Photovoltaic cells Research Paper Example | Topics and Well Written Essays - 1500 words

Photovoltaic cells - Research Paper Example PV cells energy conversion efficiency has now crossed mark of 20 percent. Several companies, universities and research institutions are doing intense research and development work to reduce the cost further so that its economics fare favorably to other competing energy systems. There has been considerable headway in the research and it is quite likely that it will become one of the most prominent technologies among all renewable sources of energy in next 10 years. Being eco friendly, it has the capacity to meet the current and future energy needs of mankind. Introduction Photovoltaic Cell is a technique to generate direct current through solar radiation using semiconductors. The PV cell technology is useful to produce electricity particularly, at the location where grid system is not available. This paper will study the technology, types of photovoltaic cells, current status, its economics, engineering issues, technological advances, future scope and the direction that the industry m ake take. Off-the-Grid Systems Off-the-grid system is useful when electricity demand cannot be met through grid due to its isolated locations. The benefit of the off-the-grid system is that it is self reliant, not dependent on any outside source, using some renewable source of energy such as solar. ... Solar radiation falls on PV cell to energize the electron producing DC current. Inverter converts DC current to AC. Energy is stored in array of batteries. The efficiency of photovoltaic cells is a key parameter to convert solar energy into usable energy. Van Geet home is a typical off-grid system for generating energy based on solar power. It is a remote location near Denver in Colorado. Several renewable-energy features along with energy-conservation measures have been incorporated in this home. The design of this home is studied as an ideal research home. It has photovoltaic based solar power system. The house is said to have achieved 89% energy savings. The system uses 1000-watt amorphous silicon PV with a tracking controller. It surpasses the norms of 70% HVAC and energy savings for Building America research homes. It has been now recognized as a model home and taken for further study and research as energy saving designs in US. (Barley et al 2004) Below mentioned diagram shows a typical off-grid energy system. Source: http://homepower.com/basics/solar/#MainDCDisconnect Mobile homes also use similar PV based energy system to meet their energy needs. Major components in such systems are PV Cells, Charge controller, Battery Bank, and inverter. PV Cells Working of Photovoltaics Solar energy is converted to electricity through photovoltaics. The technology exploits the photoelectric property of certain material that absorbs photons of light to release the electrons. These free electrons cause electric current to flow that can be used for our needs (Knier 2002). PV Cell is a chief component and the heart of such energy systems. More than 50 percent of the cost of the energy system is attributed to PV module. For this reason, the

Persuasive speech on child sex abuse Essay Example | Topics and Well Written Essays - 750 words

Persuasive speech on child sex abuse - Essay Example The immediate impact could be adverse, but in the long run, the future of these children is put into test especially the kind of adult people they become. III. National Child Abuse and Neglect Data System (NCANDS) in 2007 reported that of all the cases confirmed or substantiated as either child neglect or abuse, 9.3 percent of them were related to sexual abuse (â€Å"The national centre for victims of crime† web). These figures translated to a total of 83,800 victims in that year alone. This is a worrying trend in the modern world, despite reports indicating of a declining trend in this problem. This number represents a high number of children who have to suffer for no cause under the arms of people who are supposed to be offering them protection and love. Such reality should raise alarm to all of us since at one particular time we will be parents in case we are not are already. None of us I am sure would want their children to suffer sexual abuse or molestation. IV. Thesis Statement: due to the numerous negative effects associated with child abuse, there is needed to implement laws that will ensure that children are treated properly without worry. First I will discuss the effects of child sexual abuse, followed by proposed solutions to the problem, which would be focused on promoting good treatment among the children. Finally, I will share on the various benefits associated with adopting laws meant to oversee proper treatment of children in the society. I. Disturbing figures indicate that 1.6% or 16 out of every one thousand children suffer from rape cases, as reported by the Bureau of Justice Statics report. Annually, close to 16% of the youth in the United States are sexually abused. Results from different studies in 1986, 2000, 2002 and 2005 reveals similar results that 63% of women who had suffered sexual abuse by a family member also reported to have been