fore they were later replaced by steam turbines. The first piston engine was invented in 1690 by a French inventor named Denis Papin and was used for pumping water. ?Why not find a way to use heat energy? (Garrat 12). It had a single cylinder that operated as a boiler; a small amount of water was added and heated to form steam. The steam raised the piston in the cylinder, after it was raised the heat was removed, the steam condensed and the air pressure on the upper side forced the piston down. In 1705 Thomas Newcomen invented the first practical steam engine. Steam operates the engine by a slide directing steam from on one side of the piston to the other. As the piston moves, the piston rod turns the flywheel half a turn. The steam engine doesn't create power, I t uses steam to change heat energy released by burning fuel into mechanical energy. Steam engines are considered to be external combustion engine because, the fuel is burned outside of the cylinders. An example of internal combustion engine is an automobile. The power is provided by the rapid burning of gasoline inside the cylinders, which is ignited by the spark plug. The explosion inside the cylinder wall causes the pistion to go down and turning a shaft. Thomas Newcomen invented the first steam engine in 1705 although it wasn't very efficient; it was used for pumping water for coal mines. James Watt improved Newcomen's engine in the 1760's. He produced the first type of double acting engine. ?One after another hand operations were replaced by machines? (Lipkin). In a compound engine, steam in high pressure is used in one cylinder and then, after it has expanded and lessened in pressure, it is piped to another cylinder, in which it expands further. The first compound engine used a two-cylinder type but later other types of compound engines used triple and even quadruple cylinders. The advantage of compounding two or more cylinders is that less energy is lost in heating the cylinder walls, as a result, the engine is more efficient. Further improvements to the steam engine lead to the uniflow engine. The piston itself is a valve, and the cylinder remains at a constant temperature while operating. In the uniflow engine steam moves in only one direction, it has two inlet ports and one outlet port. This was a large engine, and was used mainly in big operations; it also was a very expensive engine compared to other engines. This type of engine was a very efficient use of high-pressure steam. Steam turbines produce a rotary motion; it works the same way as a water turbine, except its energy comes from expanding steam. It turns a set of main rotating blades on a wheel. Steam turbines rotate very fast and have no vibrations, unlike the back and forth motion of pistons. Steam engines work great in steam ships, and electric power plants. The flywheel turns at the end of the piston shaft. It was made of heavy metal cast-iron, so it helped eliminate power surges to the generator and, also provides a uniform flow of power. Since the steam engine was invented we have came along way with engines. Now we are making power by nuclear power plants and things have become much more industrialized. We are always looking for new ideas and ways to improve energy efficiency. Science Essays

Conjugate Base - Chemistry Definitions Terms

Conjugate Base - Chemistry Definitions Terms Conjugate Base Definition The Bronsted-Lowry acid-base theory includes the concepts of conjugate acids and conjugate bases. When an acid dissociates into its ions in water, it loses a hydrogen ion. The species that is formed is the acids conjugate base. A more general definition is that a conjugate base is the base member, X-, of a pair of compounds that transform into each other by gaining or losing a proton. The conjugate base is able to gain or absorb a proton in a chemical reaction. The conjugate acid donates the proton or hydrogen in the reaction. In an acid-base reaction, the chemical reaction is: Acid Base â‡Å' Conjugate Base Conjugate Acid Key Takeaways: Conjugate Base Conjugate acids and bases are part of the Bronsted-Lowry theory of acids and bases.According to this theory, the species that donates a hydrogen cation or proton in a reaction is a conjugate acid, while the remaining portion or the one that accepts a proton or hydrogen is the conjugate base.The conjugate base may be recognized as an anion. Conjugate Base Examples The  general chemical reaction between a conjugate acid and a conjugate base is: HX H2O ↔ X− H3O In an acid-base reaction, you can recognize the conjugate base because it is an anion. For hydrochloric acid (HCl), this reaction becomes: HCl H2O ↔ Cl− H3O Here, the chloride anion, Cl−, is the conjugate base. Sulfuric acid, H2SO4 forms two conjugate bases as hydrogen ions are successively removed from the acid: HSO4- and SO42-.