Application of Geography (GIS) In Biotechnology in Field Of Agriculture And Environment

Introduction Geographic information systems (GIS) have found widespread applications in many diverse fields as the number and range of such applications continue to increase with GIS extending to other fields. Biotechnology; a field in agriculture is one such area. The principal purpose of biotechnology is to improve productivity thus offering food security in areas that have faced food shortages in the past. With incorporation of GIS, meeting biotechnology goals has been realizable.Advertising We will write a custom essay sample on Application of Geography (GIS) In Biotechnology in Field Of Agriculture And Environment specifically for you for only $16.05 $11/page Learn More For instance, the South African government is realizing better crop production due to utilization of GIS coupled with biotechnology. With help of GIS, authorities are coming up with more authentic and precise crop estimates to counter uncertainty in the South African grain industry. This move helps in achieving biotechnology goals; that is, improved crop production hence, food security. Producer Independent Crop Estimate System (PICES) is currently in use in South Africa and is used primarily to estimate area covered by grain crops. Nevertheless, there are several challenges facing integration of GIS in this agricultural sector as explicated later in this paper. Why GIS in Biotechnology Elementarily, understanding geography and establishing its relationship with other fields like agriculture, enables people to make wise decisions and in this case, wise food security decisions. According to Wyland (2009, p. 4), â€Å"the ability of GIS to analyze and visualize agricultural environments and work flows has proved to be very beneficial to those involved in the farming industry.† In biotechnology, GIS is helping to foster production, manage land expeditiously, and cut unnecessary costs in production. It is true that farmers cannot control farming natural inpu ts like soil, land, and rainfall among others; however, understanding these inputs through analysis by GIS systems, would work to their advantage in achieving their objectives in farming. For instance, through GIS, farmers can determine crop yield approximates, canvass soil amendments, detect soil erosion and postulate remediation strategies. Moreover, GIS is used to study other farming practices like pest control, fertilizer application, and crop diseases among others. The Most Appropriate Data Model The most appropriate data model in this agricultural application is the vector data models/structures (Soller 1999). â€Å"This mapping approach characterizes the vertical variations of physical properties in each 3-D map unit† (Soller Berg 2003). This model addresses the issue of determining land under grain crops better. The three dimensional mapping element of this model qualifies it as the most appropriate tool.Advertising Looking for essay on agriculture? Let's see if we can help you! Get your first paper with 15% OFF Learn More Moreover, this model is the best tool for mapping geographical space; it presents spatial locations precisely and relates entities implicitly (Doe 1997). According to Johnson, (1998, p. 16), this model has â€Å"Points associated with single set of coordinates with lines connected to sequence of coordinate pairs and area sequence of interconnected lines whose 1st last coordinate points are the same.† Therefore, given the objective of using GIS in this field, vector model stands out as the best. Estimating land under crop cover has to be more accurate and reliable if farmers are to root out the nightmare of food insecurity. Above all, the vector model represents what the map really looks like including all the dimensions (Tomlinson 2005). The data obtained in this model can be stored in separate files with a link connecting them thus enhancing information sharing and preventing complete information loss a t the same time (Soller Lindquist 2000). Moreover, this model comes in diverse varieties like, spaghetti, network model, dime files, and digital line graph (DLG) among others (Berry 1993). Therefore, based on the above key points, the vector data model is the most suitable one for this exercise. Applicable Data Sets and Data Sources As aforementioned, vector data model comes in varieties and this means that there are varieties of data sets available. In this agricultural field, one would consider using data sets like, ArcAtlas; Our Earth, which contains â€Å"global geographic and attribute data at three scales†¦with 1:20,000,000 for Africa† (ESRI Data Maps 2002). Others include digital charts of the world, and ESRI data and maps. These data sets enable users to break down geographical information into manageable sizes that can fit into computerized models (Lee Kretzschmar 2003). The 1: 20, 000, 000 scales have been used successfully in South Africa to estimate land u nder grain crops as aforementioned. Applicable data sources in this case include information from farmers and crop field boundaries that have been digitalized from satellite imagery. To complete this project of determining grain cropland cover in South Africa, the government is coming up with model maps representing this land. These model maps are the only products that this exercise has been able to come up with so far. To make these maps, several steps are involved as explicated next. Steps Used in Obtaining the Maps There are five steps used in developing the required maps that represent grain cropland cover in the estimation process. As aforementioned, the South African government is using PICES in this exercise.Advertising We will write a custom essay sample on Application of Geography (GIS) In Biotechnology in Field Of Agriculture And Environment specifically for you for only $16.05 $11/page Learn More The first step is getting satellite imagery. According to Fourie (2009, p. 9), the government of South Africa via Ministry of Agriculture provides the satellite imagery where, â€Å"SPOT Image Spot 5 satellite imagery with a 2.5-meter resolution is used as the base layer for digitizing.† After obtaining this satellite imagery, it is used to digitize the crop field boundaries. This exercise uses ArchMap, which lies under ArchAtlas. For clear-cut boundaries and images, 1:10,000 scales are used then the elaborate metadata captured in ArcCatalog from one province to the other. Through this method, the nine South African provinces are already digitalized. After obtaining clean and precise digitalized crop field boundaries, point frames are designed coupled with random sample point selection (Smith, Goodchild Longley 2007). The importance of random sample point selection is to ensure representation of possible cropped fields as subjects of field survey. A square point grid (45 m by 45m), is constructed for the total area und er each of the nine provinces. All the grid points falling outside the field boundaries are eliminated from the test population for they are improbable to locate any crop. The digitalized fields are then divided depending on the possibility of getting a crop. In these divisions, there are low, medium, and high divisions depending on the probability of getting a crop. It therefore follows that, the low classes have low probability, the medium have moderate probability while the high classes have the highest probability (Thurston, Poiker Moore 2003). The purpose of this classification is to improve sampling efficiency. Therefore, majority of sample points are drawn from areas with high probability. Wise (2002, p. 6) points out that the purpose of this process is to â€Å"obtain the most useful data within the budget constraints and keep the coefficient of variance (CV) as low as possible.† CV is the â€Å"ratio of standard deviation to the mean; it is used when comparing data sets with different units or widely differing means† (Doaks 1997, p. 16). From each stratum, grid points are selected, taken to a Microsoft SQL server database, and grouped consistently from north to south and east to west to guarantee optimum distribution of sample points across a given geographical area (Elangovan 2006). Thereafter, a stochastic starting point is selected and points picked at even intervals based on the number of points needed in each stratum.Advertising Looking for essay on agriculture? Let's see if we can help you! Get your first paper with 15% OFF Learn More The fourth step is carrying aerial survey of sample points, which obtains crop data. This means that, the crops planted in each sample point are determined and the process involves use of a light aircraft. â€Å"A tablet PC, connected to a GPS running on an ArcPad is used to capture this data† (Fourie 1999, p. 1). This survey involves collecting information on the crops growing on each sample noting whether the crops grow under irrigation or on dry lands. Moreover, more information on specific natural conditions of the land is included in this survey for future references. Finally, the field data â€Å"captured and stored in shapefile format† (Burrough 1998, 69). This information is then transferred to a central server and then to SQL server database (Soller, Berg Wahl 2000). From here, the information can be used in statistical analysis to estimate cropland under grain cover. Limitations Facing GIS in Biotechnology There are numerous challenges facing proper utilizat ion of GIS in this agricultural field. The preferred GIS model is complex and utilizes complicated strategies. For instance, â€Å"Combining several polygon networks by intersection and overlay is difficult and it uses considerable computer power† (Worboys Duckham 2004). Moreover, this process is time consuming and tedious and â€Å"simulation modelling of processes of spatial interaction over paths not defined by explicit topology is more difficult because each spatial entity has a different shape and form† (Maguire, Goodchild Rhind 1997, p. 97). Additionally, this process faces other computational problems and finally it is expensive and may be not applicable in areas with poor economical background. Other issues concerning application of GIS in biotechnology include the ethical concerns surrounding use of biotechnology. Many people have not come into terms with use of biotechnology and in as much as GIS is there for improvement of food production, it may be imposs ible to implement it in areas where biotechnology is not welcomed. On the other hand, GIS has played key role in promoting biotechnology and food security. It has become easier to study arable lands for improvement of production. Conclusion In contemporary times, GIS is becoming a common place across diverse fields. In biotechnology and agriculture in general, GIS has come with numerous advantages. With GIS, the South African government has successfully estimated cropland planted with grains to predict how these lands can sustain grain requirements in the country. Biotechnology is then used to foster productivity of the surveyed lands. On its own, biotechnology would not sustain and assure food security in South Africa because there could not be estimates of what is required. The vector model of GIS has been used widely in these studies given its three dimensional nature of analyzing geographical settings. Several processes are involved starting with obtaining satellite imagery, thr ough digitalizing crop field boundaries and designing point frame to aerial survey and statistical analysis. However, this process is expensive and time consuming given the complex nature of vector data structures and the required resources. References List Berry, J 1993, â€Å"Beyond Mapping: Concepts, Algorithms, and Issues in GIS†, Fort Collins, CO: GIS World Books Burrough, A Mcdonnell, R 1998, â€Å"Principles of Geographical Information Systems†, Oxford; Oxford University Press. Doaks, J 1997, â€Å"Another Introduction to GIS, New York: Bogus Press. Doe, J 1997, â€Å"An Introduction to GIS,† New York: Bogus Press. Elangovan, K 2006 â€Å"GIS: Fundamentals, Applications and Implementations†, New Delhi New India Publishing Agency. ESRI Data Maps 2002, â€Å"GSI Models†, CA: Environmental Systems Research Institute Fourie, A 1999, â€Å"Better Crop Estimates In South Africa†, ESRI Press, 9-14. Johnson, B 1998, â€Å"Digital Geologic Map Data Model. V. 4.3: AASG/USGS Data Model Working Group Report†, Available at  https://www.usgs.gov/science/science-explorer/geology Lee, J Kretzschmar, W 1993, â€Å"Spatial Analysis of Linguistic Data with GIS Functions†, International Journal of Geographical Information Science, 7(6); 541-560. Maguire, D, Goodchild, F Rhind, W 1997, â€Å"Geographic Information Systems: Principles, And Applications†, New York; Longman Publishers. Smith, M, Goodchild, F Longley, A 2007, â€Å"Geospatial Analysis: A Comprehensive Guide to Principles, Techniques and Software Tools†, International Journal of  Geographical Information Science, 8(6); 64-78. Soller, D 1999, â€Å"Proposed Guidelines for Inclusion of Digital Map Products in The National Geologic Map Database†, U.S. Geological Survey Open-File Report 99 (386); 35–38 Soller, D Berg, T 2003, â€Å"The National Geologic Map Database Project: Overview And Progress†, U.S. Geological Survey Open-File, Report 03–471. Soller, D, Berg, T Wahl, R 2000, â€Å"Developing the National Geologic Map Database, Phase 3—An Online, â€Å"Living† Database Of Map Information†, Available at  https://www.usgs.gov/ Soller, D Lindquist, T 2000 â€Å"Development And Public Review Of The Draft â€Å"Digital Cartographic Standard for Geologic Map Symbolization†, Available at  https://www.usgs.gov/ Tomlinson, R 2005, â€Å"Thinking About GIS: Geographic Information System Planning For Managers†, ESRI Press. Thurston, J, Poiker, T Moore, J 2003, â€Å"Integrated Geospatial Technologies: A Guide To GPS, GIS, And Data Logging†, Hoboken, New Jersey: Wiley. Wise, S 2002, â€Å"GIS Basics†, London: Taylor Francis Worboys, M Duckham, M 2004, â€Å"GIS: A Computing Perspective†, Boca Raton: CRC Press. Wyland, J 1999, â€Å"Agribusiness Grows With Crop-Specific Maps†, ESRI Press. This essay on Application of Geography (GIS) In Biotechnology in Field Of Agriculture And Environment was written and submitted by user Maya D. to help you with your own studies. You are free to use it for research and reference purposes in order to write your own paper; however, you must cite it accordingly. You can donate your paper here.

10 Metals and Minerals for Metaphors

10 Metals and Minerals for Metaphors 10 Metals and Minerals for Metaphors 10 Metals and Minerals for Metaphors By Mark Nichol Metals and minerals sometimes inspire associations with human characteristics or with circumstances, as in the case of the examples below: 1. Adamant Few people realize that this word, which in adjectival form means â€Å"insistent† or â€Å"unyielding,† has a lustrous origin: It comes from a Greek noun by way of Latin and originally referred to a diamond or any hard metal. In English, it also is a noun referring to the same materials or any similarly adamantine substances (yes, adamantine is a variant adjective). 2. Brassy From an association with the stridency of brass musical instruments, this adjective has come to refer not just to a quality of sound (as well as a description for the metal compound) but also to bold, clamorous, or unruly behavior. 3. Bronze The comparison of deeply tanned skin with the color of the metallic compound has resulted in the use of bronze to refer to a person with dark skin, either due to genetics or to extensive tanning, as in the reference to a physically imposing man with this hue as â€Å"a bronzed god.† 4. Flinty This term meaning â€Å"stern, unyielding† comes from the hard variety of quartz known as flint, which sparks when struck by steel and has therefore been used for millennia to start fires (though the â€Å"flint† in cigarette lighters is actually an iron alloy). The word skinflint, a synonym for miser, evokes the image of someone attempting to peel a layer off of a hunk of flint (a futile gesture because of its hardness). 5. Golden The value placed on the element gold has led to the use of the adjective golden for various figurative references. Among these, a golden musical tone is a mellow, resonant one; someone or something that is or is expected to be excellent, popular, or otherwise remarkable is marked, for instance, as a golden boy; an age or era might be described as golden; and a favorable occasion is often referred to as a golden opportunity. 6. Iron The word for this fundamental metallic element has been appropriated as an adjective denoting strength (â€Å"iron will†), robustness (â€Å"iron constitution†), relentlessness (â€Å"iron determination†), and firmness (â€Å"iron grip†). The rarely used noun form of these figurative senses is ironness. 7. Leaden Lead, because of its density and its dull color, is associated with literal (â€Å"leaden trudge†) and figurative (â€Å"leaden skies†) heaviness, as well as with dispirited or unsubtle characteristics. 8. Ossified This term literally denotes changing into bone and figuratively refers to becoming set in one’s ways. (Although bone is not strictly a mineral, it is largely composed of various minerals, hence its inclusion on the list.) 9. Silver The adjective form of the noun silver refers to soft or dulcet sounds (as of chimes), or to eloquent persuasion (â€Å"silver tongued†). Glossy gray hair is often referred to as silver, and that description leads to connotations of mature elegance (â€Å"silver-haired dignity†). 10. Steely This adjective referring to strength and hardness is best known as part of the clichà ©s â€Å"steely determination† and â€Å"steely resolve.† Want to improve your English in five minutes a day? Get a subscription and start receiving our writing tips and exercises daily! Keep learning! Browse the Expressions category, check our popular posts, or choose a related post below:Bare or Bear With Me?Acronym vs. InitialismAdverbs and Hyphens

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Personal Statement for law school, Why do you want to go to law school - Essay Example After I saved enough money I went back to India on vacation to visit my father and family. When I was back in my home nation as an adult I saw things very differently that was a kid. Everything had changed for the worst. There was a horrible distribution between classes divided by small elite class and the rest of us who were stuck in deep poverty. Governmental corruption was latent and it seemed nobody in the system care about nothing but themselves. Serving the people was not a priority of the public servants. Restaurants would throw away food that could have given at the end of the night to the poor; the Indian society was in chaos in need of direction, order and justice. I reflected a lot during my stay in India and came back to the United States a new person. I was inspired to become a solution maker that brought change. I knew I had to continue my formal education at the undergraduate level to then move on to law school. As a lawyer I could gained the knowledge to be able chang e the public system. I want to fight injustices anywhere they manifest themselves. The trip to India changed my perspective of life. I realized I had taken for granted the liberties and opportunities people in the United States enjoy. This society built its democratic system based on set of laws and principles written in the constitution. Lawyers are important members of a society that protect the rights of the regular citizen. They law plays an instrumental role in the lives of everyone because it brings stability to a region. I had not noticed this before because I was unaware of the injustices that occur in many developing countries around the world. In order to prepare myself for a future as a lawyer I choose to study business administration with majors in accounting and finance at Hofstra University. Business school is a great way for a

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Service Quality & Customer Satisfaction - Essay Example Yet when they asked for the manager in order to voice their concerns they were told that, the manager was out on a meeting. Still they had no lack in talking to other staff in the restaurant. Lastly, the contact between staff and the client has the component of perceived command in both par ¬ties. The staff intends to control the conduct of the client to render their own job more practicable and less demanding; similarly, the consumer is attempting to obtain control over service encounter to obtain the most gain from it (Zeithaml 2010).For instance the staff who had told the students that the manager was unavailable must have said this so us to make her work easier. While the students wanted to complain to the manger in order to get a good service. Supremely, the 3 parties benefit much by functioning together to generate a useful service encounter. The decisive moment may be dysfunctional; conversely, the minute one party controls the interface by focusing exclusively on her or his own manipulation of the service encounter.The extent of subjective features of consumer service hinges on the compliance of the anticipated gain with the alleged result. This then relies upon the client's expectation concerning the service they may receive in addition to the service giver’s talent and ability to deliver this expected service. Prosperous Companies add reimbursements to their delivery that not only please the clients but also delight and surprise them. Delighting clients is a question of surpassing their expectations. Quality service can be linked to service prospective (for instance, worker's skills); service process (for instance, the rapidity of service) in addition to service result (client satisfaction). The quality service of the Burger King Restaurant is poor except for the part where the staffs are polite and courteous. The environment setting of the restaurant was not accommodative for the university students. They could not obtain a table large enoug h to cater for

Apple Inc Case Study Example | Topics and Well Written Essays - 2250 words

Apple Inc - Case Study Example In fact, it contributes to over 50% of Apple’s bottom line and with the sales of its iPhone 5 surpassing that of the iPhone 4s, the company’s market cap increased significantly. Secondly, the Apple Dividend announced in March of 2012 made its stock more attractive to income-searching retail investors, despite its small yield. However, income fund managers found its $2.65 quarterly dividend more important as the income funds require that the investments must provide income (Sutherland, 2012: p52). Having a dividend made it possible for more investors to buy its stock, which increased its market cap. In addition, although Apple’s stocks have been fluctuating, its fundamentals have stayed the same with over $100 billion in cash reserves and no debts. This ensures that investors see it as a safe bet that will climb again. Apple was able to identify market trends and capitalize on them through various means. With a diverse range of stylish products, Apple capitalized on the fact that consumers wanted to be different. The iPhone and the iPad were released after Apple recognized the high demand for computers and phones but that most products on the market looked the same with similar functionalities (Treacy, 2012: p60). Another reason for Apple’s ability to capitalize on identified market trends is its dynamic business plan, which is always set to resonate with what the market wants. By changing the company’s name to Apple Inc from Apple Computer, the company identified the need for a phone with computer functionalities and broadened their spectrum. Apple was also able to identify the fact that music retail outlets were becoming popular and that outsourcing this capability was not giving them what they wanted (Treacy, 2012: p60). ... By opening a retail store, they were able to capitalize on consumers needs for a retail outlet on their phones. Apple was able to achieve global success by leveraging brand loyalty. By taking their business to emerging markets with minimal penetration of smartphones but where their brand was already known due to mass media, the company opened up new opportunities for developers in those markets (Treacy, 2012: p72). In addition, by hiring employees from those countries and from diverse fields, including artists and musicians, they were able to create unique and different perspectives from those countries. Apple also built relationships with its customers in various regions of the world by embracing social media and the internet, which meant that people in these new regions saw Apple as a transparent and trustworthy company. In addition, they also used movement marketing, in which they marketed what Apple believed in, contending that they sought to bring personal experience of computin g to consumers across the world via innovation (Treacy, 2012: p73). By leveraging brand loyalty, Apple consumers have overlooked glitches as they have emotional connections with their products. However, in order for Apple to gain market share across the world, various companies also had to lose market share and the most affected company was Microsoft. By combining most of what Microsoft offered, including a phone, search engine, office, and operating systems, Apple was able to offer consumers a product that was more appealing (Treacy, 2012: p91). By doing this, Apple was also able to grow various market segments. One of them was the smartphone market, which, although still stagnant at 3%, has pushed its competitors to

The History Of The Kitchen Refrigerators

The History Of The Kitchen Refrigerators Today, refrigerators have become an essential part of every kitchen (Tatum, 2010). Refrigeration is used to store meat, vegetables among other foodstuffs at low temperatures, thus inhibiting spoilage due to microbial activity. The process of essentially, manufacturing or making a refrigerator was gradual and begain in the 18th century. It culminitated with Carl von Lindens work in 1876. (Bellis, 2010 Tatum, 2010) Evidence suggests that since 500 AD, man has known to produce ice by natural processes. Egyptians and Indians made ice on cold nights by setting water on earthenware pots. Later on in the 1700s, England servants in the 1700s collected ice in the winter and put into icehouses, which then provided cool storage in the summer. (Bellis, 2010 Tatum, 2010) In 1748, William Cullen of the University of Glasgow developed an entirely new process that consequently lead to an artificial cooling medium being developed. (Tatum, 2010). His experiment produced ice. However; he was unable to explain what it meant. Around 1805, the Oliver Evans was involved in designing a refrigeration apparatus, but unfortunately, he didnt build one until Robert Perkins improved on his creation in 1834. (Bellis, 2010). Thomas Moore coined the word refrigerator for these machines. However, as today Perkins and Evans machines are called iceboxes. In 1844, Dr. John Gorrie, a physician, was able to construct a working unit that was based on both Evans and Perkins model. constructed. It was because of a outbreak of yellow fever that led to Gorrie creating the unit, which was used to cooling the air. (Bellis, 2010 Tatum, 2010) Gorrie is credited as being the one who invented the refrigerator by many. (Bellis, 2010) However the situation began to change, when Carl von Linde (1842-1934), a German mechanical engineer published an essay on improved refrigeration techniques, in 1871. He proposed a continuous process of liquefying gases in large quantities. In 1873, he invented the first practical and portable compressor refrigeration machine. (Tatum, 2010) He obtained a patent for his refrigerator in 1877 from the German Imperial Patent Office. He made use of gases namely ammonia, sulphur dioxide and methyl chloride. (Bellis, 2010 Tatum, 2010) In the 1900s, various refrigeration models were seen. Noteworthy refrigerator models included Servel, Frigidaire, Electroflux among others. (Bellis, 2010) These models of the 1900s had several advancements since designs of pioneers such as Gorrie. By 1918, automatic controls were part of some models already. (Tatum, 2010) The gases used namely ammonia, sulphur and methyl chloride were replaced by Freon in the 1920s in order to comply with safety standards. When one looks at the history, it shows that in 1918, automatic parts were already installed. This included automatic dials that aid in the operation. It was rather unfortunate that the units were not self contained as different parts were separately placed from each other. It wasnt until 1923 that self contained refrigerators began appearing. (Bellis, 2010) Ice cube trays were also introduced. (Tatum, 2010) Although many advancements were made, the modern refrigerator was put in mass production until 1946 i.e., after the World War II. (Bellis, 2010 Tatum, 2010) People, in the the 1950s and 1960s were the ones that witnessed a variety of technological innovations by engineers and scientists of the day. Among them were: (i) automated defrosting and (ii) making of ice. Today, there are many features that are intertwined with the features of the olden days and includes power failure alerts, ice cabinets among others. (Bellis, 2010 Tatum, 2010) To present, domestic refrigerators are present in almost every home worldwide. Due to the models created by Gorrie, Cullen, Carl von Linche among others, the refrigerator has thus become one of the machines or applicances that is integral to us every day. (Bellis, 2010 Tatum, 2010) TYPES OF REFRIGERATORS Refrigerators are classified into three types: (Suyambazhahn, 2009) Air refrigerator Vapour compression refrigerator Vapour absorption refrigerator VAPOUR COMPRESSION REFRIGERATION SYSTEM The vapour compression refrigeration system is most commonly used in refrigerators. A refrigerant is a gas with characteristics that make is suitable for refrigeration and air conditioning. R-22 is a commonly used refrigerant. This cycle works in four phases, which are described later on because it is similar to the refrigeration cycle. Figure 1 Vapour compression refrigerator (Suyambazhahn, 2009) This type has various uses such as: (Suyambazhahn, 2009) Air conditioned cinema theaters, restaurants, hospitals, residential buildings for comfort. Advanced medicines which are manufactured and preserved only in special atmospheric conditions. Preservation of food products. VAPOUR ABSORPTION REFRIGERATION SYSTEM The principle of vapour absorption was first discovered by well known scientist Michael Faraday in 1825. But this concept is applied to refrigeration during 1860s by French Scientist Ferdinand Carve. The commonly used refrigerant for vapour absorption system is ammonia, NH3. In order to change the conditions and phase of refrigerants, heat energy is utilized in vapour absorption system where as mechanical energy is utilized in vapour compression systems. In a vapour absorption system, compressor is replaced by an absorber, a pump and a generator. The vapour at the low pressure that leaves the evaporator is then moved to the absorber. The absorber contains weak ammonia solution. The vapour leaving from the evaporator is dissolved in the weak ammonia solution to form a strong solution. Cooling water is used to cool he absorber. The strong solution from the absorber is pumped to the generator. The strong solutions pressure is increase by the pump (10 bar) and is circulated through the system by pump. Figure 2 Vapour absorption refrigerator schematic (Rajadurai, 2009) COMMONLY USED REFRIGERANTS Even though there are many types of refrigerants which are used in various applications, the following types are important from the subject point of view. AMMONIA It is the most widely used refrigerant. It is mainly used as the refrigerant in cold storage plants and also in ice making plants. Its boilined point at atmospheric pressure is -33 oC and it has a high latent heat and high critical temperature which are desirable properties of ammonia as a refrigerant. Also it is less expensive. But its usage becomes secondary due to the following characteristics: (Rajadurai, 2003) It is toxic It is flammable It has an irritating odour It attacks metals like copper and brass in the presence of moisture CARBON DIOXIDE The demerits involved in the usage of ammonia can be eliminated by using carbon dioxide. It is non toxic and odourless. It has a boiling point of -77.6 oC at atmospheric pressure. But it is not so often used because of its high operating pressure that is the operating pressure of CO2 is very high as 70 bar. (Rajadurai, 2003) SULPHUR DIOXIDE It has a boiling point of -10 oC at atmospheric pressure. IT has a very low working pressure and a large latent heat with a high critical temperature. It is non flammable and on explosive. Even though there are many positive characters mentioned, the SO2 refrigerant is very toxic and it has an irritating pungent odour. Also it is very corrosive in contact with moisture. (Rajadurai, 2003) FREON 12 (or DICHLOR DI FLUOROMETHANE) It has a boiling point of -30 oC at atmospheric pressure. It is non toxic, non explosive and on flammable. It is odorless and colourless. It is non corrosive to any metal. But it is highly costlier than other types of refrigerators. But the main demerit with respect to this is type is the large amount of refrigerant that is necessary to be circulated for a given output. It is generally abbreviated as R-12 or F-12. (Rajadurai, 2003) FREON 22 (or DICHLOR MONO CHLORO METHANE) It is widely used as the refrigerant for domestic refrigerants. It has all positive points like the characters posed by Freon 12 such as non toxicity. It is colourless, odourless and non corrosive to metal. Additionally, the amount of refrigerant required is only 1.3 kg/min per tonne for refrigeration. (Rajadurai, 2003) PRINCIPLES OF OPERATION THERMODYNAMICAL CONSIDERATION THE SECOND LAW The second law of thermodynamics is described as the most fundamental law of science (Khemani, 2008). It is fundamental in the sense that it can be used to explain not only refrigerators and heat engines but highly advanced phenomena such as the big bang. It has been put aptly in the words of Classius as it is impossible for a process to occur that has the sole effect of removing a quantity of heat from an object at a lower temperature and transferring this quantity of heat to an object at a higher temperature (Mortimer, 2008). This essentially means that heat cannot flow spontaneously from a cooler to a hotter body if nothing else happens (Mortimer, 2008) i.e. there needs to be an external agency to effect the change. In kitchen refrigerators, the closed box inside is able to be kept cool by the removal of heat from the inside of the box and deposits it to the outside. As per the second law, the heat will not move from the cold to the hot freely so it is important for it to be made to do so, this is done by using an intermediate fluid (Littlewood, 2004) which absorbed heat on the inside. This intermediate fluid is known as a refrigerant and carries the heat outside of the box whereby it it released into the air as heat as shown in Figure 3 (Littlewood, 2004). Figure 3 the flow of heat within the refrigerator a schematic (Littlewood, 2004) The fluid circulates within the pipe which passes in and out and can be found at the back of the refrigerator. It is kept by using a compressor (which uses electricity from the home) and allows it to work effectively without violating the second law of motion. (Littlewood, 2004) THE FIRST LAW Refrigerator takes in energy from a region that needs to be cooled and deposits this heat energy into some other region that is outside of the refrigerator. In order to do work, there needs to be some mechanism in place, where the work done by a compressor and its electric motor is utilized. Using the First Law of Thermodynamics we can write: (Littlewood, 2004) Figure 4 the first law of thermodynamics (Littlewood, 2004) QC QH = -W Where: Qc energy or heat of the cold system QH = energy or heat of the hot system W = work done Since work is done on the refrigerator by the compressor, the work is done is deemed negative because of sign conventions. This is part of the first law (Littlewood, 2004). The refrigerator is termed as a closed system and it possesses a constant composition: U = U + (à ¢Ã‹â€ Ã¢â‚¬Å¡U/à ¢Ã‹â€ Ã¢â‚¬Å¡V) T dV U = U + (à ¢Ã‹â€ Ã¢â‚¬Å¡U/à ¢Ã‹â€ Ã¢â‚¬Å¡T) V dT U = U + (à ¢Ã‹â€ Ã¢â‚¬Å¡U/à ¢Ã‹â€ Ã¢â‚¬Å¡V) T dV + (à ¢Ã‹â€ Ã¢â‚¬Å¡U/à ¢Ã‹â€ Ã¢â‚¬Å¡T) T dT dU = (à ¢Ã‹â€ Ã¢â‚¬Å¡U/à ¢Ã‹â€ Ã¢â‚¬Å¡V) T dV + (à ¢Ã‹â€ Ã¢â‚¬Å¡U/à ¢Ã‹â€ Ã¢â‚¬Å¡T) V dT According to Bain (2010), there are four basic parts to any refrigerator: Compressor Heat Expansion valve Refrigerant The exchanging pipes are a coiled set of pipes that is placed strategically outside of the unit. The refrigerant as will be discussed later on is a liquid that has the ability to evaporate efficiently so that inside the refrigerator is kept cooled. (Bain, 2010) A gas can be cooled by adiabatic expansion if the process is enthalphic. The gas expands through a process barrier from one constant pressure to the next and the temperature difference in observed. Insulation of the system made the process adiabatic. The result is that a lower temperature was absorbed on the on a low pressure side and the change in the temperature is proportional to the change in pressure. (Bain, 2010)  Ã¢â‚¬Å¾T  µ  Ã¢â‚¬Å¾P Figure 5 schematic of a domestic refrigerator (Bain, 2010) Figure 6 heat transfer within a refrigerator (Popular Mechanics, 1993) When an energy |qc| is removed from a cool source at some temperature Tc, and then deposited in a warmer sink at a temperature Th, the change in entropy is: (Atkins dePaula, 2006) Atkins dePaula (2006) also indicated that the process is not spontaneous because the entropy generated in the warm sink is not enough to overcome the loss of entropy from the cold souce. And because of this more energy needs to be added to the stream that enters the warm sink to generated the entropy required by the system. They further indicated that the outcome is expressed as the coefficient of performance, c: The less the work required to achieve a given transfer, the greater the coefficient of performance and the more efficient the refrigerator (Atkins dePaula, 2004). Because |qc| is removed from the cold source, the work |w| is added to the energy stream, the energy deposited as the heat in the hot sink |qh| = |qc| + |w|. Therefore, From: We can have an expression in terms of the temperature alone, which is possible if the transfer is performed reversibly (Atkins dePaula, 2006): Where: c = thermodynamic optimum coefficient of temperature Tc = temperature of the cold sink Th = temperature of the hot sink For a refrigerator, it important that a very low coefficient of performance. For a refrigerator withdrawing heat from ice cold water (Tc = 273 K) in a typical environment (Th = 293K), c = 14. As an example, to remove 10 kJ (enough to freeze 30 g of water), requires transfer of atleast 0.71 kJ as work. (Atkins dePaula, 2006) The work to maintain a low temperature is very important when designing refrigerators. No thermal insulation is perfect, so there is always some form of energy flowing as heat into a specific sample at a rate that is proportional to the temperature difference. (Atkins and de Paula, 2006). Figure 7 (a) the flow of energy as heat from a cold sink to a hot sink is not spontaneous as described the first law. Notice that the entropy increases but it is larger for the hot sink as compared to the cold sink. (Atkins dePaula, 2006). This contributes to a decrease in the NET entropy. (b) The process becomes feasible if work is provided to add to the energy stream. Then the increase in entropy of the hot sink can be made to cancel the entropy of the hot source (Atkins dePaula, 2006) The rate at which energy leaks happen is written as: Where: A = a constant that depends on the size of the sample and details of the simulation Tc = temperature of the cold sink Th = temperature of the hot sink The minimum power, P, required to maintain the original temperature difference by pumping out that energy by heating the surroundings is: As can be seen the power increases as the square of the temperature difference (Th Tc). THE REFRIGERATION CYCLE The gas is pumped continuously at a steady pressure, the heat exchanger (which brings the required temperature) and then through a porous plug inside container that is thermally insulated. A phase change heat pump uses a liquid, as described earlier, that has a very low boiling point, which is used to move heat from an area where it is cooler to one where it is warmer. The refrigerant requires energy so that it can evaporate, which essentially allows it remove the heat from the surroundings by absorbing it. When the vapor condenses, the energy absorbed in the process is released which is also in the form of heat as might be expected. A refrigerant is a compound used in a heat cycle that undergoes a phase change from a gas to a liquid and back. Latent heat describes the amount of energy in the form of heat that is required for a material to undergo a change of phase (also known as change of state). Two latent heats are typically described. (Bambooweb, 2009)For other uses, see CFC (d isambiguation). The pump operates a cycle in which the refrigerant changes state from its liquid form to the vapour form and vice versa. This process occurs repeatedly and I known as the refrigeration cycle. In this cycle, the refrigerant condenses and heat is released in one point of the cycle. It is the boiled (or evaporated) so that it absorbs heat in another point of the cycle. The widely used refrigerant is hydro fluorocarbon (HFC) known as R-134a and CCl2F2 (dichlorodifluoromethane). Other substances such as liquid ammonia, propane or butane, are be used but because of their highly flammable nature, they are disregarded as a good refrigerant. 1930 (MCMXXX) was a common year starting on Wednesday (link is to a full 1930 calendar). (Bambooweb, 2009)For other uses, see CFC (disambiguation). In the refrigerator the fluid used (e.g. CCl2F2 ) fluid is liquefied by compression then vaporized by sudden expansion which gives a cooling effect. The compressor, in itself does not create a cooling effect directly, as might be expected. The cooling effect is fashioned when the refrigerant absorbs the heat so that it is removed and the area becomes cooler. This is accomplished with a heat exchanger. (Bambooweb, 2009)For other uses, see CFC (disambiguation). A heat exchanger is a device built for efficient heat transfer from one fluid to another, whether the fluids are separated by a solid wall so that they never mix, or the fluids are directly contacted. The refrigeration cycle can be divided in two parts: The liquefaction stage The evaporation stage LIQUEFACTION STAGE The refrigerant vapour undergoes recycling by itself into the liquid form by the extraction of heat from a vapour at a higher temperature. The refrigerant is compressed by the compressor where a low pressure and low temperature condition is created. This is accomplished by an evaporating coil. During the compression process, the vapour of the refrigerant undergoes a temperature change (as an effect of the compression process). Additionally, the work of compression to create the high temperature and pressure vapour also contributes to the temperature change experienced by the vapour. The condenser that is located where the temperature is higher (i.e. the higher temperature heat sink) collects the vapour. Heat is then removed from the refrigerant and in lieu of this it condenses to its liquid state, hence the name for the condenser. (Mortimer, 2003 ; Brain, 1994 ; Bellis, 2010) Using the Joule-Thompson coefficient: For a perfect gas  µ = 0 Cp + Cv = (à ¢Ã‹â€ Ã¢â‚¬Å¡H/à ¢Ã‹â€ Ã¢â‚¬Å¡T)p (à ¢Ã‹â€ Ã¢â‚¬Å¡U/à ¢Ã‹â€ Ã¢â‚¬Å¡T)p Introducing: H = U + pV = nRT into the first term: Cp Cv = (à ¢Ã‹â€ Ã¢â‚¬Å¡U/à ¢Ã‹â€ Ã¢â‚¬Å¡T)p + nR (à ¢Ã‹â€ Ã¢â‚¬Å¡U/à ¢Ã‹â€ Ã¢â‚¬Å¡T)p = nR EVAPORATION STAGE As the refrigerant leaves the condenser, the next part of the cycle begins. This is accomplished when a high temperature and high pressure liquid passes through a metering device that is found within the refrigeration. The valve allows a specific quantity of liquid coolant to pass into the evaporation chamber. Evaporation chambers are relatively low pressure and this encourages coolant evaporation. Newly evaporated coolant is drawn though the cooling coils (typically a fan is used to blow air over the coils). Thus, the evaporative process produces the cooling effect. The refrigerant then is pulled to the compressor in the suction line where it will be compressed into a high temperature, high pressure gas and sent to the external heat sinking coils. Capillary action or capillarity is the ability of a narrow tube to draw a liquid upwards against the force of gravity. (Mortimer, 2003 ; Brain, 1994 ; Bellis, 2010) A refrigerator pumps heat up a temperature gradient. The cooling efficiency of this operation depends on the amount of heat extracted from the cold temperature reservoir (the freezer compartment), , and the work needed to do so. Since a practical refrigerator operates in a cycle to provide a continuous removal of heat, for the cycle. Then, by the conservation of energy (or first law), , where is the heat ejected to the high temperature reservoir or the outside. (Mortimer, 2003 ; Brain, 1994 ; Bellis, 2010) The measure of a refrigerator performance is defined as the efficiency expressed in terms of the coefficient of performance (). Since the purpose is to extract the most heat () per unit work input (), the coefficient of performance for a refrigerator, , is expressed as their ratio: (Mortimer, 2003 ; Brain, 1994 ; Bellis, 2010) Where, the conservation relationship given above is used to express the work in terms of heat. For normal refrigerator operation, the work input is less than the heat removed, so the is greater than 1. Refrigerators are commonly referred to as heat pumps of more specifically a it is a reversible heat pump because they basically pump heat. (Mortimer, 2003 ; Brain, 1994 ; Bellis, 2010) Figure 8 A diagram of the vapor compression refrigeration cycle that is used in heat pumps. The cycle shows the following: (i) condenser, (ii) expansion valve, (iii) evaporator, (iv) compressor. (Karin, 2003) It is commonly believed that by opening a refrigerator, itll cool the kitchen. However this is entirely opposite, opening a refrigerator or freezer heats up the kitchen because the refrigeration cycle does not accept the air from the outside (Karlin 2003). The heat is referred to as the heat dissipated from the compressors work and also includes that heat that s removed from within the refrigerator as well. (Karlin, 2003) The COP (in a heating or cooling application), provided that it undergoes steady state operation, is given by the following equation: Where: ΆQcool is the heat extracted from a cold reservoir, ΆQhot is the heat delivered to a hot reservoir. ΆA is the dissipated work by the compressor. THE CARNOT ENGINE The Carnot refrigerator is the maximum limit to the COP (efficiency) of a refrigerator system. Although we cannot make the carnot refrigerator, it tells us the maxium or best performance that can be garnered from a real refrigerator. The carnot refrigerator is sort of ideal in its design. As described earlier by Atkins dePaula (2006) with the Carnot engine, the COPc of a Carnot refrigerator depends (i) the temperature of the region that needs to be kept cool which has a characteristic temperature, TC and the temperature of the region where the heat needs to be transferred to, having a characteristic temperature, TH. It is equal to: (Littlewood, 2004) EFFICIENCY The efficiency of a refrigerator is described by a special coefficient known as a coefficient of performance and is defined in terms of the following parameters: SUMMARY OF THERMODYNAMICS OF A REFRIGERATOR AFTER ONE CYCLE Change in internal energy = 0 Change in heat is > 0 Total work > 0 Total volume change = 0 Change in Gibbs free energy = 0 Entropy change of the system = 0 Entropy change of the universe > 0

Concealment in Chesnutt’s The House Behind the Cedars Essay -- House B

Concealment in Chesnutt’s The House Behind the Cedars Who has something to hide? Everyone in The House behind the Cedars has something to hide. With the possible exception of a few minor characters and children (innocents/ innocence), most characters have something to conceal. Taking this into account, this is more than likely Chesnutt’s acknowledgement of human nature before he gets into the varying motives. Is concealment ultimately worthwhile? Who is hurt and who is helped – or is there any difference? Molly, John, Rena (The Absent/ Dead Father) This family is where much of the major concealment starts. Ironically, the family is the same place where secrets are revealed. They start as a secret themselves - hidden away, behind a row of cedars, and inside the house on Front Street. The long dead, white lover of Mis’ Molly, concealed this family from his world, just as he kept his name from his illegitimate children – denying something to each. As a result, Mis’ Molly made many sacrifices. The first sacrifice she made was herself to her lover, which in return brought some security for herself and her family. We are told by the narrator, â€Å"she worshipped the ground upon which her lord walked, was humbly grateful for his protection, and quite as faithful as the forbidden marriage vow could possibly have made her† (105). This passage does not seem to indicate a sacrifice on her part, but ultimately it was also done for her immediate family. When her immediate family began to include children, Misâ €™ Molly had to face that her children were not legitimate, had no family name, and were thrust into a world that would not easily accept them. As this escalates over time, she sacrifices her happiness for the happiness of her child... ...tood hierarchy among classes, racial and economic, that while not publicly acknowledged, is indeed common knowledge. The novel discusses this in regards to Mis’ Molly, her neighbors – darker and poorer. Word Cited Go here for websites with further Charles W. Chesnutt Information http://docsouth.unc.edu/chesnuttcolonel/about.html Biography http://www.virginia.edu/history/courses/courses.old/hius323/chesnutt.html Biography http://www.berea.edu/faculty/browners/chesnutt/biography/biography.html Biography http://www.berea.edu/faculty/browners/chesnutt/biography/familytree.html Family Tree http://www.berea.edu/faculty/browners/chesnutt/classroom/class.html Chesnutt in the Classroom http://authorsdirectory.com/biography_online_book_portrait_picture/c_authors_charles_w_chesnutt.shtml Biography, Lesson Plans, Online Text, Portrait and Pictures, etc.