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The cost totaled seven lives and millions of dollars. The disaster could have been subverted, however, if o only the several mechanical engineers that had noticed an issue with the rings had stepped f award, despite administrative pressure to continue with the launch, and brought public eaten Zion to the problem. A multitude of other such disarticulated of civic structures, technologies such as cars and trains, and even the batteries of computers and phones, capable of causing harmful explosions, all constitute infringements of people's basic right to life, and thus presents a leg l and ethical dilemma.All engineers possess two at least two democratically knowledge of standard design processes and requirements, and the capacity to apply their knowledge toward dos the creation of novel technologies and innovations. These two things qualify as intellectual pr property, which is an intangible item that is secured via the powers of reasoning of an individual (AH in 50).While some enginee rs, such as professional engineers, are credited for their intellectual pr property, it is essential that all engineers credited thusly, even at the cost Of their employer, as it pro totes their autonomy 2 and therefore creativity, lowers cost of procuring professional engineers to SE al and approve projects , and finally, holds engineers to the highest standard of ethical profess Somalis by exposing the promulgators of shoddy engineering to the scrutiny of the world at large. Companies, when hiring engineers to create technologies, often pressure the SE potential hires into signing binding agreements.These contracts force innovators to forfeit al I of their intellectual and creative output to companies. As Keith Warren, a licensed Professional E ginger, states, a technology company could take the rights Of an invention Of a â€Å"baa rubber sauce† if it so suits them (Warren). Some would argue that this provides complete owner ship provides incentive to companies allow emplo yees more creative license. The company can profit from any and all of their employee' ideas either selling the patent or investing in the † barbeques† productive capabilities it follows that they give more freedom to their novo dative members.Also, as Keith Warren, states, all clients and employers of engineers provide t he engineers with sources to conduct research, so it would seem reasonable that engineers o offer in exchange the profit to be made of of their ideas and technologies (Warren). Engineers been fit in that they are not required to go through an intensive eightieth licensing process to become e professional engineers (who are indeed held personally responsible for any flaw in their w ark, but not for an innovation), as the company will be held responsible for a problem that went unrecognized by an employee.Finally, this discourages individuals from patenting or otherwise CLC aiming ideas that hey lack the capabilities to fabricate it. This, as Koch States, causes an sills_Jew for companies and even other engineers by obligating them to verify the originality of their prod cut periodically throughout the design process using costly search engines, and even prevent Eng some technologies 3 from being commercially available, as they have been patented by small indeed pendent's that refuse to yield their rights to the idea (327). Coercing creative engineers to remain silent about their ideas can stifle create pity and even hinder the process of innovation.On a individual level, the engineer receives I title to no credit for their contributions (Warren). While, as multiple ethical codes attest, engineers should be first accountable for actions that can impact public willingness as approval of t he commercial readiness of a technology, the recognition of their intellectual property should also apply to their own innovations and inventions (â€Å"Code of Ethics†). Enabling creators to claim t heir ideas incentives the creation of trul y original products, for instance, the Apple com putter, the telescope, all created by individuals unattached to large firms.Breakthrough technologies often require extensive resources that sleepyhead individuals are unable to procure, so e engineers currently have two possessively an innovative design, patent it, and by default via pop assessing such legal power, hinder its production and benefit to society by firms with the resource s; or become employed by a firm, attempting to create and fabricate such innovations while e remaining constricted by the firm's own main objectives and directives (Koch 327).Further remorse, firms often keep breakthrough tech oenology a secret for a while, seeking a release time that will bring the most commercial gain due to market price level and other factors. This halts the pr ogress of technology. If instead engineers retained some creative rights to their products, while firm s with the resources hold reproductive rights, a mutually beneficial p artnership is available that en abeles maximum freedom for both parties. Firms are not constrained by a patent to the individual al, and engineers can produce intellectual property at will.The immediate profit of companies is not diminished. Corporate loss will occur only in the advanced autonomy of the engineer rest ensemble for 4 highhanded products, and possible competitive bids from other companies t o take on such a dynamic employee. This loss is overridden by the enhanced ability of corporate e entities to recognize such individuals and seek them for projects, and the government to employ such individuals for public projects that demand acuity in refining structures that c loud affect public welfare.The law mandates that companies must obtain the approval of a Professional Engineer for any of their engineer and design projects in order for the project to become e eligible for rejection. (Warren). This sealing involves a PEP reviewing the designs, calculate ions, and technologi es created by unlicensed engineers employed by an industrial .NET TTY.Because the majority of engineers that work for such entities are unlicensed, they are not r jugulate by the National Society of Engineers and state law to be held personally accountable for their evaluations of a work, and have not undergone the rigorous training for licenser (Warren , â€Å"Ethical Codes†). Thus, federal legislation mandates that a PEP check over a technology before it is released. This is a costly practice, and could easily be foregone if all engineers were required to obtain at least basal licenser via a less vigorous process than PEP, but nonetheless remain regular De by a national organization such as NSP.Finally, engineers should be directly credited for their intellectual OUtPUt in AP proving or disapproving civil projects. This prevents shoddy work from engineers employ De by large companies, that today have little to lose, blanketed by anonymity as they are underneath a large firm 's name, for small mistakes such the matter of a small ring deficiency, the t might build to a large and pervasive civil problem (Warren). Many engineers must battle with conflicting interesting allegiance to the public good and their melodramatically whew n bound by 5 agreements that prohibit their divergence in opinion from a company.Some ethical codes acknowledge this conflict, such as that Of the National Society Of Professional Engineers (â€Å"Code of Ethics†). However, ethical codes themselves, while meant to clarify a course o f action to take when such conflicts occur, often themselves conflict (Eligible and Davis 7 This dilemma is solved if companies cannot take direct credit for an engineer's work, and en gingers intellectual property is in turn attributed to the engineer in question.Companies still poss. sees ownership of the idea of having the sole right to produce it within a fixed number of years, but acknowledge and even provide royalties to the creator of the technology. Litton Engineering, a f roomer workplace of Keith Warren's, exemplifies this concept by providing ample royalties and eve n the ability to patent intellectual property to their employees (Warren). The Challenger Disc steer occurred after an engineer, appealing to an administrator with qualms concerning the rings, w as told to â€Å"think like a manager, not an engineer (Eligible and Heinz 4).The engineer was a c annotator with NASA, instead of a PEP that would be held to scrutiny by the NAPES and the pull ICC for the oversight. Thus, no careers were necessarily imperiled by the disaster (Ware n). Notable failures of civic architecture such as bridge collapse can have be prevented if engineer's careers are stake, instead of company's stock, which can recover more easily. The lack of some r ejaculating agency ND formalized code of ethics in those days could be partially attributed for the see problems (Christie 98).It is thereby essential that some national agency, with a universal code of teeth CSS, regulate all registered and therefore employable engineers. By having a public and private e profile that promotes interest in innovation and accountability, engineers can benefit fro m recognition that they accrue through sound ethical and innovative practice, while being penal zed for malpractice. 6 The conflicting allegiances that engineers often face, to their sponsor, client o r company, and to heir own interior moral compass, will be eliminated, as the company is oblige Ted to maintain an open profile of all works.

Juvie Three Essay

Imagine that you have stolen a car and got away to help your brother get away from the crime scene where he stole some video games. Then while you are driving after the getaway the car flips over and you wake up behind rusted bars in an orange jumpsuit. Going to juvie is tough for this 14 year old and 2 others but their second chance has luckily come. They are all offered to get out of juvie by Douglas Healy. The three boys have to live in apartment with him in NYC and they have to go to school, work, be involved in a community service and attend therapy sessions. One slipup and they are back to juvie. Terrence, one of the 3 boys tries to escape through the emergency escape but Arjay, another one of the boys, and Gecko stop him and get into an argument. Healy comes and tries to settle it down but falls over and hits the ground unconscious. The boys steal a car and rush him to a hospital. Stealing the car was something they would get sent back to juvie for, so they try to play it off that Healy is still with them even though he has lost his memory and is in the hospital. As they do that they get away from the cops chasing them when breaking Healy out. He regains memory when they are in a battle with the worst gang in NY. Three versus five man battle they were outnumbered. But the cops spot the action on the emergency escape and stop it. Gecko put the car back exactly where he found it after he stole it and they broke out Healy because of all the right reasons even though it was wrong so they are home free. Well not Terence, Gecko, and Arjay but they don’t go to juvie.

Nuclear Weapons & Cold War Essay

1) How did nuclear weapons affect the course of the cold war? The Cold War period of much conflict and tension was between the United States and the Soviet Union, along with their respective allies, was from the middle of the1940s until the early part of the 1990s. The building up of nuclear weapons was maybe, the most important of the many arenas that the rivaling countries played in. It became known as the nuclear arms race or the â€Å"competition for supremacy† The discovery that uranium was a plenty around the world shortly after the second world ar, helped to solidify the nuclear monopoly held by both the United States and USSR. While the United States had their own resources for uranium, they soon discovered that Eastern Europe was providing a steady supply to the Soviets, until they could develop a source of their own. The United States, who had predicted that the USSR would not have any nuclear weapons until the mid-1950s, was massively surprised when the Soviets detonated their first bomb â€Å"Joe One† on August 29, 1949. It was much like the bomb that the US had dropped on Japan in 1945 nown as the â€Å"Fat Man†. From that point on both governments devoted massive amounts of money, time and resources to increasing their nuclear arsenals. First off, it was the hydrogen bombs and then next came the Intercontinental ballistic missile or â€Å"ICBMs† as they are known. And on Oct. 4, 1957 the Soviet Union launched the â€Å"Sputnik†, the US followed with their own on Oct. 31, 1959. During this period of innovation, the world became nervous and scared; they discovered just how vulnerable they were. Large underground bunkers were built to save the presidents and he leadership of the nations, individuals were encouraged to construct fallout shelters and they were often taught how to react in the case of a nuclear attack. When both sides realized that any attack upon the other would be suicide for themselves as well, a new policy know as the â€Å"Mutually Assured Destruction† was adapted, and this would, in theory restrain both sides from attacking one another. â€Å"The number of nuclear weapons held by the two superpowers during the Cold War increased drastically because of the need for a first strike and later a second strike force. The highest numbers of nuclear warheads held by these powers was approximately 12,000 for the USSR and 10,000 by the US. This many nuclear weapons has the potential to destroy life on earth more than 1,500 times over† http://www. pwc. k12. nf. ca/coldwar/plain/armsrace. html. And yet, both sides kept exploring and spending large amounts of money and resources on developing nuclear weapons. In many respects, the stockpiling of these weapons was by far the most important contribution made to the world during the cold war period, than any other resource added by any other country. 2) Why has the European Union found it so difficult to achieve political, social and economic integration amongst the member states?  Shortly after the Second World War at the University of Zurich, Winston Churchill gave a speech that called for a â€Å"United States of Europe† and the creation of a â€Å"Council of Europe†. This council became the oldest organization in favor of European integration since 1949. But, in spite all the enthusiasm of the European citizens, the Council’s idea of integration has struggled for many reasons. One of the main reasons is because at the same time as the evelopment of the council another â€Å"European Union† was being formed. This Union was made up of twenty-seven European countries. It was established as the European Economic Community in 1957 under the Treaty of Rome and has undergone many changes since, most notably in 1992 by the Maastricht Treaty†. At first this Union was a welcome relief, growth and restructure was happening over night. The European Union was founded upon a number of treaties, and their laws cover a wide range of topics. Both, a legislative branch and the Parliament govern them. And the politics of he European Union primarily covered the economy. However, there is still a disagreement on how far the Union should expand. Because of the disagreement, the integration and expansion of the European Union has been slow since the end of the cold war period. Enlargement or expansion, together with the signing of new treaties, are seen by some as parallel processes, vital to the Union’s welfare. To many this is known as the â€Å"bicycle theory†. â€Å"The European Union is often compared to a bicycle: if it stops moving forwards it will fall over. The bicycle theory also applies to multilateral trade talks†. Bounds, Andrew (2007). Brussels blog: Bicycle wobbles on the way to Doha, Financial Times. And like most trade talks, both parties want to come out ahead in the end. Thus, the ongoing integration of the European Union and its member states are becoming contested on the grounds that it reduces it’s members’ national sovereignty too much. Politically, the Union struggles because neither they’re laws or their political theory offer the concept of a democracy. Their attitudes remain fixed by the idea of a nation state organization and its people. Socially, this makes them still behind the times. Economically, They struggle with the different economic and resource levels of each of the member states. All these along with the concept of Euroscepticism, or better known as the opposition to the process of European integration, the Union continues to move forward and yet has been forced to make changes to its policies. Amid the post war trauma, the European Union has become a beacon for organized political growth and upbringing. And today, in spite all the worldwide turmoil and confusion, The Union still spreads forth it’s hand in every effort to encourage global peace and umanitarian aid to its member states.  There is no set standard in the process of integration, but today there is a new focus on the complex policy making of the European Union. 3) What was `containment` and how did it influence US cold war thinking? The word containment means to isolate or to make stagnate. In the terms of the cold war, it refers to the foreign policies adapted by the United States under the direction of George Kennan. In the beginning, their policy was to stop all of the outside nations from moving politically towards Soviet Union communism and to ensure that the United States continued to ave, what they thought would be, the upper hand. For ideology as we have seen taught them that the outside world was hostile and that it was their duty to overthrow the political forces beyond their borders. â€Å"(X[Kennan], Foreign Affairs, 1947). They hoped that ultimately in the end thecontainment policies would cause the fall of the Soviet Union and its ally nations. Back in the early days of history, containment was accomplished with the use of brute force or tactics much like an army taking over a castle and then came the use of treaties and political policies, thus being the cold war period. Today this is often accomplished by politically using severe sanctions, as in the United States’ dealings with Iraq and Iran. Espionage and sabotage are other ways of creating a containment among a group of people or nations. During the United States’ cold war containment period the policies adapted by President Truman experienced some major setbacks through the opposition of the Soviet Union, and by the Time the United States pulled out of the Vietnam war and the Koran conflict, there wasn’t mush credit given to the containment policies and ideas, anymore. So the United States started a new heory of â€Å"detente† or peaceful co-existence. Until the election of Ronald Reagan this was a believable concept. President Regan believed that the containment policies did not expand far enough, He felt uneasy about the weapons being held by the foreign nations. He wanted new missiles, placed in Europe to help the United States to become immune to the first strike concept. His new policies become highly controversial and very unpopular in many of the surrounding foreign countries. In 1991, the Soviet Union collapsed under the direction of Gorbachev and the wanted nd result of the original containment policy had been achieved, this marked the official close of that policy. All though, the US still keeps its military and missile bases in the areas around the former Soviet Union, â€Å"just to be on the safe side they say†, many events have effected the world and the current containment policies. As of 2005, the United States are listed as having at least 700 military bases around the world, like the ones in Iceland and Germany. Some up to date estimates suggest that the real number is much higher.

Women In the US Army Research Paper Example | Topics and Well Written Essays - 3000 words

Women In the US Army - Research Paper Example The information provided in the paper is all factual and based on the events which are related to the role of women in the army and its political effects. The paper starts initially during the early twentieth century and leads to the twenty-first century. It mentions how the policies have evolved with time and the present state. Earlier since the idea of women in uniform was bizarre to the US society as the military leaders, Rogers’ proposition to include women as regular army was not seriously considered. Rather the women’s presence in the army was being perceived as a threat to the existing military. So the superstition that women are best suited for indoor activities such as cooking, washing, childrearing, etc. and that due to their physical weakness and psychological frailty, women would cause nuisances to the soldiers rather than contributing anything worthy during any wartime. This limited approach lead to the arousal of various issues. Considering the status of women as weak, frail and fragile who were always exploding with emotions were not considered to be feasible to be recruited for such harsh jobs. It can also be said that men even considered it to be a threat to their present status and how their dominance might get affected therefore due to which they could not accept this under any circumstances. It needs to be kept in mind that during this era the US society was not as liberal as it claims to be now therefore gender equality did not persist back then because of which problems aroused. Therefore initially they were not deployed for direct combats or trainings but were kept for womanly chores such as nursing, cooking, laundry etc. for the troops. The troops started to depend on these women for their daily necessities. Although these women were merely housekeepers for the troops but they were subjected to the armies code of conduct and had to perform their

Associated and Joint Venture Essay Example | Topics and Well Written Essays - 3750 words

Associated and Joint Venture - Essay Example The partners all sit on the joint venture corporation's board, and together have been able to provide the community with a much-needed resource. Therefore, a joint venture may be a corporation, limited liability Company, partnership or other legal structure, depending on a number of considerations such as tax and tort liability. A joint venture is often seen as a very viable business alternative in this sector, as the companies can complement their skill sets while it offers the foreign company a geographic presence. Studies show a failure rate of 30-61%, and that 60% failed to start or faded away within 5 years. (Osborn, 2003) It is also known that Joint ventures in low-developed countries show greater instability. Some countries, such as the People's Republic of China, require foreign companies to form joint ventures with domestic firms in order to enter a market. This requirement often forces technology transfers and managerial control to the domestic partner. This detailed Report provides an Earnings and Dividends history for Honda Motor Co., Ltd... Tabular results include up to a ten-year history of "as reported" Earnings per Share and Dividends per Share plus a calculation of the amount of earnings paid out over the year in dividends (i.e. Payout Ratio). Earnings and Dividends are presented on both a Quarterly and Annual basis. An annual Percent Change factor is calculated for both Earnings and Dividends. Honda Motor Co., Ltd.. The Group's principal activities are to manufacture automobiles, motorcycles and power products. The Group develops and manufactures a wide variety of products, ranging from small general-purpose engines to specialty sports cars that incorporate their internal combustion engine technology. The Group also provides financing for the sale of its motorcycles, automobiles and power products. The Group has got 319 subsidiaries and affiliates. The Group operates in the following four segments: Motorcycle business, Automobile business, Financial services and Power product and other businesses. The Group's major trademarks includes HONDA, ACURA, ACCORD, CIVIC, FIT, ODYSSEY, CR-V, PILOT, MOBILIO, ELEMENT, STEP WGN, MDX, STREAM, LIFE, ACTY, VAMOS, THAT'S, CUB, WAVE and GOLD WING. The Group has subsidiaries throughout the world including North America, Pakistan, the Philippines, India, South America and Europe. Either Associate or Venture Management is focused on the skills and practices required to manage the rapid growth of new business in highly dynamic environments. These environments are often, but now always, characterized by rapid technology change. Associates are usually identified with the following principles. A holding of 20% or more of the voting power, directly or through subsidiaries, would indicate significant influence unless it can be clearly demonstrated otherwise. If the holding is less than 20%, the investor will be presumed not to have significant influence unless such influence can be clearly demonstrated. [IAS 28.6] .The existence of significant influ

Leadership - Strategic Communication Essay Example | Topics and Well Written Essays - 1250 words

Leadership - Strategic Communication - Essay Example Six years later, Bill Clinton, would come out with a book as if to explain to the world what it really was. My life is a 1024 pages autobiography of a former president named William Jefferson Clinton or Bill Clinton who left his office in the shadow of scandal. Clinton tells about his difficult childhood and his political accomplishments, painstakingly registering his greatest successes and failures, which are perceived by some quarters as "trying to face and banish his private demons." Clinton grew up with a second father, the abusive Roger Clinton. But it is said, Mr. Clinton never told any of his friends what was going on at home. As he writes in his book, he has lived "two parallel lives" -- the public one everyone knew about, and a dark secret one he says he never talked about. His mother and he had made the decision to carry on, and just go on and try to make a normal life. Clinton had a beautiful wife, Hilary, whom he adored but unfortunately cheated; and an only daughter, Chelsea who was his pride. He, too, had thousands of men and women in his life, whether in politics, in domestic life, or in whatever social circle they were found. They were all there in Clinton's book - either as a loving mother, a father he hadn't seen and who had provided the puzzles he had wanted all to solve, an aunt who gifted Clinton with short letters from strangers about a father he never saw and which letter he was to hug later on, a half-brother he found too late, a half-sister he never met, a barber, an author invited for dinner, politicians from all spheres, and news reporters and authors. Clinton was able to name them all in his book, and with his photographic memory, sketched the instances when they figured in his life. Why was he doing this with a thousand pages The giant of a book is full of interesting stories about the workings of government and an insight into the man behind the news. It is a riveting account of a president under systematic combined assaults from his enemies, and how he survived and prevailed. The book is heavily a history of Clinton's ascent in politics and the trials of his presidency. Clinton describes an almost day-by-day account of his time in the White House. Bill Clinton started with a quiet life that had allowed him to study and work and read the thoughts of great men. At the age of ten, Clinton observed politics unfold in the family's TV set. His interest in the political process manifested every on while he studied in college, worked as an intern for Senator William Fulbright; joined the Vietnam War protest movement at Oxford, campaigned for Democratic candidates at Yale Law School, and ran for Congress, attorney general, and governor. Clinton had become a leader. But a fallen leader alas! Some see him as able to survive seemingly contradictions and draw them in as one. The stories he related showed some pain he had to struggle with, especially with politics which he described as "a contact sport." The strategy, the fighter in him said, was to "take the first hit, then counterpunch as hard as I could". My Life showed what counterpunch that was in terms of answering his enemies. The good-looking one had the ladies swooning over him which he could not resist, while the men from the other side of the fence gave him the opportunity to show his being a fighter. In this book, Clinton provides a different view to the loads of press releases and news he had

The Usefulness of Cognitive Theories of Learning for Human Resource Essay

The Usefulness of Cognitive Theories of Learning for Human Resource Practitioner - Essay Example The paper tells that nowadays, senior managers tend to invest more money, time, and thought in the learning of their employees, and consider learning and development a strategic HR function Thus, it would be important to comprehend how and why learning takes place. Theories of workplace learning are placed into three main categories; these are psychological, socio-cultural and postmodern theories. Each view has different focus and contribution to different contexts. Various cognitive theories have been put forward including the Piaget developmental stage theory, the Bandura social cognitive theory, and Vysotsky and the Zone of proximal development. All these have a contribution to the development of employees and have been implemented at different levels. Cognitive theories of learning have enhanced employee productivity and effectiveness in most of the areas that they have been applied. Learning is a very important aspect of both individuals as well as organizational development. Le arning is a wide concept that has attracted several definitions from different individuals in different contexts. According to Wilson, learning is the process whereby knowledge, attitude or behavior is changed as a result of formal training and development, or transformation of informal experiences. Many assumptions have been proposed over the years to explain different cognitive approaches. The theories of three outstanding cognitive theorists including Piaget, Vygotsky, and Bandura explain some of the cognitive aspects that are very important when it comes to influencing the workforce in an organization. The development of a person has been a subject of intensive research by psychologists all across the world. One of the outstanding theories in this area is the Piaget developmental stage theory that helps us to understand behavioral development, especially at a young age. According to Piaget’s findings, there are four developmental stages that individuals go through, both o f which are relative to cognitive development. The first is the sensory-motor period in about the first two years when the child can only focus on physical interactions with their immediate environment. Next is the preoperational period from two to seven years old. During this stage, the child develops language skills and is able to think symbolically though still cannot think completely logical and empathetically. The period from seven to eleven years old is called concrete operational stage when the child becomes more rational to solve a simple problem and develops logical thought. The formal operational stage from adolescence through adulthood was Piaget’s fourth stage of cognitive development in children. The child/ adult develop the ability to think theoretically and formulate hypotheses. This theory was immensely influential on education research and policy during the 20th century.

Analysing a web based company Essay Example | Topics and Well Written Essays - 3500 words

Analysing a web based company - Essay Example Business Planning, Retail Growth Strategy, Meal Plan Strategy, Sourcing and Procurement Strategy, Concept Development, Health and Well-Being Strategy, Information Systems Strategy, Food Facilities Planning and Design. Accommodation and food services makes up about 8.1 percent of all employment. (U.S. Bureau of Labor Statistics). Employment in the accommodation and food services industries is predicted to grow 18% between 2002 and 2012, adding more than 1.6 million new jobs. (U.S. Bureau of Labor Statistics). Of the 8,740,000 total workers employed in the accommodation and food services industry in 2003, 5,343,000 works full-time (61%), while 3,397,000 work part-time (39%). (Annual average for 2003, according to the Current Population Survey, a joint project of the U.S. Bureau of Labor Statistics and Census Bureau). The Total Industry Investment is $1,765,000 and the total leveraged resources are $5,900,000. Profit and average room rate at the UK's chain hotels continued to increase in November, according to the latest HotStats survey from TRI Hospitality Consulting. Across the total UK sample of 462 hotels, income before fixed charges (IBFC) - also known as gross operating profit - rose by 5.6 per cent to 52.81 per available room. Average room rate increased by 7.4 per cent to 95.03 in November, a similar rate of growth to the 7.2 per cent achieved during the year so far. In London, profit grew by 7.9 per cent to 82.19 per available room. London's hoteliers continued to achieve rate growth at near annual levels with an 8.9 per cent increase taking average room rate to a new high of 125.85. - Jonathan Langston, UK Chain Hotels Market Review November 2007 | TRI Hospitality, www.trihc.com Villa's Market in Florida Florida property values vary greatly depending on where you are buying. A four-bedroom, three-bathroom Florida villa in Tallahassee will cost around $275,000 whereas a similar property in Key West will cost nearer to $4 million. The Florida villa rental market is thriving because of the popularity of the sunshine state with tourists and also the growth of commerce-based localities such as Miami. Zoning restrictions on the Gulf and Atlantic coasts have pushed up the price of Florida villa rental in those regions. The average weekly rent in West Palm Beach is $1587 and $1431 in Miami. The lower costs in Orlando, a ready-made tenant base, means it may offer the best investment opportunities in the market for Florida villa rental. Florida has a number of the fastest growing property markets in the US with price rises of 36% in Naples and 28% in Orlando in recent years. The growth of the Florida property market has meant there has been a shortage of properties in some areas. This has been met by developers seemingly building a Florida villa on every spare piece of land they can find. The Florida property market now appears to be experiencing an overall slow-down with less developments being planned and prices growing at a slower rate. Mortgage rates are expected to rise in the future, pushing up the cost

AMERICAN THEATER HISTORY Assignment Example | Topics and Well Written Essays - 750 words - 1

AMERICAN THEATER HISTORY - Assignment Example Most importantly, Flanagan ensured that the Federal Theater Project established different units in different states and cities. This paper will discuss the role played by the Federal Theater Project, especially in its series of plays titled Living Newspapers. Moreover, the paper highlighted the significance of the Federal Theater Project to the understanding of American theater in the 1930s. The Federal Theater Project represented efforts by the Federal government to establish an organized presentation and production of theater Wax and events. It served as one of the projects established by President Roosevelt’s administration to provide Americans with jobs. Worth noting is the fact that Americans had experienced the great depression in the 1920s, a factor that saw the collapse of the economic system with many people losing their jobs. For this reason, the Federal Theater Project was established under the Wax Progress Administration as a strategy of providing artists with jobs. The Federal Theater Project sought to bring together actors, playwrights, designers, stage managers, directors, and other artists so that they would count in the public relief roles (About the Federal Theatre Project, 2011). Additionally, the Federal Theater Project sought to present the people with artistic works that would strengthen community life. Worth noting is the fact that the Fede ral Theater Project served its role of providing employment to the people because it hired more than 12,000 artists. In her years of experience, Flanagan had acquired expertise in a unique theater form titled the Living Newspaper. The Living Newspaper theater form made use of common people as significant characters in different plays. The plays introduced existing social and political problems and highlighted potential solutions to the problems (Klein, 2013). The

Research report Essay Example | Topics and Well Written Essays - 3000 words

Research report - Essay Example The study also found that majority of customers prefer to receive information about the new supplier via post and then by salesperson visit. Presence on the web have has also been selected. It is recommended that information be sent via post and published via web. These customers can then be followed up by salespersons for generating business. We found that 74% of customer have been approached by 0-2 suppliers for their business and 42% of customers have never switch suppliers in the last five years. This means that if the new supplier is able to market the service in accordance to the top 3 desired and top 3 existing attributes, these customer can move over to the new suppliers. 64% of the customer who have switched suppliers over the last five years indicated that they have been approached by a supplier for their business. This indicates that the general trend of the market is to be approached by the new suppliers rather than approaching the supplier with their business. For the analysis, the age of the sample has been broken down into three groups – below 30, 30 to 60 and over 60 years of age. In this sample, we found the majority of respondents between the age of 30 and 60 ( at 42%), closely followed by respondents below the age of 30 ( at 30%) and then respondents over the age of 60 (at 28%). Major of the respondents fall within the income bracket of $50,000 and above (at 64%) compared to respondents with income below $50,000 (at 36%). Considering the income bracket, the sample is unevenly distributed across various respondent profiles. During this analysis, the masses with income lesser than $50,000 are under-represented, so are females. In terms of age, the 30 to 60 age group is dominant, however this is required since this is the age group which would normally be found as a familys decision maker age group. The positive implication of these limitations is that the actual decision making age group is largely represented but the

Short stories of Sherlock Holmes Essay Example for Free

Short stories of Sherlock Holmes Essay Title: Review two stories for a magazine called Crime Monthly, saying why such old examples of the crime genre are still popular today. Introduction Many people say that the short stories of Sherlock Holmes were the best detective stories ever written. Sir Arthur Conan Doyle wrote these stories, which were first published in the Strand magazine in 1890. These stories included A Scandal in Bohemia, The Hound of the Baskervilles, The Copper Beaches, A Case of Identity, The Man With The Twisted Lip and others. People in Victorian England really enjoyed reading the stories, the main reason for which was that there were many murderers running free at the time, which the police force couldnt catch so people didnt believe that the police was sufficient. Arthur Conan Doyles character was very liked because no case seemed to challenge him and he always defeated the evil villain. The Red Headed League was first published in 1891 and The Speckled Band was first published in 1892 in the Strand magazine. One of the key elements of Victorian detective stories is that the crime must be solved by logical means, not by supernatural causes or by a lucky accident. This is what happened in all of the Sherlock Holmes stories. In both The Red Headed League and The Speckled Band Sherlock Holmes solves the crimes by using powers of deduction and his own intelligence. Another important element of Victorian detective stories is that the investigator must not wittingly conceal clues or the reasons for his deductions from the reader. At the end of both stories Sherlock Holmes explains to the villain and to his companion Dr Watson how he solved the crime. Even though the stories of Sherlock Holmes are over a century old they are still read and loved by millions of people across the world today. I think the main reason for this is because Arthur Conan Doyle used many techniques, like red herrings, twists, and very detailed descriptions of the characters and settings which makes the reader feel as though they are part of the story and encourages the reader to try and solve the mystery themselves. Also, even though the stories were written over 100 years the crime that was going on then is still going on now and people still like the thought of villains always being punished, so the Victorian society is very similar to our society at the moment. Arthur Conan Doyle used very detailed descriptions of the setting and location in the two stories to create a certain atmosphere. The Head Headed League was set in London, mainly around Saxe-Couburg Square, in 1891. Arthur Conan Doyle created an atmosphere by saying that Saxe-Couburg Square is a pokey, little, shabby-genteel place, which immediately makes the reader imagine a worn out and cramped place, also it makes the reader suspect that something bad happens there, because there is often trouble in such places. The Square is described as being dingy, which makes the reader think that the place is dark and dirty with smoke and grime. The writer even describes the atmosphere as being uncongenial so obviously it is not a very pleasant place to live in. This atmosphere is created so that the reader can deduct that Jabez Wilson wasnt very well off and that he desperately needed the money that Mr Duncan Ross gave him to look after his home and business. The Speckled Band was mainly set in Stoke Moran, Surrey, in 1883. Sir Arthur Conan Doyle created an atmosphere by saying that the house is half renovated and half in a ruin. The building itself is described as having a high central portion and two wings. This sounds like it once was a very big and grand house, but over the past couple of years Dr Roylott didnt have enough money to look after it. He didnt have enough money to look after the whole house so he modernized half of the house, so the left half was left with broken windows blocked with wooden boards and with the roof being partly caved in. In contrast, the right part of the house was comparatively modern. This atmosphere is created so that the reader can deduct that Dr Roylott didnt have enough money to look after the house, and the extra sum of money that would go to Helen Stoner after her marriage would have ruined him. The main characters in all of the Sherlock Holmes stories are Sherlock Holmes and Dr Watson. Dr Watson is Holmes colleague, who appears to be a lot weaker then him in solving crimes. The main reason for this, seems that Dr Watson doesnt notice things that Holmes does, like when they were both observing Mr Jabez Wilson in The Red Headed League Watson noticed the outside appearance, such as that he was wearing baggy grey shepherds check trousers, whereas Holmes noticed much deeper things, such as that hes done manual labour because his right hand is bigger than his left. Also the language that Holmes uses is a lot more mysterious then the language that Watson uses which suggests to the reader that Watson is less educated then Holmes. Holmes uses many different techniques to solve the crimes in both stories, mainly he follows clues and uses his own intelligence. Holmes is very skilful, he is not only a great detective but also a master of disguise. This was shown in both The Man With The Twisted Lip and A Scandal in Bohemia, where Holmes disguised himself as a drug addict and an old man. Sherlock Holmes and Dr Watson are similar to a few modern day detectives like Inspector Morse and Detective Lewis because they too follow clues to solve the crime and they work as a duo. Sherlock Holmes and Dr Watson follow clues to make deductions and solve the crimes. The first clue in The Red Headed League was that the clerk agreed to work for half wages which meant that he was either not very clever of he had a special reason for wanting to work at the pawnbrokers. Holmes assumes the second is true. The advertisement for the Red Headed League was another clue because it seemed almost as though it was targeted at Jabez Wilson, which was very suspicious. The nature of the job was another clue because it was use-less therefore we could deduct that the job was merely an activity that would get Jabez Wilson out of the shop. Then when Jabez Wilson described his assistant Vincent Spaulding, Holmes instantly recognized the description and realized that his real name is John Clay and hes a murderer. Spauldings interest in photography and his stained wrinkled trousers suggested that he did something dirty in the seller, like maybe he was digging a tunnel. Then Holmes tapped on the payment in front of Jabez Wilsons shop and the tunnel wasnt there, so he went to the back of the shop to find a City and Suburban bank, which is probably the place were the tunnel is going to. The fact that the Red Headed League was dissolved was a clue to that the digging had finished. And the fact that nineteenth-century banks were closed on weekends and Mondays so Holmes knew that John Clay would rob the bank on Saturday, leaving plenty of time to get away.

Previous chest radiation Essay Example for Free

Previous chest radiation Essay Women who menstruate at an early age and menopause at a later age are likely to develop breast cancer (American Cancer Society, n. pag). This can be associated with the longer exposure to estrogen and progesterone hormones. Women who had undergone a radiation therapy on the chest area at an early age can significantly increase the risk for breast cancer, especially if the breasts are still developing when the therapy was taken (American Cancer Society, n. pag. ). Stages Breast cancer, as other kind of cancer, starts from a single dot that develops into a threatening stage when it is not detected and treated at an earliest time. The purpose of staging the disease is to ascertain the type and degree of treatment that may be applied to the patient. Normally, the stages of breast cancer start from 0 to III. Stage 0 This is otherwise known as the non- evasive breast cancer (American Cancer Society, n. pag. ). At this stage, no evidence of cancer cell breakage or invasion into other tissues can be noticed. Stage I Stage I is known by invasive breast cancer (American Cancer Society, n. pag. ). During this stage, the cancer cells starts to invade or spread to other normal tissues. The tumor can also be noticed as grows to two centimeters (American Cancer Society, n. pag. ). Although there is no lymph nodes involved (American Cancer Society, n. pag. ). Stage II At this stage, the cancer cells expands to the lymph nodes under the arm or the tumor increases up to five centimeters (American Cancer Society, n. pag). During this stage, the lymph node are not yet united to other nodes and to other normal tissues. Stage IIIA The cancer is said to have advanced to stage III when the tumor measure more than five centimeters or when the lymph nodes are clump together or stuck to one another or to other tissues (American Cancer Society, n. pag. ). Stage IIIB This stage is characterized by the spread of the tumor, at any size, to the breast skin, internal mammary gland, or chest wall (American Cancer Society, n. pag. ). This stage also includes the inflammatory breast cancer, a very serious but rare type (American Cancer Society, n. pag. ). Inflammatory breast cancer is distinguished by the redness and warmness in some or in all part of the breast. Stage IV The breast cancer has advanced to the last stage when the tumor expands on to the breast, underarm, and internal mammary lymph nodes and also on lungs, bone, or brain (American Cancer Society, n. pag. ). This stage also includes Metastatic cancer, which is the spread of cancer. Treatments of Breast cancer At an early, the suitable treatment for is the breast conservation that involves lumpectomy. On this process, the infected tissues and the surrounding normal tissues are removed (National Breast and Ovarian Cancer Centre, n. pag. ). This shall be coupled by surgery and followed by radiation therapy which is used to kill the tumor cells left after surgery. Research has shown that radiation therapy is as effective as mastectomy, which is the surgical removal of the breast. Other medication may include prescription of hormone- blocking drug tamoxifin for post- menopausal women, and ovarian ablation to younger women. Ovarian ablation is the stopping the ovaries from producing estrogen and can be done either by removing the ovaries or by prescribing certain drugs (National Breast and Ovarian Cancer Centre, n. pag. ). Chemotherapy is also used to treat breast cancer. Chemotherapy is the medication that kills cancer cells or stops them from growing (National Breast and Ovarian Cancer Centre, n. pag. ). It can be done in three strategies namely; adjuvant chemotherapy, presurgical chemotherapy, and therapeutic chemotherapy. Adjuvant chemotherapy is given to reduce the possibility of returning of the cancer and is given to people who had surgery or radiation while presurgical chemotherapy is used to shrink or kill the stray cancer cells and to completely get rid of the cancer (National Breast and Ovarian Cancer Centre, n. pag. ). Therapeutic chemotherapy, on the other hand, is given to women whose cancer has spread beyond the breast or those who have serious case of breast cancer. For advance breast cancer, the treatment may include chemotherapy. Treatments given to metastatic breast cancer are aimed to reduce the symptoms experienced by the patient so that the quality of her life may be improved. The treatments may include stopping the growth of the cancer and using one or more anti- cancer treatments depending on the parts of the body that has been affected by the cancer (National Breast and Ovarian Cancer Centre, n. pag. ). Such therapies available are high- dose chemotherapy, immunotherapies, gene therapies, and targeting therapies. However, their efficacies are not yet measured. Among the immunotherapies, only the monoclonal antibodies (Mabs) have been approved for breast cancer (National Breast and Ovarian Cancer Centre, n. pag. ). However, there are other forms that are under observation. The Herceptin or MAb trastuzumab is on top of the list which is used by women with cancer cells having too many copies of HER2/neu gene (American Cancer Society, n. pag. ). The HER2/neu gene is able to produce extra receptors to stimulate growth on the cells resulting into a more aggressive breast cancer. When the trastuzumab are attached to the receptors, the growth is lowered because the access to the cancer cells are blocked (American Cancer Society, n. pag. ). Another form of immunotherapies is the Bevacizumab or Avastin, which is an antibody that helps slow the growth of blood vessels in the tumor (American Cancer Society, n. pag. ). Some promising treatments for advanced breast cancer are interferons and interleukons, autologous vaccine therapy, and other antigen vaccine. These immunotherapies are being studied because their effectivity has not yet been ascertained. Conclusion Among the women, the disease that is very threatening is the breast cancer. Cases of breast cancer are increasing every year and so with the mortality rate. Yet treatments do not give complete assurance. Moreover, treatments are so expensive that are not available to poor patients. Cancer, as generally known, is a disease that is traitor and known only at a later stage. In order to avoid getting breast cancer, n individual shall be aware of the risk factors and avoid it as soon as possible. Works cited Baum, Michael, and Schipper, Harvey. Fast Facts Breast Cancer. Oxford: Health Press, 1999. Cadwell, Karin, and Maffei, Cindy, T. Breastfeeding A-Z: Terminology and Telephone Triage. New York: Jones Barlett Publishers, 2006. â€Å"Detailed Guide: Breast Cancer. † 13 September 2007. American Cancer Society. 24 June 2008 http://www. cancer. org/docroot/CRI/content/CRI_2_4_2X_What_are_the_risk_factors_for_breast_cancer_5.asp. Franz, Mary. â€Å"Diet and Breast Cancer. † Vegan Handbook:Over 200 Delicious Recipes, Meal Plans and Vegetarian Resources for All Ages. Ed. Debra Wasserman Reed Mangels. Vegetarian Resource Group, 1996. 193. â€Å"Genetic Testing for BRCA1 and BRCA2: Its Your Choice. † 2 June 2002. National Cancer Institute. 24 June 2008 http://www. cancer. gov/cancertopics/factsheet/risk/brca. â€Å"Treatment options. † 28 November 2006. National Breast and Ovarian Cancer Centre. 24 June 2008 http://www. breasthealth. com. au/treatment/.

Ethical issues of Chinas one-child policy

Ethical issues of Chinas one-child policy The Chinese ideal of a family follows the Confucian belief that the family should be big and complex. The father is to have as many sons as possible so that the son can fulfill his obligations to the father and their lineage  [1]  . The family is very important for the Chinese that they even coined the term familism which is the basis of a kind of society distinctive from any other kind in the world  [2]  . This means that whatever the members of the family are doing should be only for the benefit of their family. Because of familism, a Chinese couple feels compelled to have at least one male child. The Chinese believe that having a son will benefit them in many ways and one of these is to ensure that their family line would be continued  [3]  . The family in the Confucian view stresses the significance of hierarchy. Confucius also said that in a relationship, one should command and the other should obey. It is now known that the one who commands is the man or the elder, while the one who obeys is the woman or the younger person. The Chinese family is very paternalistic in a sense that it favors the men of the family more than the women  [4]  . Unlike in the West, children in China were not as treasured by their parents. They were more of necessities for the families especially in the rural areas, so that they could help their parents with work in the fields. Sons were especially valued because of their ability to provide for their parents and to carry on their family name, something that the women can never be capable of doing  [5]  . The men are also the only ones who have direct access to Heaven and they can perform rituals for their ancestors. The one who was in charge of the rituals is called the descent-line heir or the tsung-tzu  [6]  . For the Chinese, having a daughter would not be beneficial to them in any way because daughters would eventually leave them to join her husbands family. She would worship their ancestors and serve his family. Having a son would be an assurance to a family; that the son would care for his parents and stay with them even after he gets married  [7]  . The men of the family would also inherit the property that is left to them, and there is no way that a woman would be allowed to become heir to what has been left by the ancestors. An example of this would be the opposition of Chu Hsi, one of the most influential leaders of the Learning Way Movement, in his Family Rituals that a daughter cannot inherit her parents estate even when she had no (more) brothers. A woman, without brothers, inheriting the property of her parents was a Sung practice, but Chu Hsi emphasized that the males should be the ones inheriting the properties because if it were women, then such property would be obtained inappropriately'  [8]  . Everyone knows about how China is becoming more developed and as a result, the population of China has been growing rapidly. China had to do something about the population growth because the government was not able to meet the needs of the citizens anymore. To add to that, death rates were also declining. The government had different programs to prolong a couple from having a child such as encouraging them to get married late. This policy was implemented to answer the problems of overpopulation. Couples who abided by the policy would receive incentives, while those who decide to have more than one child would have to pay the sanctions  [9]  . Chinas one child policy was launched in the year 1979 by former Premier Deng Xiao Ping  [10]  . The main purpose of this policy is to stop the rapid population growth of the country that was clearly evident during the year 1949, when the population was nearly half a billion, the same time when the Chinese Communist Party was establishing itself and thought that this concern would hinder development  [11]  . The policy was not supposed to be permanent but because it was successful, they decided to continue implementing it. It was also not applied to all places in China. Places that do not practice the policy are Macau, Hong Kong and Taiwan, and in total only about 40% of the Chinese population practice the one-child policy  [12]  . The policy itself is not fully unreasonable since it had a practical purpose of controlling the population growth which was certainly necessary at that moment. The only time it gets out of hand is when the Chinese norm of favoring sons enters th e picture. The fact that a family has to have only one child is absurd. How can the government of China expect to control millions of families in the country? Is this even possible? In the urban areas, people found it difficult to resist this policy because of their social and economic conditions as well as the strict ruling of their leaders during that time. However, this is not the case in rural areas wherein active resistance could be seen everywhere. This is because of their childrens contribution to the typical Chinese agricultural family and for their role in preserving the family line. Because of the unfairness of this policy, a lot of people resisted in three forms: first was when the targets confronted the implementers of the policy; second was the escape from the policy by either deceiving rural cadres or colluding with sympathetic ones; third was to appear to be complying with what the state wanted but defying them at the same time. This means that the state succeeds when the couple would obey the states policy of having only one child (even if they want more), but the same couple would reveal the influence of a counter-discourse that challenges the s tates ideological claim to dominate child-bearing when they practice female infanticide. Couples would then resort to ultrasound technology, wherein a rural or urban couple can engineer the sex of their baby  [13]  . The problem of population growth can be seen mostly in rural areas since 80 per cent of Chinas population is rural and 87.2 per cent of births occur there. The government tried to reason out with the peasants regarding the change in family size but they were not successful in changing their minds. By the year 1970, incentives and penalties were introduced as part of the two-child policy campaign. These were even highlighted during 1979, when the one-child policy was finally launched  [14]  . Why the Chinese peasants preferred to have a large family is due to economic reasons. They felt that having a large family would bring more advantages for them, as compared to having only one child. The advantage would be that the family would receive an allocation of grain distributed on a per capita basis. The same goes for the allocation of land that is why people in the rural areas can expand their homes when they expand their families  [15]  . Sometimes, these children would help their parents by gathering materials related to the maintaining of the land such as water and fuel. They would also feed the animals and weed private plots. These tasks could be done even by children, thus it helps the parents prepare for the more rigorous chores. Their children are also the only large-scale investments of the peasants because sons join the work force and they eventually have to provide for their families  [16]  . The preference for sons is also evident in the rural areas because they continue their family line, whereas most of the women get married outside their village, live with their in-laws and join their labor force. This preference is also reflected in a survey conducted during the year 1981. The participants are those couples who had a second child. 42.61 per cent of the 1000 participants had one son and 57.39 per cent had a daughter. When they were asked why they had another child, 50.5 per cent said that they wanted a boy and only 11.4 per cent said that they wanted a girl. This clearly indicates that majority of the respondents prefer a son over a daughter  [17]  . Because they had to, the people from the rural areas used different methods to postpone the creation of children. Some relied on the low cost methods of contraception such as IUD and the second method is sterilization. However, those with only one child have a hard time using this method because they would consider having a second child in replacement of the first one just in case the first one dies or becomes disabled. They do not take pills that much because it is more expensive and supply could be a problem for them. In some rural areas, particularly in Sichuan, vasectomy was used. Both men and women had more complaints regarding the side-effects of this method because the men claimed to be losing their strength. However, this method became very effective because Sichuan was most successful in reducing its birth rate. There was also induced abortion, which was originally just a back up method and was not really meant to be an independent option for contraception  [18]  . Despite the resistance, people still follow because there would be incentives and penalties enforced just to make sure that no one will go against the policy. Among the many incentives are a nutrition allowance, a full adult grain ration and free medical, educational and kindergarten facilities for the child. An example of the penalties on the other hand is the deduction of the couples income by 20 per cent from the time the second pregnancy is discovered but this 20 per cent will be returned to them if they had the child aborted. There are times when a couple is allowed to have a second child. Among these are if the first child suffers from a disability that would hinder him from working or if both are overseas Chinese who have just returned from another country  [19]  . The policy was more successful in the urban areas than in the rural areas. This could be due to the aim of the government that 95 per cent of the married couples in the cities and 90 per cent in the countryside will have only one child so that by the end of the century, China could limit their population to about 1.2 billion  [20]  . As early as 1955, family planning was being enforced in the urban areas of China  [21]  . Chen Da, a pioneering demographer, emphasized that people who received education overseas would more likely have less children because they have a background on birth control  [22]  . The people from the urban areas were more open and accepting of the one-child policy because for one, there were efforts to raise the status of the women by letting them enter into the labor force. Child bearing and rearing are not the only things that a woman is bound to do with all the work that she has  [23]  . The Chinese from urban areas also see children as more of an economic liability because it requires a lot of effort, attention and resources (like money) to raise them but these children contribute little to the lives of their parents  [24]  . Different families have various practices or methods to get rid of a daughter. One of these is female infanticide or the intentional killing of baby girls  [25]  . The couple will resort to female infanticide to try their luck again hoping that they would get a boy the second time around (or kill the girl when the mother gets pregnant with a boy)  [26]  just so they could comply with the policy that was being implemented  [27]  . There are also hospitals in China that have contraceptive technical guidance institutes. These institutes have lower level workers who are trained in the four operations which are tubectomy, vasectomy, insertion and removal of the IUD, and induced abortion  [28]  . IUD and sterilization are widely used in China; in fact, as many as 50 per cent of the Chinese rely on IUDs and sterilization is the second most widely used form of contraceptive method  [29]  . Partly because of these methods, it became possible for China to control its people. Again, the motive of preventing overpopulation is not a bad thing. In fact, it would be helpful to the government so that it could rule the country better. However, is this inhumane policy the only option that they had? Is it really success that they are achieving? Would they call this successful when they know that there are innocent babies killed along the way? The Chinese may have controlled the growth of their population but they are also encountering problems as they go along with their one-child policy. This policy has prevented around 4oo million births, according to Chinese officials  [30]  . Because there are fewer children that are born, there is an expanding population of the elderly. This is a problem because there would be less number of young laborers in the future when the elderly die  [31]  . Another problem is the ratio of men and women because men have been outnumbering women already by about 60 million. This imbalance between men and women would make it difficult for the former to look for wives; therefore they can result to human trafficking of women and children  [32]  . The policy is even crueler because of the inequality between men and women. The government has been addressing this issue saying that men and women must be equal at all costs and that this equality has to be promoted through media. People who commit infanticide, those who neglect or abandon their children or any act that would harm people especially female babies must be punished  [33]  . If the government really means this, then they could already stop with the payment of fines for having more than one child and just have a law against female infanticide, or better yet just abolish the policy. Unfortunately, the Chinese will still be continuing this policy in the coming decades to control the population growth in their country  [34]  . According to the official and minister of the National Population and Family Planning Commission, Zhang Weiqing, China will not make any changes for about another decade because it has been effective in controlling their population growth. Since Chinas population is growing by 17 million per year (according to China Daily as of 2008), abandoning the policy would have major fluctuations in population growth. Officials said that the one-child policy was the only choice that was available and realistic at the time of the construction of the policy, but they are now considering amendments to it, but abolishing it would cause many problems  [35]  . The Philippines is also experiencing an event that is quite similar to the policy that China has implemented on its country for a long time. There may be many people in the Philippines, but they are still able to live their lives normally because the resources are sustaining them. There would be no poor people if only there was equal distribution of resources to all the Filipino people. The church also claims that poverty is not because of overpopulation but is due to the irresponsible and corrupt government that the country has  [36]  , but what exactly is overpopulation? As defined by Merriam Webster Dictionary, overpopulation is the condition of having a population so dense as to cause environmental deterioration, an impaired quality of life, or a population crash  [37]  . The option that the lawmakers are considering is the Reproductive Health Bill that promotes information on and access to both natural and modern family planning methods, which are medically safe and legally permissible  [38]  . The difference of this from Chinas one-child policy is the variation of the Filipino and Chinese mentality; that the former does not favor any gender because Southeast Asian countries tolerate both genders. The cause is the same-which is to control population growth, but the motive is different because while China intends to just control their population, the Philippines aims to eliminate poverty by controlling the population growth. The cause may be reasonable but some parts of the bill are disadvantageous to the lives of the Filipinos, especially the Filipino women. Some institutions are supporting the RH Bill like the National Council of Churches in the Philippines or NCCP, saying that the Reproductive Health Bill does not necessarily promote anything illegal such as abortion  [39]  . However in the bill, it is said that women with post-abortion concerns will not be treated differently  [40]  . Does this mean that the government will still tolerate abortion even if they mentioned in the bill that abortion is illegal? Is what the NCCP saying about the bill not promoting abortion true? Another is the mandatory sex education for elementary students  [41]  . Some parents have a difficult time explaining to their children about how they came to life or even talk about sex with them. Usually parents would wait for the right time to educate them about these things so that the child would understand better. If the law requires mandatory sex education, then these children will be more curious and try to experiment things and be exposed at a very young age. Just like Chinas one-child policy, the RH Bill may have a good purpose but its execution and some of the policies in it are not beneficial. The bill promotes responsible parenthood  [42]  but does this responsibility involve the choice between having the baby and having the baby aborted? If there is the belief that the Philippines is overpopulated, then why not use this to our advantage? Why not use the money for creating jobs instead of spending so much on contraceptives (or letting the corrupt officials keep the money) that will not bring any benefit to a persons life? Our religion is also different from the Chinese. Filipinos do not see their children as economic liabilities because Filipinos are more emotionally attached to their children. The punishments in case of non-compliance stated in this bill will also have a great impact in the lives of the Filipinos who are compelled to comply with the provisions  [43]  . Filipinos must be alarmed that there is so much poor people because the population is rapidly increasing that is why they are assuming that the country is becoming overpopulated and we need to solve this problem. However, the Philippines does not need the RH Bill because the country is not overpopulated. There is the assumption that poverty and overpopulation are connected, and by controlling the population, poverty will be reduced. According to Simon Kuznets, a Noble Prize Winner and author of Population and Capital Growth, there is no clear connection between overpopulation and economic development  [44]  . Places such as Singapore, Hong Kong, and Taiwan are overpopulated but still flourish. The population density of Taiwan is 1,460 per square mile but CIAs World Factbook 1999 stated that Taiwans per capita gross domestic product is $16,500  [45]   What the Filipinos need is a better and more capable government instead of implementing an unnecessary law. As for China, they are also starting to question their own policy  [46]  and because they are already having doubts, then it is best that they reconsider executing it for another decade. By doing this, China would cease to harm innocent human beings and prevent the Philippines from following the footsteps of China in putting something unethical into practice.

Galileo, Science, and the Church by Jerome J. Langford Essay -- Galile

Galileo, Science, and the Church by Jerome J. Langford   Ã‚  Ã‚  Ã‚  Ã‚  Science and the church, two things that you would not ordinarily think would go together until until Galileo came along. Galileo, a man that stuck his head out to the world, but especially to the church, when maybe he should have done things a little differently. This particular book shows many accounts of the troubles between Galileo and the church, and with other bystanders. The book goes through the ups and downs of Galileo and the church, the hardships, and friendships that people held, and how hard it was to keep those friendships during the days of Galileo. The book reveals many alliances, and loyalties, but also it also reveals distrust, and clouded minds, of both Galileo and the church.   Ã‚  Ã‚  Ã‚  Ã‚  Throughout the book you learn the different approaches of scientific belief. There was of course the Aristotelian way of the universe, and there was also the Ptolemaic way. The differences between these two were not too major, they both believed the Earth did not move. There was a new system in the works the Copernican theory, which believed that the Earth was not the center and was mobile, but the sun was the center. Copernicus did not get to back his theory the way he would have wanted but Galileo assumed the ropes and brought it to the full front.   Ã‚  Ã‚  Ã‚  Ã‚  Galileo had many problems trying to introduce the Copernican theory to be relevant. Scripture from the Holy Bible was one problem that Galileo had to face. Ca...

Edgar Allen Poe :: essays research papers

Edgar Allen Poe   Ã‚  Ã‚  Ã‚  Ã‚  Who is Edgar Allen Poe? He was a 19th century American writer born to Elizabeth (â€Å"betty†) Arnold Hopkins and David Poe. (Internet source) Poe was an well-educated individual. He would attend a private school in London and then an academy in Richmond. Later being accepted to the University of Virginia, this however would not work out for him. He then would travel to Boston for work in which there would be none. Defeated he enlisted in the Army and soon regret the decision. Once out he would again try a military career, he was accepted to the U.S Military Academy. (Encyclopedia Britannica) This time he immediately regretting the decision. After his expulsion he entered a contest sponsored by the Baltimore Saturday Visitor. His story â€Å"MS. Found in a Bottle† â€Å"was considered to be the one of the world’s first science fiction stories, he won both the $50 prize and acclaim for its 24-year-old author.† (Internet source) He would then work at several different editorials, none of which really worked out for him. His dream though would be to own a magazine or paper of his own. He would come close twice but never succeed in keeping them alive due to his different habits.   Ã‚  Ã‚  Ã‚  Ã‚  What made Edgar Allen Poe? Through his lifetime many different misfortunes and disasters would strike him. All of these would shape him and his writing to what we now associate as the father of modern diabolic fiction. (Internet source) The first of the tragedies to plague him would be the abandonment by his father. He would grow never knowing who his real father was. His father had left his family when Edgar was only an infant. The next misfortune would be the death of his mother when he was three. There was yet another factor that would shape him throughout his lifetime. He would also come how from his studies in England to find that his sweetheart from childhood was engaged. This caused him to write his first serious poem â€Å"Tamerlane† out of heartbreak. His luck with women throughout his lifetime would be rather in the bottom end of the barrel. He would eventually marry Virginia Clemm, his thirteen-old cousin. He would later lose her to tuberculosis and stop writing for a while, only to concentrate on â€Å"Ulalume† to express his mourn. He would try to remarry on two different occasions the first was ruined by rumor the second by his drinking habit.

The Argument of Romans Essay -- essays research papers fc

The Wrath of God Revealed   Ã‚  Ã‚  Ã‚  Ã‚  Paul began his argument of Romans by proving that the Gentiles are sinners before God. Although God has revealed His truth to them, they have suppressed it, resulting in the darkness of their inner man and rebellion against God to the point of worshipping animals (1:18-23). As a result God gave them over to do the desires of their heart (1:24, 26): idolatry (1:25) and homosexuality (1:26-27). Seeing that they had no desire to retain God in their knowledge, God gave them over to a depraved mind to do every sort of evil (1:28-31). The Jews Condemned Judgement According to Works   Ã‚  Ã‚  Ã‚  Ã‚  Paul also addressed the Jews specifically warning them that if God judged the Gentiles who suppressed the revelation they had received, the Jews should not believe that they would escape the judgement of God simply because they had received the Law of Moses. These Jews were judging others for things that they did themselves, thinking they would escape punishment because they were Jews (2:1-3). Paul warned that they were storing up God’s wrath against themselves because they would not repent for their sins (2:4-5). God rewards or punishes individuals based on their works, not on their ethnic background or on their knowledge of the Law (2:6-13). Paul argued that the Gentile’s conscience would serve as the basis for their judgement (2:14-16) and the Law would serve as the basis for judgement for the Jew. Circumcision of the Heart   Ã‚  Ã‚  Ã‚  Ã‚  Paul continued to condemn the Jew for feeling superior to the Gentiles because of their entrustment to the special revelation of the Law, even though the whole time they were being hypocrites by not living by the Law themselves (2:17-22). They were dishonoring God and giving the Gentiles reason to blaspheme God (2:23-24). Some thought that being circumcised justified their actions, but Paul made it clear that the Law only had value to those who lived by it, not to those who simply possessed it (2:25). If the uncircumcised lived by the Law, his actions would make it as though he was circumcised, and he would be able to judge the circumcised who only profess the Law (2:26-27). To be a true Jew is not only a matter of lineage but also a matter of having circumcision of the heart and whose praise comes from God rather than man (2:28-29). Therefo... ...5:1-6). Instead of rejecting one another over differences of opinion, the Jews and Gentiles were to accept each other, seeing that both groups of people are involved in God's plan (15:7-13). Reason for Paul’s Delay in Coming to Rome Salutation's to many people at Rome   Ã‚  Ã‚  Ã‚  Ã‚  Although Paul was convinced of the churches spiritual maturity, he wrote to them to explain his reason for not coming to them sooner, and expressed his future travel plans, which included a trip to Rome (15:17-24). This trip would take place after he delivered the collection he was gathering to the saints at Jerusalem (15:25-29); a trip that Paul asked the Romans to help him with in prayer (15:30-33). Having finished his exhortations and commands, Paul finished his epistle by sending greetings to many individuals at the church in Rome (16:1-16), warning of false-teachers (16:17-20), sending greeting from his fellow-laborers (16:21), and giving glory to the God who was able to strengthen the church, and disclosed the mystery of the church to bring many to faith (16:25-27). WORKS CITED Baker, Bruce. Romans, class notes. Fall 2001 King James Study Bible, The. Thomas Nelson, Inc., 1988.

Domestic Violence and Social Class Essay

Domestic violence is something that happens every day around the world. Young, old, rich or poor, this is an issue that we must look at to better ourselves as a country. One of the things that we look at is how domestic violence relates to the different social classes of the country, this being upper, middle, and lower. Some would thing that it would be more common in lower classes, but the reality of it is domestic violence is a problem across all social classes. In this paper I will discuss different articles about domestic violence and its relation to social class. It is clear to see that any of the articles on this topic focus around women as victims and men get put into a category of the only ones committing violence. From different articles you can see that social class has a relation and an effect on domestic violence. To begin with we need to understand what domestic violence is. The National Domestic Violence Hotline describes domestic violence as pattern of behavior in any relationship that is used to gain or maintain power and control over an intimate partner. Abuse is physical, sexual, emotional, economic or psychological actions or threats of actions that influence another person. This includes any behaviors that frighten, intimidate, terrorize, manipulate, hurt, humiliate, blame, injure or wound someone. Domestic violence can happen to anyone of any race, age, sexual orientation, religion or gender. It can happen to couples who are married, living together or who are dating. Domestic violence affects people of all socioeconomic backgrounds and education levels (The National Domestic Hotline). This is one of the best definitions you will find. It’s important to realize that Domestic Violence can happen to anyone. The focus on economic background is important; there is not one ocial class that domestic violence does not occur in. It is key that we keep this in mind, otherwise we begin to label and fit certain social groups into categories. And as we will find out this is not the case at all. In Gender, Status, and Domestic Violence, by Kristin L. Anderson she discusses many issues related to domestic violence. In her article she talks about social economic status and how it can affect domestic violence. The section on social class begins with how gender and social class play very big roles with each other, or how each social class helps determine the resources available to men for the construction f masculinity (Anderson, 1995). Anderson begins with the working and lower class and how their position they hold at work lacks power and authority. This can lead to violence in the home because they search for positions of power in other aspects of their life. And many times the search for power and masculinity starts in their home life. This could be one explanation for the cause of domestic violence among low income social class. It is very clear that society even thought changing for the better over the years, still puts the man as the breadwinner of his family. And if a man annot produce for their family I agree with her that that will look for other places to find there masculinity and in some cases this is accomplished with violence against their partner. Next Anderson discusses middle and upper class together. She states with reference from another article that â€Å"Middle and upper class notions of masculinity focus on ambition, responsibility, and professional employment (Segal, society. The research done in this article shows that men or women with low income jobs and less resources are more likely to be violent in their home as a means to gain the lack of power in their life. Men who have fewer resources then there female partners will be more likely to commit domestic assault than the men with resources equal or greater than their female partners (Anderson, 1995). We can see for the research done by Anderson that she focuses on the reporting of violence. I would have like to have seen some numbers on education and or employment in ration to domestic violence. But it is clear and can be understood that men base their masculinity on their economic social status, and if that status is low they begin to search for other ways to gain power, and often that is in the means of domestic iolence against their partners. Social class plays a key role in everyday life of millions around the world. So it is clear that social class would play a role in domestic violence. Knowing that domestic violence knows no boundaries it is correct to say that wealth does not protect against violence. In the article Economic stress and Domestic Violence by Claire M. Renzetti from the National Online Resource Center on Violence against Women, they bring social class and domestic violence into clear view. One discussion in the article which we have to take into account when looking at social class and domestic violence is ell put when she stats â€Å"the data we have about domestic violence comes from samples to which researchers have greatest access, such as individuals who use social services and these individuals are more likely to have low incomes† (Renzetti, 2009). With this in mind it is clear to see why there are so many articles on low income violence. As she states from a study done by Benson and Fox (2003) from analyzing data from the National Survey of Household and Families, the family income increases the likelihood of domestic violence decrease. It is becoming clearer hat even though we know that domestic violence knows no social class, The National Crime Victimization Survey reports the chance of violence in a low income household is five times great then the households with the highest incomes (Renzetti, 2009). As stated earlier it seems that the relation to domestic violence and employment takes a big part of the problem with violence among the social classes. In the article by Anderson early discuss she makes it clear that the feeling of power is directly related to the males economic standing. Renzetti state that sever studies have documented hey deliberate sabotage to their partners efforts to maintain paid employment (2009). We can tie that back to how males base their masculinity and power on their economic status. Women have reported that their attempts to obtain paid employment outside their homes only aggravated their partners. It is becoming clear that men see power in being the main provider in the house and to lose some of that power is demining in some ways, and can result in violence against their partners. She references an article by Bush (2003) say that paid employment if a female intimate partner is threatening for some men, especially men who are unemployed r in low paying Jobs. Renzitti states that some researchers have argued that social class has a greater influence on domestic violence risk than race/ethnicity, and that even the social class of your neighborhood plays into account. Disadvantaged neighborhoods domestic violence rates are significantly higher in neighborhoods By now it is clear that there is a relation between social class and domestic violence. In domestic violence, sexual assault and stalking by Walby & Allen (2004) they discuss how it could be the domestic violence that is causing the low economical status. This is a little broader thinking then our other authors but still Walby & Allen tie mans need for masculinity and power into the equation. But first to look how they discuss domestic violence as the cause for low social status, the lack of economic resources is clearly associated with domestic violence against women. But it is how we see one leading to the other that they discuss. Walby & Allen purpose that maybe it is the other way around. For example that poverty and low social status are the consequences of domestic violence. Women who leave behind their homes and partners in order to escape violence will be much more ikely to be poorer as a consequence of the loss of their home and of their partner’s income (Walby &Allen, 2004). This is a new concept to think about but can easily be seen as possible. From what we have learned low income family are more prone to domestic violence, it is clear to see if the victim does get out of this relationship they have no means of economic support. In return this Just keeps them in poverty and most likely sinks them deeper down the status pool of the world. As Walby & Allen (2004) report that â€Å"eventually making their way back into the abusive elationship because they have no economic support. It seems that the affect that social class and domestic violence have on each other is a never ending cycle. As we found in the research social class plays a big part in domestic violence and in some cases domestic violence plays a big part in social class. Whichever way that you look at it one constant held true across all of the articles, this being that men have been socially constructed by society to have to have the need for power in relationships. And when that power is l acking and they feel there masculinity is in eopardy we see domestic violence. Now a lot of the focus of the articles was on the lower class, showing that the economic stress had a direct relation to man and the need for power. We need to understand that the lower social status groups are not the only ones with a domestic violence problem. Like I said earlier domestic violence can happen across any social class, rich or poor. Most of the research that is done focuses on women in poverty because that is where the easy samples are. We know that there is a problem there, we need to move on to research that examines women ofa higher social standing. When we open up to who is we look at then we will begin to get a real grasp on the social class and domestic violence issue. Now I know that that depends on if they are willing to report, but that is a whole different topic for a different day. We have to be careful not to stereotype individuals into this field Just because of the economic standing, but it is clear that social class and domestic violence show a clear and direct relation with each other.

Solution Manual for Fluid Mech Cengel Book

Chapter 6 Momentum Analysis of Flow Systems Chapter 6 MOMENTUM ANALYSIS OF FLOW SYSTEMS Newton’s Laws and Conservation of Momentum 6-1C Newton’s first law states that â€Å"a body at rest remains at rest, and a body in motion remains in motion at the same velocity in a straight path when the net force acting on it is zero. † Therefore, a body tends to preserve its state or inertia. Newton’s second law states that â€Å"the acceleration of a body is proportional to the net force acting on it and is inversely proportional to its mass. Newton’s third law states â€Å"when a body exerts a force on a second body, the second body exerts an equal and opposite force on the first. † r 6-2C Since momentum ( mV ) is the product of a vector (velocity) and a scalar (mass), momentum must be a vector that points in the same direction as the velocity vector. 6-3C The conservation of momentum principle is expressed as â€Å"the momentum of a system remains constant when the net force acting on it is zero, and thus the momentum of such systems is conserved†.The momentum of a body remains constant if the net force acting on it is zero. 6-4C Newton’s second law of motion, also called the angular momentum equation, is expressed as â€Å"the rate of change of the angular momentum of a body is equal to the net torque acting it. † For a non-rigid body with zero net torque, the angular momentum remains constant, but the angular velocity changes in accordance with I? = constant where I is the moment of inertia of the body. 6-5C No.Two rigid bodies having the same mass and angular speed will have different angular momentums unless they also have the same moment of inertia I. Linear Momentum Equation 6-6C The relationship between the time rates of change of an extensive property for a system and for a control volume is expressed by the Reynolds transport theorem, which provides the link between the r system and control volume concepts. The linear momentum equation is obtained by setting b = V and thus r B = mV in the Reynolds transport theorem. -7C The forces acting on the control volume consist of body forces that act throughout the entire body of the control volume (such as gravity, electric, and magnetic forces) and surface forces that act on the control surface (such as the pressure forces and reaction forces at points of contact). The net force acting on a control volume is the sum of all body and surface forces. Fluid weight is a body force, and pressure is a surface force (acting per unit area). -8C All of these surface forces arise as the control volume is isolated from its surroundings for analysis, and the effect of any detached object is accounted for by a force at that location. We can minimize the number of surface forces exposed by choosing the control volume such that the forces that we are not interested in remain internal, and thus they do not complicate the analysis. A well-chosen cont rol volume exposes only the forces that are to be determined (such as reaction forces) and a minimum number of other forces. 6-9C The momentum-flux correction factor ? nables us to express the momentum flux in terms of the r r r r & ? V (V ? n )dAc = ? mV avg . The value of ? is unity for uniform mass flow rate and mean flow velocity as ? Ac flow, such as a jet flow, nearly unity for turbulent flow (between 1. 01 and 1. 04), but about 1. 3 for laminar flow. So it should be considered in laminar flow. 6-1 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation. If you are a student using this Manual, you are using it without permission.Chapter 6 Momentum Analysis of Flow Systems 6-10C The momentum equation for steady one-dimensional flow for the case of no external forces is r r r & & F= ? mV ? ? mV ? ? out ? in where the left hand side is the net force acting on the control volume, and first term on the right hand side is the incoming momentum flux and the second term is the outgoing momentum flux by mass. 6-11C In the application of the momentum equation, we can disregard the atmospheric pressure and work with gage pressures only since the atmospheric pressure acts in all directions, and its effect cancels out in every direction. -12C The fireman who holds the hose backwards so that the water makes a U-turn before being discharged will experience a greater reaction force since the numerical values of momentum fluxes across the nozzle are added in this case instead of being subtracted. 6-13C No, V is not the upper limit to the rocket’s ultimate velocity. Without friction the rocket velocity will continue to increase as more gas outlets the nozzle. 6-14C A helicopter hovers because the strong downdraft of air, caused by the overhead propeller blades, manifests a momentum in the air stream.This momentum must be countered by the helicopter lift force. 6-15C As the air density decreases, it requires more energy for a helicopter to hover, because more air must be forced into the downdraft by the helicopter blades to provide the same lift force. Therefore, it takes more power for a helicopter to hover on the top of a high mountain than it does at sea level. 6-16C In winter the air is generally colder, and thus denser. Therefore, less air must be driven by the blades to provide the same helicopter lift, requiring less power. 6-2 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc.Limited distribution permitted only to teachers and educators for course preparation. If you are a student using this Manual, you are using it without permission. Chapter 6 Momentum Analysis of Flow Systems 6-17C The force required to hold the plate against the horizontal water stream will increase by a factor of 4 when the velocity is doubled since & F = mV = ( ? AV )V = ? AV 2 and thus the force is proportional to the square of the velocity. 6-18C The accele ration will not be constant since the force is not constant. The impulse force exerted by & water on the plate is F = mV = ( ? AV )V = ?AV 2 , where V is the relative velocity between the water and the plate, which is moving. The plate acceleration will be a = F/m. But as the plate begins to move, V decreases, so the acceleration must also decrease. 6-19C The maximum velocity possible for the plate is the velocity of the water jet. As long as the plate is moving slower than the jet, the water will exert a force on the plate, which will cause it to accelerate, until terminal jet velocity is reached. 6-20 It is to be shown that the force exerted by a liquid jet of velocity V on a stationary nozzle is & proportional to V2, or alternatively, to m 2 . Assumptions 1 The flow is steady and incompressible. 2 The nozzle is given to be stationary. 3 The nozzle involves a 90 ° turn and thus the incoming and outgoing flow streams are normal to each other. 4 The water is discharged to the atmo sphere, and thus the gage pressure at the outlet is zero. Analysis We take the nozzle as the control volume, and the flow direction at the outlet as the x axis. Note that the nozzle makes a 90 ° turn, and thus it does not contribute to any pressure force or momentum flux & term at the inlet in the x direction. Noting that m = ?AV where A is the nozzle outlet area and V is the average nozzle outlet velocity, the momentum equation for steady one-dimensional flow in the x direction reduces to r r r & & & & F= ? mV ? ? mV > FRx = ? m out V out = ? mV ? ? out ? in where FRx is the reaction force on the nozzle due to liquid jet at the nozzle outlet. Then, & m = ? AV & > FRx = ? mV = AVV = AV 2 & & or FRx = ? mV = ? m & & m m2 =? ?A ? A Therefore, the force exerted by a liquid jet of velocity V on this & stationary nozzle is proportional to V2, or alternatively, to m 2 . Liquid Nozzle V FR 6-3 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc.Limited distribution permitted only to teachers and educators for course preparation. If you are a student using this Manual, you are using it without permission. Chapter 6 Momentum Analysis of Flow Systems 6-21 A water jet of velocity V impinges on a plate moving toward the water jet with velocity ? V. The force required to move the plate towards the jet is to be determined in terms of F acting on the stationary plate. Assumptions 1 The flow is steady and incompressible. 2 The plate is vertical and the jet is normal to plate. 3 The pressure on both sides of the plate is atmospheric pressure (and thus its effect cancels out). Fiction during motion is negligible. 5 There is no acceleration of the plate. 6 The water splashes off the sides of the plate in a plane normal to the jet. 6 Jet flow is nearly uniform and thus the effect of the momentum-flux correction factor is negligible, ? ? 1. Analysis We take the plate as the control volume. The relative velocity between the plate and the jet is V when the plate is st ationary, and 1. 5V when the plate is moving with a velocity ? V towards the plate. Then the momentum equation for steady one-dimensional flow in the horizontal direction reduces to r r r & & & & F= ? mV ? ? mV > ? FR = ? mi Vi > FR = miVi ? out ? in Stationary plate: ( Vi = V and Moving plate: ( Vi = 1. 5V and & mi = ? AVi = ? AV ) > FR = ? AV 2 = F & mi = ? AVi = ? A(1. 5V ) ) > FR = ? A(1. 5V ) 2 = 2. 25 ? AV 2 = 2. 25 F Therefore, the force required to hold the plate stationary against the oncoming water jet becomes 2. 25 times when the jet velocity becomes 1. 5 times. Discussion Note that when the plate is stationary, V is also the jet velocity. But if the plate moves toward the stream with velocity ? V, then the relative velocity is 1. 5V, and the amount of mass striking the plate (and falling off its sides) per unit time also increases by 50%. 1/2V VWaterjet 6-4 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation. If you are a student using this Manual, you are using it without permission. Chapter 6 Momentum Analysis of Flow Systems 6-22 A 90 ° elbow deflects water upwards and discharges it to the atmosphere at a specified rate. The gage pressure at the inlet of the elbow and the anchoring force needed to hold the elbow in place are to be determined. v Assumptions 1 The flow is steady, frictionless, incompressible, and irrotational (so that the Bernoulli equation is applicable). The weight of the elbow and the water in it is negligible. 3 The water is discharged to the atmosphere, and thus the gage pressure at the outlet is zero. 4 The momentum-flux correction factor for each inlet and outlet is given to be ? = 1. 03. Properties We take the density of water to be 1000 kg/m3. Analysis (a) We take the elbow as the control volume, and designate the entrance by 1 and the outlet by 2. We also designate the horizontal coordinate by x (with the direction of flow as being the positive direction) and the vertical coordinate by z.The continuity equation for this one-inlet one-outlet steady flow system is & & & & m1 = m 2 = m = 30 kg/s. Noting that m = ? AV , the mean inlet and outlet velocities of water are & & 25 kg/s m m = = = 3. 18 m/s 2 ? A ? (? D / 4) (1000 kg/m 3 )[? (0. 1 m) 2 / 4] Noting that V1 = V2 and P2 = Patm, the Bernoulli equation for a streamline going through the center of the reducing elbow is expressed as V1 = V 2 = V = P V12 P V2 1 + + z1 = 2 + 2 + z2 > P ? P2 = ? g ( z2 ? z1 ) > P , gage = ? g ( z2 ? z1 ) 1 1 ? g 2 g ? g 2 g Substituting, ? ? 1 kN 2 ? P , gage = (1000 kg/m3 )(9. 81 m/s 2 )(0. 35 m)? 1 ? 1000 kg ? /s2 ? = 3. 434 kN/m = 3. 434 kPa ? ? r r r & & (b) The momentum equation for steady one-dimensional flow is F= ? mV ? ? mV . We let the x- ? ? out ? in and z- components of the anchoring force of the elbow be FRx and FRz, and assume them to be in the positive directions. We also use gage pressures to avoid dealing with the atmospheric pressure which acts on all surfaces. Then the momentum equations along the x and y axes become & & FRx + P1,gage A1 = 0 ? ?m(+V1 ) = ? ?mV & & FRz = ? m(+V 2 ) = ? mV z x FRz 2 35 cm Solving for FRx and FRz, and substituting the given values, & FRx = ? ?mV ? P1, gage A1 ? N = ? 1. 03(25 kg/s)(3. 18 m/s)? ? 1 kg ? m/s 2 ? = ? 109 N ? ? ? (3434 N/m 2 )[? (0. 1 m) 2 / 4] ? ? ? ? = 81. 9 N ? ? FRy FRx = tan -1 Water 25 kg/s FRx 1 ? 1N & FRy = ? mV = 1. 03(25 kg/s)(3. 18 m/s)? ? 1 kg ? m/s 2 ? and 2 2 FR = FRx + FRy = (? 109) 2 + 81. 9 2 = 136 N, ? = tan -1 81. 9 = ? 37 ° = 143 ° ? 109 Discussion Note that the magnitude of the anchoring force is 136 N, and its line of action makes 143 ° from the positive x direction. Also, a negative value for FRx indicates the assumed direction is wrong, and should be reversed. 6-5 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc.Limited distribution permitted only to teachers and educators for course preparatio n. If you are a student using this Manual, you are using it without permission. Chapter 6 Momentum Analysis of Flow Systems 6-23 An 180 ° elbow forces the flow to make a U-turn and discharges it to the atmosphere at a specified rate. The gage pressure at the inlet of the elbow and the anchoring force needed to hold the elbow in place are to be determined. v Assumptions 1 The flow is steady, frictionless, one-dimensional, incompressible, and irrotational (so that the Bernoulli equation is applicable). The weight of the elbow and the water in it is negligible. 3 The water is discharged to the atmosphere, and thus the gage pressure at the outlet is zero. 4 The momentumflux correction factor for each inlet and outlet is given to be ? = 1. 03. Properties We take the density of water to be 1000 kg/m3. Analysis (a) We take the elbow as the control volume, and designate the entrance by 1 and the outlet by 2. We also designate the horizontal coordinate by x (with the direction of flow as b eing the positive direction) and the vertical coordinate by z.The continuity equation for this one-inlet one-outlet steady flow system is & & & & m1 = m 2 = m = 30 kg/s. Noting that m = ? AV , the mean inlet and outlet velocities of water are & & 25 kg/s m m = = = 3. 18 m/s 2 ? A ? (? D / 4) (1000 kg/m 3 )[? (0. 1 m) 2 / 4] Noting that V1 = V2 and P2 = Patm, the Bernoulli equation for a streamline going through the center of the reducing elbow is expressed as V1 = V 2 = V = P V12 P V2 1 + + z1 = 2 + 2 + z2 > P ? P2 = ? g ( z2 ? z1 ) > P , gage = ? g ( z2 ? z1 ) 1 1 ? g 2 g ? g 2 g Substituting, ? ? 1 kN 2 ? P , gage = (1000 kg/m3 )(9. 81 m/s2 )(0. 70 m)? 1 ? 1000 kg ? m/s2 ? 6. 867 kN/m = 6. 867 kPa ? ? r r r & & (b) The momentum equation for steady one-dimensional flow is F= ? mV ? ? mV . We let the x- ? ? out ? in and z- components of the anchoring force of the elbow be FRx and FRz, and assume them to be in the positive directions. We also use gage pressures to avoid dealing with the atmospheric pressure which acts on all surfaces. Then the momentum equations along the x and z axes become & & & FRx + P1,gage A1 = ? m(? V 2 ) ? ? m(+V1 ) = ? 2 ? mV FRz = 0 Solving for FRx and substituting the given values, & FRx = ? 2 ? mV ? P1, gage A1 ? 1N = ? 2 ? 1. 03(25 kg/s)(3. 18 m/s)? 1 kg ? m/s 2 ? = ? 218 N ? ? ? (6867 N/m 2 )[? (0. 1 m) 2 / 4] ? ? 2 z x FRz Water 25 kg/s 35 cm and FR = FRx = – 218 N since the y-component of the anchoring force is zero. Therefore, the anchoring force has a magnitude of 218 N and it acts in the negative x direction. Discussion Note that a negative value for FRx indicates the assumed direction is wrong, and should be reversed. FRx 1 6-6 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation. If you are a student using this Manual, you are using it without permission.Chapter 6 Momentum Analysis of Flow Systems 6-24E A horizontal water j et strikes a vertical stationary plate normally at a specified velocity. For a given anchoring force needed to hold the plate in place, the flow rate of water is to be determined. Assumptions 1 The flow is steady and incompressible. 2 The water splatters off the sides of the plate in a plane normal to the jet. 3 The water jet is exposed to the atmosphere, and thus the pressure of the water jet and the splattered water is the atmospheric pressure which is disregarded since it acts on the entire control surface. The vertical forces and momentum fluxes are not considered since they have no effect on the horizontal reaction force. 5 Jet flow is nearly uniform and thus the effect of the momentum-flux correction factor is negligible, ? ? 1. Properties We take the density of water to be 62. 4 lbm/ft3. Analysis We take the plate as the control volume such that it contains the entire plate and cuts through the water jet and the support bar normally, and the direction of flow as the positive direction of x axis. The momentum equation for steady one-dimensional flow in the x (flow) direction reduces in this case o r r r & & & & F= ? mV ? ? mV > ? FRx = ? mV1 > FR = mV1 ? ? out ? in We note that the reaction force acts in the opposite direction to flow, and we should not forget the negative & sign for forces and velocities in the negative x-direction. Solving for m and substituting the given values, & m= FRx 350 lbf = V1 30 ft/s ? 32. 2 lbm ? ft/s 2 ? ? 1 lbf ? ? ? = 376 lbm/s ? ? Then the volume flow rate becomes V& = & m ? = 376 lbm/s 62. 4 lbm/ft 3 = 6. 02 ft 3 /s Therefore, the volume flow rate of water under stated assumptions must be 6. 02 ft3/s.Discussion In reality, some water will be scattered back, and this will add to the reaction force of water. The flow rate in that case will be less. m 1 FRx = 350 lbf Waterjet 6-7 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparati on. If you are a student using this Manual, you are using it without permission. Chapter 6 Momentum Analysis of Flow Systems 6-25 A reducing elbow deflects water upwards and discharges it to the atmosphere at a specified rate.The anchoring force needed to hold the elbow in place is to be determined. v Assumptions 1 The flow is steady, frictionless, one-dimensional, incompressible, and irrotational (so that the Bernoulli equation is applicable). 2 The weight of the elbow and the water in it is considered. 3 The water is discharged to the atmosphere, and thus the gage pressure at the outlet is zero. 4 The momentumflux correction factor for each inlet and outlet is given to be ? = 1. 03. Properties We take the density of water to be 1000 kg/m3. Analysis The weight of the elbow and the water in it is W = mg = (50 kg)(9. 1 m/s 2 ) = 490. 5 N = 0. 4905 kN We take the elbow as the control volume, and designate the entrance by 1 and the outlet by 2. We also designate the horizontal coordina te by x (with the direction of flow as being the positive direction) and the vertical coordinate by z. The continuity equation for this one-inlet one-outlet steady flow system is & & & & m1 = m 2 = m = 30 kg/s. Noting that m = ? AV , the inlet and outlet velocities of water are & 30 kg/s m V1 = = = 2. 0 m/s ? A1 (1000 kg/m 3 )(0. 0150 m 2 ) & 30 kg/s m V2 = = = 12 m/s ? A2 (1000 kg/m 3 )(0. 025 m 2 ) Taking the center of the inlet cross section as the reference level (z1 = 0) and noting that P2 = Patm, the Bernoulli equation for a streamline going through the center of the reducing elbow is expressed as ? V 2 ? V12 ? ? V22 ? V12 ? P V12 P V2 1 ? ? ? + + z1 = 2 + 2 + z2 > P ? P2 = ? g ? 2 1 1 ? 2 g + z2 ? z1 ? > P , gage = ? g ? 2 g + z2 ? ?g 2 g ? g 2 g ? ? ? ? Substituting, ? (12 m/s) 2 ? (2 m/s) 2 ? 1 kN ? = 73. 9 kN/m 2 = 73. 9 kPa P , gage = (1000 kg/m3 )(9. 81 m/s 2 )? + 0. 4 1 2 ? 1000 kg ? m/s 2 ? 2(9. 81 m/s ) ? ? The momentum equation for steady one-dimensional flow is & & ? F = ? mV ? ? ? mV . We let the x- and out in r r r z- components of the anchoring force of the elbow be FRx and FRz, and assume them to be in the positive directions. We also use gage pressures to avoid dealing with the atmospheric pressure which acts on all surfaces. Then the momentum equations along the x and z axes become & & & FRx + P1,gage A1 = ? mV 2 cos ? ? ? mV1 and FRz ? W = ? mV 2 sin ? 2 25 cm2 Solving for FRx and FRz, and substituting the given values, & FRx = ? m(V 2 cos ? ? V1 ) ? P1, gage A1 ? 1 kN = 1. 03(30 kg/s)[(12cos45 ° – 2) m/s]? ? 1000 kg ? m/s 2 ? ? (73. 9 kN/m 2 )(0. 0150 m 2 ) = ? 0. 908 kN ? ? ? Water 30 kg/s 45 ° FRz FRx 150 m2 W 1 ? ? 1 kN ? & FRz = ? mV 2 sin ? + W = 1. 03(30 kg/s)(12sin45 ° m/s)? ? 1000 kg ? m/s 2 ? + 0. 4905 kN = 0. 753 kN ? ? 0. 753 2 2 2 2 -1 FRz FR = FRx + FRz = (? 0. 908) + (0. 753) = 1. 18 kN, ? = tan = tan -1 = ? 39. 7 ° FRx ? 0. 908 Discussion Note that the magnitude of the anchoring force is 1. 18 kN, and its line of action makes –39. 7 ° from +x direction. Negative value for FRx indicates the assumed direction is wrong. 6-8 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation.If you are a student using this Manual, you are using it without permission. Chapter 6 Momentum Analysis of Flow Systems 6-26 A reducing elbow deflects water upwards and discharges it to the atmosphere at a specified rate. The anchoring force needed to hold the elbow in place is to be determined. v Assumptions 1 The flow is steady, frictionless, one-dimensional, incompressible, and irrotational (so that the Bernoulli equation is applicable). 2 The weight of the elbow and the water in it is considered. 3 The water is discharged to the atmosphere, and thus the gage pressure at the outlet is zero. The momentumflux correction factor for each inlet and outlet is given to be ? = 1. 03. Properties We take the densi ty of water to be 1000 kg/m3. Analysis The weight of the elbow and the water in it is W = mg = (50 kg)(9. 81 m/s 2 ) = 490. 5 N = 0. 4905 kN We take the elbow as the control volume, and designate the entrance by 1 and the outlet by 2. We also designate the horizontal coordinate by x (with the direction of flow as being the positive direction) and the vertical coordinate by z. The continuity equation for this one-inlet one-outlet steady flow system is & & & & m1 = m 2 = m = 30 kg/s. Noting that m = ?AV , the inlet and outlet velocities of water are & 30 kg/s m = = 2. 0 m/s V1 = ? A1 (1000 kg/m 3 )(0. 0150 m 2 ) & 30 kg/s m V2 = = = 12 m/s ? A2 (1000 kg/m 3 )(0. 0025 m 2 ) Taking the center of the inlet cross section as the reference level (z1 = 0) and noting that P2 = Patm, the Bernoulli equation for a streamline going through the center of the reducing elbow is expressed as ? V 2 ? V12 ? ? V22 ? V12 ? P V12 P V2 1 ? ? ? + + z1 = 2 + 2 + z2 > P ? P2 = ? g ? 2 1 1 ? 2 g + z2 ? z1 ? > P , gage = ? g ? 2 g + z2 ? ?g 2 g ? g 2 g ? ? ? ? or, P , gage = (1000 kg/m3 )(9. 81 m/s2 )? 1 ? ? ? (12 m/s)2 ? (2 m/s)2 2(9. 81 m/s ) ? 1 kN ? = 73. 9 kN/m 2 = 73. 9 kPa + 0. 4 1000 kg ? m/s 2 ? ? The momentum equation for steady one-dimensional flow is & & ? F = ? ?mV ? ? ? mV . We let the xout in r r r and y- components of the anchoring force of the elbow be FRx and FRz, and assume them to be in the positive directions. We also use gage pressures to avoid dealing with the atmospheric pressure which acts on all surfaces. Then the momentum equations along the x and z axes become & & FRx + P1,gage A1 = ? mV 2 cos ? ? ? mV1 and & FRy ? W = ? mV 2 sin ? Solving for FRx and FRz, and substituting the given values, & FRx = ? m(V 2 cos ? V1 ) ? P1, gage A1 ? 1 kN = 1. 03(30 kg/s)[(12cos110 ° – 2) m/s]? ? 1000 kg ? m/s 2 ? FRz ? ? ? (73. 9 kN/m 2 )(0. 0150 m 2 ) = ? 1. 297 kN ? ? ? ? 1 kN ? + 0. 4905 kN = 0. 8389 kN & = ? mV 2 sin ? + W = 1. 03(30 kg/s)(12sin110 ° m/s)? 2 ? ? 1000 kg ? m/s ? ? 2 25 cm2 110 ° 2 2 FR = FRx + FRz = (? 1. 297) 2 + 0. 8389 2 = 1. 54 kN and FRz 0. 8389 = tan -1 = ? 32. 9 ° FRx ? 1. 297 Discussion Note that the magnitude of the anchoring force is 1. 54 kN, and its line of action makes –32. 9 ° from +x direction. Negative value for FRx indicates assumed direction is wrong, and should be reversed. ? = tan -1 FRz FRx Water 1 30 kg/s 50 m2 W 6-9 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation. If you are a student using this Manual, you are using it without permission. Chapter 6 Momentum Analysis of Flow Systems 6-27 Water accelerated by a nozzle strikes the back surface of a cart moving horizontally at a constant velocity. The braking force and the power wasted by the brakes are to be determined. . Assumptions 1 The flow is steady and incompressible. 2 The water splatters off the sides of the plate in all direction s in the plane of the back surface. The water jet is exposed to the atmosphere, and thus the pressure of the water jet and the splattered water is the atmospheric pressure which is disregarded since it acts on all surfaces. 4 Fiction during motion is negligible. 5 There is no acceleration of the cart. 7 The motions of the water jet and the cart are horizontal. 6 Jet flow is nearly uniform and thus the effect of the momentum-flux correction factor is negligible, ? ? 1. Analysis We take the cart as the control volume, and the direction of flow as the positive direction of x axis. The relative velocity between the cart and the jet is V r = V jet ?Vcart = 15 ? 10 = 10 m/s 15 m/s 5 m/s Therefore, we can assume the cart to be stationary and the jet to move Waterjet with a velocity of 10 m/s. The momentum equation for steady onedimensional flow in the x (flow) direction reduces in this case to r r r & & & & F= ? mV ? ? mV > FRx = ? mi Vi > Fbrake = ? mV r FRx ? ? out ? in We note that the brake force acts in the opposite direction to flow, and we should not forget the negative sign for forces and velocities in the negative x-direction. Substituting the given values, ? 1N & Fbrake = ? mV r = ? (25 kg/s)(+10 m/s)? ? 1 kg ? m/s 2 ? ? ? = ? 250 N ? ?The negative sign indicates that the braking force acts in the opposite direction to motion, as expected. Noting that work is force times distance and the distance traveled by the cart per unit time is the cart velocity, the power wasted by the brakes is 1 kW ? ? & W = FbrakeV cart = (250 N)(5 m/s)? ? = 1. 25 kW ? 1000 N ? m/s ? Discussion Note that the power wasted is equivalent to the maximum power that can be generated as the cart velocity is maintained constant. 6-10 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation.If you are a student using this Manual, you are using it without permission. Chapter 6 Momentum Analysis of Fl ow Systems 6-28 Water accelerated by a nozzle strikes the back surface of a cart moving horizontally. The acceleration of the cart if the brakes fail is to be determined. Analysis The braking force was determined in previous problem to be 250 N. When the brakes fail, this force will propel the cart forward, and the accelerating will be a= F 250 N ? 1 kg ? m/s 2 ? = m cart 300 kg ? 1N ? ? ? = 0. 833 m/s 2 ? ? Discussion This is the acceleration at the moment the brakes fail.The acceleration will decrease as the relative velocity between the water jet and the cart (and thus the force) decreases. 5 m/s 15 m/s 300 kg Waterjet FRx 6-11 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation. If you are a student using this Manual, you are using it without permission. Chapter 6 Momentum Analysis of Flow Systems 6-29E A water jet hits a stationary splitter, such that half of the flow is diverted up ward at 45 °, and the other half is directed down.The force required to hold the splitter in place is to be determined. vEES Assumptions 1 The flow is steady and incompressible. 2 The water jet is exposed to the atmosphere, and thus the pressure of the water jet before and after the split is the atmospheric pressure which is disregarded since it acts on all surfaces. 3 The gravitational effects are disregarded. 4 Jet flow is nearly uniform and thus the effect of the momentum-flux correction factor is negligible, ? ? 1. Properties We take the density of water to be 62. 4 lbm/ft3. Analysis The mass flow rate of water jet is & & m = ? V = (62. lbm/ft 3 )(100 ft 3 /s) = 6240 lbm/s We take the splitting section of water jet, including the splitter as the control volume, and designate the entrance by 1 and the outlet of either arm by 2 (both arms have the same velocity and mass flow rate). We also designate the horizontal coordinate by x with the direction of flow as being the positive direction and the vertical coordinate by z. r r r & & The momentum equation for steady one-dimensional flow is F= ? mV ? ? mV . We let ? ? out ? in the x- and y- components of the anchoring force of the splitter be FRx and FRz, and assume them to be in the & & positive directions.Noting that V2 = V1 = V and m 2 = 1 m , the momentum equations along the x and z 2 axes become & & & FRx = 2( 1 m)V 2 cos ? ? mV1 = mV (cos ? ? 1) 2 & & FRz = 1 m(+V 2 sin ? ) + 1 m(? V 2 sin ? ) ? 0 = 0 2 2 Substituting the given values, 1 lbf ? ? FRx = (6240 lbm/s)(20 ft/s)(cos45 ° – 1)? ? = ? 1135 lbf 32. 2 lbm ? ft/s 2 ? ? FRz = 0 The negative value for FRx indicates the assumed direction is wrong, and should be reversed. Therefore, a force of 1135 lbf must be applied to the splitter in the opposite direction to flow to hold it in place. No holding force is necessary in the vertical direction.This can also be concluded from the symmetry. Discussion In reality, the gravitational effects will cau se the upper stream to slow down and the lower stream to speed up after the split. But for short distances, these effects are indeed negligible. 20 ft/s 100 ft/s FRz 45 ° 45 ° FRx 6-12 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation. If you are a student using this Manual, you are using it without permission. Chapter 6 Momentum Analysis of Flow Systems 6-30E Problem 6-29E is reconsidered.The effect of splitter angle on the force exerted on the splitter as the half splitter angle varies from 0 to 180 ° in increments of 10 ° is to be investigated. g=32. 2 â€Å"ft/s2† rho=62. 4 â€Å"lbm/ft3† V_dot=100 â€Å"ft3/s† V=20 â€Å"ft/s† m_dot=rho*V_dot F_R=-m_dot*V*(cos(theta)-1)/g â€Å"lbf† ?,  ° 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 8000 7000 6000 5000 & m , lbm/s 6240 6240 6240 6240 6240 6240 6240 6240 6240 6240 624 0 6240 6240 6240 6240 6240 6240 6240 6240 FR, lbf 0 59 234 519 907 1384 1938 2550 3203 3876 4549 5201 5814 6367 6845 7232 7518 7693 7752 FR, lbf 000 3000 2000 1000 0 0 20 40 60 80 100 120 140 160 180 ?,  ° 6-13 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation. If you are a student using this Manual, you are using it without permission. Chapter 6 Momentum Analysis of Flow Systems 6-31 A horizontal water jet impinges normally upon a vertical plate which is held on a frictionless track and is initially stationary. The initial acceleration of the plate, the time it takes to reach a certain velocity, and the velocity at a given time are to be determined.Assumptions 1 The flow is steady and incompressible. 2 The water always splatters in the plane of the retreating plate. 3 The water jet is exposed to the atmosphere, and thus the pressure of the water jet and the splattered water is the a tmospheric pressure which is disregarded since it acts on all surfaces. 4 The tract is nearly frictionless, and thus fiction during motion is negligible. 5 The motions of the water jet and the cart are horizontal. 6 The velocity of the jet relative to the plate remains constant, Vr = Vjet = V. 7 Jet flow is nearly uniform and thus the effect of the momentum-flux correction factor is egligible, ? ? 1. Properties We take the density of water to be 1000 kg/m3. Analysis (a) We take the vertical plate on the frictionless track as the control volume, and the direction of flow as the positive direction of x axis. The mass flow rate of water in the jet is & m = ? VA = (1000 kg/m 3 )(18 m/s)[? (0. 05 m) 2 / 4] = 35. 34 kg/s The momentum equation for steady one-dimensional flow in the x (flow) direction reduces in this case to r r r & & & & F= ? mV ? ? mV > FRx = ? mi Vi > FRx = ? mV ? ? out ? in where FRx is the reaction force required to hold the plate in place.When the plate is released, a n equal and opposite impulse force acts on the plate, which is determined to ? 1N & Fplate = ? FRx = mV = (35. 34 kg/s)(18 m/s)? ? 1 kg ? m/s 2 ? ? ? = 636 N ? ? Then the initial acceleration of the plate becomes a= Fplate m plate = 636 N ? 1 kg ? m/s 2 ? 1000 kg ? 1 N ? ? ? = 0. 636 m/s 2 ? ? 18 m/s 1000 kg Waterjet Frictionless track This acceleration will remain constant during motion since the force acting on the plate remains constant. (b) Noting that a = dV/dt = ? V/? t since the acceleration a is constant, the time it takes for the plate to reach a velocity of 9 m/s is ? t = ? V plate a = (9 ? ) m/s 0. 636 m/s 2 FRx = 14. 2 s (c) Noting that a = dV/dt and thus dV = adt and that the acceleration a is constant, the plate velocity in 20 s becomes V plate = V0, plate + a? t = 0 + (0. 636 m/s 2 )(20 s) = 12. 7 m/s Discussion The assumption that the relative velocity between the water jet and the plate remains constant is valid only for the initial moments of motion when the plate velocity is low unless the water jet is moving with the plate at the same velocity as the plate. 6-14 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation.If you are a student using this Manual, you are using it without permission. Chapter 6 Momentum Analysis of Flow Systems 6-32 A 90 ° reducer elbow deflects water downwards into a smaller diameter pipe. The resultant force exerted on the reducer by water is to be determined. Assumptions 1 The flow is steady, frictionless, one-dimensional, incompressible, and irrotational (so that the Bernoulli equation is applicable). 2 The weight of the elbow and the water in it is disregarded since the gravitational effects are negligible. 3 The momentum-flux correction factor for each inlet and outlet is given to be ? 1. 04. Properties We take the density of water to be 1000 kg/m3. Analysis We take the elbow as the control volume, and designate the entrance by 1 and the outlet by 2. We also designate the horizontal coordinate by x (with the direction of flow as being the positive direction) and the vertical coordinate by z. The continuity equation for this one-inlet one-outlet steady flow system is & & & & m1 = m 2 = m = 353. 4 kg/s. Noting that m = ? AV , the mass flow rate of water and its outlet velocity are 2 & m = ? V1 A1 = ? V1 (? D1 / 4) = (1000 kg/m 3 )(5 m/s)[? (0. 3 m) 2 / 4] = 353. 4 kg/s & & 353. kg/s m m = = = 20 m/s 2 ? A2 D 2 / 4 (1000 kg/m 3 )[? (0. 15 m) 2 / 4] The Bernoulli equation for a streamline going through the center of the reducing elbow is expressed as V2 = P V12 P V2 1 + + z1 = 2 + 2 + z2 ? g 2 g ? g 2 g > ? V 2 ? V22 ? ? P2 = P + ? g ? 1 1 ? 2 g + z1 ? z2 ? ? ? Substituting, the gage pressure at the outlet becomes ? (5 m/s)2 ? (20 m/s)2 1 kPa ? 1 kN ? P2 = (300 kPa) + (1000 kg/m 3 )(9. 81 m/s 2 )? + 0. 5 = 117. 4 kPa 2 ? 1000 kg ? m/s 2 1 kN/m 2 ? 2(9. 81 m/s ) ? ? The momentum equation for steady one-dimensional flow is & & ? F = ? ?mV ? ? ? mV . We let the xout in r r and z- components of the anchoring force of the elbow be FRx and FRz, and assume them to be in the positive directions. Then the momentum equations along the x and z axes become & FRx + P1,gage A1 = 0 ? ? mV1 & FRz ? P2,gage A2 = ? m(? V 2 ) ? 0 Note that we should not forget the negative sign for forces and velocities in the negative x or z direction. Solving for FRx and FRz, and substituting the given values, ? 1 kN & FRx = ? ?mV1 ? P1, gage A1 = ? 1. 04(353. 4 kg/s)(5 m/s)? ? 1000 kg ? m/s 2 ? ? ? (0. 3 m) 2 ? ? (300 kN/m 2 ) = ? 23. 0 kN ? 4 ? ? ? (0. 15 m) 2 ? + (117. 4 kN/m 2 ) = ? 5. 28 kN ? ? FRz ? 1 kN & FRz = ? ? mV 2 + P2, gage A1 = ? 1. 04(353. 4 kg/s)(20 m/s)? ? 1000 kg ? m/s 2 ? and 2 2 FR = FRx + FRz = (? 23. 0) 2 + (? 5. 28) 2 = 23. 6 kN FRx 30 cm Water 5 m/s ? = tan -1 FRz ? 5. 28 = tan -1 = 12. 9 ° FRx ? 23. 0 Discussion The magnitude of the anchoring force is 23. 6 kN, and its line of action makes 12. 9 ° from +x direction. Negative values for FRx and FRy indicate that the assumed directions are wrong, and should be reversed. 15 cm 6-15 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation.If you are a student using this Manual, you are using it without permission. Chapter 6 Momentum Analysis of Flow Systems 6-33 A wind turbine with a given span diameter and efficiency is subjected to steady winds. The power generated and the horizontal force on the supporting mast of the turbine are to be determined. vEES Assumptions 1 The wind flow is steady and incompressible. 2 The efficiency of the turbine-generator is independent of wind speed. 3 The frictional effects are negligible, and thus none of the incoming kinetic energy is converted to thermal energy. Wind flow is uniform and thus the momentum-flux correction factor is nearly unity, ? ? 1. Properties The density of air is given to be 1. 25 kg/m3. Analysis (a) The power potential of the wind is its kinetic energy, & which is V2/2 per unit mass, and mV 2 / 2 for a given mass flow rate: ? 1 m/s ? V1 = (25 km/h)? ? = 6. 94 m/s ? 3. 6 km/h ? & m = ? 1V1 A1 = ? 1V1 Wind V1 1 2 D V2 ?D 2 4 2 = (1. 25 kg/m 3 )(6. 94 m/s) ? (90 m) 2 4 2 = 55,200 kg/s V (6. 94 m/s) & & & W max = mke1 = m 1 = (55,200 kg/s) 2 2 ? 1 kN ? ? 1000 kg ? m/s 2 ? 1 kW ? 1 kN ? m/s ? = 1330 kW ? ? FR Then the actual power produced becomes & Wact = ? wind turbineW max = (0. 32)(1330 kW) = 426 kW (b) The frictional effects are assumed to be negligible, and thus the portion of incoming kinetic energy not converted to electric power leaves the wind turbine as outgoing kinetic energy. Therefore, V2 V2 & & & & mke 2 = mke1 (1 ? ? wind turbine ) > m 2 = m 1 (1 ? ? wind turbine ) 2 2 or V 2 = V1 1 ? ? wind turbine = (6. 94 m/s) 1 – 0. 32 = 5. 72 m/s We choose the control volume around the wind turbine such that the wind is norm al to the control surface at the inlet and the outlet, and the entire control surface is at the atmospheric pressure.The momentum r r r & & equation for steady one-dimensional flow is F= ? mV ? ? mV . Writing it along the x-direction ? ? out ? in (without forgetting the negative sign for forces and velocities in the negative x-direction) and assuming the flow velocity through the turbine to be equal to the wind velocity give ? 1 kN & & & FR = mV 2 ? mV1 = m(V 2 ? V1 ) = (55,200 kg/s)(5. 72 – 6. 94 m/s)? ? 1000 kg ? m/s 2 ? ? ? = ? 67. 3 kN ? ? The negative sign indicates that the reaction force acts in the negative x direction, as expected.Discussion This force acts on top of the tower where the wind turbine is installed, and the bending moment it generates at the bottom of the tower is obtained by multiplying this force by the tower height. 6-16 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for c ourse preparation. If you are a student using this Manual, you are using it without permission. Chapter 6 Momentum Analysis of Flow Systems 6-34E A horizontal water jet strikes a curved plate, which deflects the water back to its original direction.The force required to hold the plate against the water stream is to be determined. Assumptions 1 The flow is steady and incompressible. 2 The water jet is exposed to the atmosphere, and thus the pressure of the water jet and the splattered water is the atmospheric pressure, which is disregarded since it acts on all surfaces. 3 Friction between the plate and the surface it is on is negligible (or the friction force can be included in the required force to hold the plate). 4 There is no splashing of water or the deformation of the jet, and the reversed jet leaves horizontally at the same velocity and flow rate. Jet flow is nearly uniform and thus the momentum-flux correction factor is nearly unity, ? ? 1. Properties We take the density of w ater to be 62. 4 lbm/ft3. Analysis We take the plate together with the curved water jet as the control volume, and designate the jet inlet by 1 and the outlet by 2. We also designate the horizontal coordinate by x (with the direction of incoming flow as being the positive direction). The continuity equation for this one-inlet one-outlet steady & & & flow system is m1 = m 2 = m where & m = ? VA = ? V [? D 2 / 4] = (62. 4 lbm/ft 3 )(140 ft/s)[? (3 / 12 ft) 2 / 4] = 428. lbm/s r r r & & The momentum equation for steady one-dimensional flow is F= ? mV ? ? mV . Letting the ? ? out ? in reaction force to hold the plate be FRx and assuming it to be in the positive direction, the momentum equation along the x axis becomes & & & FRx = m(? V 2 ) ? m(+V1 ) = ? 2mV Substituting, 1 lbf ? ? FRx = ? 2(428. 8 lbm/s)(140 ft/s)? ? = ? 3729 lbf 2 ? 32. 2 lbm ? ft/s ? Therefore, a force of 3729 lbm must be applied on the plate in the negative x direction to hold it in place. Discussion Note that a nega tive value for FRx indicates the assumed direction is wrong (as expected), and should be reversed.Also, there is no need for an analysis in the vertical direction since the fluid streams are horizontal. 2 140 ft/s Waterjet FRx 1 140 ft/s 3 in 6-17 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation. If you are a student using this Manual, you are using it without permission. Chapter 6 Momentum Analysis of Flow Systems 6-35E A horizontal water jet strikes a bent plate, which deflects the water by 135 ° from its original direction. The force required to hold the plate against the water stream is to be determined.Assumptions 1 The flow is steady and incompressible. 2 The water jet is exposed to the atmosphere, and thus the pressure of the water jet and the splattered water is the atmospheric pressure, which is disregarded since it acts on all surfaces. 3 Frictional and gravitational effec ts are negligible. 4 There is no splattering of water or the deformation of the jet, and the reversed jet leaves horizontally at the same velocity and flow rate. 5 Jet flow is nearly uniform and thus the momentum-flux correction factor is nearly unity, ? ? 1. Properties We take the density of water to be 62. 4 lbm/ft3.Analysis We take the plate together with the curved water jet as the control volume, and designate the jet inlet by 1 and the outlet by 2. We also designate the horizontal coordinate by x (with the direction of incoming flow as being the positive direction), and the vertical coordinate by z. The continuity equation for & & & this one-inlet one-outlet steady flow system is m1 = m 2 = m where & m = ? VA = ? V [? D 2 / 4] = (62. 4 lbm/ft 3 )(140 ft/s)[? (3 / 12 ft) 2 / 4] = 428. 8 lbm/s r r r & & The momentum equation for steady one-dimensional flow is F= ? mV ? ? mV . We let the x- ? ? out ? in nd z- components of the anchoring force of the plate be FRx and FRz, and assu me them to be in the positive directions. Then the momentum equations along the x and y axes become & & & FRx = m(? V 2 ) cos 45 ° ? m(+V1 ) = ? mV (1 + cos 45 °) & (+V 2 ) sin 45 ° = mV sin 45 ° & FRz = m Substituting the given values, 1 lbf ? ? FRx = ? 2(428. 8 lbm/s)(140 ft/s)(1 + cos45 °)? 2 ? ? 32. 2 lbm ? ft/s ? = ? 6365 lbf 1 lbf ? ? FRz = (428. 8 lbm/s)(140 ft/s)sin45 °? = 1318 lbf 2 ? ? 32. 2 lbm ? ft/s ? 2 140 ft/s Waterjet 135 ° FRz FRx 3 in 1 and 2 2 FR = FRx + FRz = (? 6365) 2 + 1318 2 = 6500 lbf , ? = tan -1 FRy FRx = tan -1 1318 = ? 1. 7 ° = 168. 3 ° ? 6365 Discussion Note that the magnitude of the anchoring force is 6500 lbf, and its line of action makes 168. 3 ° from the positive x direction. Also, a negative value for FRx indicates the assumed direction is wrong, and should be reversed. 6-18 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation. If you are a student using this Manual, you are using it without permission. Chapter 6 Momentum Analysis of Flow Systems 6-36 Firemen are holding a nozzle at the end of a hose while trying to extinguish a fire.The average water outlet velocity and the resistance force required of the firemen to hold the nozzle are to be determined. Assumptions 1 The flow is steady and incompressible. 2 The water jet is exposed to the atmosphere, and thus the pressure of the water jet is the atmospheric pressure, which is disregarded since it acts on all surfaces. 3 Gravitational effects and vertical forces are disregarded since the horizontal resistance force is to be determined. 5 Jet flow is nearly uniform and thus the momentum-flux correction factor can be taken to be unity, ? ? 1. Properties We take the density of water to be 1000 kg/m3.Analysis (a) We take the nozzle and the horizontal portion of the hose as the system such that water enters the control volume vertically and outlets horizontally (thi s way the pressure force and the momentum flux at the inlet are in the vertical direction, with no contribution to the force balance in the horizontal direction), and designate the entrance by 1 and the outlet by 2. We also designate the horizontal coordinate by x (with the direction of flow as being the positive direction). The average outlet velocity and the mass flow rate of water are determined from V= V& A = V& ? D / 4 2 = 5 m 3 /min ? (0. 06 m) 2 / 4 1768 m/min = 29. 5 m/s & m = ? V& = (1000 kg/m 3 )(5 m 3 /min) = 5000 kg/min = 83. 3 kg/s (b) The momentum equation for steady one-dimensional flow is & & ? F = ? ?mV ? ? ? mV . We let out in r r r horizontal force applied by the firemen to the nozzle to hold it be FRx, and assume it to be in the positive x direction. Then the momentum equation along the x direction gives ? ? 1N ? = 2457 N & & FRx = mVe ? 0 = mV = (83. 3 kg/s)(29. 5 m/s)? ? 1kg ? m/s 2 ? ? ? Therefore, the firemen must be able to resist a force of 2457 N to hold t he nozzle in place. Discussion The force of 2457 N is equivalent to the weight of about 250 kg.That is, holding the nozzle requires the strength of holding a weight of 250 kg, which cannot be done by a single person. This demonstrates why several firemen are used to hold a hose with a high flow rate. FRz FRx 5 m3/min 6-19 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation. If you are a student using this Manual, you are using it without permission. Chapter 6 Momentum Analysis of Flow Systems 6-37 A horizontal jet of water with a given velocity strikes a flat plate that is moving in the same direction at a specified velocity.The force that the water stream exerts against the plate is to be determined. Assumptions 1 The flow is steady and incompressible. 2 The water splatters in all directions in the plane of the plate. 3 The water jet is exposed to the atmosphere, and thus the pressure o f the water jet and the splattered water is the atmospheric pressure, which is disregarded since it acts on all surfaces. 4 The vertical forces and momentum fluxes are not considered since they have no effect on the horizontal force exerted on the plate. 5 The velocity of the plate, and the velocity of the water jet relative to the plate, are constant. Jet flow is nearly uniform and thus the momentum-flux correction factor can be taken to be unity, ? ? 1. Properties We take the density of water to be 1000 kg/m3. Analysis We take the plate as the control volume, and the flow direction as the positive direction of x axis. The mass flow rate of water in the jet is & m = ? V jet A = ? V jet 10 m/s 30 m/s FRx 5 cm Waterjet ?D 4 2 = (1000 kg/m 3 )(30 m/s) ? (0. 05 m) 2 4 = 58. 9 kg/s The relative velocity between the plate and the jet is V r = V jet ? V plate = 30 ? 10 = 20 m/s Therefore, we can assume the plate to be stationary and the jet to move with a velocity of 20 m/s.The r r r & & F= ? mV ? ? mV . We let the horizontal momentum equation for steady one-dimensional flow is ? ? out ? in reaction force applied to the plate in the negative x direction to counteract the impulse of the water jet be FRx. Then the momentum equation along the x direction gives ? ? 1N ? & & ? FRx = 0 ? mVi > FRx = mV r = (58. 9 kg/s)(20 m/s)? ? 1kg ? m/s 2 ? = 1178 N ? ? Therefore, the water jet applies a force of 1178 N on the plate in the direction of motion, and an equal and opposite force must be applied on the plate if its velocity is to remain constant.Discussion Note that we used the relative velocity in the determination of the mass flow rate of water in the momentum analysis since water will enter the control volume at this rate. (In the limiting case of the plate and the water jet moving at the same velocity, the mass flow rate of water relative to the plate will be zero since no water will be able to strike the plate). 6-20 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Comp anies, Inc. Limited distribution permitted only to teachers and educators for course preparation. If you are a student using this Manual, you are using it without permission.Chapter 6 Momentum Analysis of Flow Systems 6-38 Problem 6-37 is reconsidered. The effect of the plate velocity on the force exerted on the plate as the plate velocity varies from 0 to 30 m/s in increments of 3 m/s is to be investigated. rho=1000 â€Å"kg/m3† D=0. 05 â€Å"m† V_jet=30 â€Å"m/s† Ac=pi*D^2/4 V_r=V_jet-V_plate m_dot=rho*Ac*V_jet F_R=m_dot*V_r â€Å"N† Vplate, m/s 0 3 6 9 12 15 18 21 24 27 30 Vr, m/s 30 27 24 21 18 15 12 9 6 3 0 FR, N 1767 1590 1414 1237 1060 883. 6 706. 9 530. 1 353. 4 176. 7 0 1800 1600 1400 1200 1000 FR, N 800 600 400 200 0 0 5 10 15 20 25 30 Vplate, m/s 6-21PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation. If you are a student using this Manual, you ar e using it without permission. Chapter 6 Momentum Analysis of Flow Systems 6-39E A fan moves air at sea level at a specified rate. The force required to hold the fan and the minimum power input required for the fan are to be determined. v Assumptions 1 The flow of air is steady and incompressible. 2 Standard atmospheric conditions exist so that the pressure at sea level is 1 atm. Air leaves the fan at a uniform velocity at atmospheric pressure. 4 Air approaches the fan through a large area at atmospheric pressure with negligible velocity. 5 The frictional effects are negligible, and thus the entire mechanical power input is converted to kinetic energy of air (no conversion to thermal energy through frictional effects). 6 Wind flow is nearly uniform and thus the momentum-flux correction factor can be taken to be unity, ? ? 1. Properties The gas constant of air is R = 0. 3704 psi? ft3/lbm? R. The standard atmospheric pressure at sea level is 1 atm = 14. 7 psi.Analysis (a) We take the control volume to be a horizontal hyperbolic cylinder bounded by streamlines on the sides with air entering through the large cross-section (section 1) and the fan located at the narrow cross-section at the end (section 2), and let its centerline be the x axis. The density, mass flow rate, and discharge velocity of air are 14. 7 psi P ? = = = 0. 0749 lbm/ft 3 RT (0. 3704 psi ? ft 3 /lbm ? R)(530 R) & m = ? V& = (0. 0749 lbm/ft 3 )(2000 ft 3/min) = 149. 8 lbm/min = 2. 50 lbm/s V2 = V& A2 = V& 2 ? D 2 / 4 = 2000 ft 3 /min ? (2 ft) 2 / 4 = 636. 6 ft/min = 10. ft/s & & ? F = ? ?mV ? ? ? mV . Letting the out in The momentum equation for steady one-dimensional flow is r r r reaction force to hold the fan be FRx and assuming it to be in the positive x (i. e. , the flow) direction, the momentum equation along the x axis becomes 1 lbf ? ? & & FRx = m(V 2 ) ? 0 = mV = (2. 50 lbm/s)(10. 6 ft/s)? ? = 0. 82 lbf 2 ? 32. 2 lbm ? ft/s ? Therefore, a force of 0. 82 lbf must be applied (through frict ion at the base, for example) to prevent the fan from moving in the horizontal direction under the influence of this force. (b) Noting that P1 = P2 = Patm and V1 ? , the energy equation for the selected control volume reduces to ?P V2 ? ?P V2 ? & & & & & m? 1 + 1 + gz1 ? + W pump, u = m? 2 + 2 + gz 2 ? + W turbine + E mech,loss > ? ? ? ? 2 2 ? ? ? ? Substituting, V & & Wfan, u = m 2 2 2 V2 (10. 6 ft/s) 2 ? 1 lbf 1W ? & & Wfan,u = m 2 = (2. 50 lbm/s) ? ? = 5. 91 W 2 2 2 ? 32. 2 lbm ? ft/s 0. 73756 lbf ? ft/s ? Therefore, a useful mechanical power of 5. 91 W must be supplied to 2000 cfm air. This is the minimum required power input required for the fan. Discussion The actual power input to the fan will be larger than 5. 1 W because of the fan inefficiency in converting mechanical power to kinetic energy. Fan 1 2 24 in 6-22 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation. If you are a student using this Manual, you are using it without permission. Chapter 6 Momentum Analysis of Flow Systems 6-40 A helicopter hovers at sea level while being loaded. The volumetric air flow rate and the required power input during unloaded hover, and the rpm and the required power input during loaded hover are to be determined. Assumptions 1 The flow of air is steady and incompressible. 2 Air leaves the blades at a uniform velocity at atmospheric pressure. 3 Air approaches the blades from the top through a large area at atmospheric pressure with negligible velocity. 4 The frictional effects are negligible, and thus the entire mechanical power input is converted to kinetic energy of air (no conversion to thermal energy through frictional effects). 5 The change in air pressure with elevation is negligible because of the low density of air. 6 There is no acceleration of the helicopter, and thus the lift generated is equal to the total weight. Air flow is nearly uniform and thus the momentum-flux correction factor can be taken to be unity, ? ? 1. Properties The density of air is given to be 1. 18 kg/m3. Analysis (a) We take the control volume to be a vertical hyperbolic cylinder bounded by streamlines on the sides with air entering through the large cross-section (section 1) at the top and the fan located at the narrow cross-section at the bottom (section 2), and let its centerline be the z axis with upwards being the positive direction. r r r & & F= ? mV ? ? mV . Noting The momentum equation for steady one-dimensional flow is ? out ? in that the only force acting on the control volume is the total weight W and it acts in the negative z direction, the momentum equation along the z axis gives W & & ? W = m(? V 2 ) ? 0 > W = mV 2 = ( ? AV 2 )V 2 = ? AV 22 > V2 = ? A 1 where A is the blade span area, 15 m A = ? D / 4 = ? (15 m) / 4 = 176. 7 m 2 2 2 Then the discharge velocity, volume flow rate, and the mass flow rate of air in the unloaded mode become V 2,unloaded = m unloaded g = ? A (10,000 kg)(9. 81 m/s 2 ) (1. 18 kg/m 3 )(176. 7 m 2 ) = 21. 7 m/s Sea level 2 V&unloaded = AV 2,unloaded = (176. 7 m 2 )(21. m/s) = 3834 m 3 /s & munloaded = ? V&unloaded = (1. 18 kg/m 3 )(3834 m 3/s) = 4524 kg/s Load 15,000 kg Noting that P1 = P2 = Patm, V1 ? 0, the elevation effects are negligible, and the frictional effects are disregarded, the energy equation for the selected control volume reduces to ? P V2 ? ?P V2 ? V2 & & & & & & & m? 1 + 1 + gz1 ? + W pump, u = m? 2 + 2 + gz 2 ? + W turbine + E mech,loss > Wfan, u = m 2 ? ? ? ? 2 2 2 ? ? ? ? Substituting, ? V2 ? 1 kW ? (21. 7 m/s) 2 ? 1 kN & ? ? & = (4524 kg/s) W unloaded fan,u = ? m 2 ? ? = 1065 kW 2 ? 1 kN ? m/s ? 1000 kg ? m/s ? ? 2 ? 2 ? ? ? ? nloaded (b) We now repeat the calculations for the loaded helicopter, whose mass is 10,000+15,000 = 25,000 kg: V 2,loaded = m loaded g = ? A (25,000 kg)(9. 81 m/s 2 ) (1. 18 kg/m 3 )(176. 7 m 2 ) = 34. 3 m/s & mloaded = ? V&loaded = ? AV2, loaded = (1. 18 kg/m 3 )(176. 7 m 2 )(34. 3 m/s) = 7152 kg/s ? V2 ? (34. 3 m/s)2 & & = (7152 kg/s) Wloaded fan,u = ? m 2 ? ? 2 ? 2 ? ?loaded ? 1 kW ? 1 kN ? ? ? 1000 kg ? m/s 2 1 kN ? m/s ? = 4207 kW ? ? 6-23 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation.If you are a student using this Manual, you are using it without permission. Chapter 6 Momentum Analysis of Flow Systems Noting that the average flow velocity is proportional to the overhead blade rotational velocity, the rpm of the loaded helicopter blades becomes & V 2 = kn > V 2,loaded V 2, unloaded = & n loaded & n unloaded > & n loaded = V 2,loaded V 2, unloaded & n unloaded = 34. 3 (400 rpm) = 632 rpm 21. 7 Discussion The actual power input to the helicopter blades will be considerably larger than the calculated power input because of the fan inefficiency in converting mechanical power to kinetic energy. -24 PROPRIETARY MATERIAL.  © 200 6 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation. If you are a student using this Manual, you are using it without permission. Chapter 6 Momentum Analysis of Flow Systems 6-41 A helicopter hovers on top of a high mountain where the air density considerably lower than that at sea level. The blade rotational velocity to hover at the higher altitude and the percent increase in the required power input to hover at high altitude relative to that at sea level are to be determined. Assumptions 1 The flow of air is steady and incompressible. 2 The air leaves the blades at a uniform velocity at atmospheric pressure. 3 Air approaches the blades from the top through a large area at atmospheric pressure with negligible velocity. 4 The frictional effects are negligible, and thus the entire mechanical power input is converted to kinetic energy of air. 5 The change in air pressure with elevation while hovering at a given locatio n is negligible because of the low density of air. 6 There is no acceleration of the helicopter, and thus the lift generated is equal to the total weight. Air flow is nearly uniform and thus the momentum-flux correction factor can be taken to be unity, ? ? 1. Properties The density of air is given to be 1. 18 kg/m3 at sea level, and 0. 79 kg/m3 on top of the mountain. Analysis (a) We take the control volume to be a vertical hyperbolic cylinder bounded by streamlines on the sides with air entering through the large cross-section (section 1) at the top and the fan located at the narrow cross-section at the bottom (section 2), and let its centerline be the z axis with upwards being the positive direction. r r & & F= ? mV ? ? mV . Noting The momentum equation for steady one-dimensional flow is ? ? out ? in that the only force acting on the control volume is the total weight W and it acts in the negative z direction, the momentum equation along the z axis gives W & & ? W = m(? V 2 ) ? 0 > W = mV 2 = ( ? AV 2 )V 2 = ? AV 22 > V2 = ? A where A is the blade span area. Then for a given weight W, the ratio of discharge velocities becomes V 2,mountain V 2,sea = W / ? mountain A W / ? sea A = ? sea ? mountain = 1. 18 kg/m 3 0. 79 kg/m 3 = 1. 222Noting that the average flow velocity is proportional to the overhead blade rotational velocity, the rpm of the helicopter blades on top of the mountain becomes & n = kV 2 > & n mountain V 2, mountain = & n sea V 2,sea > & n mountain = V 2, mountain V 2,sea & nsea = 1. 222(400 rpm) = 489 rpm Noting that P1 = P2 = Patm, V1 ? 0, the elevation effect are negligible, and the frictional effects are disregarded, the energy equation for the selected control volume reduces to ? P V2 ? ?P V2 ? V2 & & & & & & & m? 1 + 1 + gz1 ? + W pump, u = m? 2 + 2 + gz 2 ? W turbine + E mech,loss > Wfan, u = m 2 ? ? ? ? 1 2 2 2 ? ? ? ? or V2 V2 V3 & & Wfan,u = m 2 = ? AV2 2 = ? A 2 = 2 2 2 1 2 ?A? ? ? W ? ? = ? ? ? A ? 3 1 2 ?A? ? ?W ? ? ? ? ? A ? 1 . 5 = W 1 . 5 2 ? A 15 m Then the ratio of the required power input on top of the mountain to that at sea level becomes & Wmountain fan,u 0. 5W 1. 5 / ? mountain A = & Wsea fan,u 0. 5W 1. 5 / ? sea A 2 ? mountain ?sea = 1. 18 kg/m3 = 1. 222 0. 79 kg/m3 Sea level Load 15,000 kg Therefore, the required power input will increase by 22. 2% on top of the mountain relative to the sea level.Discussion Note that both the rpm and the required power input to the helicopter are inversely proportional to the square root of air density. Therefore, more power is required at higher elevations for the helicopter to operate because air is less dense, and more air must be forced by the blades into the downdraft. 6-25 PROPRIETARY MATERIAL.  © 2006 The McGraw-Hill Companies, Inc. Limited distribution permitted only to teachers and educators for course preparation. If you are a student using this Manual, you are using it without permission.Chapter 6 Momentum Analysis of Flow Systems 6-42 The flow rate in a channel is controlled by a sluice gate by raising or lowering a vertical plate. A relation for the force acting on a sluice gate of width w for steady and uniform flow is to be developed. Assumptions 1 The flow is steady, incompressible, frictionless, and uniform (and thus the Bernoulli equation is applicable. ) 2 Wall shear forces at surfaces are negligible. 3 The channel is exposed to the atmosphere, and thus the pressure at free surfaces is the atmospheric pressure. 4 The flow is horizontal. Water flow is nearly uniform and thus the momentum-flux correction factor can be taken to be unity, ? ? 1. Analysis We take point 1 at the free surface of the upstream flow before the gate and point 2 at the free surface of the downstream flow after the gate. We also take the bottom surface of the channel as the reference level so that the elevations of points 1 and 2 are y1 and y2, respectively. The application of the Bernoulli equation between points 1 and 2 gives P1 V12 P V2 + + y1 = 2 + 2 + y 2 ? g 2 g ? g 2 g > V 22 ? V12 = 2 g( y1 ? y 2 ) (1)The flow is assumed to be incompressible and thus the density is constant. Then the conservation of mass relation for this single stream steady flow device can be expressed as V&1 = V&2 = V& > A1V1 = A2V 2 = V& > V1 = V& A1 = V& wy1 and V2 = V& A2 = V& wy 2 (2) Substituting into Eq. (1), ? V& ? ? wy ? 2 ? ? V& ? 2 g ( y1 ? y 2 ) & ? ? ? ? wy ? = 2 g ( y1 ? y 2 ) > V = w 1 / y 2 ? 1 / y 2 ? ? 1? 2 1 2 2 2 g ( y1 ? y 2 ) > V& = wy 2 2 2 1 ? y 2 / y1 (3) Substituting Eq. (3) into Eqs. (2) gives the following relations for velocities, V1 = y2 y1 2 g ( y1 ? y 2 ) 1? y2 / 2 y1 and V2 = 2 g ( y1 ? y 2 ) 2 2 1 ? y 2 / y1 (4) We choose the control volume as the water body surrounded by the vertical cross-sections of the upstream and downstream flows, free surfaces of water, the inner surface of the sluice gate, and the bottom surface of r r r & & F= ? mV ? ? mV . The the channel. The momentum equation for steady one-dimensional flow is ? ? out ? in force acting on the sluice gate FRx is horizontal