Precessing Vortex Core Literature review Example | Topics and Well Written Essays - 3250 words

Precessing Vortex Core - Literature review Example While this appears to be an indication of perpetuated turbulence in fluid flow, experimental results have shown that the vortex tends to adapt to the force causing the spiral flow [10]. Fig 1: Precession of the vortex tending towards the equilibrium Fluid Flow in the Precessing Vortex Core Perhaps, it is on the basis of this tendency of vortex precession that the concept of swirl flow stabilization was developed for turbines. The precessing vortex core (PVC) has been defined by [14] as â€Å"...a three-dimensional time-dependent coherent structure developed in the exhaust nozzle of many swirl devices...† p. 147. Some of the challenges faced in adopting the concept of precessing vortex core point at the significance of the geometry of the combustor (for gaseous flow) as well as the instabilities in the thermo-acoustic. These are noted by [2] as significant sources of losses in stabilization process. According to [3], â€Å"...a precessing vortex core can be a source that drive s combustion instability† (p.1) and may lead to obvious undesirable results. This overshadows the beneficial effect of precessing vortex core sought for in a chamber such as an improved mixing of the fuel and air as well as stabilization of the flow. From the observation, the precessing vortex core can be linked to flow instabilities [3]. This was demonstrated by the interactions among the zones of recirculation during the flow process. Therefore, by considering the intricacies of precessing vortex core, research continues to expose the need for successful prediction of the mechanism and physics of flow stabilization. In such cases, efforts have been made to set up simulations that would properly model the speed of the flow propagation. This has been used by [3] to determine, with near precision, the exact position at which the flow propagation speed equalled the velocity of the incident flow at that very point of flow. From this simulation, it was expected that the turbulence at the base of the flow would enhance the speed of propagation of the flow. However, the investigation failed to simulate the desirable flow base structure that would give such results. This could be attributed to the challenge of flow stabilization that is attributed to the precessing vortex core. As such, to better understand the precessing vortex core and its effect on the fluid flow in swirl models used in fluid flow experiments, complications in swirl flow propagation models offer a good guideline [4]. Studies of the PVC are mainly done with reference to the operation of a gas turbine. Gas turbine models in such experiments were made to operate on lean combustion mixture that is premixed before injection in the fluid flow chamber of the turbine. These experiments have shown that introducing this premixed mixture in a swirl into the vortex is helpful in aerodynamic stabilization of the highly turbulent flows in the fluid flow chamber [4]. Fig 2: The view of the swirler (the out er and inner views) [4] At the core of the vortex, is a vortex line around which, every particle introduced into the chamber circulates. This results in the recirculation of the combusting mixture. This is because of the low pressure zone created by the circulating fluids. Experimental approaches have been developed to characterize structures of swirl generators. It is shown by these experiments that structural forms, flow interaction, and shape of the vortex play a role in precessing vortex

Cosmic Creation Myths Across Cultures Essay Example for Free

Cosmic Creation Myths Across Cultures Essay The two creation myths selected to compare and contrast centers on the Norse culture of Iceland Vikings and the Genesis creation of the Hebrew origin of Christian culture. Both creation myths originate with a hollow abyss where anarchy or war cultivates. The Norse myth relates a struggle in the middle of the blistering realm of Muspell and the murky, icy realm of Niflheim inside the hollowness named ginnungagap and where nothing could cultivate. The Genesis struggle was involving God and nothing, seclusion, and the craving to generate something wonderful. There are exactly nine categorizations of creation myths and numerous utilize more than one notion. Genesis cosmogonies utilizes both the deus faber and ex nihilo ideas. The account frequently deemed the ex nihilo myth, implying out of nothing is the story in the first book of the Old Testament, Genesis, of Gods creation in six days by communicating into existence light and blackness, moon and sun, animals and plants, birds and fish, stars and earth, God then creates Adam in His image from the dust and inhales life into him and Eve was molded from one of Adams ribs, consequently joining deus faber (the maker-God) with ex nihilo motifs. The Nordic creation myths incline to merge accretion/conjunction, exudation, and sacrifice ideas. It introduces the combining of fire and ice in an arbitrary linking of components. When the tepid breath of Muspell encounters the chill of glacial Nieflheim, ice dissolves and the subsequent water droplets come to life, generating the wicked gigantic Ymir. As the titan slumbers, perspiration from his armpits produces the first man and woman. These added titans mature to loathe Ymir and the creation story goes on with the slaughter and disfigurement of the dreadful giant. The Norse culture consist what we call Vikings. They had a pantheon of 14 main gods and conceived the cosmos as separated into three levels: Asgard, Aesir, is the higher level and land of the main gods, fertility gods, and where light elves also existed. Midgard is the middle  level where men, giants, dwarves, and dark elves lived. Niflheim is the lower level, better known as the underworld, where the evil dead died a second time in the fortress city of Hel. Running through and ultimately reaching above heaven is Yggdrasil, the enormous ash tree that apparently existed before the beginning. The Genesis creation myth is comparable in that the world was shapeless also emptiness, and obscurity laid in the deep. God soul was touching above the top of the seawaters when, he generated the skies and the planet. The scriptural writers considered the universe as a horizontal round formed planet in the axis, an illicit world for the lifeless underneath, and paradise overhead. Underneath the planet stood the waters of chaos, the intergalactic ocean, and nest to mythological ogres conquered and killed by means of God. In Genesis, the earth was formless, empty, and dark, and Gods Spirit moved over the waters preparing to perform Gods creative Word (Fairchild, 2013). God initiated speaking his creation into existence. The first day, he generated luminosity and parted it from the blackness, calling sunlit day and obscurity night. The second day, God made the sky to detached the seawaters. The third day, he formed the waterless earth, called land, and congregated the seawaters, naming them seas. The Divinity as well formed flowers and plants on this day. God created the sun, moon, and the stars to give light to the earth and to govern and separate the day and the night on the fourth diurnal (Fairchild, 2013). These elements would also serve to establish days, seasons, and years. On the fifth day, he formed each existing organism of the oceans and of the skies, sanctifying them to flourish. Also formed the creatures to saturate the world on the sixth diurnal. Adam and Eve, believed to be the first man and woman, were also created in his reflection on this day to communicate. He blessed them and gave them every creature and the whole earth to rule over, care for, and cultivate (Fairchild, 2013). Finally, on the seventh diurnal, he completed his labor of conception and relaxed, consecration it and formulating it consecrated. The Norse story did not have one maker of good, but multiple elements and events that emerged from one evil giant in this creation myth. The cattle stroked off whole Alps of rime, gradually licking rime of other two additional existences, the god Buri and his spouse. They had a son named Bor, and his son was named Odin, who became the king of all  the gods (Distant Train, Inc., 2011). Ymir was malicious and wicked and when Odin along with the divinities may well no more endure Ymirs wicked deeds, they united to kill the giant. Ymir’s huge body formed the earth, his blood became the sea, his flesh became the land, his bones the mountains and his hair the trees (Distant Train, Inc., 2011). He and the additional deities shaped the heavens with his cranium, sustained up by four immense columns. He created the sun and moon from flashes from the blistering pits of Muspell and placed them in the sky. The ice began to melt in the new world of Ginnungagap from the illumination of the sun and moon and vegetation began to grow. The largest tree, called Yggdrasil, grew from the center of the world and became known as The Tree of Life. Its roots penetrated into the bottom of creation and its leaves reached the very top of the sky (Distant Train, Inc., 2011). To his satisfaction of the newborn earth, Odin baptized it Midgard, meaning The Middle Land. However, Midgard needed tending to while the gods ascend to Asgard. Odin discovered two collapsed trees, an elm and an ash, which Odin removed from the dirt and shaped the incipient male and female. Odin breathed life into the beings, gave them reason and feelings, hearing and sight (Distant Train, Inc., 2011). Similar to the Genesis story of Adam and Eve, Odin called the male Ask and the female Embla and from them, launched the whole hu mankind. In summary, the Genesis creation story identifies God as the writer of conception. In Genesis 1 we are presented with the beginning of a divine drama that can only be examined and understood from the standpoint of faith. How long did it take? How did it happen, exactly? (Fairchild, 2013). It is impossible to definitively answer these questions, but these inscrutabilities are not the emphasis of the conception account. The point, is for ethical and religious epiphany. Verse 26, God states, Let us make man in our image, in our likeness The story goes that a serpent tricked Eve into eating the fruit from the forbidden tree and she offered it to Adam and he also ate from it. As a result, Eve and Adam were expelled from the Garden of Eden, men will labor over the earth, women will experience excruciating pain bearing children, and all humans will die. Readers from Western cultures tend to rank â€Å"metaphysical or spiritual† cosmogonies like the account of Elohim-God speaking the world into existence in Genesis higher than â€Å"physical, natural, or elemental accounts of creation by  accretion, excretion, copulation, division, dismemberment, or parturition (Leonard McClure, 2004). If, however, we are self-conscious about our culture’s assumptions about what is â€Å"normal,† we see that at least as many cosmogonic myths have presented creation as part of a natural process as have conceived it as an exercise of divine and creative will. Ranking one kind of myth as lower or more primitive and our own myths as higher or more cultured derives from a cultural bias. To study myth effectively, we need to free ourselves as much as possible from the prejudices we inherit from our cultural surroundings. References Distant Train, Inc. (2011). Norse Creation. Retrieved from http://bigmyth.com/download/NORSE_CREATION.pdf Fairchild, M. (2013, January 4). The Creation Story Bible Story Summary. About.com Christianity. Retrieved from http://christianity.about.com/od/biblestorysummaries/p/ creationstory.htm Gill, N. S. (2012, April 13). Creation of the World Norse Mythology on the Creation of the World. About.com Ancient / Classical History. Retrieved from http://ancienthistory.about.com/od/creationmyths/a/11083199Norse.htm Ginzberg, L. (2012, April 13). Legends of the Jews, By Louis Ginzberg. Legends of the Jews. Retrieved from http://ancienthistory.about.com/library/bl/bl_text_jewslegends1a.htm Leonard, S., McClure, M. (2004). Myth Knowing: An introduction to world mythology. New York, NY: McGraw-Hill. Shmoop Editorial Team. (November 11, 2008).The Myth of Norse Creation Myth. Retrieved June 20, 2014, from http://www.shmoop.com/norse-creation-myth/

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Margaret Thatcher is an iconic political figure that goes down in history as the longest serving, and only woman, British Prime Minister in the history of politics in the United Kingdom. Famous for her stern political stance and policies on international policies and relations, Thatcher was nick-named the ‘Iron Lady’, a name that well stuck with her considering her general approach to policies and outlook into international politics. Having served Britain for 20 years, Thatcher stands as an important political figure that brought with her great political changes in the United Kingdom. Not only is she notable for her efforts to revolutionize the British economy from Statism to Liberalism, but also her unending efforts to lower inflation and greatly reduce the high unemployment levels that were present in the country when she took office. Thatcher not only involved herself with her home politics, but also those of other countries bringing Britain politics to the internati onal map. She became a commonly familiar figure with Ronald Reagan, the then President of the United States of America, and even most surprisingly gained praise and popularity with the then Soviet Union leader, Gorbachev. During her long and eventful stay in office, Thatcher attracted praise and criticism in equal measure. Nevertheless, she remains a political enigma in relation to British and International politics. Margaret Thatcher was born in 1925, in the town of Grantham, to a local businessman who doubled as a grocer and Mayor of Grantham town. She was sent to a local grammar school where her oratory skills sprout roots at a tender age. It has been widely argued that her father served as an influential figure in her life and the towering figure behind her in... ...Britain`s economy behind. Thatcher also introduced a new strategy on government spending in addition to introducing the concept of home ownership to tenants (The Economist). Thatcher is highly remembered for her involvement in keeping the value of the Pound high, a move that has shielded Britain over the recent financial crisis being experienced in Europe. She also restored Britain`s sovereignty as a power to reckon with in international politics and the defeat of Argentina over the Falkland Islands(James). Margaret Thatcher remains one of the most famous politicians of all time. Having adopted controversial policies to save her own country from the economic mess that it was in, Thatcher became more popular to the rest of the world than in her own country. Nevertheless, she will remain in the books of history as one of the most iconic political enigmas of all time.

Salmonella †description, pathogenesis, symptoms Essay -- Medicine Foo

Salmonella – description, pathogenesis, symptoms Salmonella is a gram-negative bacillus that causes inflammation of the GI tract and in some cases, if the immune response is not sufficiently powerful and treatment is not administered, can become systemic and cause even more serious conditions throughout the body. After ingestion, these bacteria cause infection by invading the epithelial cells of the small intestine and macrophages. Though there are more than two thousand different subspecies of Salmonella, few of them are able to cause serious conditions in humans—for most, the disease resolves itself in a matter of days. Those who are most affected by Salmonella infection are infants, the elderly, and people with compromised immune systems. Some of the main conditions caused by Salmonella are gastroenteritis, enteric fever, and bacteremia, while the general symptoms of salmonella include vomiting, nausea, diarrhea, and abdominal pain. While there are typically few to no long-term effects as a result of a Salmonella infectio n, more serious complications may arise. The mention of the latest salmonella outbreak is often enough to make anyone’s stomach turn—people in the US and other countries have long maintained a strong aversion to, and even anxiety towards, the very idea of salmonella entering the food supply. It is this fear that drives the government and the agricultural industry, which are also prey to the overwhelming dread of the salmonella contamination, to take extreme measures to prevent the slightest risk of salmonella contamination and that continually puts the public on edge—but despite this widespread apprehension, much of the public remains ignorant of what salmonella really is. For many, it is but an ominous nam... ...=0>. Lunsford, Andrea A. â€Å"MLA Format for In-text Citations.† The St. Martin’s Handbook. Fifth Edition. Bedford/St. Martin’s. 20 July 2008. . MayoClinic. â€Å"Salmonella infection.† Infectious Disease. 12 Apr. 2007. Mayo Foundation for Medical Education and Research. 19 July 2008. . MedicineNet. â€Å"Salmonella.† Diseases and Conditions. MedicineNet, Inc. 19 July 2008. . Slack, John M. and I. S. Snyder. Bacteria and Human Disease. Chicago: Year Book Medical Publishers, Inc., 1978. World Health Organization (WHO). â€Å"Drug-resistant salmonella.† Media Centre. April 2005. World Health Organization. 19 July 2008. .

Indian Societies: Gender roles in the Ramayana Essay

In the early patriarchal era of the Ramayana, men dominated over the Indian societies. All areas of social prominence were entirely run by men in the form of warriors, priests and tribal chiefs. Women had very little or no power at all in the political and public arena. They were raised to look after their families as well as being dutiful wives. Women had the task of being loyal, faithful, loving and compassionate towards their husbands. Individual families were normally set up on a â€Å"Male authority† basis, with the husband and father determining fundamental conditions and making the key decisions for their well being. Women’s main role in society was that of influencing their family by providing love and affection to their husbands and children while the man was in charge of satisfying his family’s needs. Male oriented societal values allowed little or no space for women to express their interests and be influential in their everyday lives. Women were traditionally expected to serve their husbands and to have no autonomous interests. Only men could be rulers and leaders in the patriarchal society where the story of the Ramayana developed. Rama once said on his designation as prince regent: â€Å"Mother, my father has appointed me to the task of protecting the people† (Mack 584). This passage clearly illustrates how power was transferred from father to son in order to provide for the people’s needs and for the community as a whole. Rama then as a leader of society must enforce values among others and express his desire to bring remarkable attributes to the people that surround him. â€Å"Sovereignty falls to your share, too, for you are my second self† (585). The need for a sovereign ruler is thus expressed among the community and desired for all individuals in the society. Women were projected as passive victims of the male-ruled system in which they were trapped. Females were responsible for the well being of the family as a whole. Women were raised with a limited perception of their role and placement in the community. To be a respectful and a good house wife meant for these women to shed themselves of any ambitions and desires they might dream of. They had to conform to what was expected from them, which was to â€Å"have no identity besides being a wife or a mother† (Qazi). If they did not conform that way, they were subject to indignity while treated as mere  objects whose main role was to tempt men into sin. History has proven that women were alienated if they did not conform according to what was expected of them. These kinds of women were stereotyped as villains or perceived as being tainted. Men were perceived as being in a role of power, no matter how large their families were. They were brought up with the belief that they were the sole providers for the family. Their failure to perform as it was expected from them led the family into constant perish. Males were in charge of many aspects of society including: making decisions for the community, serving as spiritual guiders, choosing leaders and maintaining an equitable place to live in. Men often made decisions and enforced those decisions upon the family. As Raghunathan noted in his work, â€Å"Men lead and women follow†. Women had no chance but to agree to the male’s decisions they imposed to women. The fact that they were born males gave them an advantage over women in the way that they could achieve anything they wanted and become anything they desired. Men were highly valued and respected if they possessed certain values and ideals within the society. They were educated and trained to be ambitious and to have idealistic values, which were admirable in this specific society. On the other hand, women were taught to shed any ambitions and ideas they may have for themselves. The characteristics valued in men were not valued in women; on the contrary, these characteristics in women were disapproved because of the male-ruled system of the time. â€Å"Patriarchy leads to gender inequality in society† (Seeger). Eventually this could lead these women to become isolated from society since they were not allowed to perform the same tasks and duties as men. Women then, had to rely on the love and devotion they would bring to the family while having other interests and aspirations. In conclusion, the male and female roles in the Ramayana were pre-established by the rigorous society in which the story developed. Males had certain expectations they had to fulfill such as being rulers and leaders in order to be good men. Females, on the other hand, were limited to being faithful  to their husbands while expressing their love for the family. Each had a role in society that they could not differ from due to extreme moral valuation. Men were to become the best warriors and to desire power through leadership; women were to become good mothers and proper wives with no intent or desire to achieve higher goals or expectations. Patriarchy led men into high power positions in the community leaving women with no chance of participation in this field. This type of society facilitated men into possessing key roles in the religious and political arena which served them as a platform to pursue and achieve higher goals. In the story of the Ramayana, men were empowered and women were often subdued due to the patriarchal era that they were living in at the time of the story, which facilitated these typical gender roles. Works cited Mack, Maynard. â€Å"The Ramayana of Valkimi†. The Norton Anthology of World Masterpieces. New York: W.W. Norton, 1997. 576-612Qazi, Uzma. â€Å"Ramayana Lecture Notes†. Grant MacEwan, Edmonton, 2008. Seeger, Elizabeth. â€Å"The Ramayana†. New York: William R. Scott, 1969. Raghunathan, N. â€Å"Srimad Valkimi Ramayana†. Madras: Vighneswara Publishing House, 1981.

Compare & Contrast essay about technologies essays

Compare & Contrast essay about technologies essays Email, Cell phones, Internet, Television, Pagers, and Computers is the way of the future, or is it now trademarks of everyday life? Today in 2002 peoples lives seem so interconnected with the ways that technology has been able to bridge the gap in communications. Fifty years ago, you had limited options, sending mail from the post office (which today has been labeled "snail mail") or calling them. We now have a wide variety of communication devices accessible to us so that we are never out of touch. Multimedia, Television, and internet bring into our homes images of violence, sex, ideals, and everything that is out there in the world. One of the current issues that has been approached is "Is there to much information accessible to us?" Since we are overwhelmed with so much information, scenes of sex, violence, and also by ways of communication, we are slowly loosing the sensors of right and wrong, everything is becoming almost like a video game. Compared to fifty years ago, America today is facing a whole new set of problems that was not even a consideration or a thought of Americans of yesteryear. Morals, communication, societys beliefs, trends, value of life, and even workplace environments are worlds apart from our past, and all this within a short span of time. We do not reflect the utopia that people from 1952 may have imagined for us with flying cars, ray guns, and life in space. We are a generation caught up in the world of high speed information and instant everything, even instant life (cloning and genetic research). The world of communication is so egregious; we dont know what to do. From email, to computers, to chat rooms; its how people meet and interact with each other now. These so called Internet cafes" how does this affect people? Are people more open today about meeting people than they were 50 yea ...

jayson williams is guilty essays

jayson williams is guilty essays Former NBA player Jayson Williams, 36, is fully responsible for the February fourteenth (2002) shooting of Costas Christofi. Christofi, 55, had been hired to drive Williams's friends from a Bethlehem, Pa. charity event back to his estate. Williams shot Christofi while giving his house guests a tour of his Hunterdon County estate after a night out. Williams's brother, and eleven other guests, including four players from the Harlem Globetrotters, were at the house the night of the shooting. According to the witnesses who testified at the trial, while Williams was showing his guests around his master bedroom, he grabbed a twelve-gauge shotgun from his gun cabinet, opened it, and then jerked it shut. When the gun closed, it fired, striking Christofi in the chest. He was found shot to death in the master bedroom. Williams was charged with manslaughter and other charges which include hindering apprehension, evidence tampering, witness tampering, fabricating physical evidence and conspi racy to obstruct the law for the death of his limousine driver (Free Press). What is hard to understand is why Williams even took the shotgun out of his gun cabinet. Something which is even more difficult to understand is how he could not realize the shotgun was loaded. If he did realize it was loaded, could he actually be that reckless to play around with it. Also, why was the gun even facing Christofi? There is no doubt that he did nott mean to kill Christofi, but how could he be so reckless? The fact that he shot Christofi is not even the disturbing part. Christofi's death was initially reported as a suicide, but it was later ruled a homicide after an autopsy confirmed it. A 911 tape actually reveals Williams saying that a man committed suicide in his house. Williams told his guests to agree on saying that Christofi killed himself. During the time in which Christofi was shot, Williams wiped down the gun and then tried to t...