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Main » Photo album » Star clusters » M 92
Globular cluster in constellation Hercules.

Authors: Nosikov Pavel & Kuznetsov Cyrill.

Views: 1991 | Dimensions: 600x467px/152.2Kb
Date: 2010.04.20 | Tags: NGC NGC 6341, M 92 | Added by: Aylindel
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1 Lyn   (2012.07.16 08:41) [Material]
I am a international suedtnt, and this is the second draft for my final essay in English class.It's a compare/contrast essay, please fix my grammar errors, word choice, verb tense and enhance the conclusion paragraph. Thank you! Green Roofs or Solar Roofs ? You want to contribute to our earth but have no idea? Everyone knows Global warming and unban heat island effect are making inroads into the places where you and your family live. We all know that is a serious issue, and also have positive attitude toward it.Suppose that you are not a boss of an enterprise, therefore, you are powerless to decide how to emission air pollution or recycle resources. Don’t be discouraged! You still have a way that is to develop the idea of green design to protect our earth. Green design is an internationaltheme that has been discussing for many years, and was promoted in “Leaders Summit Meeting” in Brazil in 1992. It is called Ecological Building in Japan and Sustainable Building in Europe. How to put the idea in use? Home Green Design is an affordable way for everyone. I am going to introduce two ways to save energy. They are green roof and a roof covered by solar panels. This essay will show their advantages and disadvantages of the following: 1. Expense; 2. Workingrequirement; 3.Function. Despite the fact that everyone knows the benefit of solar panels, I will argue that green roof is worth than solar panels. First, you do really care about the expense that green roof and solar panels might cost. For a100 sq foot, you need about $25,000 to install solar panels on your rooftop. The system works at least 25 years. On the other hand, it will cost you $1,000 per year. Is that worth? Itdepends on your personal utility rate of electricity. You would save a small amount of money if you are living with a big family. But a fact that you have to consider is one dollar tomorrow probably won’t have same value as today. Otherwise, you still need to pay the upkeep of the system every year and the charge of basic power for keeping it working. It is priced $1,500 for the same area as 100 sq foot, and the maintenance will not be the problem. Basically then, all you need is a waterproof rooftop, a layer of soil and a bag of seeds. The idea of Green Roof is much cheaper obviously and has lower maintenance than solar panels by comparison. Next is the working conditions that for each one. Before you choose one of them, you might need to consider that the area you live is sunnier or cloudier. Solar panels that as the name hints, is a system that has to be solarized under sunshine. In addition to sunshine, theGreen Roof also needs adequate raining to support them growing. If we simply consider that the best environments for them, solar panels need less conditions than green roof. Actually, solar panels will still work on a cloudy day. Of course, no one expects that the system can maintain same efficiency as it used to be on a sunny day. However, that is probably enough for keeping a lamp plus a computer working for one day. Unfortunately, solar panels do not fit in a winded area, because the panels might be damaged by blown stuff. In this stage, they are almost in a tie. Taking that green roof is working 24 hours a day into account, I guess that green roof is a little bit better than solar panels. Lastly I will compare the most important part which is the function of them. In theory, solar panels can basically reduce your energy consumption. What would be powered with solar electricity are the things such as the refrigerator, the computers, the TVs and the airconditioning, etc. Sounds great! But something you do not know is solar panels efficiency averages only 20% to 40%. Solar panels catch sunlight and convert to another type of power that we usually use for home electronic appliances. The system loses much energy during theconversion process. You can’t make appliances working unless you get enough energy from sunlight. So how about green roof and its benefits? It not only filters rains and air pollutants, but also keeps the house warmer in winter and emissions heat in summer. Sometimes it caneven provide a habitat for birds and some small animals. To choose solar panels or green roof is a fascinating question. It is a tough choice for either, I will personally choose green roof anyway. Solar panels are still an immature technology somehow, especially in converting energies. In addition, price is also a point to be considered. I believe that to protect living environments is important for individuals, but it is unacceptable ifno one can solve the problems that I mentioned before.

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