Dulce Et Decorum Est Essays - Dulce Et Decorum Est, Wilfred Owen

Dulce et Decorum Est Based on the Poem "Dulce et Decorum Est" by Wilfred Owens The poem is one of the most powerful ways to convey an idea or opinion. Through vivid imagery and compelling metaphors, the poem gives the reader the exact feeling the author wanted. The poem "Dulce et Decorum Est," an anti-war poem by Wilfred Owen, makes great use of these devices. This poem is very effective because of its excellent manipulation of the mechanical and emotional parts of poetry. Owen's use of exact diction and vivid figurative language emphasizes his point, showing that war is terrible and devastating. Furthermore, the utilization of extremely graphic imagery adds even more to his argument. Through the effective use of all three of these tools, this poem conveys a strong meaning and persuasive argument. The poem's use of excellent diction helps to more clearly define what the author is saying. Words like "guttering", "choking", and "drowning" not only show how the man is suffering, but that he is in terrible pain that no human being should endure. Other words like writhing and froth-corrupted say precisely how the man is being tormented. Moreover, the phrase "blood shod" shows how the troops have been on their feet for days, never resting. Also, the fact that the gassed man was "flung" into the wagon reveals the urgency and occupation with fighting. The only thing they can do is toss him into a wagon. The fact one word can add to the meaning so much shows how the diction of this poem adds greatly to its effectiveness. Likewise, the use of figurative language in this poem also helps to emphasize the points that are being made. As Perrine says, people use metaphors because they say "...what we want to say more vividly and forcefully..." Owen capitalizes greatly on this by using strong metaphors and similes. Right off in the first line, he describes the troops as being "like old beggars under sacks." This not only says that they are tired, but that they are so tired they have been brought down to the level of beggars who have not slept in a bed for weeks on end. Owen also compares the victim's face to the devil, seeming corrupted and baneful. A metaphor even more effective is one that compares "...vile, incurable sores..." with the memories of the troops. It not only tells the reader how the troops will never forget the experience, but also how they are frightening tales, ones that will the troops will never be able to tell without remembering the extremely painful experience. These comparisons illustrate the point so vividly that they increase the effectiveness of the poem. The most important means of developing the effectiveness of the poem is the graphic imagery. They evoke such emotions so as to cause people to become sick. The images can draw such pictures that no other poetic means can, such as in line twenty-two: "Come gargling from the froth corrupted lungs." This can be disturbing to think about. It shows troops being brutally slaughtered very vividly, evoking images in the reader's mind. In the beginning of the poem the troops were portrayed as "drunk with fatigue." With this you can almost imagine large numbers of people dragging their boots through the mud, tripping over their own shadow. Later in the poem when the gas was dropped, it painted a psychological image that would disturb the mind. The troops were torn out of their nightmarish walk and surrounded by gas bombs. How everyone, in "an ecstasy of fumbling" was forced to run out into the mist, unaware of their fate. Anyone wanting to fight in a war would become nervous at the image of himself running out into a blood bath. The graphic images displayed here are profoundly affecting and can never be forgotten. The poem ties it all together in the last few lines. In Latin, the phrase "Dulce et decorum est pro partria mori" means: "It is sweet and becoming to die for one's country." Owen calls this a lie by using good diction, vivid comparisons, and graphic images to have the reader feel disgusted at what war is capable of. This poem is

Common Sense essays

Common Sense essays When someone says that psychology is a process of using simply common sense, this is far fetched. Psychology is the science of behavior and mental processes. (Myers,1998) Psychology is filled with hundreds of different theories and has been using studies to observe peoples behavior for years. Some parts of psychology are common sense, but every thing in life has some part of common sense in it. There are six major perspectives that the psychologists use when trying to figure out what is wrong with one of their patients. These different perspectives cover almost every possible area that can be covered. Psychologists use these different perspectives to try and decipher what the persons problems are and why they react the way they do. The first is a perspective called Neuroscience; this is how the body and brain create emotions, memories, and sensory experiences. The psychologists use this to perspective to try and figure out how the messages that the brain sends out are transmitted through out the body. (Myers. 1998) The psychologists use another perspective to find out how evolution influences behavior tendencies. This is called the evolutionary perspective. Behavior genetics is another perspective that is used to see how much our genes, and our environment, influence our individual differences. (Myers, 1998) These are all biological perspectives; the others have to do with the persons environment. Environment has a lot to do with the way that people react and behave in different situations. The psychologists use the behavioral perspective to find out how we learn observable responses. (Myers, 1998) The cognitive perspective is used to figure out how we process, store, and retrieve information. (Myers, 1998) The last of the perspectives is the behavioral one. This is when they try and figure out the different state of thinking and behavior between different cultures and situations. (Myers, 1998) The ...

Philosophy 101 Essay Example | Topics and Well Written Essays - 250 words - 1

Philosophy 101 - Essay Example Thus, he began to doubt his beliefs on sense perception, material objects and physical sciences, for these all depend on our senses, which are by nature, deceptive. Furthermore, he doubted mathematics, for the reason that there perhaps may be an evil deceiver that deceives him to fall into error. Herein, Descartes uses this evil deceiver in attaining his permanent truth. I quote: â€Å"Even though there may be a deceiver of some sort†¦ who bends all his efforts to keep me perpetually deceived, there can be no slightest doubt that I exist, since he deceives me; and let him deceive me as much as he will, he can never make me be nothing as long as I think that I am something† (Descartes 82). This is Descartes absolute and certain truth. For, inasmuch as he would doubt all the beliefs he has ever had, there is one thing, which he cannot doubt, i.e. that he exists. For to claim that he cannot tell the difference between a dream and reality, or to claim that an evil deceiver de ceives him to fall into error, is not possible without him existing. In order for doubting to take place, a doubter must exist. In order for Descartes to be deceived to fall into error, he must exist. Therefore, Descartes arrives at his foundational truth: â€Å"I exist.† Works Cited Descartes, R., 1960.

International Planning Frameworks Much Depend on the Context Coursework

International Planning Frameworks Much Depend on the Context - Coursework Example It is true that context is everything. Planning and execution vary according to every demography, geography, and climate is different for implementing a plan. There are no magic bullets or universal solutions for any plan. The United Nations Development Program has proved this many times while developing a plan in a geographical area. The tasks and types of tools are different in every area. The social and cultural norms of a particular place decide modes of execution for a plan.Many problems arise while managing the funds in cross-national projects. These problems are usually linked with accessing comparable datasets as well as in achieving agreement over functional equivalence in research parameters. When it comes to the interpretation many problems arise. Any shift in an orientation dependent on an interpretation of the policies usually gives rise to a conflict.The cross-national comparative planning studies are generally perceived as flexible. The common notion exists that they d o not have distinct features and comparative planning is different from holistic planning only when the factor of cross-national dimension is considered. This idea agrees with that quote under discussion. When the same plan is executed in different areas needs to comply to different work schedules, tools and other modes of execution only when the same plan is executed in different countries.This notion should not give the impression that a plan goes wayward when it is applied in different countries. The very definition of comparative planning research emphasizes the link between planning problems and execution in different regions, and there a connection with their regional institutional contexts. The emphasis on such a relationship between the matter of the investigation and the context stems from Friedmann’s paper on institutional context. Despite simple variations the general agreement is different styles of national planning dependent on a combination of system variables. They also depend on the level of economic development already attained, the nature of politics and culture.

Management information Essay Example | Topics and Well Written Essays - 1500 words

Management information - Essay Example Finally, it is cumbersome to make a complete list of all the population members since in some instances it does not cover an effective area of the sample (Creswell, 2009). The advantages of a postal survey: it is less costly, especially with very large samples; it can integrate long and complex questions because the respondent can see the question and evaluate it at their own pace; it makes provisions for a picture to be made known as part of a question; it can also cover a large number of people thus increasing the sample size; they are highly targeted. The disadvantages of a postal survey consist of the following: since there is little control of who completes and returns the survey, there numerous mailed surveys that are never returned making the sample less random and self-selective; the method is that it does not offer the option of someone explaining the questions as well as following up or probing the responses since some of the questions can be misunderstood; the sample is usually more self-selected with a lower response level; the body language of the respondent cannot be observed; lastly, only a few individuals will be interested to fill the mailed questionnaire (Frankfort-Nachimias, & Nachimias, 2008, p.34-38). In the survey, female and male customers responded to the questionnaires. A total 48 of 100 respondents were male while 52 were female. This means that 48% of the respondents were male while 52% were female. Of these, 12 males use public transport to visit the store, 12 also walk to the store, and 24 are in possession of personal cars thus drive to the store. From these statistics, it can be deduced that the majority of male customers that visit ABC are high-end clientele. On the other hand, 9 females use public transport to visit the store, 12 walk to the store, while 37 come with cars driving to the store. However, majority of the shoppers are women and most

Analyzing A Selection Of Childrens Literature English Literature Essay

Analyzing A Selection Of Childrens Literature English Literature Essay With the birth of the field of childrens literature over two centuries old, Carnegie Medal winners represent only a small part of the history and tradition of childrens literature. The Graveyard Book (2009), the most recent addition recipient of the award, follows some of the traditions of the field, and differs in others. In my attempt to discuss how The Graveyard Book fits into the history and tradition of childrens literature, I will be comparing it with other notable works in the field, specifically, Robert Louis Stevensons Treasure Island (1883), J. K. Rowlings Harry Potter and the Philosophers Stone (1997), and Philippa Pearces Toms Midnight Garden (1958). As a fellow Carnegie winner, Toms Midnight Garden, offers a comparison of fantasy fiction, and when considered with Harry Potter and the Philosophers Stone provides an interesting view of the changes that have occurred in the genre over the years. Treasure Island is structured similarly to The Graveyard Book, and both novels are good examples of the bildungsroman genre. In the course of this essay I will be referring to a range of critical material relevant to my discussion. The effect of childrens literature on children, and the reverse, is circular; as childrens attitudes to the world around them change, so too does the literature written for them, and as that literature changes, it again affects childrens attitudes. Furthermore, the evolution of adults understanding of childhood has affected which books are deemed suitable for publication. Childrens literature commonly exemplifies the beliefs and context of the culture in which it is written, however, since the majority of childrens literature is written by adults, it often reflects issues that concern adults, and not the intended audience. Adult-authors must make assumptions about the reaction of a child-reader or the behaviour of a child-protagonist, and in doing so, can sometimes offer a poor representation of a childs perspective. This difference between the adults and childs attitude to childrens literature can often be seen in the contrast between best-selling books, and those books that win lit erary prizes. Contrary to this, The Graveyard Book has won the Newbery Medal, Hugo Award for Best Novel, and the Locus Award for Best Young Adult novel in 2009, and the 2010 Carnegie Medal (Wikipedia contributors, 2011), spent fifteen weeks on the New York Times best-seller list for childrens chapter books (Rich, 2009), and has a film adaptation currently in production (Wikipedia contributors, 2011). Gaiman himself recognized the unusual nature of a book being both popular and prestigious, saying that typically there are books that are best sellers and books that are winners (Gaiman quoted in Rich, 2009). The popularity and prestige of a childrens book is dependent on a number of different elements; instruction and/or delight, and social, cultural and historical contexts (Maybin, 2009, p. 116). Maybin states that prizes signify a books prestige in the eyes of the critics, but they are not necessarily an indication of its appeal to children (Maybin, 2009, p. 118). The division between the childrens books awarded literary prizes, and those that are popular with children is significant. An example of such division can be seen when comparing Philip Pullmans Northern Lights (1995) and Rowlings Harry Potter and the Philosophers Stone; Northern Lights was the 1995 Carnegie Medal winner, while Harry Potter and the Philosophers Stone only reached the shortlist for the 1997 Medal, but went on to win the Nestlà © Smarties Book Prize, The British Book Award for Childrens Book of the Year and the Childrens Book Award, all of which, suggestively, have involved children in the judging process. Like The Graveyard Book, both books are fantasy-adventure novels featuring a young protagonist. All three novels are read an enjoyed by adults and children, but while Northern Lights is considered by adults to be quality literature, Harry Potter is criticised being not literature but a phenomenon (Zipes, 2009, p. 289). Nicholas Tucker (2009) argues that the criteria for judging the quality of childrens books varied according to conceptions of childhood; for those with a romantic conception, the emphasis is on an exciting, imaginative storyline, whilst those who view childhood primarily as preparation for adulthood favour books that are truly representative (Tucker, 2009, p. 153). If compared to earlier childrens books, it appears that modern childrens literature reflects the development of a clearer concept of childhood. The debate surrounding instruction and delight in childrens literature is one that has occupied scholars for centuries. The first childrens book to combine the two concepts was A Little Pretty Pocket-Book (1744), published by John Newberry, and featuring the motto, deluctando monemus instruction with delight. (Montgomery, 2009, p. 13) Prior to A Little Pretty Pocket-Book, the majority of childrens literature was Puritan in nature, and advocated childrens conversion to Christianity in order to save their souls from eternal damnation. Their concept of original sin resulted in explicitly didactic literature intended to educate children both religiously and morally. Newberys childrens book was, according to Jack Zipes, the first childrens book in which amusement rather than religious indoctrination is the central concern (Montgomery, 2009, p. 13). In contrast to the clearly religious books generated by the Puritans, Newberys books appealed to parents more interested in social and financ ial improvement; Letter to Sir declares that learning is a most excellent thing and can raise a boy from a mean State of Life to a Coach and Six (Montgomery, 2009, p. 14). A Little Pretty Pocket-Book marks the beginning of an evolution of the purpose of childrens literature into a concern more for the moral development of a child; with an emphasis on becoming a good person for the sake of ones emotional well-being rather than for fear of eternal damnation. The Bildungsroman novel, considered to have begun with the publication of Johann Wolfgang von Goethes The Apprenticeship of Wilhelm Meister in 1795-6, emphasizes this psychological development. The genre is generally distinguished by a number of topical and thematic elements (Iversen, 2009), and narrates the protagonists maturation over the course of the novel. The protagonist is usually young, and, following early unhappiness leaves home on a long and demanding journey, along the way maturing into a self-aware, socially-responsible young adult. Structurally, a Bildungsroman will often favour inter-character dialogue over extensive plot development, which causes the readers attention to be centered firmly on the protagonist. Whilst a Bildungsroman is deemed to be a German novel, many scholars use the term (spelled without a capital) to refer to other novels of a similar style that have been published elsewhere. With this in mind, it can be reasoned that The Graveyard Book follows the traditions of a bildungsroman novel. The Graveyard Book incorporates a number of the elements present in other coming-of-age novels indeed, Gaiman himself has admitted that the novel was greatly influenced by Kiplings The Jungle Books (1894), which may be considered one of the best-known of such novels (Horn, 2010). Gaiman described the idea as, something a lot like The Jungle Book and set it in a graveyard (Gaiman quoted in Rich, 2009). The similarities between the two books are clear; in the book titles, the protagonist, even in individual chapters, for example the comparisons between the third chapter in The Graveyard Book, The Hounds of God and the second chapter in Book One of The Jungle Books, Kaas Hunting. Gaimans ability to take the premise of a popular book over a hundred years old and develop it into an enjoyable childrens book that is both modern and relevant, demonstrates how the traditions of childrens literature can be transformed to meet the demands of a new audience. A further example of the on-going tradition of the coming-of-age novel is the Harry Potter series, specifically Harry Potter and the Philosophers Stone. The protagonists in both the Harry Potter novels and The Graveyard Book are orphaned as babies when their parents/family are killed by a murderer who, after failing to kill them, continues to hunt them until the two meet in a final show-down. This premise features in numerous books for children throughout the history of childrens literature, from the already mentioned Jungle Books to Lemony Snickets A Series of Unfortunate Events (1999-2006). The similarities between Harry Potter and Voldemort and Nobody Owens and the man Jack extend further than the latters desire to kill; the plots of both novels build from the murder of the protagonists family, and in both cases these murders are prompted by a prophecy that the protagonist would be the downfall of the antagonist. This concept of the child-hero is a popular one in childrens fiction and features throughout the history of childrens literature, from Wart in T. H. Whites The Sword in the Stone (1938) to Percy Jackson in Rick Riordans Camp Half-Blood series. Orphaned (whether literally or figuratively) protagonists appear frequently in childrens literature, from folk tales to contemporary fiction. A valuable literary device, an orphan provokes sympathy and can generate a perceived alliance between protagonist and reader. An orphaned child protagonist can also be convenient for the author since without parents, the budding child hero has more freedom to experience the, sometimes life-threatening, adventures that encourage his maturation. This can be seen in Toms Midnight Garden, the 1958 winner of the Carnegie Medal, and one of the Carnegie Medal 70th Anniversary top ten (The CILIP Carnegie Kate Greenaway Childrens Book Awards, 2007). Tom is able to visit the garden partly because of the absence of his parents whilst he is being cared for by his aunt and uncle, it is clear from the novel that neither adult is accustomed to caring for a child, and Tom takes advantage of this to pursue his nightly visits to the garden. Whilst Tom can be c onsidered a temporary orphan in a figurative sense, Hatty is literally an orphan, having lost both of her parents at a young age. Their status as orphans is not the only thing that Hatty and Bod share; as Hatty grows up, she ceases to see Tom, in the same way that Bod ceases to see the residents of the graveyard. Alison Waller (2009) argues that in young adult fiction the ending is always presumed to be a realisation of adulthood and maturity. (Waller, 2009, p. 54) This idea of maturation is reminiscent of Barries Peter Pan (1911) and Wendys realisation that she and her brothers cannot stay in Never Land, but must return home to grow-up. Humphrey Carpenter (1985) compares Tom and Peters attitudes to their ageing, arguing that the storys conclusion describes Toms acceptance of what Peter Pan can never accept: that Time must be allowed to pass, and growth and even old age must be accepted as necessary and even desirable facets of human nature (Carpenter, 1985). Like his predecessors in the traditions of the coming-of-age novel, Nobody Bod Owens is a likeable character, intriguing, and often contradictory in his behaviour; obedient, yet always questioning, determined, yet often managing to find trouble, courageous, yet sensitive. Happy as he is with his adoptive family in the graveyard, at the end of the novel, when he has become a young man, Bod declares that he want[s] to see lifeà ¢Ã¢â€š ¬Ã‚ ¦ I want everything (Gaiman, 2009, p. 286). While this journey of maturation shares a theme with Treasure Island, Bods declaration is in contrast to Jims final words which, rather than being optimistic at the possibility of future adventure, are fearfully reminiscent of the accursed island (Stevenson, 2008, p. 191). Structurally, The Graveyard Book and Treasure Island share some similarities; both novels centre around the adventures of a single, male protagonist, both novels can be described as being coming-of-age stories, and both novels have resolv ed endings. The novels differ in their point of view; where The Graveyard Book is generally narrated in the third-person, Treasure Island is narrated in the first-person, by Jim Hawkins. However, both novels do deviate from their standard narrative form there are several parts of The Graveyard Book where the events are recounted by either the man Jack or by Scarlett, and in Treasure Island, for chapters 16-18, Stevenson shifts the control of the narrative from Jim to Doctor Livesey. In an illustrated talk, Kim Reynolds suggests that childrens literature in its current state has been moulded by practices that began in the nineteenth century, and that whilst the content of books today differs significantly from those of the nineteenth century, there were still the same kinds of divisions then, that we have now in terms of what we might call good literature (Reynolds, EA300 DVD1, no. 5). A recurring theme in childrens literature across the years is the idea of home. Central to the domestic and school stories popular with girls in the nineteenth century, and to adventures stories popular with boys during the same period, home is either the setting for such novels, for example in Little Women, or a place of safety that the protagonist can return to after his adventures, like in Treasure Island. The Graveyard Book parts from this traditional notion of home; what should have been Bods place of safety became the place where the man Jack murdered his family, so home beca me a place that does not follow the traditional domestic image. When he leaves the graveyard as a young man, he realizes that if he does return, it will be a place, but it wont be home any longer (Gaiman, 2009, p. 286). Contrary to many earlier childrens novels advocating the traditional correlation of home and safety, in The Graveyard Book Bod is in fact safer among the dead in the graveyard, a place that is stereotypically considered scary or even dangerous. In the last two centuries, there has been a significant change in how ghosts are portrayed in childrens literature; early literature saw ghosts that were frightening, and used to teach children morals, while in contemporary literature they are just as likely to be friendly or even amusing. Both interpretations can be seen in the Harry Potter series, with the Bloody Baron representing the fearsome ghost, and Nearly Headless Nick representing the friendly. The tradition of friendly ghosts in childrens literature, such as those in The Graveyard Book, appears to have begun with William Pà ¨ne du Bois book, Elisabeth the Cow Ghost (1936) (Pearce, 1995). The appearance of ghosts in childrens fiction increased during the 1970s and 1980s, with a numb er of novels that used ghosts to teach their readers about historical events, and others that a child protagonist helping a ghost to accept his fate and move on. This is in direct contrast to The Graveyard Book, where it is Bod that has to move on into the world of the living, while the ghosts are left in the graveyard. The publication of The Graveyard Book follows a recent rise in the popularity amongst children and young adults of paranormal fiction. Fantasy fiction as it is today has been developing since the revival of folk and fairy tales in the early 1800s, advancing particularly during the First Golden Age of childrens literature. Modern fantasy tends to reject traditional sentimentality, exploring instead complex moral and sociological issues. In a similar way to modern realism, modern fantasy fiction has broached a number of taboo subjects, the most significant in The Graveyard Book, being death. In the early history of childrens literature, when death occurred in a book, it was often as a punishment, used to illustrate where the wrong path could lead. In contrast, in The Graveyard Book death is treated as a natural part of life not to be either welcomed or feared. However, unlike other childrens fiction that handles the subject, death in The Graveyard Book is largely regarded light-hearte dly, unlike for example in The Other Side of Truth, where their mothers death acts at the catalyst for Sade and Femis subsequent ordeals. The acceptance of subjects that have previously been considered taboo is, according to Rachel Falconer (2009) a result of changing conditions of contemporary childhood (Falconer, 2009, p. 373). The Graveyard Book encapsulates some of the major traditions of childrens literature and is reminiscent of some of the most noteworthy works in the history of the field. At the same time, the novel pushes the boundaries of what is accepted, unmasking a taboo subject and treating it positively but tastefully. A best-seller, the novel continues the current trend of paranormal fiction, and bridges the gap between the popular and the prestigious by winning numerous literary awards. Neil Gaimans description of his book as a book about life and childhood and the value of childhood (Gaiman quoted in Horn, 2010), places it firmly amongst the fields traditions, and the books double-win of the Newbery Medal and the Carnegie Medal gives it a significant role in the continuing development of the field of childrens literature.

Alternatives to High Fructose Corn Syrup Essay -- Artificial Sweetener

High Fructose Corn Syrup: Alternatives/Prevention Abstract: This report presents alternative foods to replace the ones with the dangerous sugar, high fructose corn syrup. The effects of high fructose corn syrup consumption were researched to find alternative methods of obtaining the same types of foods without the nasty effects. Alternative foods that ranged from diet bars to cough syrup were found. These foods don’t contribute to the rise in obesity and diabetes type II and taste just as good at the ones that do contribute to obesity and diabetes type II. It was also observed that the foods that are eaten on the Atkins diet are good alternatives because of the low carbohydrate intake. High carbohydrate foods are the prime source of high fructose corn syrup. Alternatives and Prevention Nobody thinks of sugar when they see a field of corn, but most of us would find that most of the sweeteners that sweeten our food are made with corn rather than sugar. High fructose corn syrup is made by processing corn starch to yield glucose, then processing the glucose to yield a high percentage of fructose. This fructose may be cheaper than using glucose as a sweetener, but it has horrible effects on the body. There are tests when rats were fed high fructose corn syrup for a period of time, which yielded disastrous results. The rats all developed high cholesterol, anemia, and hypertrophy, which means that their hearts grew until they exploded! As for humans, diabetes and obesity skyrocketed when high fructose corn syrup was released (Linda Forristal, 2001). High fructose corn syrup is found in an abundance of foods. It is found in foods that one would use on a daily basis. For example, high fructose corn syrup is found in the crumbs used ... ... Sources Forristal, Linda Joyce. â€Å"The Murky World of High Fructose Corn Syrup.† http://www.westonaprice.org/motherlinda/cornsyrup.html. 2003. Weston A. Price Foundation. 25 July 2006. Hopkins, Kate. â€Å"Foods and Products Containing HFCS.† http://www.accidentalhedonist.com/index.php/2005/06/09/ foods_and_products_containing_high_fruct. 2005. 25 July 2006. Adams, Mike. â€Å"Consumption of soft drinks and high-fructose corn syrup linked to obesity and diabetes.† http://www.newstarget.com/003002.html. 2004. 25 July 2006. Dimas, Jennifer. â€Å"GROUNDBREAKING DIABETES AND OBESITY PREVENTION PROGRAM AT COLORADO STATE UNIVERSITY RECEIVES NATIONAL RECOGNITION.† http://newsinfo.colostate.edu/index.asp?page=news_item_display&news_item_id=220682550. 2005. Colorado State University. 25 July 2006 Anonymous. â€Å"Atkin’s Diet and Low-Carb News.† http://www.lowcarb.ca/. 2006. 25 July 2006.

Aerofoil Design Xflr5

Aashiq Zakir Hussain12108227 | Supervisor : | Dr. Patrick Frawley | Submission : Date | 26th October 2012 | ABSTRACT Airfoil is the main part of the airplane which contributes the lift required by the airplane to fly in the air. By varying the wing’s area and the angle of attack, different lift can be created and can be used to fly the airplane. This program named XFLR5 is used for determining the airfoil characteristics.It will help them to save a lot of time on computing the equations and on the trial and error method. The program can also be used as basic tool to show the users what will happen when some variables like Reynolds number, the AOA of the wings and the speed of the aircraft are changed and how it will affect the results and lift generated. This project report deals with the analysis of widely used airfoils in the modern aircrafts. In this analysis, the lift, drag, pressure profiles and their coefficients of the airfoils are been calculated using xflr5 program.Th ese are obtained in the form of graphical representation by feeding data such as Reynolds number, Mach number, Angle of Attack and dimensions of the airfoils to the program. The results such as maximum lift coefficient, stalling angle, maximum lift to drag ratio and such parameters are obtained and are been compared with each other.Re| Reynolds number| -| ?| Angle of Attack| -| M| Mach number| -| Cp | Pressure Coefficient| -| Cl| Lift Coefficient| -| Cd| Drag Coefficient| -| Cl / Cd| Glide Ratio| -| T| Thickness| mm| c| Chord| -| INTRODUCTION Airfoils are the primary shapes which allow streamlined flow over it when it is driven through air. These shapes do not produce much drag compared to other shapes as so it is used in all aircraft structural parts which is subjected to airflow. Basically airfoils can be divided into many types by slightly varying their thickness, length, camber area and so on without after the shape.In this analysis we deal with airfoil shapes known as NACA airf oils. The  NACA airfoils  are just  shapes of airfoils used for aircraft wings, which is developed by the  National Advisory Committee for Aeronautics  (NACA). The shape of the NACA airfoils is determined using a  series  of digits followed by the word â€Å"NACA. † The series is divided using digits from 1-8. We only deal with the 4-digit series of airfoils in this analysis. The 4 digit airfoils we are going to discuss in this analysis are 0004, 0008, 0012, 0016, 0020, 0312, 1312, 2312, 3312, 2112, 2512 and 2712.In this 4 digit series, 1st digit denotes the maximum  camber  as percentage of the  chord, 2nd digit denotes the distance of maximum camber from the airfoil leading edge in tens of percent's of the chord and this last 3rd and 4th digits denotes  maximum thickness of the airfoil as percent of the chord. The key features we are going to discuss about in this analysis are the effects of Angle of Attack, Reynolds number, Mach number, Camber and Thi ckness. The basic aerodynamic design is to obtain maximum lift and minimum drag which will be expressed in terms of coefficient of lift (Cl) and coefficient of drag (Cd).Using this program known as XFLR5, we are going to compare the characteristics of all the airfoils. As the operating valves such as Angle of Attack, Mach number, Reynolds number are to be fed in to the program and this will give us the required graph of the parameters such as Cl, Cd, alpha, Cp and so on. Using these results achieved from the program, it will be easier to find out the airfoil with highest Cl at various angles of attack, which has got highest stalling angle and the airfoil with best glide ratio and so on. OBJECTIVESThis report is basically done to find out airfoils with maximum lift to drag ratio by comparing many airfoils each other and allowing their camber area, thickness and the location of the camber to deviate to the small percentage of the chord. By doing this, we can achieve a best airfoil des ign that can be used in live aircrafts. LITERATURE REVIEW Introduction: * If an aircraft has to fly, force has to be counter balanced by the weight as it must be opposite to its magnitude. This force is known as lift. Lift plays a major factor on the airplane flight.The main plane (wings) generates more lift as it is the important load carrying member. * The aerofoil sections have been started to get developed in late 1800’s. In 1884 H. F. Phillips with the help of wind tunnel, tested and made series of airfoils. At the same time Otto Lilienthal with the help of the bird’s wings, designed airfoil shapes. It was found that the key factor is that the wing curvature or camber. The early airplanes were biplanes because, the airfoils were thin and cambered as shown in figure 2. 1. Figure 2. 1: Hanson http://www. biplanefun. om/assets/Image/Hanson_215217_001. jpg Nowadays these types of aircrafts are not used, as all airfoils are made by trial and error method. Airfoils used in 1920’s (NACA). ( http://www. desktop. aero/appliedaero/airfoils1/images/sections1. gif) Figure 2. 2: Ancient development in airfoils For the project, the NACA 4 digit airfoil format will be use for the program which is generating the airfoil’s shape and the thin airfoil theory will be use for computing the important parameters of the wing. * 1. ii Terminology for Airfoil and Airplane:Basic parts of an airfoil that must be known before getting in to the chapter of NACA 4 digit series. The diagram below describes the parts of an airfoil from which series are determined. Figure 2. 3: Airfoil Terminology airfoil (http://www. copters. com/aero/pictures/Fig_2-10. gif) Figure 2. 5: Plane Axes (http://www. allstar. fiu. edu/aero/images/fig25. gif) 1. iii Definitions: The line drawn midway between the upper and lower surfaces of the airfoil is known as mean camber.The straight line joining the leading and trailing edges of the airfoil is known as chord. Leading edge is the front of the airfoil. Trailing edge is the end of the airfoil. The angle between the chord and the line representing the relative airflow is known as the angle of attack (AOA). Camber of an airfoil is the upper and lower surfaces curvature. The airfoil’s thickness and amount of lift the airfoil will generate is determined by the cambered area. When the term upper camber is used, it is referring to the upper surface of the airfoil. When the term lower camber is used, it is referring to the lower surface of the airfoil.Span is the distance from a tip of the wing to the other tip of the wing. * 1. iv The Four Forces on the Airplane Figure 2. 6: Forces on an airplane (http://anjungsainssmkss. files. wordpress. com/2011/09/plane_forces. jpg) * The four main forces that maintain the aircraft in steady flight and helps fly are Lift, Drag, Weight and Thrust. Thrust is a forward pulling which is generated by the engine(powerplant). Thrust opposes the drag. Thrust depends upon the powe r of the engine as high power engines produce more thrust and the type of the engines with respect to their mounted location.Drag is a force which opposes the thrust as when the aircraft moves in high speed the air passes over and below the surface produce drag. It is a resistive force. The weight is a force of an airplane which is acting downwards due to the force of gravity. This force pulls down on the plane and opposes the lift force. This force mainly depends upon the weight of the aircraft and so it depends upon how much we load and the total weight we use to build the aircraft. Lift is an important force in the aircraft which tends the aircraft to fly.It is generated as aircraft moves at high speed and is generated below the airfoil surface of the main plane. At this time, there will be low pressure acting over the wing and high pressure under the wing. The four forces act on any airplanes in flight and are interconnected. In order for the airplane to take off, lift must over come weight and thrust must overcome drag. During landing, thrust must be reduced below the level of drag and lift must be reduced below the weight of the airplane. * * * 1. v Theory of Lift: * Lift is an important force as it sustains an airplane in ir and enables it to manoeuvre. The theory of lift has been debated for a long time and currently still debating. However this project is not about debating the theory of lift but to design the airfoil. Therefore to cover the theory of lift, the 2 more popular explanations which are the Newton’s Law and the Bernoulli’s Principle will be discuss briefly. * Principles of Physics such as the principle of conservation of momentum, the principle of the conservation of mass and the principle of the conservation of energy are the basic principles to be known and to be considered to understand lift force.The principle of the conservation of momentum is covered by Newton’s Law. And the principle of the conservation of energy is covered Bernoulli Principles. Both can be use to explain the basics principles on how lift is form and are compatible with each other. In the following explanations, air is assumed as an ideal fluid and therefore 3 major assumptions about the physical properties of the airflow are made: * The airflow over a wing is incompressible. The airflow is inviscid which means the viscosity of air is approaching zero. The airflow around the wing is steady. * * * 1. vi Newton’s Law Explanation: Lift is generated by a wing as it moves through the air at an angle of attack. This will turn the airflow downward and the wing itself will have the force acting in an upward direction. In order to make use of the Newton’s Law, we need to know a theory known as the Coanda Effect. Coanda Effect stated â€Å"A moving stream of fluid in contact with a curved surface will tend to follow the curvature of the surface rather than continue travelling in a straight line. † This states tha t, when the air hits the wing when it is subjected through air, the angle changes the wing dimension as it is tilted to an extent.At this stage air do not reflect back as it stays over the wing. From Coanda Effect, we know that the wing is changing the direction of the airflow and also changing the velocity. Since lift is a force, according to Newton’s 2nd law of motion: * Force = mass x acceleration (F=ma) * Acceleration is a change in velocity with respect to time and force will be: * Force = mass x (change in velocity / change in time) * Therefore a change in velocity will generate a force and a force will cause a change in velocity.Velocity has both a magnitude called speed and a direction is associated with it. It is a vector quantity. Therefore by changing the direction of the airflow, the wing is also causing an increase in velocity which results in an acceleration. This change in velocity also generates a reaction force on the wing acting in an upwards direction. * Th is principle of Newton’s 3rd law which states â€Å"Every action has an equal and opposite reaction† helps to explain the nature of lift. The reaction force experienced by the wing is the total reaction. Figure 2. : Forces on an airfoil (http://www. free-online-private-pilot-ground-school. com/images/forces_airfoil. gif) * 1. vii Bernoulli’s Principle: Bernoulli’s Principle can be referred to as the law of conservation of energy and the total energy in a moving mass of fluid consists of potential energy, kinetic energy and the fluid’s pressure energy. It states that sum of all energies result in a constant value for the steady flow of an ideal fluid. Bernoulli’s Principle shows that as the velocity of a fluid flow changes, the pressure will change as well.This means that when the fluid’s velocity increases, the pressure will decrease and vice versa. Using this principle of pressure variation with velocity change, lift force developed by the wing can be accurately predicted in the same way as Newton’s Law. Figure 2. 8: Example of Bernoulli’s Principle (http://images. rcuniverse. com/magazine/reviews/455/bernoulli. jpg) Using Bernoulli’s Principle, the kinetic energy of the air will be highest where the pressure energy is the lowest and lowest where the pressure energy is the highest.This will result in an increase of the airflow for the upper surface of the wing and decreases for the lower surface of the wing. Therefore there will be a lower pressure on the upper surface of the wing and a higher pressure on the lower surface of the wing. This will result in a force acting in an upwards direction. Using equation: Force = Pressure x Area The lift force will be proportional to the pressure differential across the wing multiplied by the wing’s surface area. For Bernoulli’s Principle, it does not provide any explanation on why the airflow is faster on the top surface of the wing.The Newton’s Law also did not explain why the air deflects downward. Both theories only explain how lift is created. * 1. viiiThe Factors affecting Lift: Lift is the main source of force which enables the airplanes to fly. In order to generate enough lift, several factors have to be taken into consideration as they affect the amount of lift the airplane can generate. The general equation for lift is Lift = lift coefficient x {(air density x velocity2)/2} x wing area Where the lift coefficient is given by: Lift coefficient = 2 x pi x (AOA – calculated AOA at zero lift) Therefore the factors affecting lift are: The Angle of Attack (AOA). * The airfoil shape. * Airspeed. * Wing size. * Air density. The air density depends on the height which the airplane is flying. As the height of the airplane decreases, the air density will increase which will also result in higher lift generated. Therefore to generate the same amount of lift when the air density increases, the velocity of the airplane must increase. The Angle of Attack (AOA) of the airplane’s wing which is denoted by the Greek letter alpha ?. AOA is the angle between the oncoming air or relative wind and a reference line on the wing which in this case is the chord.It is one of the important parameters for handling and designing of a plane as a typical wing only has a limited range of angles of attack As the AOA increases, the lift generated by the airfoil is also increased. However, once the AOA reaches a certain angle known as the Critical Angle, the airplane will stall as the airflow will separate from the upper surface, resulting in a loss of lift which means the airplane will stall. This will result in cavitations and lose in lift force. It will also produce drag force as shown in figure 2. 9. Figure 2. 9: Diagram of how AOA affects the air flow (http://www. ero-mechanic. com/wp-content/uploads/2008/12/2-8-283Ãâ€"300. jpg) The lift depends upon the airfoil and the force the air flows over it. Thus when airflow is more, lift produced is maximum. Comparing a cambered airfoil and a symmetric airfoil, a cambered airfoil produced more lift than a symmetric airfoil. Even a flat plate subjected to the air will produce lift. Thus the airfoil should be designed in such a way that it produces high lift to drag ratio. * 1. ix NACA 4 series: In the 1930s, the National Advisory Committee for Aeronautics (NACA) developed several sets of airfoils and camber lines.The â€Å"Characteristics of 78 Related Airfoil Sections from Tests in the Variable Density Wind Tunnel† report was published by the NACA. In this report, the authors discovered that the airfoils that are successful had many similarities. The two primary variables that affected the airfoil shapes are the slope of the airfoil mean camber line and the thickness distribution above and below the line. Many of this airfoil shapes have been in use as tails and wings of airplanes over the years. The first family of airfoi ls designed using this approached is the NACA 4 series.In the NACA 4 series, the 1st digit indicates the maximum camber (m) in percentage of the chord, the 2nd digit indicates the position of the maximum camber (p) in tenths of cord and the last 2 digits provide the maximum thickness (t) of the airfoil in percentage of chord. For example, the NACA 2412 airfoil will have a maximum camber of 2% located at 40% from the leading edge with maximum thickness of 12% cord. 4-digit series airfoils by default have a maximum thickness of 30% of the chord from the leading edge. Therefore with the first 2 digits 00, it indicates that there is no camber and is a symmetrical airfoil.To find the mean camber line, it can be calculated using: To calculate for the thickness distribution, equation 2. 3 is used. Currently in the market, there are several NACA 4 series airfoil generators. These generators calculate the coordinates of the airfoil shape. However, it does not take into consideration of the l oad that the airfoil will be taking, meaning the surface area of the wings are not taking into consideration. There is also not much program which enables the user to calculate the whole wing surface area and the lift generated by the wing with different airfoil design. 1. x Thin Airfoil Theory: For this project, the Thin Airfoil Theory will be use to compute the model airplane’s airfoil thickness and wing dimension as the thickness for the model airplane’s wing is not very thick. Thin airfoil theory was devised by German mathematician Max Munk and further refined by British aerodynamicist Hermann Glauert and others in 1920s. It is a simple theory of airfoils that relates the angle of attack to lift. The theory idealizes the flow around an airfoil as a 2 dimensional flow around a thin airfoil.At low angles of incidence, the boundary layer growth on an airfoil is thin and remains attached to the airfoil. Therefore the airflow is assumed to be inviscid and irrotational. Since the thickness of any lifting airfoil is less than a fifth of its chord length, the effect of the airfoil’s thickness can be neglected and the airfoil will be represented by its mean camber line. A mathematically conceived function in the form of a vortex sheet is then placed along the length of the camber line to simulate the airfoil. This essentially makes it a streamline of the flow.By applying the circulation theory of lift to this streamline, the aerodynamic properties of the airfoils are obtained. The airfoil is considered as having zero thickness and infinite wingspan. This the reason why the theory does not take into consideration the induced drag that arises from the wing tips of an airfoil. Therefore it is only good for approximating an airfoil with medium and large aspect ratio and only up to the stall angle which is usually 10 to 15 degree for typical airplane configuration. Any angle beyond 15 degree, the thin airfoil theory cannot be used to calculate the c oefficient of lift.Thin airfoil theory is important as it provided a theoretical basis for the important properties of the airfoils in 2 dimensional flows: * The centre of pressure lies exactly ? of the chord behind the leading edge on a symmetric airfoil. * The aerodynamic centre lies exactly ? of the chord behind the leading edge for cambered airfoil. * The slope of the lift coefficient versus angle of attack line is 2? units per radian. There are many formulae that states the derivation of the thon airfoil theory, but we don’t require those for our project and so its neglected. xi Flat Plate Airfoil Theory:Flat plate theory is applied to airfoils as the thickness is also the constituent of drag in the airfoil. The flat plate when it is subjected to airflow the drag minimum as compared to the other shapes with reasonable thickness. Thickness cannot be neglected as it also plays a vital role in the camber surface as it produces lift. The transition point can be pushed back a s we reduce the drag in an airfoil by which we can get a good lift curve for higher degrees. In case of boundary layer, the drag in a flat plate will be laminar for a certain period of time and it then become turbulent.There is no unique valve where the stream gets turbulent, but by keeping the laminar surface clean and free stream, one can delay the renolds number. Figure 2. 10: Velocity profiles for laminar and turbulent boundary layer EXPERIMENTAL PROCEDURE AND ANALYSIS Introduction: These experiments below are done using xflr5 program. NACA 4 digit series airfoils are been used in the analysis. In the final analysis, NACA airfoils ranging from 0 to 9% of camber magnitude, 10 to 70% of camber location and 3% to 30% of thickness airfoils are analysed to get an airfoil of better performance with high to lift to drag ratio.Exercise A: Effect of Angle of Attack Airfoil = NACA 0012 Re number = 1000000 M = 0. 00 Part 1: In this part, the pressure profiles for different angle of attack are to be discussed. AOA( Alpha ) : -4 to 16 degrees with a step of 4 degrees Figure 3. 1: Pressure profiles plot of NACA 0012 Angle of attack(alpha)| Cl| Cd| -4| -0. 429| 0. 007| 0| -0. 00| 0. 005| 4| 0. 429| 0. 007| 8| 0. 910| 0. 012| 12| 1. 242| 0. 020| 16| 1. 301| 0. 050| Part 2: In this part we discuss about the lift, drag and their coefficients. Angle of Attack (alpha) = -4 to 18 degrees with a step of 0. degrees Figure 3. 2: Drag coefficient and Angle of attack plot Figure 3. 3: Lift coefficient and Angle of attack plot Figure 3. 4: Glide ratio and Angle of attack plot Figure 3. 5: Lift coefficient and Drag coefficient plot Analysis: Part 1: In this part, the angle of attack is changed from -4 degrees to 16 degrees with fixed Reynolds number and Mach number. The pressure profiles seem to have gradual increase in both negative and positive values on Cp. As the angle of attack increases, the lift and drag increases to a certain limit and stalls.Maximum lift is at 14 degrees and thus stall occurs. Cl max is 1. 36. It is consistent as Bernoulli’s approach on analysis. Part 2: In this part, the angle of attack is varied from -4 degrees to 18 degrees. Re and M is same as above. The lift curve passes through the origin, so zero lift is at origin (0 degrees). Max Cl is at 1. 36 where the stall angle is at 4 degrees. The maximum glide ratio is 75. 86 and at this point the values of Cl is 0. 8685, value of Cd is 0. 0115 and the value of alpha is 7. 5 degrees. Exercise B: Effect of Reynolds number Airfoil = NACA 0012 Alpha (AOA) = 4 degrees M = 0. 00Part 1: In this part, we discuss about the effects due to change in Reynolds number in NACA 0012 airfoil. Re number = 100000 to 2. 1 million with an increment of 400000 Figure 3. 6: Pressure profiles plot Part 2: In this part, we discuss about the effects due to change in Reynolds number and Angle of attack in NACA 0012 airfoil. Re number = 100000, 500000, 900000, 2100000, 4000000. AOA (alpha) = -4 to 20 degrees with a step of 0. 5 degrees. Figure 3. 7: Glide ratio and alpha plot Figure 3. 8: Drag coefficient and alpha plot Figure 3. 9: Lift coefficient and alpha plot Figure 3. 10: Lift and Drag polarRe number| Max Cl| Stall angle(degrees)| Max Cl/Cd| Cl at Max Cl/Cd| Cd at Max Cl/Cd| Alpha at Max Cl/Cd| 100000| 0. 97| 10. 5| 36. 5| 0. 61| 0. 017| 5 degrees| 500000| 1. 21| 13. 5| 61. 9| 0. 72| 0. 012| 6 degrees| 900000| 1. 35| 14. 5| 73. 6| 0. 86| 0. 011| 7. 5 degrees| 2100000| 1. 57| 17| 92. 5| 0. 97| 0. 0105| 8. 5 degrees| 4000000| 1. 67| 18. 5| 107. 3| 1. 073| 0. 010| 9. 5 degrees| Analysis: Part 1: In this case there is an increase in the pressure values as increase in Re number and the transition is point is pushed backwards in the curve with Reynolds number 4000000 than the curves with Reynolds number less than that.Part 2: In this case, the transition point is brought backwards as there is an increase in the boundary layer. It just pushes the stall angle further towards the leading edge. For Re= 100000, drag is increased more at high angle of attack. For high Re number, lift coefficient is more than low Re number and the drag is minimised at high angle of attack in high Re number curves. Exercise C: Effect of Mach number Airfoil = NACA 0012 Re number = 2 million Part 1: In this part, we are discussing about the effects in forces due to change in Mach number. Alpha (AOA) = 4 degrees M = 0. 00, 0. 1, 0. 02, 0. 03 Figure 3. 11: Pressure plot of M=0. 00 Figure 3. 12: Pressure plot of M=0. 01 Figure 3. 13: Pressure plot of M=0. 2 Figure 3. 14: Pressure plot of M=0. 3 Part 2: In this part, we are going to see the difference in the curves for different Mach numbers mentioned in part 1 and also with Angle of attacks from -4 to 30 degrees with a step of 0. 5 degrees. Figure 3. 15: Lift coefficient and Alpha Figure 3. 16: Drag coefficient and Alpha Figure 3. 17: Glide ratio and Alpha Figure 3. 8: Lift and Drag polar M| Cl Max| Stall angle(degrees)| Cl/Cd Max| Cl at Cl/C d Max| Cd at Cl/Cd Max| Alpha at Cl/Cd Max| 0. 0| 1. 560| 17| 91. 5| 0. 975| 0. 0104| 8. 5 degrees| 0. 1| 1. 540| 16. 5| 91. 25| 0. 985| 0. 0105| 8. 5 degrees| 0. 2| 1. 475| 15. 5| 90. 3| 1. 00| 0. 0115| 8. 5 degrees| 0. 3| 1. 355| 73| 88. 4| 0. 97| 0. 0110| 8 degrees| Analysis: Part 1: In this analysis, there is a change in pressure (Cp). As the Mach number increases, the value of Cp increases in the negative values. Due to the increase in speed, the transition point in moved towards the leading edge and stall angle decreases.Part 2: In this part, the angle of attack is also changed with the Mach number. We can see the effect of lift and drag from the values in the table given above in part 2. At the highest AOA the Cl value is increased. As the Mach number increases, the value of Cl max and the stalling angle drops down as it tends to stall soon in high ach number. Exercise D: Effect of Thickness In this exercise, various airfoils of different thickness are used. The values are ta ken from the program and compared with each other. Re = 2000000, M = 0. 00, AOA(alpha) = -4 to 20 degrees with a step of 0. Airfoils = NACA 0004, NACA 0008, NACA 0012, NACA 0016, NACA 0020 Figure 3. 19: Drag coefficient and Alpha plot Figure 3. 20: Glide ratio and Alpha plotFigure 3. 21: Lift coefficients and Drag coefficient plot Figure 3. 22: Lift coefficient and Alpha plot NACA airfoils| Max Cl| Stalling angle(degrees)| Max Cl/Cd| Cl at Max Cl/Cd| Cd at Max Cl/Cd| Alpha at Max Cl/Cd| 0004| 0. 96| 20| 48. 1| 0. 325| 0. 007| 3 degrees| 0008| 1. 15| 11. 5| 79. 85| 0. 775| 0. 010| 7 degrees| 0012| 1. 563| 17| 91. 52| 0. 977| 0. 010| 8. 5 degrees| 0016| 1. 578| 18| 93. 10| 1. 228| 0. 013| 11 degrees| 0020| 1. 45| 18. 5| 92. 4| 1. 000| 0. 010| 9. 5 degrees| Analysis: Due to the thickness, there is a change in lift as it can be observed in figure 3. 13. As NACA 0004 is thin, it stalls soon. But NACA 0020 and NACA 0016 airfoils has high value of Cl and this attains at almost 18 degrees o f AOA. From this it can be said that, if thickness increases the lift increases, but its for certain limit as Cl max drops in NACA 0020. The curves given above for each airfoil cannot be believed till end. This is only applicable theoretically that if an airfoil begins to stall, it can regain its lift after some angle further.In practical application, it is false. The curves can be believed till the first major stall occurs which attains Cl max. Exercise E: Effect of camber, magnitude In this exercise, the airfoils of different camber are been discussed i. e. the first digit of the NACA 4 digit series is been changed and compared. Re number = 2000000, M = 0. 00, AOA (alpha) = -4 to 20 degrees with a step of 0. 5 degrees Airfoils = NACA 0012, NACA 0312, NACA 1312, NACA 2312, NACA 3312 Figure 3. 23: Glide ratio and Alpha plot Figure 3. 23: Drag coefficient and Alpha plot Figure 3. 24: Lift coefficient and Alpha plot Figure 3. 5: Lift and Drag coefficients plot NACA Airfoils| Max Cl| S talling angle(degrees)| Max Cl/Cd| Cl at Max Cl/Cd| Cd atMax Cl/Cd| Alpha at Max Cl/Cd| Zero Lift| 0012| 1. 546| 17| 91. 5| 0. 955| 0. 0105| 8. 5degrees| 0 degree| 0312| 1. 546| 17| 91. 5| 0. 955| 0. 0105| 8. 5degrees| 0degree| 1312| 1. 610| 17| 98. 4| 0. 901| 0. 0094| 7 degrees| -1degree| 2312| 1. 664| 17| 122. 3| 0. 865| 0. 0071| 5. 5degrees| -2degree| 3312| 1. 712| 16. 5| 140. 5| 1. 008| 0. 0072| 6 degrees| -3degree| Analysis: As the magnitude of the camber is changed, the lift is attained way before than a normal airfoil with less camber surface.Symmetrical airfoil is that in which upper and lower surface are same and asymmetrical has various shapes in it. In these two types, the symmetrical airfoil produces less lift-drag ratio than asymmetrical airfoils. Due to the camber in the airfoil, in NACA 1312, NACA 2312 and NACA 3312 has started producing lift at negative angles as other two produces only after 0 degrees. Hence the lift is acquired soon and as angle increases, the drag produced is also less than in airfoils NACA 0012 and NACA 0312. Exercise F: Effect of camber, locationIn this exercise, we change the location of the camber and analyse their changes in curves. Re number = 2000000, M = 0. 00, AOA (alpha) = -4 to 20 with a step of 0. 5 degrees Airfoils = NACA 0012, NACA 2112, NACA 2312, NACA 2512, NACA 2712 Figure 3. 26: Drag coefficient and Alpha plot Figure 3. 27: Lift coefficient and Alpha plot Figure 3. 28: Glide ratio and Alpha plot Figure 3. 29: Lift coefficient and Drag coefficient plot NACA Airfoils| Max Cl| Stall angle(degrees)| Max CL/Cd| Cl at Max Cl/Cd| Cd at Max Cl/Cd| Alpha at MaxCL/Cd| Zero lift(degrees)| 0012| 1. 563| 17| 91. 5| 0. 55| 0. 0103| 8. 5degrees| 0| 2112| 1. 726| 17| 117. 0| 1. 145| 0. 0128| 12degrees| -1. 85| 2312| 1. 675| 17| 122. 3| 0. 865| 0. 0072| 5. 5degrees| -2. 02| 2512| 1. 694| 17| 111. 0| 0. 769| 0. 0068| 4. 5degrees| -2. 37| 2712| 1. 741| 17| 102. 5| 0. 962| 0. 0093| 6 degrees| -3. 056| Analysis: In this analysi s, the location of the camber is changed in each airfoil and hence so, we can find the change in Cl max and glide ratio which are key factors here. Fluctuation in the glide ratio can be seen, as it increases in NACA 2312 and decreases when going further increase in camber location.There are minor deflections in the stalling angle as that cannot be accurately calculated. Thus changing the camber location increases lift to some extend as further increase in camber value may cause drag. Exercise G: Finding the best values of a NACA airfoils In this section of analysis, we are using the airfoils of wide range with about 0-9%c camber magnitude, with 10-70%c of camber location and with 3-30% thickness range. We are yet to find the best airfoil with Cl max, largest stalling angle and Cl/Cd(Glide ratio). Re = 2000000, M = 0. 00, AOA(alpha) = -4 to 20 degrees with a step of 0. degrees. Graphs: Figure 3. 30: Lift coefficient and Alpha plot Figure 3. 31: Glide ratio and Alpha plot Figure 3. 32 : Glide ratio and Alpha(Re= 200000) Analysis: From the graph 3. 30, we can figure out the maximum Cl value is given by NACA 9318 of about 2. 3. And maximum Cl value when alpha(AOA) is 0 is given by NACA 9718 as per the figure. And hence the airfoil with largest stalling angle also can be seen, as it is NACA 9718. This airfoil though it has less Cl max, it stalls late compared to other airfoils. Its stall angle is going more than 20 degrees.

Responsible factors for climate change

Responsible factors for climate change By definition, climate change is an average long-term shift in weather patterns that is manifested by altering in the contributing factors including precipitation, temperature and pressure among other indicators. Climate change can be a consequence of a modification in variability typified by extreme weather conditions, for example, erratic rainfalls that cause floods.Advertising We will write a custom essay sample on Responsible factors for climate change specifically for you for only $16.05 $11/page Learn More The earth’s climate is synonymous to this variability, however, its long-term climatic state is harmonized by the energy balance â€Å"between the incoming and the outgoing energy† (Ewing, 2012). As such, any external factor (climate forcers) affecting this energy balance may lead to climate changes. Importantly, these factors occur in different time-periods. Hence, the factors that affected climate change centuries back may not be the ones standing currently. Climate forcers can be categorized into two groups including human and natural causes. In addition to the duo, there are other changes that happen internally within the climate system, affecting the climate either as short-lived or long-lived. These modifications may be attributed to the atmospheric circulations among others factors. Human beings contribute to climate change when they engage in burning of fossil fuel, deforestation activities notwithstanding. These effects have been aggravated further since the inception of the era of industrial revolution. As a consequence, the face of the land has been altered tremendously, and the atmosphere is filled with fumes dominated by carbon dioxide gas, one of the greenhouse gases. These changes constitute what we can consider ourselves ‘climate forcers,’ who are responsible for destabilizing the earth’s energy system. To this end, the overall effect on the earth’s atmosphere has been a warming effect. The cumulative effect of the gas emissions on the planet is called the greenhouse effect. This is the reason of the global warming, and as such, it is believed that it may lead to erratic weather patterns, consequently affecting both the social and economic activities of man.Advertising Looking for essay on environmental studies? Let's see if we can help you! Get your first paper with 15% OFF Learn More Apart from the human activities, natural factors are other elements responsible for climate change. Such activities as volcanicity and the Sun insolation are among the external factors central to climate change. These two basically fall within the timescale of the contemporary causes of climate change. The duo have a significant effect on the incoming energy, however, volcanicity has a short-lived effect on the climate change. The intensity of the Sun insolation has considerably increased since the inception of the industrial revolution. This h as been estimated to have increased by ten folds, consequently affecting climate significantly. The internal elements within the climate that affect the climate change could be due to the emitted gases that stem from human activities. These gases, for example, CO2, can be classed as long-lived because they take a while before they are eliminated from the atmosphere. Conversely, the short-lived gases, for instance, methane, clear off the atmosphere very fast. Class aside, if remained unchecked, short-lived gases have a potential of causing adverse climate change. They are responsible for the greenhouse effect. The history of the climate trend Climate has been changing to the worst since the era that is called industrial revolution. On analyzing the trend of the world’s mean temperature dating back to the 19th century, one can underscore the fact that, indeed, the Earth is experiencing global warming. In the 1960s, though, there was a compelling evidence of a shifting trend whe re experts reported that the planet was cooling. Nevertheless, new findings stipulated that this was a brief interruption and the trend would assume the previous modification process in the 1970s. These findings elicited a serious debate among climatologists with some predicting a sustained cooling trend over time. To this end, they cited a phase of a sustained natural cycle or perhaps the elements of smog and dust particles that continue to fill the atmosphere due to the human activities.Advertising We will write a custom essay sample on Responsible factors for climate change specifically for you for only $16.05 $11/page Learn More Those predicting otherwise believed that the effects of the greenhouse gas emissions would surpass those due to the concentration of particles in the atmosphere, and as such, global warming would resume. In a conclusion, the two opposing groups acknowledged the fact that their stands were just mare guesswork. In the meantime, th ere were advances in the climatology science. Nonetheless, in 1970s, the view that the warming would resume triumphed highlighting that the cooling was a brief interruption. With the turn of the century, the warming effect aggravated further as evident by the changing temperatures even at the depth of the ocean base. To scientists, this was a compelling evidence of a gross change in climate that had never been witnessed before. The specific pattern â€Å"of changes, revealed in objects ranging from ship logs to ice caps to tree rings, closely matched the predicted effects of greenhouse gas emissions† (Bredenberg, 2012). Ideally, one would wonder how meteorologists came up with the conclusion that the world was warming. Indeed, the journey to establishing of this fact was not an easy feat. Scientists had to deal with voluminous and uncertain data collected over a long period of time, and using different methods to come up with the conclusion. Among the pioneer groups of scient ists who tried to establish this fact were the NASA and the Climate Research Unit (CRU), a British based group. In their research, they reached an almost similar answer that the planet’s average temperatures had raised by at least 0.50C in the past century. In the meantime, several other groups over the world were dedicated to measuring the weather patterns. Vitally, while some were engaging in careful, recording and securing of records in archives, the others were busy standardizing the instruments.Advertising Looking for essay on environmental studies? Let's see if we can help you! Get your first paper with 15% OFF Learn More Even with these data, no scientist would stake a claim that the world would warm in the future, especially with the 1940-70 dip as shown in below (fig. 1). With these findings, one is tempted to hold the thought that the current highs could be temporal. Current geopolitical response to climate change One may notice the tug of war concerning the causes of climate change that continue to illicit mixed reactions among the science and anti-science zealots. On one hand, science holds the thought that the planet is experiencing global warming, and that the anti-science zealots are embedding efforts meant to stem this trend. On the other hand, the anti-scientists hold the view that global warming is not a consequence of the human activities, and that the scientists’ views are for selfish gains meant to transform the world’s economy. Surprisingly, the skeptics consider that even if the planet is warming, it is not a cause for alarm. Some critics of the scientific view base th eir argument on the alleged dishonesty amongst scientists. To this end, they cite the ‘Climategate Scandal’ as one of their evidences of scientists’ dishonesty. The details of the scandal, as revealed later, showed that someone had hacked into the server of the CRU and sent more than 1000 e-mails to people all over the world with a plot to falsify an average global temperature trend. This allegation was investigated by several agencies from both the US and the UK, revealing that the scientists were genuine in their findings. If not enough, skeptics find dishonesty in an e-mail that was written by Phil Jones to Micheal Mann, both from the CRU, disputing the latter’s chart as a ‘trick’ to mean that he was hiding a temperature decline (Ewing, 2008). However, in a bid to dilute skeptical views, scientists have a well established database in the blog, DeSmogBlog, of the individuals who are in dissent industry of global warming. Some critics hold th e view that the idea of the man-engineered global warming emanates from neo-colonialism. As such, the idea is meant to shift focus of the development agenda from the developed economies to the third world economies. The opposing faction, however, believe that the skeptics’ view that global warming is not a man-made effect is a tactic to bar governments from interfering with their businesses (free-market). Free-market fundamentalists feel that governments are threatened by the fact that free-markets can resolve both the social and economic problems if given a freehand. Moreover, they tend to think that market fundamentalism has been a principal factor in determining the US’s public policy debates in the past three decades. If not enough, critics argue that most of these scientists holding the consensus view were cold-war research artillery, and that following the crumple of the Soviet Union, they sought solace in another global issue in the name of global warming to see k the world control. The response to climate change due to global warming is a universal issue defying commitments to the nations where the greenhouse gas emissions are more pronounced. This is owed to the fact that the greenhouse gases defuse rapidly and evenly over the world. To this end, the UN has been the platform, upon which responses to climate change has been addressed. Global bodies established under the UN umbrella, for instance, the Kyoto Protocol and the UNFCCC (United Nation Framework Convention on Climate Change), have made massive steps in trying to reverse this change. Chiefly, international policies have been adopted globally at a national cum regional level, signaling a consolidated approach aimed at stemming this change. The objective of the UNFCCC (formed in 1990) was to stabilize the greenhouse gases by the turn of the 21st century. However, subsequent meetings prior to the 21st century led to the establishment of the Kyoto Protocol in the year 1997. Its objecti ve focused on the developed economies to reduce their greenhouse gas emissions by 5.2% with their respective 1990 levels as a baseline. This had to be achieved by the year 2012. This was not an easy feat to achieve, and as such, it took three meetings for the stakeholders to reach the Marrakesh Accord, which outlined the processes that were to be followed to achieve the Kyoto Protocol (Nicole, 2004). Importantly, in order for the Kyoto Protocol to be a legally binding document, it had to be ratified by more than 55 nations. The Annex 1 nations had to make up the 55 nations ratifying the protocol in order to account for at least 55% of the total emissions of the 1990 levels. For political and economic reasons, the US chose not to ratify the Protocol even though its emissions accounted for more than 25% of the total greenhouse gas emissions emanating from the developed economies. One political reason that the US chose not to ratify the Protocol is that the treaty was partial. To this, the US claims that the design of the treaty would leave out some economies known for their massive greenhouse gas emissions. Moreover, the US has been reluctant to ratify the Protocol for the reason that it would result in job losses by its citizens. Akin to the US, the Australian government temporarily failed to confirm the Protocol only to ratify it in 2007. Russia validated the Protocol after a while in the year 2004. The countries that were party to the treaty relied on three flexible means including Emission Trading, Joint Implementation (JI), and the Clean Development Mechanism (CDM) to achieve the Kyoto Protocol. However, many investors hold a negative view over the JI and CDM mechanisms, citing too much bureaucracy involved in getting an approval. Vital remedies to mitigate greenhouse gas emissions One of the remedies that governments ought to apply is the need to engage in the energy conservation practices. Economical utilization of energy goes all the way to reducing the levels of greenhouse gases (GHGs) a great deal. Designs meant for appliances at homes should aim at enhancing energy efficiencies. The state of California is a typical example of a region in the US that has taken its own initiative to engage in efficient utilization of energy. As such, striking research shows that between 1976 and 2005, this state has maintained its energy requirements at a fairly constant rate. This is opposed to the rest of the US, where the energy requirements had increased by 60%. Another striking revelation is that the total energy losses by the US economy surpass the total energy requirements of the Japanese economy. This shows that the Japanese machinery designs are energy-efficient. Economies should adopt sequestration models meant to capture CO2 instead of releasing it to the atmosphere (U.S. Department of Transportation, 2010). Another remedy that governments should adopt is the use of alternative sources of clean, renewable sources of energy instead of us ing bio-fuels. Among the major contributors of GHGs is coal. This energy source is far less efficient in its utilization (30% efficient). Among the clean, renewable energy sources that fit the billing one could name solar and wind energy. These two can play a major role in curbing GHG emissions. Another alternative is the use of nuclear energy. However, it is risky since some nations might use it as an arsenal. Therefore, to use it, all nations should be honest. Urbanization is one of the ‘enemies’ of the GHG-free atmosphere. It comes with deforestation, a practice that is believed to deny the atmosphere the ‘lungs’- which is meant to clear the CO2 from it. While urbanization and industrialization change the world’s face in the name of creating wealth, these two practices are suicidal to the atmosphere. They basically utilize the land, a limited resource, without replacing it, leaving the land bare and depriving it of its ‘lungs’. To cu rb this trend, afforestation practices ought to be given a global attention and enhance the GHG-free atmosphere. Transport industry and hence the gasoline industry are the ones that contribute immensely to the GHGs, globally. There is need for engineers to come up with the engine designs that are more sensitive to our environment. The designs should be a hybrid formation of gasoline/electric engines to limit on the gasoline requirements. This would go all the way to limiting the GHG emissions into the atmosphere. In addition, some economies have adopted safe utilization policies whereby transportation to public destinations/institutions has to be done using a bigger unit (a bus) as opposed to smaller and numerous units (cars). This would curtail the GHG emissions. Future solutions to climate change After adopting the energy-efficient designs as well as conservation strategies, the void left to suffice the energy requirements has to be met by the GHG-free renewable energy sources. Th is has to be provided by the wind, solar, hydroelectric, and geothermal energy. The use of the wind energy as a ‘green power’ has been among the buzzwords of the greenhouse-free atmosphere advocates. It is a renewable source of energy that can be converted to mechanical energy, and eventually electrical energy before it is utilized. Ideally, to generate electricity, the site where the plant is mounted should be favorably windy in order to drive the giant turbines for generating electricity. The energy generated from wind can be used in home appliances as well as to drive industrial machines. Engineers have come up with the efficient turbine designs that can achieve maximum output from the wind power. The solar energy is another source of ‘green power’. This energy is derived from ultraviolet rays that emanate from the Sun. Through different mechanisms, this energy can be converted to electrical energy or can be used directly to serve the peoples needs. To c onvert the solar energy to electrical energy, one applies a photovoltaic cell. However, the efficiency of the solar energy is dependent on the insolation received per day. The maximum insolation got in a region is influenced by the latitude and the season of the same. To this end, the regions falling within the equator zone receive maximum insolation at midday. Moreover, one can use larger panels in regions that experience limited insolation to meet his/her needs. Directly, one may use the solar energy for heating and lighting. This is one of the best alternatives to fossil fuels since it is clean and renewable. The hydroelectric power is a ‘green power’ that may help in mitigating the greenhouse gas emissions. This energy is derived from water that drives a turbine to generate power. However, this energy is limited to regions that have no waterfalls. Nonetheless, they generate enough electricity that can be supplied to a far place. The energy received from this source can be used domestically as well as for driving industrial machines. Biomass is another source of energy, an alternative to fossil fuel though it is not a GHG-free source of energy. Recently, in such economies like Brazil, the use of biodiesel is slowly becoming popular. Akin to biomass, we do have fuel cells, which are powered by coal to generate electricity. Finally, the geothermal power accounts for another source of ‘green power.’ This form of energy is limited to regions that are endowed with hot springs. As such, this form of energy is not common. Nonetheless, the energy derived from this source can be converted to electricity to find application both domestically and in industries. References Bredenberg, A. (2011). The Climate Change Controversy – What’s It Really About? Green and Clean Journal, 2(3), 3-7. Ewing, R. (2008). Growing Cooler: The Evidence on Urban Development and Climate Change. Washington, DC: Urban Land Institute. Nicole, N. (2004). United States Problems with the Kyoto Treaty. New York, NY: New York University Press. U.S. Department of Transportation. (2010). Transportation’s Role in Reducing U.S. Greenhouse Gas Emissions. South Melbourne, Australia: Thomson Learning.

Essay Sample on Different Types of Communication

Essay Sample on Different Types of Communication To write an essay on communication, students should know what communication is. Communication is a two way process in which the receiver and sender, both should be involved actively. Communication involves means such as listening, speaking, writing and reading. All these means can be used for an active communication process. Essays on communication should be able to depict any one or many means of communication. Essays on communication can be of many types like essay on communication skills, essay on interpersonal communication, essay on team communication and essay on public relations. ‘Communication skills’ is a broad field and essay on communication skills should contain some information about the communication skills that are relevant to the topic of essay on communication. For essay on interpersonal communication, the relationships between the two communicators should be highlighted in the essay on communication. Similarly, essay on team communication should contain information about how a team can develop interpersonal communication between each other. For all kinds of communication essays, the writers of the communication essays should keep in mind that they should write keeping view the topic of the communication essays. The matter in an essay on communication should be relevant to the topic and should be informative regarding to the topic of communication essay. For writing communication essays, the writers have to follow some guidelines, which will help them in writing a communication essay that will be of good quality. Essay in also a form a communication so it should be communicated with clear messages and simple language so the reader faces no problem in comprehension of the idea delivered in the essay on communication. Essays on communication should have a well-defined introduction, some body paragraphs for the discussion in terms of communication topic and a conclusion, which should summarize the whole essays and should come to one point after the discussion that is done in the body section. In case of well-organized communication essay, the reader of an essay on communication will be able to get the arguments written by a writer of essay on communication. Every paragraph given in an essay on communication should be able to describe only one idea or thought, in case of more than one idea or thought in one paragraph, the reader faces di fficulty in getting the meaning of the whole passage as it is jumbled down with a number of ideas. The introductory paragraph should have the description of the topic of your essays on communication. There should be a thesis statement. A thesis statement is stated in one sentence or more than one sentence but it is suggested that it should be one sentence. The thesis statement gives the main idea of the essays on communication. There are also custom writing sites like us from where you can get plagiarism free essay on communication, and get professional assistance how to write an essay on communication issues.

Recruitment and Selection Essay Example | Topics and Well Written Essays - 4000 words

Recruitment and Selection - Essay Example Heavy reliance on internal sources is thought to perpetuate the racial, gender, and age composition of the workforce. Thus, a balance between promoting current employees and hiring outside applicants is needed. Newspaper ads. Running ads in periodicals such as local newspapers or professional journals is a common method of recruiting employees. In fact, in a survey of 188 organisations, personnel executives claimed newspaper advertising to be one of the most effective avenues of applicant recruitment (N.A. Mason & Belt, 1986). Although little research is available, there is plenty of expert advice on the best way for an employer to write recruitment advertisements. Kaplan, Aamodt, and Wilk (1991) tested some of this expert advice by first determining the characteristics of help-wanted ads and then comparing the design of actual help-wanted ads in 10 newspapers with the quantity and quality of applicants who responded After examining thousands of ads, Kaplan et al (1991) found 23 advertising characteristics, as follows: Ad Design: company emblem included, creative illustrations used, creative wording, white space around ad, job title enlarged or in bold face. Legal Information: affirmative action statement, EEO statement. Information about the Job: Benefit package listed, job title mentioned, salary description, multiple jobs listed in the same ad. Information about the Company: company address listed, company description included, company name mentioned, phone number listed. Applicant qualifications: educ ation requirements, personality traits desired, pervious experience requirements, skills needed by applicants, salary history requested. After comparing the presence or absence of the 23 characteristics with the presence or absence who responded to the ad, the researchers found that ads displaying the company

Macdonald's Term Paper Example | Topics and Well Written Essays - 3750 words

Macdonald's - Term Paper Example It has been recognized that such grave issues tend to hamper the overall effectiveness of the organization. In order to resolve the issues, it is quite significant for the company to revise its strategies. It must also desire to focus upon the creation of sound incentive structures. It is also imperative to enhance the working condition of the employees. Top management needs to play an active role in this regard. Position The company that has been chosen for the study is McDonald’s Corporation. It is considered to be one of the biggest food chains in the globe pioneering in hamburger fast-food based restaurant. It is based in the United States, though McDonald’s has a global presence as at present the restaurant chain is operating in over 100 nations. In various places of the world where the company operates, it is either run by a franchise, an associate or the corporation itself. The company sells numerous products such as hamburgers, French fries along with chicken an d other breakfast item (McDonald’s, â€Å"Mission and Values†). McDonald’s mission statement aims at becoming one of the favorite places for the consumers. Its worldwide branches and subsidiaries have been linked with the global strategy which is known as ‘Plan to Win’. ... It believes in the fact that for the purpose of attaining success it is quite significant to have a trained workforce belonging to diverse backgrounds working in an environment as a team. The company assists its customers to build improved societies, endorses Ronald McDonald House contributions and thus these aspects positively impact upon their size, scope as well as possession to make the world a healthier place (McDonald’s, â€Å"Mission and Values†). The vision statement of the company is to be one of the top service restaurants offering speedy services to the customers. It wants to offer its customers with best quality, service, and cleanliness and value (McDonald’s, â€Å"Mission and Values†). McDonald’s is a business entity which is famous for its burgers and meals. The business of the company has been extended all over the world. The major stakeholders of the company are customer, employees, managers, financiers, and suppliers along with com munities in which it operates (McDonald’s Corporation, â€Å"The Values We Bring to the Table†). Thesis Statement The main objective of the paper is to discover the problems faced by McDonald’s and to identify the ways through which the problems can be resolved. Sense It can be observed that McDonald’s has been developing and extending its operations all over the globe since past few years. Even though the company seems to be convenient, clean and cheap there are a number of negative aspects related to the company especially its operational procedure. Despite paying the employees of the company with low wages and impacting other culture negatively to a certain extent, it has been observed that the company has been capable of positioning itself as having