Fusion Essays - Fusion Power, Plasma, Tokamak,

Fusion Fusion reactions are inhibited by the electrical repulsive force that acts between two positively charged nuclei. For fusion to occur, the two nuclei must approach each other at high speed to overcome the electrical repulsion and attain a sufficiently small separation (less than one-trillionth of a centimeter) that the short-range strong nuclear force dominates. For the production of useful amounts of energy, a large number of nuclei must under go fusion: that is to say, a gas of fusing nuclei must be produced. In a gas at extremely high temperature, the average nucleus contains sufficient kinetic energy to undergo fusion. Such a medium can be produced by heating an ordinary gas of neutral atoms beyond the temperature at which electrons are knocked out of the atoms. The result is an ionized gas consisting of free negative electrons and positive nuclei. This gas constitutes a plasma. Plasma, in physics, is an electrically conducting medium in which there are roughly equal numbers of p ositively and negatively charged particles, produced when the atoms in a gas become ionized. It is sometimes referred to as the fourth state of matter, distinct from the solid, liquid, and gaseous states. When energy is continuously applied to a solid, it first melts, then it vaporizes, and finally electrons are removed from some of the neutral gas atoms and molecules to yield a mixture of positively charged ions and negatively charged electrons, while overall neutral charge density is maintained. When a significant portion of the gas has been ionized, its properties will be altered so substantially that little resemblance to solids, liquids, and gases remains. A plasma is unique in the way in which it interacts with itself with electric and magnetic fields, and with its environment. A plasma can be thought of as a collection of ions, electrons, neutral atoms and molecules, an photons in which some atoms are being ionized simultaneously with other electrons recombining with ions to form neutral particles, while photons are continuously being produced and absorbed. Scientists have estimated that more than 99 percent of the matter in the universe exists in the plasma state. All of the observed stars, including the Sun, consist of plasma, as do interstellar and interplanetary media and the outer atmospheres of the planets. Although most terrestrial matter exists in a solid, liquid or gaseous state, plasma is found in lightning bolts and auroras, in gaseous discharge lamps (neon lights), and in the crystal structure of metallic solids. Plasmas are currently being studied as an affordable source of clean electric power from thermonuclear fusion reactions. The scientific problem for fusion is thus the problem of producing and confining a hot, dense plasma. The core of a fusion reactor would consist of burning plasma. Fusion would occur between the nuclei, with electrons present only to maintain macroscopic charge neutrality. Stars, including the Sun, consist of plas ma that generates energy by fusion reactions. In these ?natural fusion reactors? the reacting, or burning, plasma is confirmed by its own gravity. It is not possible to assemble on Earth a plasma sufficiently massive to be gravitationally confined. The hydrogen bomb is an example of fusion reactions produced in an uncontrolled, unconfined manner in which the energy density is so high that the energy release is explosive. By contrast, the use of fusion for peaceful energy generating requires control and confinement of a plasma at high temperature and is often called controlled thermonuclear fusion. In the development of fusion power technology, demonstration of ? energy breakeven? is taken to signify the scientific feasibility of fusion. At breakeven, the fusion power produced by a plasma is equal to the power input to maintain the plasma. This requires a plasma that is hot, dense, and well confined. The temperature required, about 100 million Kelvins, is several times that of the Su n. The product of the density and energy confinement time of the plasma (the time it takes the plasma to lose its energy if not replaced) must exceed a critical value. There are two main approaches to controlled fusion ? namely, magnetic confinement and inertial confinement. Magnetic confinement of plasmas is the most highly developed approach to controlled fusion. The hot plasma is contained by magnetic Fusion Essays - Fusion Power, Plasma, Tokamak, Fusion Fusion reactions are inhibited by the electrical repulsive force that acts between two positively charged nuclei. For fusion to occur, the two nuclei must approach each other at high speed to overcome the electrical repulsion and attain a sufficiently small separation (less than one-trillionth of a centimeter) that the short-range strong nuclear force dominates. For the production of useful amounts of energy, a large number of nuclei must under go fusion: that is to say, a gas of fusing nuclei must be produced. In a gas at extremely high temperature, the average nucleus contains sufficient kinetic energy to undergo fusion. Such a medium can be produced by heating an ordinary gas of neutral atoms beyond the temperature at which electrons are knocked out of the atoms. The result is an ionized gas consisting of free negative electrons and positive nuclei. This gas constitutes a plasma. Plasma, in physics, is an electrically conducting medium in which there are roughly equal numbers of p ositively and negatively charged particles, produced when the atoms in a gas become ionized. It is sometimes referred to as the fourth state of matter, distinct from the solid, liquid, and gaseous states. When energy is continuously applied to a solid, it first melts, then it vaporizes, and finally electrons are removed from some of the neutral gas atoms and molecules to yield a mixture of positively charged ions and negatively charged electrons, while overall neutral charge density is maintained. When a significant portion of the gas has been ionized, its properties will be altered so substantially that little resemblance to solids, liquids, and gases remains. A plasma is unique in the way in which it interacts with itself with electric and magnetic fields, and with its environment. A plasma can be thought of as a collection of ions, electrons, neutral atoms and molecules, an photons in which some atoms are being ionized simultaneously with other electrons recombining with ions to form neutral particles, while photons are continuously being produced and absorbed. Scientists have estimated that more than 99 percent of the matter in the universe exists in the plasma state. All of the observed stars, including the Sun, consist of plasma, as do interstellar and interplanetary media and the outer atmospheres of the planets. Although most terrestrial matter exists in a solid, liquid or gaseous state, plasma is found in lightning bolts and auroras, in gaseous discharge lamps (neon lights), and in the crystal structure of metallic solids. Plasmas are currently being studied as an affordable source of clean electric power from thermonuclear fusion reactions. The scientific problem for fusion is thus the problem of producing and confining a hot, dense plasma. The core of a fusion reactor would consist of burning plasma. Fusion would occur between the nuclei, with electrons present only to maintain macroscopic charge neutrality. Stars, including the Sun, consist of plas ma that generates energy by fusion reactions. In these ?natural fusion reactors? the reacting, or burning, plasma is confirmed by its own gravity. It is not possible to assemble on Earth a plasma sufficiently massive to be gravitationally confined. The hydrogen bomb is an example of fusion reactions produced in an uncontrolled, unconfined manner in which the energy density is so high that the energy release is explosive. By contrast, the use of fusion for peaceful energy generating requires control and confinement of a plasma at high temperature and is often called controlled thermonuclear fusion. In the development of fusion power technology, demonstration of ? energy breakeven? is taken to signify the scientific feasibility of fusion. At breakeven, the fusion power produced by a plasma is equal to the power input to maintain the plasma. This requires a plasma that is hot, dense, and well confined. The temperature required, about 100 million Kelvins, is several times that of the Su n. The product of the density and energy confinement time of the plasma (the time it takes the plasma to lose its energy if not replaced) must exceed a critical value. There are two main approaches to controlled fusion ? namely, magnetic confinement and inertial confinement. Magnetic confinement of plasmas is the most highly developed approach to controlled fusion. The hot plasma is contained by magnetic

Internet History Essays - Humancomputer Interaction, Free Essays

Internet History Essays - Humancomputer Interaction, Free Essays Internet History Starting out as a small military experiment some 35 years ago, the Internet is quickly becoming one of the most popular forms of communication. With a present population of about 40 million users world wide, it seems to have a very promising future. Uncensored and almost impossible to monitor, it's a breeding ground for all sorts of offensive and derogatory information. On the other hand, it is probably the biggest single source of data in the world brought home into your personal computer. Will this form of communication survive in the future, or will it simply die out like many others have in the past? History The first nodes of the Internet were built 36 years ago by the RAND corporation. They faced the problem of keeping communication between U.S. authorities active in the aftermath of a nuclear war. The country needed a command-and-control network. The biggest problem was protecting the main server, which could be knocked out by a single atomic warhead. RAND came up with the solution in 1964. The new network would have no central authority, and secondly, it would be designed to operate in shambles. " During the 60s, this intriguing concept of a decentralized, blastproof, packet-switching network was kicked around by RAND, MIT and UCLA. The National Physical Laboratory in Great Britain set up the first test network on these principles in 1968. Shortly afterward, the Pentagon's Advanced Research Projects Agency decided to fund a larger, more ambitious project in the USA. The nodes of the network were to be high-speed supercomputers (or what passed for supercomputers at the time). These were rare and valuable machines which were in real need of good solid networking, for the sake of national research- and-development projects." (Sterling 1-2) The first was put in place during the fall of 1969. By December of the same year four nodes were installed. They were connected by dedicated high-speed transmission lines. This allowed the computers to communicate and be programmed from one of the other computers. In the year of 1971 there were 15 nodes, and by 72 there were 37. This number kept increasing rapidly as the years passed. The network was also becoming more of a person to person way of communicating. Many military personnel began using it as a way to gossip with friends instead of a way to transmit documents and projects. This became even more evident in the following years. How it works The Internet may seem a very complex form of communication but that is not really the case. First, you must have a reasonably fast computer (80386 or higher) with a modem and a phone line. The next step is to contact your local Internet provider and get him to give you a password and an SLIP address. At this time you will also be given the software to get you started. All of this costs about 140 dollars, depending on how many hours you wish to purchase. "We charge using an hourly rate because it gives our users more flexibility with their time. When run on a monthly payment, you are limited to an hour a day, whereas with our system you can use any amount of time whenever you want" (Schulmeister). The costs are as follows: 10 hrs-$30.00 20 hrs-$50.00 40 hrs-$80.00 60 hrs-$90.00 Once you have your software installed and want to start "surfing the net," you must first login to the server (located at the Northwest Community College) by dialling in its phone number using a specific program. The two local numbers are 638-1543 and 638-1593. Even with the two numbers, the server is often busy because of the constantly increasing number of users in our area. These numbers can be used by a number of people at a time, not just two. Once connected to the college server, you travel down to a larger server in Vancouver, and from there you can access any other computer connected as long as your server has permission to do so. Diagram: How the Internet works Impact on Society The Internet is just starting to have a large impact on society. It seemed to come out of nowhere, popping up in magazines and on the news. The Internet is now becoming an influential communications medium to

Unusual Life of the Ocean Research Paper Example | Topics and Well Written Essays - 250 words

Unusual Life of the Ocean - Research Paper Example Their cells are the largest on this planet, with the ability to grow up to four inches (Piper). Though large, their ability to survive lies in their fragility. Their structure can easily be destroyed by a larger movement of water, yet they are able to absorb large amounts of water, mercury, lead and other metals, thus being immune to pollution. At the same time, they can grow in almost complete darkness, at a high pressure. Besides xenophyophores, other forms of life exist at such deep levels. Jellyfish survive there as well (Piper). Over 200 different types of microorganisms were found to exist there as well (Dohrer). Unusual â€Å"translucent, sea-cucumber-like animals called holothurians† live there as well (Dohrer). Though also found on the surface, snails in the Trench have adapted to the pressure by developing soft shells (Dohrer). Though high pressure makes survival for most species impossible, in the Mariana Trench animal life managed to adapt. Precisely because it is more fragile, life in the deep is more able to withstand the pressure and darkness than life forms we are accustomed to