Energy, Technology & Sustainability - Report Example

Question Distance of the Neutral axis from the upper edge: Y= ay Total Area Total Y = 56100 1620 = 34.63 mm Moment of Inertia about upper edge = Iuu = Total Iself + Total ay2 Iuu = 53500 + 2720500 = 2774000 Iuu = Ixx + Total Area * y*y 2774000 = Ixx + 1620 * 34.63 * 34.63 Ixx = 831277.78 Bending Moment = 500 Nm = 50000 Nmm M/I = Ft/Yt 500000 / 831277.78 = Ft /25.37 Ft = 42.18Nmm2 Fc/Ft = Yc / Yt Fc = Yc * Ft / Yt Fc = 34.63 * 42.18 / 25.37 Fc = 57.58 Nmm2 Question 2: IMPORTANT: Please note that generally a down word shear force on the right hand side of a beam element is considered to be a positive shear force for plotting the shear force diagram. The opposite sign conventions are also used. Please ensure what sign conventions are used in your case. 1 P1 = 150 N, W1=50 N/m Length = 8 m . Shear Force Diagram: 2. Shear Force Diagram: 3. Shear Force Diagram: Question 3: 1. Bending Moment Diagram: Bending Moment at X = M = -wx * x/2 Mx = -w/2 * x*x If x = 4m then Mx = -45/2 * 4 * 4 = -360Nm 2. Bending Moment Diagram: 4. ω0 = Initial Velocity = 0 Nuber of Revolutions of the wheel = 6 Total angle turned by the wheel = Ѳ = 6 * 2 π = 12 π Ѳ = ω0 + ½ * α * t * t 12 π = 0 + .5 * α * 10 * 10 Angular Acceleration = α = 0.24 π rad/sec² Angular Velocity = ω = ω0 + α * t Angular Velocity = 0 + 0.24 π * 10 Angular Velocity = 2.4 π rad/sec Diameter = 0.4 m Number of revolutions = 6 Total distance travelled = 2 * π * R * 6 = 2 * π * 0.2 * 6 = 7.53m Linear Velocity Vc = r* ω Linear Velocity = 0.2 * 2.4 π = 1.50 m/s Linear Acceleration = r * α = 0.2 * 0.24 π = 0.150 m/sec² Ways of Heat Transfers Solar Energy: The sun is the main source of thermal energy, it supplies the earth with the heat and light that are essential to life. Inside the Sun the pressure and temperature is sufficient for nuclear fusion reactions to occur. The hot surface of the Sun radiates the electromagnetic wave energy(Hi, Para 1). This form or energy transferred to the Earth through near vacuum of the space. The Solar energy is transferred to the earth in two ways: (1) in the form of heat (or thermal energy), and (2) in the form of light energy. Solar thermal technologies uses the solar heat energy to heat substances (such as water or air) for applications such as space heating, pool heating and water heating for homes and businesses (Hi, Para 2). Often the products used for this application are called solar thermal collectors and can be mounted on the roof of a building or in some other sunny location. The solar heat can also be used to produce electricity on a large utility-scale by converting the solar energy into mechanical energy. The Solar is used in the three following ways: 1. Solar Cells: Solar cells are semi-conductor devices formed into p-n junction in silicon. p refers to silicon doped with a substance which results in the absence of a chemical bond electron and n refers to and excess electron to chemical bonding requirements. When these doped mixtures in silicon are brought into contact charge migrates from one side of the junction to the other and sets up a voltage of ~0.5 volts. The effect of the light photons is to release bound electrons in the junction so that the 0.5 V can drive a current in an external circuit (Ho, Para 2). The energy comes from interaction with light photons. There is again a threshold set by the minimum energy to release a bound electron. The more photons/second (brighter) the more current can be driven by the solar cell. Power output related to solar power input: Expressed in peak watts out for 1000W/cm2 solar energy input. Typical efficiency is 10% rest of solar power input results in increased heat energy of cells i.e. higher temperature that reduces efficiency of electrical power generation. 2. Solar Water Heating: (Image Source: www.darvill.clara.net) In Solar heating the solar heat energy is transferred to the water in the glass panels on the roof (Ho, Para 2).. 3. Solar Furnace: (Image Source: www.darvill.clara.net) A Solar furnace uses a huge number of mirrors to transfer the suns energy into a small space and produce very high temperature. Advantages of Solar Power: It is free Solar power can be used where there is no access to electricity. Disadvantages of Solar power: Solar power does not work at night. It is expensive to build. It is very unreliable as it depends on the climatic conditions. Hydroelectric Energy: Hydroelectric energy means generation of electricity from water power. More that 35 nations today obtain their 2/3 of the power from water. 20% of the worlds electricity comes from water. (Image Source: http://www.darvill.clara.net/altenerg/hydro.htm) Hydroelectricity is generated when the water flows because of the conversion of the gravitational potential energy of a stored volume of water to kinetic energy at the place where a device to convert this kinetic energy into mechanical energy is located. In the Hydroelectric Dam the water is stored in the reservoir. The water then travels through the penstock whee it gains kinetic energy. The kinetic energy of the water is transferred to the turbine which in turn rotates the shaft connected to the generator. The generator contains copper coils that produce an alternating current. After the generator generates the AC current it is converted to a high voltage by using a transformer. This helps in easier transfer of electricity. Advantages of Hydroelectricity: It produces low pollution It is renewable and inexpensive The lake water can be shared for irrigation purpose as well as drinking prupose Disadvantages of Hydroelectricity: Downstream river temperature rises Sol erosion Changes in flora and fauna Nuclear Energy: Nuclear power is generated using Uranium, which is a metal mined in various parts of the world. Some military ships and submarines have nuclear power plants for engines. Nuclear power produces huge amount of energy from comparatively small amount of fuel. The nuclear reactor works in the same way as the fossil fuel burning stations except that the chain reaction generates the heat. The reactor uses Uranium rods as fuel and the heat is generated by nuclear fission. The neutrons are bombarded on the nucleus of uranuim which split in half and release the heat energy. This generated heat is then transferred to water which in turn generates steam. The staem then transfer this energy to the turbines that are connected to generators. Nuclear power plants are often built around coasts so that sea water can be used for cooling purposes. The reactor is controlled by control rods, made of boron, which absorbs neutrons. When the rods are lowered into the reactor the fission process slows down. Advantages of Nuclear Energy: The production cost is the same as conventional fuels It does not produce smoke or carbon dioxide Produces huge amont of energy from small amount of fuel Produces small amount of waste Neclear energy is reliable. Disadvantages of Nuclear Energy: Although very less waste is generated, it is very very dangerous. A lot of money has to be spent on safety. Mechanical Energy Transfer: In Mechanical type Work is the transfer of energy. Work is the amount of energy transferred into or out of a system, not counting energy transferred by heat conduction. In an automobile engine most of the energy generated by the burning of the fuel is directly converted into heat energy which is then carried away by exhaust gases and the air flowing over the radiator. In a typical automobile engine the fuel is burned inside a cylinder. By doing this the chemical energy is converted into mechanica energy and the piston is pushed away. Hence the chemical energy is transferred to the piston which in turn is connected to the crank shaft. The energy generated at the crank shaft is transferred to the wheels throufg a gear box mechanism. (Image Source: http://www.engr.colostate.edu/~dga/mech324/handouts/cam_stuff/four_stroke_cycle.jpg) Conclusion: In this report we have seen the four types of energy transfers. The Sun form the main source of energy wich is directly or indirectly responcible for other forms. The solar energy even though freely available has restricted applications because of expensive equipment and unreliability. The fossil fuels are fast being consumed. The nuclear energy seems to be the solution however managing the waste is an issue. The best current option seems to be Hydroelectric energy. References: http://www.freesolaronline.com/ http://www.darvill.clara.net/altenerg/nuclear.htm http://www.lightandmatter.com/html_books/2cl/ch03/ch03.html Read More