Comparative Formal Analysis of Artworks

The rise of civilization follows hen humankind decided to build for themselves a more stable and promising life. Culture shifts then occurred between the Paleolithic and Sumerian periods due to the civilization of Mesopotamia, and humankind developed a polytheistic culture In which rituals and worshipping came Into play. Statuettes of Worshippers (ca. 2700 BCC. ) from the Square Temple at Susquehanna, Iraq, were one of the representations of the Sumerian culture. The emphasis on different body parts of the sculptures signifies a shift in culture due to the rise of civilization.Life during the Paleolithic period was plain tit meager cultural resources. Venus of Wildflower is a tiny three-dimensional female figure, approximately 4 1/4†³ high, created with simple sculpting tools, probably something similar to a chisel, and a piece of Limestone. The sculpture displays a woman with her pair of thin forearms resting on her breasts and a huge belly hanging above her pubic triangle. The roundness of her body parts dominates the whole sculpture.The tools and media available at that time period set a limit on the techniques of creation, leading to the rugged coarseness of this sculpture. In imprison with a normal human figure, Venus of Hellbender Is exaggerating out of proportions, which seems to misrepresent women from the Paleolithic period. The title of this sculpture, Venus, may be an attempt to explain the distortion and the nakedness of her body. Venus, who is the goddess of beauty and love according to the Roman mythology, might be depicted as the goddess of fertility during the Paleolithic period.The figure, lacking facial features which may be covered by the braided hair, leads the audiences' focuses to her enormous body parts, especially ere breasts and belly. Her belly bulging out may suggest pregnancy while the conspicuous outline of her pubic triangle may represent fertility. From another point of view, Venus of Wildflower, with the fullness of her body , may also be a symbolization of desire for abundance. The Intention of this relatively small sculpture might have been some kind of amulet men carried around or maybe It even acted as a motivation for men hunter to hunt for abundant amount of food.In this sculpture, the emphasis of women's delectate body parts Implies that mankind in the Paleolithic period tends to create what they desire, in the case of The way of living, as well as the culture, changed with the rise of civilization in Mesopotamia. No longer did people in Sumerian period live a hunter's live; instead, they worked to create a more stable life by farming and herding, which was an evidence of civilization. Significant inventions during the Sumerian period equipped people with improved tools and media to create sculptures with better techniques.Apparently, the Statuettes of two worshippers have a smoother surface and texture comparing to Venus of Wildflower. The material of the statuettes was soft gypsum inlaid with s hell and black limestone while Venus of Wildflower was created with limestone only. Clothing and facial features were carved onto the statuettes of the two worshippers unlike the sculpture of Venus of Wildflower. The men wear a fringe skirt with a belt while the women wear a long robe. And instead of enormous breasts and belly, these statuettes have in common outstanding, round eyes.This reveals a cultural meaning of the Sumerian period that gender is differentiated not by sexual body features, but by appearance and clothing. Comparing to that of the Venus of Wildflower, the statuettes have a more normal proportion, despite the size of their eyes and hands. Although these statuettes of worshippers were manufactured in a wide range of sizes, they all have a common body gesture: having a neutral facial expression and standing upright with their small hands together placed in front of their chests.The position of the hands, along with their head slightly tilted upwards, may suggest tha t they are praying or begging for something from deities or any other gods and goddesses they believe in. Also, the small hands of the statuettes may imply that they have a limited ability and their huge, pitiful eyes seem to represent a desire for something in return; for instance, help from the deities to cure a disease.These statuettes of worshippers were found in homes as votive figures probably because common people were not allowed to visit the Gujarat in that time period. Not only do these statuettes signifies a civilization, they also mark the shift of culture and the development of religions and beliefs. The similarities and differences of Venus of Wildflower and the Statuettes of two reshipped from two different historical time periods display a major change in the culture along with the way of living among a group of people in a society.Moreover, the emphasis on certain body parts can be viewed as the main symbolization of the individual sculpture. In this comparison, the breasts, belly and pubic area of Venus of Wildflower represent fertility and abundance while the eyes and hand gesture of the Statuettes of two worshippers symbolize belief and desire for help. In general, different artworks created in different historical time periods usually reveal a major revolution or a shift in culture.

Street Light

INDEX |S.NO |TITLE |PAGE NO | |1 |Introduction |1 | |2 |Solar Energy |4 | |3 |Photovoltaics |24 | |4 |Solar Cell |28 | |5 |Solar Roadway |51 | |6 |Component description |55 | |7 |Working of Project |82 | |8 |Conclusion |86 | |9 |Images |91 | |10 |Bibliography |93 | INTRODUCTION INTRODUCTION: Solar energy, radiant light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies.Solar energy technologies include solar heating, solar photovoltaics, solar thermal electricity and solar architecture, which can make considerable contributions to solving some of the most urgent energy problems the world now faces. Solar power is the conversion of sunlight into electricity, either directly using photovoltaic (PV), or indirectly using concentrated solar power (CSP). Concentrated solar power systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. Photovoltaics convert light into electric cur rent using the photoelectric effect. A Street light, lamppost, street lamp, light standard, or lamp standard is a raised source of light on the edge of a road or walkway, which is turned on or lit at a certain time every night.Modern lamps may also have light-sensitive photocells to turn them on at dusk, off at dawn, or activate automatically in dark weather. In older lighting this function would have been performed with the aid of a solar dial. It is not uncommon for street lights to be on posts which have wires strung between them; such as on telephone poles or utility poles. New street lighting technologies, such as LED or induction lights, emit a white light that provides high levels of scotopic lumens allowing street lights with lower wattages and lower photopic lumens to replace existing street lights. Photovoltaic-powered LED luminaires are gaining wider acceptance.Preliminary field tests show that some LED luminaires are energy-efficient and perform well in testing environme nts. This project is a LED based Solar Lights is an automatic street lightening system using a LDR and 6V/5W solar panel. During day time, the internal rechargeable battery receives charging current from the connected solar panel. Here IC 555 is wired as a medium current inverting line driver, switched by an encapsulated light detector (LDR). When ambient light dims, the circuits drive the white LEDs. When the ambient light level restores, circuit returns to its idle state and light(s) switched off by the circuit. Block Diagram: SOLAR ENERGY SOLAR ENERGYSolar energy, radiant light and heat from the sun, has been harnessed by humans since ancient times using a range of ever-evolving technologies. Solar energy technologies include solar heating, solar photovoltaics, solar thermal electricity, solar architecture and artificial photosynthesis, which can make considerable contributions to solving some of the most urgent energy problems the world now faces. Solar technologies are broadly characterized as either passive solar or active solar depending on the way they capture, convert and distribute solar energy. Active solar techniques include the use of photovoltaic panels and solar thermal collectors to harness the energy.Passive solar techniques include orienting a building to the Sun, selecting materials with favorable thermal mass or light dispersing properties, and designing spaces that naturally circulate air. In 2011, the International Energy Agency said that â€Å"the development of affordable, inexhaustible and clean solar energy technologies will have huge longer-term benefits. It will increase countries’ energy security through reliance on an indigenous, inexhaustible and mostly import-independent resource, enhance sustainability, reduce pollution, lower the costs of mitigating climate change, and keep fossil fuel prices lower than otherwise. These advantages are global.Hence the additional costs of the incentives for early deployment should be co nsidered learning investments; they must be wisely spent and need to be widely shared†. The Earth receives 174 petawatts (PW) of incoming solar radiation (insolation) at the upper atmosphere. Approximately 30% is reflected back to space while the rest is absorbed by clouds, oceans and land masses. The spectrum of solar light at the Earth's surface is mostly spread across the visible and near-infrared ranges with a small part in the near-ultraviolet. Earth's land surface, oceans and atmosphere absorb solar radiation, and this raises their temperature. Warm air containing evaporated water from the oceans rises, causing atmospheric circulation or convection.When the air reaches a high altitude, where the temperature is low, water vapor condenses into clouds, which rain onto the Earth's surface, completing the water cycle. The latent heat of water condensation amplifies convection, producing atmospheric phenomena such as wind, cyclones and anti-cyclones. Sunlight absorbed by the o ceans and land masses keeps the surface at an average temperature of 14  °C. By photosynthesis green plants convert solar energy into chemical energy, which produces food, wood and the biomass from which fossil fuels are derived. The total solar energy absorbed by Earth's atmosphere, oceans and land masses is approximately 3,850,000 exajoules (EJ) per year. In 2002, this was more energy in one hour than the world used in one year.Photosynthesis captures approximately 3,000 EJ per year in biomass. The technical potential available from biomass is from 100–300 EJ/year. The amount of solar energy reaching the surface of the planet is so vast that in one year it is about twice as much as will ever be obtained from all of the Earth's non-renewable resources of coal, oil, natural gas, and mined uranium combined. Solar energy can be harnessed at different levels around the world, mostly depending on distance from the equator. [pic] Average insolation showing land area (small black dots) required to replace the world primary energy supply with solar electricity. 18 TW is 568 Exajoule (EJ) per year.Insolation for most people is from 150 to 300 W/m2 or 3. 5 to 7. 0 kWh/m2/day. Solar energy refers primarily to the use of solar radiation for practical ends. However, all renewable energies, other than geothermal and tidal, derive their energy from the sun. Solar technologies are broadly characterized as either passive or active depending on the way they capture, convert and distribute sunlight. Active solar techniques use photovoltaic panels, pumps, and fans to convert sunlight into useful outputs. Passive solar techniques include selecting materials with favorable thermal properties, designing spaces that naturally circulate air, and referencing the position of a building to the Sun.Active solar technologies increase the supply of energy and are considered supply side technologies, while passive solar technologies reduce the need for alternate resources and are g enerally considered demand side technologies. APPLICATIONS OF SOLAR TECHNOLOGY Average  insolation  showing land area (small black dots) required to replace the world primary energy supply with solar electricity. 18 TW is 568 Exajoule (EJ) per year. Insolation for most people is from 150 to 300 W/m2  or 3. 5 to 7. 0 kWh/m2/day. Solar energy refers primarily to the use of  solar radiation  for practical ends. However, all renewable energies, other than  geothermal  and  tidal, derive their energy from the sun. Solar technologies are broadly characterized as either passive or active depending on the way they capture, convert and distribute sunlight.Active solar techniques use photovoltaic panels, pumps, and fans to convert sunlight into useful outputs. Passive solar techniques include selecting materials with favorable thermal properties, designing spaces that naturally circulate air, and referencing the position of a building to the Sun. Active solar technologies incr ease the supply of energy and are considered  supply side technologies, while passive solar technologies reduce the need for alternate resources and are generally considered demand side technologies ARCHITECTURE AND URBAN PLANNING [pic] Darmstadt University of Technology  in Germany  won the 2007  Solar Decathlon  in Washington, D. C. with this  passive house designed specifically for the humid and hot subtropical climate.Sunlight has influenced building design since the beginning of architectural history. Advanced solar architecture and urban planning methods were first employed by the  Greeks  and  Chinese, who oriented their buildings toward the south to provide light and warmth. The common features of  passive solar  architecture are orientation relative to the Sun, compact proportion (a low surface area to volume ratio), selective shading (overhangs) and  thermal mass. When these features are tailored to the local climate and environment they can produce well-lit spaces that stay in a comfortable temperature range. Socrates'  Megaron House is a classic example of passive solar design.The most recent approaches to solar design use computer modeling tying together  solar lighting,  heating  and  ventilation  systems in an integrated  solar design  package. Active solar equipment such as pumps, fans and switchable windows can complement passive design and improve system performance. Urban heat islands (UHI) are metropolitan areas with higher temperatures than that of the surrounding environment. The higher temperatures are a result of increased absorption of the Solar light by urban materials such as asphalt and concrete, which have lower  albedos  and higher  heat capacities  than those in the natural environment. A straightforward method of counteracting the UHI effect is to paint buildings and roads white and plant trees.Using these methods, a hypothetical â€Å"cool communities† program in  Los Ang eles  has projected that urban temperatures could be reduced by approximately 3  Ã‚ °C at an estimated cost of US$1  billion, giving estimated total annual benefits of US$530  million from reduced air-conditioning costs and healthcare savings. [23] AGRICULTURE AND HORTICULTURE [pic] Greenhouses  like these in the Westland municipality of the  Netherlands  grow vegetables, fruits and flowers. Agriculture  and  horticulture  seek to optimize the capture of solar energy in order to optimize the productivity of plants. Techniques such as timed planting cycles, tailored row orientation, staggered heights between rows and the mixing of plant varieties can improve crop yields. [24][25]  While sunlight is generally considered a plentiful resource, the exceptions highlight the importance of solar energy to agriculture.During the short growing seasons of the  Little Ice Age, French and  English  farmers employed fruit walls to maximize the collection of solar energ y. These walls acted as thermal masses and accelerated ripening by keeping plants warm. Early fruit walls were built perpendicular to the ground and facing south, but over time, sloping walls were developed to make better use of sunlight. In 1699,  Nicolas Fatio de Duillier  even suggested using a  tracking mechanism  which could pivot to follow the Sun. [26]  Applications of solar energy in agriculture aside from growing crops include pumping water, drying crops, brooding chicks and drying chicken manure. [27][28]  More recently the technology has been embraced by vinters, who use the energy generated by solar panels to power grape presses. [29]Greenhouses  convert solar light to heat, enabling year-round production and the growth (in enclosed environments) of specialty crops and other plants not naturally suited to the local climate. Primitive greenhouses were first used during Roman times to produce  cucumbers  year-round for the Roman emperor  Tiberius. [30]à ‚  The first modern greenhouses were built in Europe in the 16th century to keep exotic plants brought back from explorations abroad. [31]  Greenhouses remain an important part of horticulture today, and plastic transparent materials have also been used to similar effect in  polytunnels  and  row covers. TRANSPORT AND RECONNAISSANCE [pic] Australia hosts the  World Solar Challengewhere solar cars like the Nuna3 race through a 3,021  km (1,877  mi) course from Darwin to Adelaide.Development of a solar powered car has been an engineering goal since the 1980s. The  World Solar Challenge  is a biannual solar-powered car race, where teams from universities and enterprises compete over 3,021 kilometres (1,877  mi) across central Australia from  Darwin  to  Adelaide. In 1987, when it was founded, the winner's average speed was 67 kilometres per hour (42  mph) and by 2007 the winner's average speed had improved to 90. 87 kilometres per hour (56. 46  mph). [32]à ‚  The  North American Solar Challenge  and the planned  South African Solar Challenge  are comparable competitions that reflect an international interest in the engineering and development of solar powered vehicles. [33][34]Some vehicles use solar panels for auxiliary power, such as for air conditioning, to keep the interior cool, thus reducing fuel consumption. [35][36] In 1975, the first practical solar boat was constructed in England. [37]  By 1995, passenger boats incorporating PV panels began appearing and are now used extensively. [38]  In 1996,  Kenichi Horie  made the first solar powered crossing of the Pacific Ocean, and the  sun21  catamaran made the first solar powered crossing of the Atlantic Ocean in the winter of 2006–2007. [39]  There are plans to circumnavigate the globe in 2010. [40] [pic] Helios UAV  in solar powered flight. In 1974, the unmanned  AstroFlight Sunrise  plane made the first solar flight.On 29 April 1979, the  Sol ar Riser  made the first flight in a solar powered, fully controlled, man carrying flying machine, reaching an altitude of 40 feet (12  m). In 1980, the  Gossamer Penguin  made the first piloted flights powered solely by photovoltaics. This was quickly followed by the  Solar Challenger  which crossed the English Channel in July 1981. In 1990  Eric Scott Raymond  in 21 hops flew from California to North Carolina using solar power. [41]  Developments then turned back to unmanned aerial vehicles (UAV) with the  Pathfinder  (1997) and subsequent designs, culminating in the  Helios  which set the altitude record for a non-rocket-propelled aircraft at 29,524 metres (96,864  ft) in 2001. 42]  The  Zephyr, developed by  BAE Systems, is the latest in a line of record-breaking solar aircraft, making a 54-hour flight in 2007, and month-long flights are envisioned by 2010. [43] A  solar balloon  is a black balloon that is filled with ordinary air. As sunlig ht shines on the balloon, the air inside is heated and expands causing an upward  buoyancy  force, much like an artificially heated  hot air balloon. Some solar balloons are large enough for human flight, but usage is generally limited to the toy market as the surface-area to payload-weight ratio is relatively high. [44] DAYLIGHTING [pic] Daylighting features such as this  oculusat the top of the  Pantheon, in  Rome, Italy have been in use since antiquity.The history of lighting is dominated by the use of natural light. The Romans recognized a  right to light  as early as the  6th century  and English law echoed these judgments with the Prescription Act of 1832. [45][46]  In the 20th century artificial  lighting  became the main source of interior illumination but daylighting techniques and hybrid solar lighting solutions are ways to reduce energy consumption. Daylighting  systems collect and distribute sunlight to provide interior illumination. This pass ive technology directly offsets energy use by replacing artificial lighting, and indirectly offsets non-solar energy use by reducing the need for  air-conditioning. 47]  Although difficult to quantify, the use of  natural lighting  also offers physiological and psychological benefits compared to  artificial lighting. [47]  Daylighting design implies careful selection of window types, sizes and orientation; exterior shading devices may be considered as well. Deciduous trees at the east and west ends of buildings offer shade in the summer and do not block the sun in the winter. [48]  Individual features include sawtooth roofs,  clerestory windows, light shelves,  skylights  and  light tubes. They may be incorporated into existing structures, but are most effective when integrated into a  solar design  package that accounts for factors such as  glare, heat flux and  time-of-use.When daylighting features are properly implemented they can reduce lighting-rel ated energy requirements by 25%. [49] Hybrid solar lighting  (HSL) is an  active solar  method of providing interior illumination. HSL systems collect sunlight using focusing mirrors that  track the Sun  and use  optical fibers  to transmit it inside the building to supplement conventional lighting. In single-story applications these systems are able to transmit 50% of the direct sunlight received. [50] Solar lights that charge during the day and light up at dusk are a common sight along walkways. [51]  Solar-charged lanterns have become popular in developing countries where they provide a safer and cheaper alternative to kerosene lamps. [52]Although  daylight saving time  is promoted as a way to use sunlight to save energy, recent research reports contradictory results: several studies report savings, but just as many suggest no effect or even a net loss, particularly when  gasoline  consumption is taken into account. Electricity use is greatly affected by g eography, climate and economics, making it hard to generalize from single studies. [53] SOLAR THERMAL Solar thermal technologies can be used for water heating, space heating, space cooling and process heat generation. [54] WATER HEATING [pic] Solar water heaters facing the  Sun  to maximize gain. Solar hot water systems use sunlight to heat water.In low geographical latitudes (below 40  degrees) from 60 to 70% of the domestic hot water use with temperatures up to 60  Ã‚ °C can be provided by solar heating systems. [55]  The most common types of solar water heaters are evacuated tube collectors (44%) and glazed flat plate collectors (34%) generally used for domestic hot water; and unglazed plastic collectors (21%) used mainly to heat swimming pools. [56] As of 2007, the total installed capacity of solar hot water systems is approximately 154  GW. [57]  China is the world leader in their deployment with 70  GW installed as of 2006 and a long term goal of 210  GW by 2 020. [58]  Israel  and  Cyprus  are the per capita leaders in the use of solar hot water systems with over 90% of homes using them. 59]  In the United States, Canada and Australia heating swimming pools is the dominant application of solar hot water with an installed capacity of 18  GW as of 2005. [18] HEATING, COOLING AND VENTILATION [pic] Solar House #1 of  Massachusetts Institute of Technology  in the United States, built in 1939, used  Seasonal thermal energy storage (STES)  for year-round heating. In the United States,  heating, ventilation and air conditioning  (HVAC) systems account for 30% (4. 65  EJ) of the energy used in commercial buildings and nearly 50% (10. 1  EJ) of the energy used in residential buildings. [49][60]  Solar heating, cooling and ventilation technologies can be used to offset a portion of this energy.Thermal mass is any material that can be used to store heat—heat from the Sun in the case of solar energy. Common therm al mass materials include stone, cement and water. Historically they have been used in arid climates or warm temperate regions to keep buildings cool by absorbing solar energy during the day and radiating stored heat to the cooler atmosphere at night. However they can be used in cold temperate areas to maintain warmth as well. The size and placement of thermal mass depend on several factors such as climate, daylighting and shading conditions. When properly incorporated, thermal mass maintains space temperatures in a comfortable range and reduces the need for auxiliary heating and cooling equipment. [61]A solar chimney (or thermal chimney, in this context) is a passive solar ventilation system composed of a vertical shaft connecting the interior and exterior of a building. As the chimney warms, the air inside is heated causing an  updraft  that pulls air through the building. Performance can be improved by using glazing and thermal mass materials[62]  in a way that mimics green houses. Deciduous  trees and plants have been promoted as a means of controlling solar heating and cooling. When planted on the southern side of a building, their leaves provide shade during the summer, while the bare limbs allow light to pass during the winter. [63]  Since bare, leafless trees shade 1/3 to 1/2 of incident solar radiation, there is a balance between the benefits of summer shading and the corresponding loss of winter heating. 64]  In climates with significant heating loads, deciduous trees should not be planted on the southern side of a building because they will interfere with winter solar availability. They can, however, be used on the east and west sides to provide a degree of summer shading without appreciably affecting winter solar gain. [65] WATER TREATMENT [pic] Solar water disinfection  in  Indonesia [pic] Small scale solar powered sewerage treatment plant. Solar distillation can be used to make  saline  or  brackish water  potable. The firs t recorded instance of this was by 16th century Arab alchemists. [66]  A large-scale solar distillation project was first constructed in 1872 in the  Chilean  mining town of Las Salinas. 67]  The plant, which had solar collection area of 4,700  m2, could produce up to 22,700  L  per day and operated for 40  years. [67]  Individual  still  designs include single-slope, double-slope (or greenhouse type), vertical, conical, inverted absorber, multi-wick, and multiple effect. [66]  These stills can operate in passive, active, or hybrid modes. Double-slope stills are the most economical for decentralized domestic purposes, while active multiple effect units are more suitable for large-scale applications. [66] Solar water  disinfection  (SODIS) involves exposing water-filled plastic  polyethylene terephthalate  (PET) bottles to sunlight for several hours. 68]  Exposure times vary depending on weather and climate from a minimum of six hours to two days dur ing fully overcast conditions. [69]  It is recommended by theWorld Health Organization  as a viable method for household water treatment and safe storage. [70]  Over two million people in developing countries use this method for their daily drinking water. [69] Solar energy may be used in a water stabilisation pond to treat  waste water  without chemicals or electricity. A further environmental advantage is thatalgae  grow in such ponds and consume  carbon dioxide  in photosynthesis, although algae may produce toxic chemicals that make the water unusable. [71][72] COOKING [pic]The Solar Bowl in  Auroville,  India, concentrates sunlight on a movable receiver to produce  steam  for  cooking. Solar cookers use sunlight for cooking, drying and  pasteurization. They can be grouped into three broad categories: box cookers, panel cookers and reflector cookers. [73]  The simplest solar cooker is the box cooker first built by  Horace de Saussure  in 1767. [7 4]  A basic box cooker consists of an insulated container with a transparent lid. It can be used effectively with partially overcast skies and will typically reach temperatures of 90–150  Ã‚ °C. [75]Panel cookers use a reflective panel to direct sunlight onto an insulated container and reach temperatures comparable to box cookers.Reflector cookers use various concentrating geometries (dish, trough, Fresnel mirrors) to focus light on a cooking container. These cookers reach temperatures of 315  Ã‚ °C and above but require direct light to function properly and must be repositioned to track the Sun. [76] The  solar bowl  is a concentrating technology employed by the Solar Kitchen at  Auroville, in  Tamil Nadu,  India, where a stationary spherical reflector focuses light along a line perpendicular to the sphere's interior surface, and a computer control system moves the receiver to intersect this line. Steam is produced in the receiver at temperatures reaching 150   Ã‚ °C and then used for process heat in the kitchen. [77]A reflector developed by  Wolfgang Scheffler  in 1986 is used in many solar kitchens. Scheffler reflectors are flexible parabolic dishes that combine aspects of trough and power tower concentrators. Polar tracking  is used to follow the Sun's daily course and the curvature of the reflector is adjusted for seasonal variations in the incident angle of sunlight. These reflectors can reach temperatures of 450–650  Ã‚ °C and have a fixed focal point, which simplifies cooking. [78]  The world's largest Scheffler reflector system in Abu Road,  Rajasthan, India is capable of cooking up to 35,000 meals a day. [79]As of 2008, over 2,000 large Scheffler cookers had been built worldwide. [80] PROCESS HEATSolar concentrating technologies such as parabolic dish, trough and Scheffler reflectors can provide process heat for commercial and industrial applications. The first commercial system was the  Solar Total Energy Project  (STEP) in Shenandoah, Georgia, USA where a field of 114 parabolic dishes provided 50% of the process heating, air conditioning and electrical requirements for a clothing factory. This grid-connected cogeneration system provided 400  kW of electricity plus thermal energy in the form of 401  kW steam and 468  kW chilled water, and had a one hour peak load thermal storage. [81] Evaporation ponds are shallow pools that concentrate dissolved solids through  evaporation. The use of evaporation ponds to obtain salt from sea water is one of the oldest applications of solar energy.Modern uses include concentrating brine solutions used in leach mining and removing dissolved solids from waste streams. [82] Clothes lines,  clotheshorses, and clothes racks dry clothes through evaporation by wind and sunlight without consuming electricity or gas. In some states of the United States legislation protects the â€Å"right to dry† clothes. [83] Unglazed transpired collecto rs (UTC) are perforated sun-facing walls used for preheating ventilation air. UTCs can raise the incoming air temperature up to 22  Ã‚ °C and deliver outlet temperatures of 45–60  Ã‚ °C. [84]  The short payback period of transpired collectors (3 to 12  years) makes them a more cost-effective alternative than glazed collection systems. 84]  As of 2003, over 80 systems with a combined collector area of 35,000  m2  had been installed worldwide, including an 860  m2  collector in  Costa Rica  used for drying coffee beans and a 1,300  m2  collector in  Coimbatore, India used for drying marigolds. [28] ELECTRICITY PRODUCTION [pic] The  PS10  concentrates sunlight from a field of heliostats on a central tower. Solar power is the conversion of sunlight into  electricity, either directly using  photovoltaics  (PV), or indirectly using  concentrated solar power  (CSP). CSP systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. PV converts light into electric current using the  photoelectric effect. Commercial CSP plants were first developed in the 1980s. Since 1985 the eventually 354 MW  SEGS  CSP installation, in the Mojave Desert of California, is the largest solar power plant in the world.Other large CSP plants include the 150 MW  Solnova Solar Power Station  and the 100 MWAndasol solar power station, both in Spain. The 250 MW  Agua Caliente Solar Project, in the United States, and the 214 MW  Charanka Solar Park  inIndia, are the  world’s largest  photovoltaic plants. Solar projects exceeding 1 GW are being developed, but most of the deployed photovoltaics are in small rooftop arrays of less than 5 kW, which are grid connected using net metering and/or a feed-in tariff. [85] Concentrated solar power Concentrating Solar Power (CSP) systems use lenses or mirrors and tracking systems to focus a large area of sunlight into a small beam. The concen trated heat is then used as a heat source for a conventional power plant.A wide range of concentrating technologies exists; the most developed are the parabolic trough, the concentrating linear fresnel reflector, the Stirling dish and the solar power tower. Various techniques are used to track the Sun and focus light. In all of these systems a  working fluid  is heated by the concentrated sunlight, and is then used for power generation or energy storage. [86] PHOTOVOLTAICS PHOTOVOLTAICS A solar cell, or photovoltaic cell (PV), is a device that converts light into electric current using the photoelectric effect. The first solar cell was constructed by Charles Fritts in the 1880s. In 1931 a German engineer, Dr Bruno Lange, developed a photo cell using silver selenite in place of copper oxide.Although the prototype selenium cells converted less than 1% of incident light into electricity, both Ernst Werner von Siemens and James Clerk Maxwell recognized the importance of this discove ry. Following the work of Russell Ohl in the 1940s, researchers Gerald Pearson, Calvin Fuller and Daryl Chapin created the silicon solar cell in 1954. These early solar cells cost 286 USD/watt and reached efficiencies of 4. 5–6%. By 2012 available efficiencies exceed 20% and the maximum efficiency of research photovoltaics is over 40%. OTHERS Besides concentrated solar power and photovoltaics, there are some other techniques used to generated electricity using solar power. These include: †¢Dye-sensitized_solar_cells, Luminescent solar concentrators (a type of concentrated photovoltaics or CPV technology), †¢Biohybrid solar cells, †¢Photon Enhanced Thermionic Emission systems. Development, deployment and economics Beginning with the surge in coal use which accompanied the Industrial Revolution, energy consumption has steadily transitioned from wood and biomass to fossil fuels. The early development of solar technologies starting in the 1860s was driven by an exp ectation that coal would soon become scarce. However development of solar technologies stagnated in the early 20th century in the face of the increasing availability, economy, and utility of coal and petroleum. [109]The 1973 oil embargo and 1979 energy crisis caused a reorganization of energy policies around the world and brought renewed attention to developing solar technologies. Deployment strategies focused on incentive programs such as the Federal Photovoltaic Utilization Program in the US and the Sunshine Program in Japan. Other efforts included the formation of research facilities in the US (SERI, now NREL), Japan (NEDO), and Germany (Fraunhofer Institute for Solar Energy Systems ISE). Commercial solar water heaters began appearing in the United States in the 1890s. These systems saw increasing use until the 1920s but were gradually replaced by cheaper and more reliable heating fuels.As with photovoltaics, solar water heating attracted renewed attention as a result of the oil crises in the 1970s but interest subsided in the 1980s due to falling petroleum prices. Development in the solar water heating sector progressed steadily throughout the 1990s and growth rates have averaged 20% per year since 1999. [57] Although generally underestimated, solar water heating and cooling is by far the most widely deployed solar technology with an estimated capacity of 154 GW as of 2007. The International Energy Agency has said that solar energy can make considerable contributions to solving some of the most urgent problems the world now faces: The development of affordable, inexhaustible and clean solar energy technologies will have huge longer-term benefits.It will increase countries’ energy security through reliance on an indigenous, inexhaustible and mostly import-independent resource, enhance sustainability, reduce pollution, lower the costs of mitigating climate change, and keep fossil fuel prices lower than otherwise. These advantages are global. Hence the additional costs of the incentives for early deployment should be considered learning investments; they must be wisely spent and need to be widely shared. In 2011, the International Energy Agency said that solar energy technologies such as photovoltaic panels, solar water heaters and power stations built with mirrors could provide a third of the world’s energy by 2060 if politicians commit to limiting climate change. The energy from the sun could play a key role in de-carbonizing the global economy alongside improvements in energy efficiency and imposing costs on greenhouse gas emitters. The strength of solar is the incredible variety and flexibility of applications, from small scale to big scale†. We have proved †¦ that after our stores of oil and coal are exhausted the human race can receive unlimited power from the rays of the sun. —Frank Shuman, New York Times, July 2, 1916 SOLAR CELL SOLAR CELL A solar cell made from amonocrystalline silicon wafer Sola r cells can be used devices such as this portable monocrystalline solar charger. A solar cell (also called a photovoltaic cell) is an electrical device that converts the energy of light directly into electricity by the photovoltaic effect. It is a form of photoelectric cell (in that its electrical characteristics—e. g. urrent, voltage, or resistance—vary when light is incident upon it) which, when exposed to light, can generate and support an electric current without being attached to any external voltage source. The term â€Å"photovoltaic† comes from the Greek (phos) meaning â€Å"light†, and from â€Å"Volt†, the unit of electro-motive force, the volt, which in turn comes from the last name of the Italian physicist Alessandro Volta, inventor of the battery (electrochemical cell). The term â€Å"photo-voltaic† has been in use in English since 1849. Photovoltaics is the field of technology and research related to the practical application of photovoltaic cells in producing electricity from light, though it is often used specifically to refer to the generation of electricity from sunlight.Cells can be described as photovoltaic even when the light source is not necessarily sunlight (lamplight, artificial light, etc. ). In such cases the cell is sometimes used as a photodetector (for example infrared detectors), detecting light or other electromagnetic radiationnear the visible range, or measuring light intensity. The operation of a photovoltaic (PV) cell requires 3 basic attributes: 1. The absorption of light, generating either electron-hole pairs or excitons. 2. The separation of charge carriers of opposite types. 3. The separate extraction of those carriers to an external circuit. In contrast, a solar thermal collector collects heat by absorbing sunlight, for the purpose of either direct heating or indirect electrical power generation. Photoelectrolytic cell† (photoelectrochemical cell), on the other hand, refe rs either a type of photovoltaic cell (like that developed by A. E. Becquerel and modern dye-sensitized solar cells) or a device that splits water directly into hydrogen and oxygen using only solar illumination. FURTHER IMPROVEMENTS In the time since Berman's work, improvements have brought production costs down under $1 a watt, with wholesale costs well under $2. â€Å"Balance of system† costs are now more than the panels themselves. Large commercial arrays can be built at below $3. 40 a watt,[12][13]  fully commissioned. As the semiconductor industry moved to ever-larger boules, older equipment became available at fire-sale prices.Cells have grown in size as older equipment became available on the surplus market; ARCO Solar's original panels used cells with 2 to 4  inch (51 to 100  mm) diameter. Panels in the 1990s and early 2000s generally used 5  inch (125  mm) wafers, and since 2008 almost all new panels use 6  inch (150  mm) cells. This material has less e fficiency, but is less expensive to produce in bulk. The widespread introduction of  flat screen televisions  in the late 1990s and early 2000s led to the wide availability of large sheets of high-quality glass, used on the front of the panels. In terms of the cells themselves, there has been only one major change. During the 1990s, polysilicon cells became increasingly popular.These cells offer less efficiency than their monosilicon counterparts, but they are grown in large vats that greatly reduce the cost of production. By the mid-2000s, poly was dominant in the low-cost panel market, but more recently a variety of factors has pushed the higher performance mono back into widespread use. CURRENT EVENTS Other technologies have tried to enter the market. First Solar  was briefly the largest panel manufacturer in 2009, in terms of yearly power produced, using a thin-film cell sandwiched between two layers of glass. Since then silicon panels reasserted their dominant position bo th in terms of lower prices and the rapid rise of Chinese manufacturing, resulting in the top producers being Chinese.By late 2011, efficient production in China, coupled with a drop in European demand due to budgetary turmoil had dropped prices for crystalline solar-based modules further, to about $1. 09[13]  per watt in October 2011, down sharply from the price per watt in 2010. A more modern process, mono-like-multi, aims to offer the performance of mono at the cost of poly, and is in the process of being introduced in 2012[citation needed]. APPLICATIONS [pic] Polycrystalline  photovoltaic cells laminated to backing material in a module [pic] [pic] Polycrystalline photovoltaic cells Solar cells are often electrically connected and encapsulated as a  module. Photovoltaic modules often have a sheet of glass on the front (sun up) side, allowing light to pass while protecting the emiconductor  wafers  from abrasion and impact due to wind-driven debris,  rain,  hail, etc . Solar cells are also usually connected in  series  in modules, creating an additive  voltage. Connecting cells in parallel will yield a higher current; however, very significant problems exist with parallel connections. For example, shadow effects can shut down the weaker (less illuminated) parallel string (a number of series connected cells) causing substantial power loss and even damaging the weaker string because of the excessive  reverse bias  applied to the shadowed cells by their illuminated partners. Strings of series cells are usually handled independently and not connected in parallel, special paralleling circuits are the exceptions.Although modules can be interconnected to create an  array  with the desired peak DC voltage and loading current capacity, using independent MPPTs (maximum power point trackers) provides a better solution. In the absence of paralleling circuits, shunt diodes can be used to reduce the power loss due to shadowing in arrays with ser ies/parallel connected cells. To make practical use of the solar-generated energy, the electricity is most often fed into the electricity grid using inverters (grid-connected  photovoltaic systems); in stand-alone systems, batteries are used to store the energy that is not needed immediately. Solar panels can be used to power or recharge portable devices. THEORYThe solar cell works in three steps: 1. Photons  in  sunlight  hit the solar panel and are absorbed by semiconducting materials, such as silicon. 2. Electrons  (negatively charged) are knocked loose from their atoms, causing an electric potential difference. Current starts flowing through the material to cancel the potential and this electricity is captured. Due to the special composition of solar cells, the electrons are only allowed to move in a single direction. 3. An array of solar cells converts solar energy into a usable amount of  direct current  (DC) electricity. EFFICIENCY Solar panels on the Internatio nal Space Station absorb light from both sides.These Bifacial cells are more efficient and operate at lower temperature than single sided equivalents. The efficiency of a solar cell may be broken down into reflectance efficiency, thermodynamic efficiency, charge carrier separation efficiency and conductive efficiency. The overall efficiency is the product of each of these individual efficiencies. A solar cell usually has a voltage dependent efficiency curve, temperature coefficients, and shadow angles. Due to the difficulty in measuring these parameters directly, other parameters are measured instead: thermodynamic efficiency, quantum efficiency,integrated quantum efficiency, VOC ratio, and fill factor.Reflectance losses are a portion of the quantum efficiency under â€Å"external quantum efficiency†. Recombination losses make up a portion of the quantum efficiency, VOC ratio, and fill factor. Resistive losses are predominantly categorized under fill factor, but also make up minor portions of the quantum efficiency, VOC ratio. The fill factor is defined as the ratio of the actual maximum obtainable power to the product of the open circuit voltage and short circuit current. This is a key parameter in evaluating the performance of solar cells. Typical commercial solar cells have a fill factor ; 0. 70. Grade B cells have a fill factor usually between 0. 4 to 0. 7. 14] Cells with a high fill factor have a low equivalent series resistance and a high equivalent shunt resistance, so less of the current produced by the cell is dissipated in internal losses. Single p–n junction crystalline silicon devices are now approaching the theoretical limiting power efficiency of 33. 7%, noted as the Shockley–Queisser limit in 1961. In the extreme, with an infinite number of layers, the corresponding limit is 86% using concentrated sunlight. [pic] Reported timeline of solar cell energy conversion efficiencies (from National Renewable Energy Laboratory (USA)) MATERIALS [pic] [pic] The  Shockley-Queisser limit  for the theoretical maximum efficiency of a solar cell. Semiconductors with  band gapbetween 1 and 1. eV, or near-infrared light, have the greatest potential to form an efficient cell. (The efficiency â€Å"limit† shown here can be exceeded by  multijunction solar cells. ) Various materials display varying efficiencies and have varying costs. Materials for efficient solar cells must have characteristics matched to the spectrum of available light. Some cells are designed to efficiently convert wavelengths of solar light that reach the Earth surface. However, some solar cells are optimized for light absorption beyond Earth's atmosphere as well. Light absorbing materials can often be used in  multiple physical configurations  to take advantage of different light absorption and charge separation mechanisms.Materials presently used for photovoltaic solar cells include  monocrystalline silicon,  polycrystalline sil icon,  amorphous silicon,  cadmium telluride, andcopper indium selenide/sulfide. [25][26] Many currently available solar cells are made from bulk materials that are cut into  wafers  between 180 to 240  micrometers thick that are then processed like other semiconductors. Other materials are made as  thin-films  layers, organic  dyes, and organic  polymers  that are deposited on  supporting substrates. A third group are made from  nanocrystals  and used as  quantum dots  (electron-confined  nanoparticles). Silicon remains the only material that is well-researched in both  bulkand  thin-film  forms. CRYSTALLINE SILICON [pic]Basic structure of a silicon based solar cell and its working mechanism. By far, the most prevalent bulk material for solar cells is crystalline silicon (abbreviated as a group as c-Si), also known as â€Å"solar grade silicon†. Bulk silicon is separated into multiple categories according to crystallinity and crystal siz e in the resulting ingot, ribbon, orwafer. 1. monocrystalline silicon (c-Si): often made using the Czochralski process. Single-crystal wafer cells tend to be expensive, and because they are cut from cylindrical ingots, do not completely cover a square solar cell module without a substantial waste of refined silicon. Hence most c-Si panels have uncovered gaps at the four corners of the cells. 2. olycrystalline silicon, or multicrystalline silicon, (poly-Si or mc-Si): made from cast square ingots — large blocks of molten silicon carefully cooled and solidified. Poly-Si cells are less expensive to produce than single crystal silicon cells, but are less efficient. United States Department of Energy data show that there were a higher number of polycrystalline sales than monocrystalline silicon sales. 3. ribbon silicon is a type of polycrystalline silicon: it is formed by drawing flat thin films from molten silicon and results in a polycrystalline structure. These cells have lower efficiencies than poly-Si, but save on production costs due to a great reduction in silicon waste, as this approach does not require sawing from ingots. 4. ono-like-multi silicon: Developed in the 2000s and introduced commercially around 2009, mono-like-multi, or cast-mono, uses existing polycrystalline casting chambers with small â€Å"seeds† of mono material. The result is a bulk mono-like material with poly around the outsides. When sawn apart for processing, the inner sections are high-efficiency mono-like cells (but square instead of â€Å"clipped†), while the outer edges are sold off as conventional poly. The result is line that produces mono-like cells at poly-like prices. Analysts have predicted that prices of polycrystalline silicon will drop as companies build additional polysilicon capacity quicker than the industry's projected demand. On the other hand, the cost of producing upgraded metallurgical-grade silicon, also known as UMG Si, can potentially be one- sixth that of makingpolysilicon.Manufacturers of wafer-based cells have responded to high silicon prices in 2004–2008 prices with rapid reductions in silicon consumption. According to Jef Poortmans, director of IMEC's organic and solar department, current cells use between eight and nine grams of silicon per watt of power generation, with wafer thicknesses in the neighborhood of 0. 200 mm. At 2008 spring's IEEEPhotovoltaic Specialists' Conference (PVS'08), John Wohlgemuth, staff scientist at BP Solar, reported that his company has qualified modules based on 0. 180 mm thick wafers and is testing processes for 0. 16 mm wafers cut with 0. 1 mm wire. IMEC's road map, presented at the organization's recent annual research review meeting, envisions use of 0. 08 mm wafers by 2015. Gallium arsenide multijunction:High-efficiency multijunction cells were originally developed for special applications such as satellites and space exploration, but at present, their use in terrestrial conc entrators might be the lowest cost alternative in terms of $/kWh and $/W. [35] These multijunction cells consist of multiple thin films produced using metalorganic vapour phase epitaxy. A triple-junction cell, for example, may consist of the semiconductors: GaAs, Ge, and GaInP2. [36] Each type of semiconductor will have a characteristic band gap energy which, loosely speaking, causes it to absorb light most efficiently at a certain color, or more precisely, to absorb electromagnetic radiation over a portion of the spectrum.Combinations of semiconductors are carefully chosen to absorb nearly the entire solar spectrum, thus generating electricity from as much of the solar energy as possible. GaAs based multijunction devices are the most efficient solar cells to date. In October 15, 2012, triple junction metamorphic cell reached a record high of 44%. [37] Tandem solar cells based on monolithic, series connected, gallium indium phosphide (GaInP), gallium arsenide GaAs, and germanium Ge p–n junctions, are seeing demand rapidly rise. Between December 2006 and December 2007, the cost of 4N gallium metal rose from about $350 per kg to $680 per kg. Additionally, germanium metal prices have risen substantially to $1000–1200 per kg this year.Those materials include gallium (4N, 6N and 7N Ga), arsenic (4N, 6N and 7N) and germanium, pyrolitic boron nitride (pBN) crucibles for growing crystals, and boron oxide, these products are critical to the entire substrate manufacturing industry. Triple-junction GaAs solar cells were also being used as the power source of the Dutch four-time World Solar Challenge winners Nuna in 2003, 2005 and 2007, and also by the Dutch solar carsSolutra (2005), Twente One (2007) and 21Revolution (2009). The Dutch Radboud University Nijmegen set the record for thin film solar cell efficiency using a single junction GaAs to 25. 8% in August 2008 using only 4  µm thick GaAs layer which can be transferred from a wafer base to glass or pl astic film. THIN FILMS [pic]Market share of the different PV technologies  In 2010 the market share of thin film declined by 30% as thin film technology was displaced by more efficient crystalline silicon solar panels (the light and dark blue bars). Thin-film technologies reduce the amount of material required in creating the active material of solar cell. Most thin film solar cells are sandwiched between two panes of glass to make a module. Since silicon solar panels only use one pane of glass, thin film panels are approximately twice as heavy as crystalline silicon panels. The majority of film panels have significantly lower conversion efficiencies, lagging silicon by two to three percentage points. 31]  Thin-film solar technologies have enjoyed large investment due to the success of First Solar and the largely unfulfilled promise of lower cost and flexibility compared to wafer silicon cells, but they have not become mainstream solar products due to their lower efficiency and corresponding larger area consumption per watt production. Cadmium telluride  (CdTe),  copper indium gallium selenide  (CIGS) and  amorphous silicon  (A-Si) are three thin-film technologies often used as outdoor photovoltaic solar power production. CdTe technology is most cost competitive among them. [32]  CdTe technology costs about 30% less than CIGS technology and 40% less than A-Si technology in 2011. CADMIUM TELLURIDE SOLAR CELLA cadmium telluride solar cell uses a cadmium telluride (CdTe) thin film, a  semiconductor  layer to absorb and convert sunlight into electricity. Solarbuzzhas reported that the lowest quoted thin-film module price stands at US$0. 84 per  watt-peak, with the lowest crystalline silicon (c-Si) module at $1. 06 per watt-peak. [33] The  cadmium  present in the cells would be toxic if released. However, release is impossible during normal operation of the cells and is unlikely during ? res in residential roofs. [34]  A square meter of CdTe contains approximately the same amount of Cd as a single C cell  Nickel-cadmium battery, in a more stable and less soluble form. [34]COPPER INDIUM GALLIUM SELENIDE Copper indium gallium selenide (CIGS) is a  direct band gap  material. It has the highest efficiency (~20%) among thin film materials (see  CIGS solar cell). Traditional methods of fabrication involve vacuum processes including co-evaporation and sputtering. Recent developments at  IBM  and  Nanosolar  attempt to lower the cost by using non-vacuum solution processes. GALLIUM ARSENIDE MULTIJUNCTION High-efficiency multijunction cells were originally developed for special applications such as  satellites  and  space exploration, but at present, their use in terrestrial concentrators might be the lowest cost alternative in terms of $/kWh and $/W. 35]  These multijunction cells consist of multiple thin films produced using  metalorganic vapour phase epitaxy. A triple-junction cell, for example, may consist of the semiconductors:  GaAs,  Ge, and  GaInP2. [36]  Each type of semiconductor will have a characteristic  band gap  energy which, loosely speaking, causes it to absorb light most efficiently at a certain color, or more precisely, to absorb  electromagnetic radiation  over a portion of the spectrum. Combinations of semiconductors are carefully chosen to absorb nearly all of the solar spectrum, thus generating electricity from as much of the solar energy as possible. GaAs based multijunction devices are the most efficient solar cells to date.In October 15, 2012, triple junction metamorphic cell reached a record high of 44%. [37] Tandem solar cells based on monolithic, series connected, gallium indium phosphide (GaInP), gallium arsenide GaAs, and germanium Ge p–n junctions, are seeing demand rapidly rise. Between December 2006 and December 2007, the cost of 4N gallium metal rose from about $350 per kg to $680 per kg. Additionally, germanium metal p rices have risen substantially to $1000–1200 per kg this year. Those materials include gallium (4N, 6N and 7N Ga), arsenic (4N, 6N and 7N) and germanium, pyrolitic boron nitride (pBN) crucibles for growing crystals, and boron oxide, these products are critical to the entire substrate manufacturing industry.Triple-junction GaAs solar cells were also being used as the power source of the Dutch four-time  World Solar Challenge  winners  Nuna  in 2003, 2005 and 2007, and also by the Dutch solar carsSolutra (2005),  Twente One (2007)  and 21Revolution (2009). The Dutch  Radboud University Nijmegen  set the record for thin film solar cell efficiency using a single junction GaAs to 25. 8% in August 2008 using only 4  Ã‚ µm thick GaAs layer which can be transferred from a wafer base to glass or plastic film. Light-absorbing dyes (DSSC) Dye-sensitized solar cells  (DSSCs) are made of low-cost materials and do not need elaborate equipment to manufacture, so they can be made in a  DIY  fashion, possibly allowing players to produce more of this type of solar cell than others. In bulk it should be significantly less expensive than older  solid-state  cell designs.DSSC's can be engineered into flexible sheets, and although its  conversion efficiency  is less than the best  thin film cells, its  price/performance ratio  should be high enough to allow them to compete with  fossil fuel electrical generation. Typically a  ruthenium  metalorganic  dye  (Ru-centered) is used as a  monolayer  of light-absorbing material. The dye-sensitized solar cell depends on a  mesoporous  layer of  nanoparticulate  titanium dioxide  to greatly amplify the surface area (200–300 m2/g TiO2, as compared to approximately 10 m2/g of flat single crystal). The photogenerated electrons from the  light absorbing dye  are passed on to the  n-type  TiO2, and the holes are absorbed by an  electrolyte  on the other side of the dye.The circuit is completed by a redox couple in the electrolyte, which can be liquid or solid. This type of cell allows a more flexible use of materials, and is typically manufactured by  screen printing  or use of  Ultrasonic Nozzles, with the potential for lower processing costs than those used for  bulk  solar cells. However, the dyes in these cells also suffer from  degradation  under heat and  UV  light, and the cell casing is difficult to  seal  due to the solvents used in assembly. In spite of the above, this is a popular emerging technology with some commercial impact forecast within this decade. The first commercial shipment of DSSC solar modules occurred in July 2009 from G24i Innovations. [38] Quantum Dot Solar Cells (QDSCs)Quantum dot solar cells  (QDSCs) are based on the Gratzel cell, or  dye-sensitized solar cell, architecture but employ low  band gap  semiconductor  nanoparticles, fabricated with such small crystallite sizes th at they form  quantum dots  (such as  CdS,  CdSe,  Sb2S3,  PbS, etc. ), instead of organic or organometallic dyes as light absorbers. Quantum dots (QDs) have attracted much interest because of their unique properties. Their size quantization allows for the  band gap  to be tuned by simply changing particle size. They also have high  extinction coefficients, and have shown the possibility of  multiple exciton generation. [39] In a QDSC, a  mesoporous  layer of  titanium dioxide  nanoparticles forms the backbone of the cell, much like in a DSSC.This TiO2  layer can then be made photoactive by coating with semiconductor quantum dots using  chemical bath deposition,  electrophoretic deposition, or successive ionic layer adsorption and reaction. The electrical circuit is then completed through the use of a liquid or solid  redox couple. During the last 3–4 years, the efficiency of QDSCs has increased rapidly[40]  with efficiencies over 5% show n for both liquid-junction[41]  and solid state cells. [42]  In an effort to decrease production costs of these devices, the  Prashant Kamat  research group[43]  recently demonstrated a solar paint made with TiO2  and CdSe that can be applied using a one-step method to any conductive surface and have shown efficiencies over 1%. [44] Organic/polymer solar cellsOrganic solar cells  are a relatively novel technology, yet hold the promise of a substantial price reduction (over thin-film silicon) and a faster return on investment. These cells can be processed from solution, hence the possibility of a simple roll-to-roll printing process, leading to inexpensive, large scale production. Organic solar cells and  polymer solar cells  are built from thin films (typically 100  nm) of  organic semiconductors  including polymers, such as  polyphenylene vinylene  and small-molecule compounds like copper phthalocyanine (a blue or green organic pigment) and  carbon ful lerenes  and fullerene derivatives such as  PCBM. Energy conversion efficiencies achieved to date using conductive polymers are low compared to inorganic materials.However, it has improved quickly in the last few years and the highest  NREL  (National Renewable Energy Laboratory) certified efficiency has reached 8. 3% for the  Konarka  Power Plastic. [45]  In addition, these cells could be beneficial for some applications where mechanical flexibility and disposability are important. These devices differ from inorganic semiconductor solar cells in that they do not rely on the large built-in electric field of a PN junction to separate the electrons and holes created when photons are absorbed. The active region of an organic device consists of two materials, one which acts as an electron donor and the other as an acceptor.When a photon is converted into an electron hole pair, typically in the donor material, the charges tend to remain bound in the form of an  exciton, a nd are separated when the exciton diffuses to the donor-acceptor interface. The short exciton diffusion lengths of most polymer systems tend to limit the efficiency of such devices. Nanostructured interfaces, sometimes in the form of bulk heterojunctions, can improve performance. [46] In 2011, researchers at the Massachusetts Institute of Technology and Michigan State University developed the first highly efficient transparent solar cells that had a power efficiency close to 2% with a transparency to the human eye greater than 65%, achieved by selectively absorbing the ultraviolet and near-infrared parts of the spectrum with small-molecule compounds. 47]  [48]Researchers at UCLA more recently developed an analogous polymer solar cell, following the same approach, that is 70% transparent and has a 4% power conversion efficiency. [49]  The efficiency limits of both opaque and transparent organic solar cells were recently outlined. [50]  [51]  These lightweight, flexible cells can be produced in bulk at a low cost, and could be used to create power generating windows. Silicon thin films Silicon thin-film cells  are mainly deposited by  chemical vapor deposition  (typically plasma-enhanced, PE-CVD) from  silane  gas and  hydrogen  gas. Depending on the deposition parameters, this can yield:[52] 1. Amorphous silicon  (a-Si or a-Si:H) 2. Protocrystalline  silicon or 3. Nanocrystalline silicon  (nc-Si or nc-Si:H), also called microcrystalline silicon.It has been found that protocrystalline silicon with a low volume fraction of nanocrystalline silicon is optimal for high open circuit voltage. [53]  These types of silicon present dangling and twisted bonds, which results in deep defects (energy levels in the bandgap) as well as deformation of the valence and conduction bands (band tails). The solar cells made from these materials tend to have lower  energy conversion efficiency  than  bulk  silicon, but are also less expensive to p roduce. The  quantum efficiency  of thin film solar cells is also lower due to reduced number of collected charge carriers per incident photon. An amorphous silicon (a-Si) solar cell is made of amorphous or microcrystalline silicon and its basic electronic structure is the  p-i-n  junction. -Si is attractive as a solar cell material because it is abundant and non-toxic (unlike its CdTe counterpart) and requires a low processing temperature, enabling production of devices to occur on flexible and low-cost substrates. As the amorphous structure has a higher absorption rate of light than crystalline cells, the complete light spectrum can be absorbed with a very thin layer of photo-electrically active material. A film only 1 micron thick can absorb 90% of the usable solar energy. [54]  This reduced material requirement along with current technologies being capable of large-area deposition of a-Si, the scalability of this type of cell is high.However, because it is amorphous, i t has high inherent disorder and dangling bonds, making it a bad conductor for charge carriers. These dangling bonds act as recombination centers that severely reduce the carrier lifetime and pin the Fermi energy level so that doping the material to n- or p- type is not possible. Amorphous Silicon also suffers from the Staebler-Wronski effect, which results in the efficiency of devices utilizing amorphous silicon dropping as the cell is exposed to light. The production of a-Si thin film solar cells uses glass as a substrate and deposits a very thin layer of silicon by  plasma-enhanced chemical vapor deposition  (PECVD).A-Si manufacturers are working towards lower costs per watt and higher conversion efficiency with continuous research and development on  Multijunction solar cells  for solar panels. Anwell Technologies Limited  recently announced its target for mul

Is nutrition intervention an essential component to the management of Essay

Is nutrition intervention an essential component to the management of diabetes in the ELDERLY - Essay Example The prevalence of type 2 DM has nearly doubled over the past 25 years, with certain groups - native Americans, Hispanics, and African-Americans - at particularly high risk of developing the disease (HORNICK & ARON, 2008). Diabetes is the fifth leading cause of death by disease in the United States, killing approximately 225,000 people each year. The direct cost of diabetes is $92 billion a year, representing 11 percent of total health care expenditures in the U.S. (Hayashi, 2007). At least 20% of persons 65 years of age or above and 26% of long-term care facility residents have diabetes, and the annual cost of caring for the latter is estimated at $6 billion (American Diabetes Association, 2008) (Pandya, 2003). Older diabetics are two to three times more likely to need hospital admission than their non-diabetic counterparts (Damsgaard, Froland, & Green, 1987). An analysis of the 1999-2004 National Health and Nutrition Examination Survey (NHANES), including subjects over 65 y.o. and type 2 DM, found an alarmingly high prevalence of comorbid conditions in this population: 31.5% had renal insufficiency, 20.2% had a history of myocardial infarction, and 17.9% had heart failure (Suh, Kim, Choi, & Plauschinat, 2007). Physiologic and pathologic changes of ageing may concur to induce malnutrition. After the age of 65, weight loss occurs at rate of up to 0.65 kg/year (Lehmann & Bassey, 1996), although there is substantial variation between individuals. A decline in muscle mass begins from 30 to 40 years of age, and continues into advanced old age (Elia, 1992). Failure to thrive in the elderly was described as "a syndrome manifested by weight loss greater than 5% of baseline, decreased appetite, poor nutrition, and inactivity, often accompanied by dehydration, depressive symptoms, impaired immune function, and low cholesterol levels." (Lonergan, 1991) It is estimated that 15 to 50 percent of Americans over the age of 65 consume too few calories, protein or essential vitamins and minerals for good health. (2007) The various causes of malnutrition can be summarized in a useful mnemonic "Meals On Wheels"(2007): Medications, including digoxin, diuretics, anti-inflammatory agents, antacids, H2-blockers, antidepressants, anticonvulsants etc, which may induce side effects like anorexia, nausea, vomiting, diarrhea, cognitive disturbance and increased metabolism, Emotional problems, such as depression, Anorexia (loss of appetite), commonly due to age-related changes in taste and smell, Late-life paranoia, Swallowing problems (dysphagia), that may arise from poor teeth, ill-fitting dentures, gastroesophageal reflux disease, stroke, Parkinson's disease, or throat tumors, Oral factors, like tooth loss and periodontal disease, Neoplasia, Wandering, in the setting of Alzheimer's disease and other forms of dementia, which are often associated with poor feeding, Hypermetabolic disorders, Enteric problems or malabsorption, Eating difficulties, because of impaired vision, disturbed motor function, or physical disabilities like arthritis or Parkinson's disease, Low-salt and low-cholesterol diets, often resulting in reduced intake due to poor taste, Social problems, including poverty, lack of care, and poor living conditions. There are severals

Define the appropriate methods of communication and discuss the Essay

Define the appropriate methods of communication and discuss the challenges experienced with surgical patients - Essay Example 2). Electronic patient-controlled alert devices notify practitioners of meaningful responses from surgical patients during surgical procedures. They detect meaningful responses from patients and alert practitioners about them. Hand holding by nurses is intended to make patients comfortable in order to boost confidence, deal with pain, and reassure the patient about their own safety. Communication between patients and practitioners should be effective so that suregeons can improve surgical outcomes, promote healing, and build trust (Griffen 2007, p. 11). Some challenges experienced with surgical patients include delivering bad news, discussing informed consent, participating in shared decision making, and patient education. These challenges occur when practitioners do not have proper communication skills, or when they ignore basic communication tenets. These challenges may occur as a result of the condition of patients. They may be addressed by practitioner by sitting down when talking to patients, understanding the patient as individuals, showing respect and empathy, creating partnership, listening attentively, calming fears, eliciting concerns, being honest, educating patients on their treatment options, and involving patients (Silverman, Kurtz & Draper 1998, p.

Why you like Risk Management Plans Essay Example | Topics and Well Written Essays - 750 words

Why you like Risk Management Plans - Essay Example A risk management plan is a document that is created by the project manager to estimate risks, assess the impact of the risks and define solutions to the challenges. Risk management plans also contain a risk assessment matrix that determines the impact of a risk over a specific period (Power, 2008). The procedure of creating a risk management plan starts with understanding how risk management works then the project is defined, stating all the risks and their possible impact. Input from other stakeholders is crucial at this stage. All irrelevant issues are removed then probability of each risk occurring is calculated. The possible losses from the risks are then assigned with an impact number on a scale from 0.00 to 1 with less risky activities having a small value. Next, the total risk is computed then mitigation strategies are developed. After that, the project manager creates contingency plans and analyzes the efficiency of the strategies. Finally, an effective risk is calculated. A risk management plan has several objectives. The plan calculates risks and the probability of the risks resulting in loss. This is important when determining whether to pursue a business project. A risk management plan creates strategies for managing risks or managing the losses from the risk. The plan reduces the possibility of surprises and supports efficient use of organizational resources (Rejda, 2011). Risk management plans contain strategies on how to tackle risks. These strategies include risk avoidance, loss reduction, and risk control, spreading the risk, self-retention, and duplication of resources, accepting risks and transferring risks. Risk avoidance is the most efficient risk management technique. By avoiding a risk, the possibility of loss is eliminated completely. Risk avoidance is the most effective approach but not the most practical one. It is impossible to eliminate all aspects of risk in a project. Some

Create a Title Essay Example | Topics and Well Written Essays - 750 words

Create a Title - Essay Example ive of business the commercialization of education as entertainment might seem a step towards improvement, the same picture might not be so beautiful while considering the total benefit from the human point of view. Neil Postman in his essay, Learning in the Age of Television, speaks about how the toddlers are targeted and how from the tender age they are made to understand and feel the importance of entertainment. He stresses on the steps that the television serials takes to capture the attention of the children and teaches them to abhor the regular classroom learning. From the very beginning, the television instills in the child’s mind the colorful world of entertainment and commercializes education. Edmundson in his essay On the Uses of a Liberal Education too continues this same fact. While Postman concentrates on the childhood potion of this generation, Edmundson concentrates on the teenage and pre adulthood portion or segments, which includes his observations of his own students. Neil Postman and Edmundson both stresses on the use of guilt that is stressed by the television and how it inculcates the need for entertainment into the minds of the children of this generation from their very birth. Postman argues that the shows like Sesame Street offers the parents guilt free pass this is because in most cases both the parents who are busy in their career cannot give time to their children. This is the reason that their children spend long hours watching TV (Postman). By allowing, their children to watch Sesame Street the parent feel that their children are learning something. This reduces their guilt considerably. Further, it also allows them time away from their children. It helps them to keep their children busy while they work. What they do not understand is the effect that TV has on their children in the later age. Edmundson traces the effect of this childhood TV watching and need for entertainment in his own classroom when he would

The Power of The Vote Essay Example | Topics and Well Written Essays - 500 words

The Power of The Vote - Essay Example As the discussion explores the people who are elected have a tremendous impact on our daily lives. These are our representatives, and they enact thousands of statutes that affect us. They determine how to spend tax and how the tax burden will be shared, and they define state policy in thousands of problems and issues. This paper declares that leadership refers to an exceptionally wide range of roles that have great influence. A leader needs to have the qualities and the ability to protect the nation at all times and hence it is essential that they have strong ethics and values. The leader has to impress as a role model in ethical values, intellectual caliber, professional expertise and solid achievements if he/she is to stir up the ready and willing cooperation of others. As a leader he is duty bound to fix responsibility and take corrective measures, but this he should do in a constructive and positive spirit, without leaving a trail of bitterness and acrimony. In any case, he should regard genuine and honest errors of judgment as the inevitable price of learning and growth, and not as something to be condemned or punished. Leaders come with various temperaments and traits. They may be all types: Aggressive, gruff, reserved, blustery, bluff, forthcoming, formal and so on. Not all leaders are made for all kinds of situations and enterprises, since their capabilities are not identical. A war leader, like Winston Churchill, may be a misfit in peacetime.

Issue 3 Coursework Example | Topics and Well Written Essays - 750 words

Issue 3 - Coursework Example Today, all public organizations are required to comply with the act. Additionally, SOX keeps check of the accountability standards for directors, the legal counsel, and auditors. SOX does not affect the corporate financial aspect only, but also the IT department that is tasked with storing and maintaining the corporate electronic records in a cost effective way. The management of the records involves storage of all business records following the required guidelines set for public accountants. Because of its stringent measures, it is believed that SOX will review its policies and the requirements may be reduced significantly and countries like the UK may implement their own version of Sarbanes Oxley as it is part of the existing legislation. SOX require that both the Chief Executive Officer and the Chief Financial Controller certify that financial reports are accurate and complete. It is also their responsibility to assess and report on the effectiveness of the financial reports. An auditing firm should review these reports annually (Graziano, 2003). Moreover, it is a requirement that the issuers publish their annual reports in regards to the internal control structure and policies. The accounting firm that is registered should provide a report that shows the effectives of these structures. For the purposes of effectiveness of internal controls over the financial reports, companies should watch and control the amount of fraud that may occur in the organization. Additionally, the weaknesses in the materials as well as the internal control deficiencies in relation to Sarbanes Oxley should be reviewed. For those companies that are Sarbanes-Oxley compliant, they must have a documentation that shows all their internal contro l processes that are tested by the external auditors. The act has been successful in its implementation of improving the internal control levels within the registered companies (Graziano, 2003). On the other hand, the act has been

Relate the theme the american dream to death of a salesman and arthur Research Paper

Relate the theme the american dream to death of a salesman and arthur miller's life - Research Paper Example The play â€Å"Death of a Salesman† by Arthur Miller encapsulates within its tight-lipped plot, fall of a myth pertaining to American Dream and its vision that â€Å"success is obtained by being well-liked†. The essay intends to perceive and examine the theme of American Dream and its failure closely woven within the plot of the play that sets challenges to the capitalistic concepts and desires of new America. Arthur Miller was born on October 17th in the year of 1915 and expired on 10th February 2005. He was an eminent playwright and essayist from America. He was a very poignant figure in the American theatre and composed many important socio-political plays like â€Å"All My Sons (1947)†, â€Å"Death of a Salesman (1949)†, â€Å"The Crucible (1953)†, â€Å"A View from the Bridge (1955)† among others. Miller’s â€Å"Death of a Salesman† is acclaimed as the first great American tragedy and while projecting it, Miller gained name for the American to understand the true essence of the nation and its tragedy. As a university graduate, he witnessed the hollow pursuit of the good life entwined with the American Dream in the society of America. The disillusioned socio-economic perspective and dystopia led Miller to compose the play, â€Å"Death of a Salesman† which was only possible for a person like Miller who came up from the mundane and meagre streets of Harlem in New York and was able to witness the unveiled mask of American Dream. The concept of American Dream operates at the national level in United States which includes a promise of freedom, possibility of prosperity and freedom and success. The definition of American Dream contended by James Torso Adams in the year 1931 was envisaged as â€Å"life should be better and richer and fuller for everyone, with opportunity for each according to ability or achievement† irrespective of social class or background. With this glittering vision in life, people of America started reconstructing their nation and society in the post-war period with immense faith on their destiny more than their hard-work or potentials. American Dream got concentrated on being rich overnight and the parameter for the pursuit of happiness got captivated to the scale of owing big house, glamorous cars and all the comfort which consumerism and materialism can bring to their citizens. This led to the death of spirituality and made every citizen hollow where the potentials of every American were being judged with their skilled salesmanship and not with their courage or hard-work. Soon, it became the society of the salesman whose only goal became selling commodities to earn profit and ceasing to be a man; every American is soon seen putting a mask of fraud and the ability to sell the commodities regardless of its intrinsic uselessness. â€Å"Death of a Salesman†: American Dream Realized or Shattered During the fall of the values associated with the A merican Dreams, many writers in their work captivated the concept with its shattering image. Arthur Miller is not an exception in this regard. He envisioned the dark side of the American Dream and in the year 1949, Miller yielded one of his finest plays which captivate the shattering of the American Dream in the post-war period. The tragedy is presented as the democratization of classical form of tragedy

Face Recognition Technology Research Paper Example | Topics and Well Written Essays - 1000 words

Face Recognition Technology - Research Paper Example Availability of ‘biometrics’ technology provides controls for verifying true identity of an individual. These controls are automated processes that recognize physiological characteristics such as fingerprints, face, eyes, DNA etc. of a living person which are not easy to forge as they are attributes of an individual gifted by nature. There are also automated processes that recognize individual behaviors such as handwriting style, key stroke patterns etc. (Lin, 2000) Physiological controls are more stable when compared with behavioral controls. The main reason is that the features of physiological controls are non-alterable unless some serious injury is inflicted on a living being. On the other hand the patterns of behavior controls fluctuate with the mood and activities of an individual. In real-life, it is found that verification of physiological attributes is although very accurate, yet it is far more intrusive than the behavior attributes (Lin, 2000) One of the few biometrics controls that have the merits of both low intrusiveness and high accuracy is the Face Recognition technology. Researches in the field of image processing, security and psychology were attracted towards the concepts of computer vision which led to the designing of face recognition technology. (Lin, 2000) The real-world image has only size in inches or centimeters. The capturing device such as camera or scanners uses digitization process through which it stores the number of pixels that contains in an image. It is called Resolution which is of two types; Spatial Resolution and Colour Resolution (JISC Digital Media, 2006) The capturing device in Spatial Resolution is concerned with the frequency at which samples are taken from the real-world object or art-work. Frequency is mostly expressed as samples per inch (spi) when scanning and pixels per inch (ppi) when processing the digital image. The resolution to use for capturing an image is dependent mostly on its ‘end-use’.

Elements of Gothic Literature Essay Example for Free

Elements of Gothic Literature Essay Gothic literature was born in 1764 when Horace Walpole published The Castle of Otranto, which is considered to be the first gothic novel ever written. Gothic literature was originally written as a reaction to the age of reason, order, and the politics of eighteenth-century England. Containing anti-Catholic sentiments and mythical aspects, Gothic literature explored the tension between what we fear and what we desire. The stories were usually set in some kind of castle or old building that showed human decay and created an atmosphere of mystery and suspense. Often, one of the main characters would be some sort of damsel in distress, threatened by some man. The words chosen in these novels and short stories were very descriptive, creating overwrought emotion and often, feelings of gloom and horror. Also, within the plot, some sort of ancient prophecy, along with omens and visions, could usually be found. The most important elements to the structure of canonical gothic literature, however, are supernatural and unexplainable events. In The Castle of Otranto, much of the plot surrounds one unexplainable incident: a giant black helmet falls on Prince Conrad, thus killing him. Because of Prince Conrads death, Manfred, his father, captures a passing peasant, Theodore, and pursues Isabella, Conrads fiancee. Later, it is learned that Jerome (the minister) is Theodores father. If the helmet had never fallen on Conrad, Manfred never would have stopped Theodore, and Jerome would never have found his long lost son. Manfred, still believing that Theodore is guilty of dropping the helmet by sorcery, is ready to execute him. At this point in the story, Isabellas long lost father appears, which halts Theodores execution. It is later learned that Isabellas father found her because a dream he had led him to a monk, who led him to Otranto. The supernatural event here is the dream, which turned out to forecast reality. He accuses Manfred of not being the rightful ruler of Otranto. Eventually, everything is confirmed when the giant version of Alfonso the Good that has been living in the castle (another mysterious incident) breaks through the walls and proclaims Theodore the natural heir of Alfonso and the rightful ruler of Otranto. The Ruins of the Abbey of Fitz-Martin, whose author remains anonymous, also has a similar dependency on a chain of supernatural events. Sir Thomas Fitz-Martin acquires an abbey, which he finds in ruins. He is certain it can be repaired, so he and his people venture inside. Upon exploring the abbey, Fitz-Martin opens a door with difficulty, only to be met with severe shrieks from inside that particular room. Later in the story, the superstition surrounding those screams is explained. Evidently, every night, the ghost of St. Anna can be seen walking up to the altar. She stays there until midnight, and then walks to the south tower. She screams three times, and the ghost of the evil Baron, who possessed the abbey years before, comes. Then, Anna chases him with a fire-brand in one hand and a dead baby in her other arm. The two ghosts eventually come to the Barons old room, where dismal yells and dying groans can be heard from. Fiery lights surround the Barons old room until the clock that hasnt been touched in years strikes two, or sometimes three oclock. This story of supernatural occurrence strikes the curiosity of Rosaline, Sir Thomas Fitz-Martins daughter, who then decides to go investigate the south tower. When she does, she finds the torture chamber where they killed St. Anna so many years ago. She is debating whether or not to go in, when she hears a voice commanding her to enter. She feels almost possessed, as the voice tells her to reach inside the coffin. When she does, she pulls something out and takes it with her, fleeing in terror. It is the supernatural phenomenon of this voice that brings in St. Annas story, which is written on the papers with which Rosaline fled in terror. The Vampyre by John Polidori casts an interesting slant on the element of supernatural events. The entire story is a supernatural event because Lord Ruthven is a vampire, a supernatural creature. Before this is revealed to the reader, however, there are important unexplainable events that allude to his being a vampire and are of utmost importance to the story. It is the mystery of Lord Ruthvens appearance that first attracts Aubrey to him, and thus begins the story. Aubrey wants to get to know him better, hopefully to  understand the enigma of his demeanor. They leave on a trip together, and Aubrey notices that Lord Ruthven is extremely charitable. He also notices, though, that Lord Ruthven always gives his money to the scoundrels of society, those who will piddle away the charity pursuing their vices. Then he realizes that all who receive money from Lord Ruthven end up far worse than they were before the charity. Although Aubrey cannot explain this, it intrigues him and makes him wonder if there isnt a spark of evil in Lord Ruthven. Some time later, Aubrey receives letters from his sister and his guardians. The letter from his sister is very loving, but the letter from his guardians bears only bad and mysterious news. They tell him that his traveling companion is pure evil, that all the women at home that he wooed because of their virtues, have now come forth and shown that they are tainted, and pursue their vices publicly. The people of their town find this unexplainable and very unnerving. He was suspicious of Lord Ruthvens evil before, but upon reading the letter, Aubrey decides that he must leave Lord Ruthven for the remainder of the trip. Aubrey travels to Greece, where he stays with a kind family and falls in love with their daughter, Ianthe, although he does not act on it. It is here that he learns the legend of the vampire. One day he goes to a place to research, and they tell him to be back before dark because of the vampire. He loses track of time and it is soon dark. He hears a scream and runs toward it. He finds a hut, and picks up a dagger that is inside. However, he is too late. Ianthe was murdered by the vampire. Aubrey falls into a fever and Lord Ruthven returns to him and nurses him back to health. Soon after this, they are attacked by robbers and Lord Ruthven is wounded. He dies, but makes Aubrey promise to him that he will not speak a word of his death. When Aubrey goes back for Lord Ruthvens body, it is gone, and the robbers tell Aubrey that they had to put it in the moonlight the first night of Lord Ruthvens death. They go to where they left the corpse, but it has mysteriously disappeared. Aubrey decides that it is time to go home. On his way home, he goes through Lord Ruthvens things and finds a shaft that matches the dagger he found in the hut exactly. This confirms for Aubrey  that Lord Ruthven is the vampire. When he arrives home, his sister holds a drawing-room. Here, Aubrey is snatched by the arm and told to remember his oath. Aubrey is dumbfounded because Lord Ruthven is supposed to be dead, but here he is, pursuing his sister. This drives him into a terrible fever. During this fever, he figures out that his sister is engaged to Lord Ruthven and fears for her. He tries to stop the wedding, but everyone thinks that he is crazy and dismisses him. His sister is killed at the end of the story. The fact that Lord Ruthven is a supernatural creature accounts for all of the supernatural events and the entire story. If he was not a vampire, his demeanor would never have attracted Aubrey initially, and Aubrey never would have gone traveling with Lord Ruthven. Had Aubrey not gone traveling with him, he never would have discovered that Lord Ruthven was a vampire, and gone crazy. If Aubrey had not gone crazy, he would have been able to stop the wedding and save his sisters life. Supernatural and unexplainable events are crucial to the plot of a gothic story. Often, they act as the backbone of the plot and many of the circumstances and coincidences rest upon them. In The Castle of Otranto, they act as the coincidence drivers as well as supply some of the omens and visions, another element of gothic literature. They bring the real story to the surface in The Ruins of the Abbey of Fitz-Martin, and provide the foundation for the story in The Vampyre. Without the element of supernatural and unexplainable events, much of the canonical gothic literature would not stand on its own.

Fluid Management System

Fluid Management System CAREER EPISODE 1 INTRODUCTION CE 1.1: Project title Fluid Management System was completed in my last year of Bachelor Degree program. I completed my Bachelors of Engineering Technologist in Mechatronics from Chisholm Institute, Dandenong, Australia. My first career episode is based on this project experience that I gained and performed for the fulfillment of my work placement. The project was completed in 13 weeks, from July 2015 to October 2015. I was assisted and guided by Prof. Francis Percy, lecturer of Advance PLC. BACKGROUND CE 1.2 Nature of project My project water management system operated on six different modes, operator can switch between different modes with the help of control panels that are mounted on each operating mode switch. It has 2 modes for each operational mode i.e. Automatic and Manual mode. 1 is used to represent Automatic mode and 2 for Manual mode. There are also auto-manual switch selectors. The mode is chosen based on the way user wants to operate. For this purpose, SCADA PLC programming is done to provide user friendliness. CE 1.3 The pump MDC 118 operates when the tank 1 or 2 is filled from the holding tank whereas MDC 103 operates when filling it between tank 1to tank 2 or vice-versa. The six operational modes are: Operation mode 1 fills tank 1 from holding tank through SV321 value (energized) and SV322(deenergized). Operational mode 2 fills tank 2 from holding tank through SV321 and SV322 valves (deenergized). Operational mode 3 fills tank 1 which has an analog sensor to manage the start and stop level for the filling with exact value from tank 2 through SV323 deenergized valve and SV324 energize value. Operational mode 4 fills tank 3 which has a digital and capacitive sensor to manage the start and stop level for the filling with capacitive sensors, LSL 532 and LSH 531 from tank 2 through SV323 energized valve and SV324 deenergize value. Operational mode 5 fills the holding tank to tank 1 and at the same time, transfers tank 1 to tank 2 through SV321 (energized), SV322 (de-energized), SV323 (de-energized) and SV324 (energized). It also maintains a set point for filling the tanks. Operation mode 6 fills the holding tank to tank 2 and at the same time, transfers tank 2 to tank 1 through SV321 (energized), SV322 (energized), SV323 (energized) and SV324 (de-energized). It also maintains a set point for filling the tanks. CE 1.4 Objectives To prove my overall understanding on automation system, I had to complete a project. I chose a project that was based on how the automation system works in manufacturing industry of advance PLC department. And as per my project requirement I had to perform PLC and SCADA programming. Based on the two choices given to me, from Fluid management system and Pressure management system, I chose Fluid management system. The objective was to make a complete a fully automated fluid management system using PLC programming with an HMI/SCADA in 13 weeks duration. It should consist of 3 water tanks, 2 pumps, number of 2 3 way valves using Allen Bradely software IFIX SCADA software and various fluid level measuring instrument. It was further required to: Program PLC for six operating modes While implementing all the hardware like fault lights operating lights SCADA programming Interfacing. CE 1.5 The chart of organizational structure CE 1.5 Duties I studied and researched the basic architecture of the fluid management system which included PLC CPU (Allan Bradley), Device Net Scanner and Flex I/O, RSlogix 5000(PLC programming software), HMI interact and software. I prepared the fluid management trainer system Device Net Network Set up. I created the PLC CPU DeviceNet scanner Module interface I create the mapping DeviceNet Nodes Input and outputs to the DeviceNet Scanner Module input and output registers. Performed commissioning and testing of a PLC system Coded the PLC programming for the water station for six different operating modes. Represent all the different modes to supervisor, explaining them how it works. Diving and providing time slots to team members. Maintaining balance and peace to avoid conflict among each other. Kept good relations with supervisor. Reporting the development of the project to the lab supervisor and coordinator. PERSONAL ENGINEERING ACTIVITY CE 1.6 The project I have done related to the educational qualifications that I have obtained in my degree course. The relationship between the different modules and project processes is explained below: PLC (Program logic control): Here, I learned how to write PLC program with Allen Bradley software by using RS logic 5000. This skill was helpful in completing my programming design for water station. Instrumental Principal: This module gave me the knowledge about sensors, how they work and wiring of the sensors, how you can program them. For this project, I have used electronics level sensor LK31 and Impeller flow meter. Electronics level sensor determine the level of fluid according to the capacitive measuring principal. Industrial Networking: My project involved the knowledge of DeviceNet and scanner which was learnt from this module. Project management: Project management module skills were completely applied at all the stages of project. The project was also divided in to two parts. All the tasks were scheduled and divided accordingly. I applied various techniques to practical implementation that learnt from project management. Mathematics and Fluid Mechanics: My project involved a lot of calculation for example, the calculations to find torque, force, and power for the motor along with the calculations done to find the physical parameters of components. I also did the calculations to select the pulley and belt as well. Professional Engineering Technologist: During the project life cycle, while working with Water station, I had to rely on the communication skills. The work experience gained during this project demonstrated how important the communication skills are to the professional engineering technologist. CE 1.7 As a group project, I had to separate the system which contains two main part PLC programming and SCADA programming. I decided to complete the PLC programming and assigning my mate mater the SCADA programming. In PLC Program subroutine, to make the programming easy for controlling, for finding faults and for easy access to different part of programming, I had to split the main routine into different subroutine. This process can be seen below:   Ã‚   Figure 1 PLC Program design methodology CE 1.8 To prevent the occurrence of PLC program interlocking, this technique of energization of one contractor prevents the energization of other until it is in use. This method is called interlocking and I used interlock as a pre-requirement of the task to run the program. Various safety factor and other reasons such as Pump/Motor Faults, pressure requirement of system etc. are considered to run the function of PLC properly. It also makes the programming part easy, for this only writing the code logic of interlocking at one place is required and the same code is used as a pre-requirement of task at another place. Figure 2 logic of interlock in one place and use interlock as pre-requirement of task CE 1.9 Considering the program logic interlock as Pump fault. It means, that if there is no pump fault, then the PLC will start running normally. Once the PLC starts running, it starts to operate in mode 1. In programming mode one, filling the tank 1 from holding tank through SV 321 valve (energized) and SV 322 valve (de-energized) is done. For the PLC program to be permissive, i.e. each process condition undertaken is called a permissive. For example, consider permissive to be a burner control for large combustion furnaces. To start the burners in a large furnace safely, the control system requests permission from several process switches, including high and low fuel pressure, air fan flow check, exhaust stack damper position, access door position, etc. Every process condition that it undergoes is called a permissive. In the below diagram, it is control to fill the tank 1 by tank level permissive, if water level is below 10cm it will start filling tank until to reaches 13cm. Figure 3 PLC program permissive CE 1.10 Once the PLC program was completed and along with all the DeviceNet IOs pre-commissioned, registered and labelled in the PLC controller memory I started to design each operating modes. I started with operating mode 1. Once the programming of operation mode 1 and 2 was completed and it started working as intended, I could test the rest of the inputs in the system which were the water level sensors. While programming I constantly referred to operating mode table that I made using various engineering tools. Once the basic idea was plotted in the table format, the programming of remaining operating modes was successfully completed and also some extra additional features were added. Figure 4 Operating mode table CE 1.11 In the system architecture, there is a PLC CPU, DeviceNet Scanner and Flex I/O, RS logic 5000, PLC program and SCADA IFIX program. DeviceNet is a network system that is used in the automation industry to interconnect control devices for data exchange. In the water management system, there is a DeviceNet scanner node. In a typical configuration, the scanner module acts as an interface between DeviceNet devices and the programmable controller. The scanner module communicates with DeviceNet devices over the network to: Read inputs from slave devices Write outputs to slave devices Communicate with peer devices. DeviceNet nodes setup as follows: Node 0: 1794-SDN Compact Logix DeviceNet Scanner/Master Module used for DeviceNet network control and data exchange with the PLC CPU. Node 1: Allen Bradley Flex IO distributed IO system. Node 2: Allen Bradley DeviceNet interface Stack Light system. Node 4: Allen Bradley Variable Speed Drive used for speed control of pump MDC118 CE 1.12 I started performing test runs at the final stage, which includes: Checked all the cable connections between the PLC and the plant are complete, safe, and to the required specification that meets the local standards. Checked that all the incoming power supply matches the voltage setting for which the PLC is set. Checked all protective devices are set to their appropriate trip settings. Checked that emergency stop button. Checked that all input/output devices are connected to the correct input/output points and giving the correct signals. And checked the FLEX I/O system that contains a network adapter, terminal bases, and I/O modules. CE 1.13 After performing the above troubleshooting, the only problem I faced during the implementation of the whole system was that the Emergency stop button wasnt working. To solve this issue, I took various steps. I started by checking the connections. The first module is 1794-ADN DeviceNet Gateway module which is used to communicate and transfer data between the DeviceNet Master Module and the Flex IO modules 2 4. And the module the next 3 modules in order from 2 to 4 are 1794-IB32 Digital Input Module 1794-IE4XOE2 Analog Input/output combination module 1794-OB16 Digital Output Module. I checked the digital and analog input connection with emergency button with help of my lab supervisor and realized the problem was regarding the analog and digital input only, so I tried to resolve it by doing a research and taking suggestions from supervisors. SUMMARY CE 1.14 I successfully achieved all the objectives of the project within specified time limit and I gained good knowledge from this project as I did intense research about sensors and PLC programing for my project in the form of literature review. This had added many useful engineering techniques to my knowledge and enhanced my problem solving and analytical skills. In addition to that, I also implemented and used my engineering knowledge to make this project successful. I used concepts of various Engineering techniques and PLC programing which I had studied during my course of Bachelor of engineering technologist in Mechatronics. I presented a project thesis and seminar on my work on submission of my project.