Energy Harvesting Dissertation Example | Topics and Well Written Essays - 2000 words

Energy Harvesting - Dissertation Example Energy harvesting, therefore, can be defined as â€Å"The process in which energy is captured from a system’s environment and converted into usable electric power† (Maxim, 2011). The law of conservation of energy is the basis for energy harvesting. Energy can be converted from one form to another and the total amount of energy in an isolated system remains the same (Clark, 2004). Therefore, energy whether in form of wind, kinetic, chemical and others can be converted to electrical energy. 2. METHODS OF HARVESTING ENERGY Energy harvesting produces electric energy from ambient energy sources, present in large and small systems. Recovering a fraction of this energy can have a significant economic and environmental impact. These systems widely vary in sizes. On the macro scale, hydro electricity, tidal power, solar panels and wind turbines can produce MegaWatts. On a smaller scale, immediately available energy such as vibration, heat and light energy can be used to produce milliWatts. A typical energy harvesting system converts energy from the source and stores that energy. Capacitors are used in large scale systems, whereas, batteries are used in small scale systems for storage of energy. ... Photovoltaic cells, which are made up of silicon are used to convert solar energy into electricity. Most of these photovoltaic cells operate at an efficiency of less than 15 % (Asimov, 1969). The maximum theoretical efficiency attainable, however, is only 32.3 % (Clark, 1974). Solar energy is also indirectly used to produce electricity by concentrated solar power plants. The solar collectors are used to concentrate or focus sunlight onto a receiver that heats a liquid to produce steam, which in turn is used to produce electricity in the same way coal or fossil fuel plants do. 2.2 Wind Energy Wind turbines are used to harvest electrical energy from the wind. The wind passes over the blades of wind turbines, which in turn produces a turning force. The rotating blades turn the shaft which passes through the gearbox. The gearbox increases the rotational speed for the generator. The generator uses magnetic fields to convert the rotational energy harvested from the wind into electrical ene rgy. Wind farms, which are clusters of wind turbines, are used to harvest electrical energy from wind. The minimum wind speed for generating electricity is 4-5 m/s and the theoretical maximum power that can be extracted from the wind is 59.3 %. In reality this figure is usually around 45 % maximum for a large turbine. Wind energy has great potential for energy harvesting in the future and even smaller turbines (50-150 watts) are available for household connection (Golding, 1976). Energy harvested from the wind largely depends on siting of the wind farm. 2.3 Hydroelectric Hydroelectric systems create energy by harvesting energy by force of water. Water is collected in a dam or a reservoir. The water near the bottom of the reservoir is forced by the pressure of the water above it to be

Paper for Reading for Research Example | Topics and Well Written Essays - 500 words

For Reading for - Research Paper Example The idea that Donny’s father entailed four wives, whereby three consisted of whites demonstrated that he wanted to manifest to the parents that his race never prevented him from accessing love from both divides, especially the whites. The author demonstrates that their family stayed disowned by the grandparents, an issue that presented cruelties in their life. This expounds that racial discrimination inflicts torture to persons that fall prey and makes their stay miserable. The author also demonstrates that places like Hyde Park entail reservations as being settlements for biracial persons (Terry). This intents demonstrating that US consist of allocated places inhabited by certain half-colored persons, which manifests discrimination at its heightened levels. Donny remembers the grandmother threatening that he should shower well because his being black-skinned never prevented her knowing whether he was clean. The author also recalls numerous references as being ‘nigga’ by children that he encountered when playing (Terry). ‘Nigga’ meant that the children never recognized that Donny emanated from a mixed race, but dominantly noted the African as opposed to the white race, a case that reveal s ill racial relations exhibited by persons in US. Kwei-Armah explains that his immigration into US culminated to acquire a deepened knowledge concerning racial relations. For instance, the author notably expounds that race entails a subject of intense reference amongst the US compared to its minimal consideration in Britain (Kwei-Armah 64). I render support to the author’s sentiment on the bases that US presents an ill perception regarding to the Afro-Americans together with other minority groupings in the state. In addition, the author explains that US natives encounter hectic times trying to categorize persons of African-Britain descent because of the dominant American