Construction resources Essay Example for Free

Construction resources Essay Construction resources make use of physics in many of their products. Two that I have picked are solar collectors and their use of insutation. Insulators have the purpose of preventing conduction, convection and radiation to unwanted areas. There are a wide range of techniques and materials used in doing this and I am going to look in depth at this idea. The company uses solar collectors in many different ways, their main purpose is to collect solar energy and heat energy. They can be used to heat and power many different appliances. Photovoltaic cells: Photovoltaic cells transfer the energy carried by the electromagnetic waves that make up sunlight directly to an electrical circuit in order to make a current flow. Light excites electrons to move from one layer to another through semi conductive silicon materials. Only a fraction of a volt is produced so a large array is needed to produce appreciable currents, usually about 20W to 100W. The Photovoltaic cells produce DC current so if alternate current AC is desired then an inverter is required. AC form is commonly available from the mains. Solar cells: Sunlight may also be used to heat water directly. This can be done in two ways, water can be circulated through pipes which run through the back of the solar cells, producing water at around 60oC suitable for household use. The other method is to focus sunlight from a large are to a small spot using an array of mirrors, this can produce temperatures of up to 4000oC and its quite feasible to produce power stations from this, however it has not been implemented yet. Here is on way in which the hot water can be used, this is quite economical and environmentally friendly. Solar panels are quite versatile and can be put on many roofs of simply in the garden, which makes them popular when it comes to heating swimming pools of hot water for showers. Any material that is a poor conductor of heat and electricity can be used as an insulator. Thermal insulating materials reduce the flow of heat between hot and cold regions. Thermal insulation may have to fulfill one or more of three functions: to reduce thermal conduction in the material, in which heat is transferred by electrons; to reduce thermal convection currents, which can be set up in air- or liquid-filled spaces; and to reduce radiation heat transfer, in which thermal energy is transported by electromagnetic waves. These are three ways in which heat energy can be transferred. Conduction, where heat energy is transferred through solid materials, metals are normally the best conductors. There are a number of factors that affect thermal conductivity. Increasing the area of the cross-section of the solid through which hear flows increases the rate of flow, however increasing the thickness of the wall decreases the flow of heat. Provided that a steady state has been reached (where the temperature of any point is not changing through time) then the rate of flow of heat ? Q/? t is given by: ?Q/? t A ? T/? x Besides the physical dimensions of the materials, another factor affecting rate of flow is the properties of the material, the Thermal Conductivity of the materials ? through which the heat energy is travelling is the constant of proportionality in this relationship, so:?Q/? t = -? A ? T/? x The units for thermal conductivity are watts per metre per kelvin. The Quantity ? Q/? t is called the temperature gradient. On my visit to Construction resources I noticed that they have used these Physical conclusions in there insulation. One in particular is Homatherm a wall and roof insulator. The slabs are thick which means less flow of heat, and have a thermal conductivity is only 0. 04 W/mK. Conduction in terms of particles: The particles in metals and non-metals are arranged differently, which gives them their different characteristics. In a non-metal the particles have forces between them that can be described like springs. When heat is delivered to the solid the oscillations of the particles being heated will increase in amplitude. For heat to be conducted the neighboring particles must also receive the extra energy, as particles oscillations increase in frequency the neighboring particles also gradually increase in frequency as heat is transferred to them. This is a very slow process. In a metal the arrangement is different, metallic boding occurs between metal atoms where a sea of delocalized electrons hold the positive metal ions together in a lattice. It is these free electrons that are responsible for the high conductivity character of metals. When a metal is heated the metals ions vibrate with an increase frequency. When an electron hits these ions with extra energy, they receive this extra energy and move faster. This electron can then travel to another parts of the lattice, to an ion that hasnt received any of this heat energy and collide with it, transferring its energy to this ion. Now that ion has extra energy and vibrates with a greater frequency. This process is a lot faster as there are many electrons in a metal lattice. U-Values: Architects and heating engineers use U-Values to calculate the flow of heat energy through building materials. The U-Values is quoted for a given thickness of a particular material, and is based on actual measurements made using the material. The U-Value is defined as: U-value = Rate of energy flow Area X Temperature difference Construction resources uses this knowledge of U-Values when designing building materials to reduce the energy wasted in the form of heat going out of the build and to achieve the ultimate goal of reducing CO2 emissions. But there are obvious limitations with reducing thermal conductivity, you can only reduce it to a certain amount, 0. 025 in air, so there will always be heat loss. Also too much insulation in the house will lead to what construction resources refers to as internal pollution. This has lead to construction resources researching in trying to lower the energy that is used to build and transport he construction materials. Bibliography: Microsoft Encarta Heinemann Advanced Science Salters Horners AS Advanced Physics Strengths and Limitations of Photovoltaic cells: Since one photovoltaic cell only produces a small fraction of a volt, large arrays are required to produce appreciable voltages. This requires a lot of space and the cells need to be in a place where no shadows will be cast on them. This limits what they can be used for. Also the amount of power produced by the photovoltaic cells directly depends on the amount of sunlight, so they cannot be relied on to produce power for something that constantly needs it. The only way this can be overcome is if some power was stored for a rainy day. But this again would take up space. Also an array of solar collector will be expensive and have a long pay back time. However it is environmentally friendly and after the pay back time, savings can be made. Also photovoltaic cells can be made look attractive depending on where they are placed. Strengths and Limitations of solar cells: The solar cells have similar limitations to the photovoltaic cells in regards to positioning and cost but a small array is only required to produce enough hot water for something like residential showers or central heating. This is economical and environmentally friendly and solar cells are quite versatile.

In The Fruit at the Bottom of the Bowl by Ray Bradbury and The Tell :: English Literature

In The Fruit at the Bottom of the Bowl by Ray Bradbury and The Tell Tale Heart by Edgar Allen Poe both authors have to convince the reader that the main character is mad. How do they do that? Which portrayal is more effective? Why? This essay will explore which madman is portrayed the best. Both stories deal with an obsession and a madness of some sort. In ' The Fruit at the Bottom of the Bowl' by Ray Bradbury the main character is William Action who frantically cleans trying to cover up the murder. Not knowing he is going mad. In ' The Tell Tale Heart' the man has an obsession with his masters eye, which drives him mad but he does not believe himself that he is mad. In 'The Tell Tale Heart' the characters motive is his masters "vulture's eye" which is shown by saying " I think it was his eye! Yes, it was this! Also when he says " One of his eyes resembled that of a vulture. In 'The Fruit at the Bottom of the Bowl" the characters motive is that his wife is having an affair this is shown by the character saying, " Where's my wife, Huxley? " and " I need one. I can't believe Lily's gone that she-". The first characters motive suggests madness because why would you want to kill a man just because of his eye. The second one stands to reason because if you find out your wife was having an affair the first thing you would want to do is kill the other person In ' The Tell Tale Heart' the narration is first person, so that the readers can put themselves there, the character addresses them directly, It also give you an insight into the characters most inner thoughts and feelings. In ' Fruit at the Bottom of the Bowl ' the narration is third person with stream of consciousness. This allows you to feel as thought you are watching the events unfold and that you become omnipotent. The narration method of ' The Tell Tale Heart' is more effective and convinces the reader of the main characters madness because you can tell the characters most inner thoughts and feelings as he addresses you unlike ' Fruit at the Bottom of the Bowl ' which only shows you the actions and doesn't give you an insight to his mental well being. In 'Fruit at the Bottom of the Bowl ' the characters attitude to the dead body and crime is one of calmness, although he was still conscious that his actions could be traced via his fingertips on the

Ontario Teacher’s Pension Plan Essay

Ontario Teacher’s Pension Plan Board: Hedging Foreign Currency Exposure Ontario Teacher’s Pension Plan Board: Hedging Foreign Currency Exposure Issue Identification The Ontario Teacher’s Pension Plan (OTPP) is a defined contribution plan that was created in 1917 to provide and administer a pension plan for Ontario school teachers. Sponsored by the Ontario Government and the Ontario Teacher’s Federation, the plan currently supports 343,000 teachers, former teachers and pensioners. The recent government decision to eliminate the 30% constraint on foreign investments and the increased volatility in the currency market has prompted the OTPP Investment Committee to address the following: 1. Whether to continue the International Equity Swap Program 2. Whether to administer changes to the Foreign Exchange Hedging Policy Goals and Objectives In order to come to a decision, it is necessary that any solution put forth must align with the goals and objectives of the fund. OTPP is a long-term fund determined to minimize risk, costs and the additional contributions required to fund the plan while maximizing its returns. OTPP Investment Strategy In the early 1990’s the OTPP board realized that it was essential to begin investing abroad to diversify risk and to capitalize on international opportunities to achieve greater returns, given the size of the fund. However, it was not until 1996 that the Foreign Exchange Hedge Program (FX Hedge Program) was implemented in response to a significant rise in currency exposure. As the fund faced increased foreign currency risk, risk management became essential and thus, a hedging policy of 50% of its foreign currency exposure was introduced. Due to the fact that OTPP has a continual commitment in supporting its pensioners, it must expose itself to limited risk and effectively hedge against any unexpected changes in its investments. Hence, a conservative policy of hedging 50% of foreign exchange exposure was enforced. Additionally, the International Equity Swap Program (IE Swap Program) was implemented as a solution to the government restriction of 30% ownership of foreign investments. Since most assets were tied up in non-marketable Ontario Debentures, a swap program enabled OTPP to reallocate its assets. OTPP Performance Evaluation The strategic decision to diversify beyond Canada and into global markets has proved to be beneficial to the OTPP investment portfolio. It has contributed substantial value to the fund over the 10 year period (1995-2005) by reducing potential losses, since five of the six foreign currencies appreciated against the Canadian dollar. For the past 15 years, OTPP investments have also consistently outperformed the benchmark rate of returns, generating a 10-year average rate of return of 11. 4% and a gross return of $15. billion over benchmark returns. Despite the portfolio’s negative rate of returns in 2001-2002, it has still produced considerable investment growth in relation to the benchmark, demonstrating the strength of OTPP’s investment policies in risk management. However, since interest rates have declined by approximately 3% (1990-2004), the value of the pension fund has increased. This has resulted in larger amount of payments made to pen sioners. Additionally, the demographics of the OTPP plan membership have changed significantly over the past 30 years. The ratio of active members per retiree has decreased from 10:1 in the 1970s to the present ratio of 1. 6:1. Moreover, the expected years retirees rely on the pension have also increased to 29 years. All these factors have exerted a great deal of pressure on the pension plan to sustain its funding with contributions from fewer working teachers. With the foreign currency market being increasingly volatile, OTPP is concerned regarding its future ability to support pension payments. Decision Criteria The Investment Committee must consider the following criteria when deciding whether to implement changes to the International Equity Swap Program and Foreign Exchange Hedging Policy: the fund’s exposure to foreign exchange risk, transaction costs, and an alignment of goals and objectives of the fund. Alternative: Although OTPP has performed well in the past, the future outlook of the pension plan remains uncertain. Therefore, OTPP has four alternatives to the future direction of the fund. OTPP can continue or discontinue the IE Swap Program and maintain or revise the current 50% FX Hedge Policy. Continue/Discontinue the Swap Program Previously, the swap program was used as a means to bypass the government restriction on foreign investment. With the regulation being lifted, OTPP has to now evaluate whether the swap program remains necessary. The program has allowed OTPP to reallocate their assets cost-effectively as it eliminates OTPP’s cost of transacting directly in foreign exchange market. Moreover, since OTPP does not gain ownership of the securities, it has reduced the amount of cash required and limited its risk by transferring the risk to counter-parties (UBS, Credit Suisse, JP Morgan, etc. ).

The Best American President Abraham Lincoln Essay - 550 Words

There have been forty-four U.S. Presidents over the past two hundred and twenty four years. Some were very successful. Of those few historians, Abraham Lincoln was one of the greatest presidents that ever live. He is responsible for preserving the union, freeing the slaves, and enacting various new policies. Lincoln was a president that never gave up and put his people first. He was strong, confident and believes in his principles. Some of the presidents were least successful. Of those few historians, Herbert Hoover wasn’t very successful while he was in office. He was considered to be a terrible president because an awful thing occurred on his watch. Which was the Great Depression. Lincoln did not agree with slavery ever since he was†¦show more content†¦Abraham Lincoln started all that before he was in office, so imagine what he did when he became president of the United States. When Lincoln was elected there was a long series of policy clashes between the South and the North. The clash wasn’t just about slavery. It was a clash of elites. The Northern elite wanted economic expansion. Such as, free land; free labor, free market, and much more. Lincoln had all of this in mind, even the slaves. The slaves saw Lincoln as their ticket to freedom. The South was for slavery, so when they notice Lincoln was trying to abolish slavery they started to secede from the union. Lincoln tried to get some of the states back and more seceded. The confederacy was formed; the civil war was on. The Civil war was one of the bloodiest in human history up to that time. In September 1862, Lincoln issues his preliminary Emancipation Proclamation, it was a military move, giving the south four months to stop rebelling, threatening to emancipate their slaves if they continued to fight, promising to leave slavery untouched in states that came over to the North. 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