Fusion is the energy source for the sun. Sun have enormous heat and gravitational pressure to compress nuclei of certain atoms into heavier nuclei, hence energy is release. When fusion occur, tiny amount of mass is lost and transformed into energy as quantified by Einstein’s famous equation, E=MC^2. Earthbound reactor cannot achieve the high pressures of the sun’s interior. But temperatures much higher than the sun’s can be created to compensate for lesser pressure. Heavier forms of hydrogen, known as deuterium can be use in nuclear fusion. Also, since water comprise of hydrogen, it is abundant enough to make deuterium supplies essentially unlimited. The challenges face by engineers is how to scale up fusion process to commercial proportion. While other approaches to fusion are being studied, the most advanced involves using magnetic forces to hold the fusion ingredients together. In order for fusion reaction work, one thing that has to consider is the materials than can withstand the assaults from product of the fusion reaction. Besides, methods also will be needed for confining the radioactivity include by neutrons as well as preventing releases of the radioactive tritium fuel. Advance superconductor magnet and vacuum is need to build full-scale fusion-generation facilities. If all this can be done, we are able to have unlimited energy.
References
Girard, J.P., et al. 2007. ITER, safety and licensing. Fusion Engineering and Design 82(5-14): 506-510. DOI: 10.1016/j.fusengdes.2007.03.017.
Holtkamp, N. 2007. An overview of the ITER project. Fusion Engineering and Design 82(5-14): 427-434. DOI: 10.1016/j.fusengdes.2007.03.029.
Magaud, P., G. Marbach, and I. Cook. 2004. Nuclear Fusion Reactors. Pp. 365-381 in Encyclopedia of Energy, Volume 4, ed. C.J. Cleveland. Elsevier Science: Oxford, U.K. DOI: 10.1016/B0-12-176480-X/00305-3.
Sunday, October 5, 2008
Wednesday, September 17, 2008
One Common Grammar Mistake
One of the most common grammar mistakes that i always make is the word " had ". I am always confused between the words (has and had) and (have and had).
Has is a verb.
Has is singular simple present.
Have is prular of the word has.
Had is used as simple past and past participle .
1. Example between has and have:
-I have two sisters.
-The dog down the street has a lax owner.
2. Example between have and had.
(auxiliary verb, taking a past participle) Used in forming the perfect aspect and the past perfect aspect.
-I have already eaten today.
-I had already eaten.
EXERCISE USING HAS, HAVE AND HAD.
1.I ___ a house and a car.
2.I'm going to ___ some pizza and some Pepsi right now.
3.I ___ already eaten.
4.She ___ him arrested for trespassing.
5.He ___ completed his homework today.
6.The hospital ___ several patients contract pneumonia last week.
Answers:
1.have
2.have
3.had
4.had
5.has
6.had
Has is a verb.
Has is singular simple present.
Have is prular of the word has.
Had is used as simple past and past participle .
1. Example between has and have:
-I have two sisters.
-The dog down the street has a lax owner.
2. Example between have and had.
(auxiliary verb, taking a past participle) Used in forming the perfect aspect and the past perfect aspect.
-I have already eaten today.
-I had already eaten.
EXERCISE USING HAS, HAVE AND HAD.
1.I ___ a house and a car.
2.I'm going to ___ some pizza and some Pepsi right now.
3.I ___ already eaten.
4.She ___ him arrested for trespassing.
5.He ___ completed his homework today.
6.The hospital ___ several patients contract pneumonia last week.
Answers:
1.have
2.have
3.had
4.had
5.has
6.had
Thursday, August 21, 2008
The most important challenges for engineering
In the 21st century , issues related to energy conservation is the main concern of every developed and developing countries. One of the main concerns is the use of fossil fuels . Besides fossil fuels , nuclear energy, hydro energy and solar energy are used as alternative sources of energy. Why is fossil fuels so important? Fossil fuels are largely used in the industry of aerospace, automobile and heavy industry. This is because fossil fuels are cheap , convenient to store, and easy to obtain.
Now, the great challenges are how do we deal with the decreasing of fossil fuels. It is estimated that fossil fuels will be used up in 50 years time. To minimize the use of fossil fuels and to obtain energy once fossil fuels is completely used up, engineers have think of alternative ways to solve it. Currently the use of solar energy is not ideal due to the high cost of materials and maintenance. In addition there is also limited energy to be stored since solar panel is only able to store energy during day time. This is the reason why the use of solar energy is not suitable to those country situated in the polar region. It will be great if we are able to think of ways to improve the efficiency of solar panel and use it as an energy storage. Using solar energy is environmental friendly unlike fossil fuel . We can directly obtain energy from sunlight without producing any waste product. However fossil fuels produce carbon dioxide that will lead to global warming. This will create a major concern to deal with global warming too.
In conclusion , to find alternative ways to replace fossil fuel is not an easy task . A lot of obstacles have to be tackled before it can be done. For example , political issues, safety and cost. All this issue create a great challenge for engineers.
Now, the great challenges are how do we deal with the decreasing of fossil fuels. It is estimated that fossil fuels will be used up in 50 years time. To minimize the use of fossil fuels and to obtain energy once fossil fuels is completely used up, engineers have think of alternative ways to solve it. Currently the use of solar energy is not ideal due to the high cost of materials and maintenance. In addition there is also limited energy to be stored since solar panel is only able to store energy during day time. This is the reason why the use of solar energy is not suitable to those country situated in the polar region. It will be great if we are able to think of ways to improve the efficiency of solar panel and use it as an energy storage. Using solar energy is environmental friendly unlike fossil fuel . We can directly obtain energy from sunlight without producing any waste product. However fossil fuels produce carbon dioxide that will lead to global warming. This will create a major concern to deal with global warming too.
In conclusion , to find alternative ways to replace fossil fuel is not an easy task . A lot of obstacles have to be tackled before it can be done. For example , political issues, safety and cost. All this issue create a great challenge for engineers.
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