Forced Convection (in a cross flow heat exchanger) Essay Example for Free

Forced Convection (in a cross flow heat exchanger) Essay The aim of this lab is to determine the average convective heat transfer coefficient for forced convection of a fluid (air) past a copper tube, which is used as a heat transfer model. Introduction The general definition for convection may be summarized to this definition energy transfer between the surface and fluid due to temperature difference and this energy transfer by either forced (external, internal flow) or natural convection. Heat transfer by forced convection generally makes use of a fan, blower, or pump to provide high velocity fluid (gas or liquid). The high-velocity fluid results in a decreased thermal resistance across the boundary layer from the fluid to the heated surface. This, in turn, increases the amount of heat that is carried away by the fluid. [1] Theory Background [2] Considering the heat lost by forced convection form the test rod. The amount of heat transferred is given by (1) Where = rate of heat transfer, unknown value. ?= film heat transfer coefficient, this is what we need to found out. A= area for heat transfer, this is the area of the cross section area of test section. T= temperature of the copper rod, the temperature after heating. Ta= temperature of air, surrounding temperature. So, in any period of time, dt, then the fall in temperature, dT, will be given as: (2) Where m= mass of copper rod, cp= specific heat of the copper rod, J/kgK Eliminating Q from (1) and (2) then Since Ta is constant, dT=d(T-Ta) Integrating gives: At t = 0, T=To, hence C1 = ln(T-To), hence: Or Therefore a plot of ln((T-Ta)/(Tmax-Ta))) against t should give a straight line of gradient from which the heat transfer coefficient, ? , can be found. To find the velocity of air passing the rod, first the velocity upstream must be found.

The Kite Runner Essay -- Literary Analysis, Khaled Hosseini

"There is a way to be good again". By putting this quote at the very first beginning of the book, "The Kite Runner", Khaled Hosseini has introduced a theme that goes throughout the story of the book, redemption. Everything has a path that leads to the final destination, sometimes there are more than one path to go. It depends on people to choose which one that suitable for them. In the book, by telling the story, the author has shown a road to redemption. Baba, Sanaubar and Amir, different characters in the book represent different types of people in reality, stories of how they would do to redeem their mistakes. Redemption, the definition of this term is a controversial subject. Through the book, the author shows his side of understanding the word. Redemption is an act of goodness from the regretful heart, from guilt of the past. A person who had made a mistake before would be corroded slowly by his regret and the pain that haunts him days by days. However, "there is a way to be good again", he may have killed a life, but he can save another life to pay back for the sin. That's how redemption simply works. People could not change the past; therefore, they would do a good thing that brings to a better future, which makes them become better people than the ones in the past. The road to redemption is not from when the person makes up for his guilt, but it starts when he feel regretful, a difficult start, and ends with a relief of redemption. The author puts characters into different situations of sins and how they try to resolve problems, as examples for his ideas of road to redemption. For instance, Baba is always an honorable man in people's eyes. They admire him for his power, they are jealous with his wealth and they love ... ...uilty feeling inside people. It is pointless for doing thousands of good things in the present when they could not change a sin in their past. Redemption can be considered as a comfort, that gives people "the illusion", a feeling of believing that they could pay back for their sins. However, it is not true; what has been done could not be inversed again. For example, Amir may have saved Sohrab's life by rescuing the boy from Assef, but that is what he does for Sohrab, not Hassan. His half-brother had still been raped by Assef, he got shot and already died. That truth is unchangeable. In fact, redemption is an action that may be kind of selfishness because most parts of redemption are all about sinners, when they try to make themselves feel better. Therefore, the author's statement of the redemption, "there is a way to be good again", is not always true.

Eliminating the 12th Grade

Would eliminating the twelfth grade in Utah affect seniors? Currently Senator Buttars says it will save money for schools if senior year was to be eliminated. I believe that the Utah state legislation should not eliminate the twelfth grade because there are classes that you have to take senior year, catch up, and preparation for college. Firstly, I think the Utah legislation should not eliminate the twelfth grade because there are classes that you can only take your senior year. These days we have four years of english and science. It would be a bummer if we as students have to take those classes again in college. Also some students need the credits to graduate. Without those two or three credits then how will they graduate? Then the rest of the year could be enjoyable. Secondly it gives them time to catch up on classes they may have failed in previous years. I know it would be terrible, but retaking those classes would really help, especially when you failed the past years. Other than just making up the class up with packets, it would be easier for you. Also it would give others a second chance to be someone. Thirdly, seniors won’t be as prepared for college as they should be. If this is so, then we coming up seniors won’t be able to have the knowledge for what is in store in college. If we go to college without all the knowledge that we have from high school, then what is the use of going? It would also drop motivation for the upcoming, knowing that the twelfth grade won’t be able to be taken anymore. Also bringing down students dreams of being what they want to be when they grow up. It would be a disappointment to see that students won’t be able to fulfill their dreams. However some students think the twelfth grade should be eliminated because some students don’t go to their classes. On the contrary they are wrong because there are some students that come to class and care about their grades. In conclusion, I still believe the twelfth grade should not be eliminated because some classes have to be taken senior year, they won’t have to play catch up and they will be prepared for college. Now ask yourself, ‘Am I ready for college?’

How to Write an Essay on Globalization

How to Write an Essay on Globalization Creating your own piece of work, first of all, requires well-planned work process. To start with, it is recommended to build up an outline for your essay. Let us use as an example the topic â€Å"The opportunities that globalization provides will lead to a more equitable world†. The structure we are going to offer is typical and standard, that is: introduction, body, and conclusion. Gather all information concerning the globalization opportunities using different sources like printed books, online libraries, journals or have an interview with qualified experts in this area. While getting acquainted with the notion of globalization, you can already have your own point of view concerning the globalization process and express your own opinion throughout the essay. Start working on the introduction part. In this section you will light up the main points you are going to discuss in your essay and the main ideas of your work. First of all, give the definition of what the globalization is. It is recommended to mention that the end of the 20th and the beginning of the 21st century were notable for changing from the sovereignty of nation to the globalization. You can mention that in such areas like finance, trade, environmental law and others the world community is moving away from the individual state control to the global solutions, networks and policies. Industrialized and developing nations get their own opportunities from the national economic integration. In the body of your essay, you can pay attention to the main opportunities of globalization. The first and the most important opportunity is the free trade and, as a result, the consequential effect on the global economy. The second opportunity provided by the globalization process, can be called TRF’s or transnational regulatory frameworks. As we have already mentioned, there’s less and less individual industry and economy control that nations have. When the question is about global network, it usually assumes more control. At the same time, global network should be also concerned about the welfare of both nations each taken separately and for the global community in general. The third and the last opportunity of globalization to mention, is the rights’ institution of intellectual property. As we see, the global community becomes more and more limitless, copyrights honoring within a nation state becomes more and more inadequate. Thus, rights of intellectual property were established in order to provide world copyrights with protection. In the conclusion part, you can summarize what has been already said and express your own opinion concerning the problem which will be the main point of your essay.