What are mitigating factors in learning math in saudi arabia Assignment

What are mitigating factors in skill math in saudi arabia - Assignment ExampleThe discussion of the results essentially focused on elaboration of the behavioral patterns of students in relation to motivation in undertaking math as a subject.MRP6 This was the last section of the report it focused on a discussion of the purpose of the search followed by the conclusion section that basically provided summarized information of the entire research.Adler, N. E., & Stewart, J. 2009 Recommended reading for the research provides pertinent information regarding motivation among human beings. This reference has noted that many human beings have a natural tendency of avoiding work.The DOS Based VBPro This is the content compendium software that was used to facilitate the analysis of the data collected in this research. The rational for selecting this software for the research is based on the fact that it is easily applicable in analyzing qualitative data.Manipulative in learning This is on e factor that arised in the course of data analysis manipulative method as a form of learning entails a scenario whereby student utilizes certain items i.e. calculators, toothpicks and markers to support hand-in learning. In my research, this is one factor that appeared to among the motivation factors used among students to learn math.School Quiz logic Puzzles This is another issue that emerged as I canvas my data. It is a tool that was applied in most Saudi Schools to improve the performance of students in mathematics. Logic puzzles are basically brain games where a student is subjected to a scenario where he has to apply logic in order to solve a problem.Qualitative Techniques This is the procedures that were used to collect and analyze data that guided my research. The precept for selecting qualitative technique as my research designed was based on the fact that it facilitated asking and reply questions such as Why? Where? How?

The right to privacy for self and business Research Paper

The right to privateness for self and business - question Paper ExampleThe privacy rights are usually balance by the interests of the nation or resign so that the regulations are consistent (especially in the promotion of safety of the public, as well as the progression of the quality of life (Ribstein Para 4). The context and boundary of what is perceived hush-hush depend on individuals though common themes list to be shared across the board. Suppose something or an issue is perceived private to an individual or a group then that issue or something is inherently sensitive or special to them. In the United States, privacy laws encompass numerous varieties of legal concepts. One of these concepts is the privacy violation (Roger and Gaylord 103). A tort in reference to the common laws provide the platform for which the party that is aggrieved to file a lawsuit against a person or individuals who intrude affairs considered private by disclosure of breeding deemed private. In addi tion, it provides protection for individuals private information and public falsification. However, the public figures usually throw off less privacy. The laws pertaining, privacy rights advocates for individuals to be left alone. However, it exempts matter or issues that are deemed personal or those activities that tend to generate the interest of the public. An example is the case of celebrities. The invasion of privacy rights provides the ground for lawsuit against individuals or groups violating or infringing the right. Moreover, the fourth amendment stipulates the right to protection from search that is unwarranted while the first advocates for the assembly freedom. The Supreme romance is mandated with the responsibility of protecting privacy rights within the US.Various amendments to the constitution of the US have been employed in the numerous ranges of success in the determination of rights to autonomy of individuals. The first or initial amendment provides protection of p rivacy

Semantic technology for improving business process management and Essay

Semantic technology for improving blood carry out fill inment and E-Business - Essay ExampleFrom traditional to contemporary perspectives, core objective of the coursees has been to manage business operations so that enables business to achieve the competitive advantage over competitors (Dean, DiGrande, Field, and Zwillenberg, 2012). Since introduced learning technology has been a constantly upgrading paradigm and so business are attempting to align the functions developing more concrete connections within and outside business environment hence, entire stakeholders. Technology expansion has changed the perspectives and businesses are now be viewed as system having core components of input, process and output. Around these core components, business processes are continuously evolving for overture with changing dynamics mainly arising from other perspectives. Broadly the sequence can be regarded as the information technology to recent integration of semantic technology in busi ness processes. Thereby, the report herein attempts to research the contribution of semantic technology in improving specific business areas of business process perplexity and e-business conduct. In addition to specifically explore the understudy perspectives the report has developed the detailed reference with extol to technological banking leader Citibank. DISCRIPTION OF THE possible action SEMANTIC BUSINESS PROCESS MANAGEMENT Business process worry has over years achieved success to a great extent automating the critical components of the life cycle of business process. Semantic business process management has an objective of attaining process space in an organization to an increase level of knowledge. Success in achieving the process space in the organization benefits business with reasoning with abide by to entire business processes including combination as hale as execution of process. Integration of semantics technologies in business process management is achieved with the use of ontology that facilitates the semantic information to the business process. Further, business process automation is intensify with provision of the semantic web techniques. Business ontology is build using conceptualized core Semantic Web run as well as Web Service Modeling Language. Sample organizational is depicted in the image below (Pedrinaci, Domingue, and Brelage, ) As visible from the image above the organizational ontology has various segments and connection in the midst of the resources, structure, functions, policies, setup and strategies. The interconnection built between various aspects being facilitated by the core components of the semantic integration in the business process. These interconnections enhance the role of bidirectional interconnection in the business process. Hence, business process management has gained gain efficiencies in entire processes specifically the bottleneck avenues of business processes. ORIGIN AND EVOLUTION OF THEORY Over years of development, information systems are attempting to enhance the dual perspective in the computers languages first, increasing computers qualification to enhance understanding the human language with greater comprehension and intelligence while second refers to techniques aimed at providing existing content with labeling related to the domain (Mika, Elfring, & Groenewegen, 2006 Warren, Thurlow, & Alsmeyer, 2006). Further, semantic technology enables metaphorical as well as logical analysis from the queries in the similar context in which it is asked irrespective of the language as well as pattern it is asked and hence

Is Online Privacy Dead Research Paper Example | Topics and Well Written Essays - 2500 words

Is Online Privacy Dead - Research Paper Example contempt being a digital world where every kind of transaction, application or interaction requires the revelation of personal information, the privacy rules have become less relevant (Jose, 2013). No one seems to care rough the advertising of personal, private and confidential information on the internet. No one seems to be bothered by the fact that personal information belonging to uninformed individuals are traded on the internet like unstained business commodities.Purpose StatementThe question that begs, therefore, is who is to carry the blame for all this. Who should be held responsible? Should it be the individuals who fearlessly and un conservatively discloses all their personal information online or are we to blame those who are in custody of the alike private information. The purpose of this research is, therefore, to delve deeper into this issue and find the root of the problem and suggest the viable cure to the same. Th e paper discusses whether online privacy is still in operation and how far it goes to secure personal information. only put, the paper discusses whether or not online privacy is dead. This has been a controversial issue that has left many in endless debates (House, 2014). While some argue that the current level of technology is not sufficient to sentry duty private information online, some are of the opinion that those charged with the safeguarding duty have terribly failed at it. In addition, the paper discusses the real motive behind the revealing of such information.

Story Response #3 Assignment Example | Topics and Well Written Essays - 250 words

Story Response 3 - Assignment ExampleHe fell in sock with her reasons beyond her schoolwork and the fact that he thought she knew much despite her tender age of thirteen.At first, the story seemed confusing. Why was it that Hannah chose on this boy and not any other in the class? It is not clear that they are close boosters in as much as he was willing to bend down rules so as to revel Hannah who had caught his attention. It would be vanquish preferred if the central character explain to him what the makeup kit entailed and to whom he was to repel to. It was shocking when he later came to realize the Mick guy in the B-building was Hannahs boyfriend. He cognize he is an innocent culprit whom the teachers would not suspect quickly.Next time, if the boy would fall in love with a woman, I find it useful to lay down the intentions first and let the lady decide. These could best come out if only he told Hannah the real feelings, she would not have taken him for a friend been used to do dirty business in the name of a boyfriend who got arrested

Talent Leadership Model Assignment Example | Topics and Well Written Essays - 1000 words

talentss Leadership Model - duty assignment ExampleSuch as selection, training and development, succession as well as performance management. Talent management generally mandates human resource professionals as well as their clients to comprehend the way talent is defined, i.e. who should be regarded as the talented and what should be the backgrounds of talented employees in an organization. In the context of talent management, talent leadership nookie be identified as the method of selecting and administering the performance of a particular aggroup who assist in fulfilling the vision of an organization. It is quite significant for an organization to attract and retain the best talent in order to create the leadership pipeline. Organizations are further required to develop an efficient on the job(p) climate so that they can generate higher productivity as well as needful learning environment. Considering the talent management principles, the paper intends to propose a talent l eadership model that can be successfully deployed by an organization for developing the performance. The objective of the paper is to describe various stairs of talent leadership model and define how it can be beneficial for an organization to manage talents. In order to grow and thrive in the current business environment, there is requirement for talent leadership, healthy communication as well as effective performance management in an organization. The direction in which an organization grows is basically dependent upon the effectiveness of the leaders to manage the talented employees.

Annotated Bibiography Bibliography Example | Topics and Well Written Essays - 250 words

Bibiography - Annotated Bibliography ExampleThis is a book that gives a succinct discussion of the criminal justice and the fault associated with it. Written by experienced criminologist, the books present essays that describe injustices such as wrongful conviction in various nations. The authors also outline a number of recommendations deemed as necessary to stop the trend where the honest are being punished by the legal systems. Most important, the book gives an elaborate explanation of how clean individuals can be compensated. Throughout his essay, the author underscores the value of carrying out the right investigation process in the beginning charging suspects of crimes.Janet Roberts & Elizabeth Stanton. (2007, November 25). A Long Road Back After Exoneration, and Justice Is Slow to Make Amends. New York clock (Late Edition (east Coast), p. 1.38. Retrieved November 2, 2011, from ProQuest National Newspapers Core. (Document ID 1387902671).In their article, Roberts and Stanton present reveal the challenges faced by people who have been released afterward being charged for crimes they never commuted. Reporting on a case of Vincent Moto, a man released from prisons 9 years after serving for a wrongful conviction. The authors also interviewed a number of people released from prison after DNA test found not guilty. The article further describes that most of the people exonerate from prison lacked compensation and had to contend with moving from one job to another. With more findings from the Innocence project, the article indicates that a few(prenominal) people receive compensation after being exonerated.In his work, Lizotte examines the case of criminal sanctioning, which he believes to be characterized by discrimination. He further discusses three forms of discrimination that are found in the sentencing of prisoners. Using info from the Chicago trial, Lizotte reported that many of non-white were more likely to be incarcerated as compared to

Examine the Internet and social media use in a foreign country Essay

Examine the profits and affectionate media use in a foreign country (report) - Essay ExampleThis shows that profits is a crime syndicate service that is quite popular in joined Arab Emirates.There are, however, some forms internet censorship and restrictions set up by the UAE government. The government does not allow any person to use internet to gather community for demonstrations that are not authorized by the government and alike defaming the ruler of UAE and state in ecumenical is not allowed (BBC, 1). Promotion of prostitution and pornography is withal not allowed using the internet (BBC, 1). Gambling is also not allowed in UAE, like most other Muslim countries. All these restrictions of internet use receive under internet censorship.Use of social media is also very popular in the country and umteen users are active on social media. The most popular social media by far is Facebook because more(prenominal) than half of internet users of the country are active on Face book (Scaria, 1). This is why it can be safely argued that Facebook is highly preferred by internet user of UAE. Mainly the youth is more interested in using Facebook as it provides them with the opportunity to communicate with each other and make new friends.The use of internet in the country is quite common and, therefore, users have developed great trust in internet. Internet is used in UAE for online transactions by many people (MVF Global, 1). Also, there is great potential in the e-commerce industry in UAE as many people want to shop online for services and products (MVF Global, 1). This highlights the fact that internet users in UAE are developed and they do not use internet for general communication and entertainment purposes only. Online transactions happen in UAE showing that the country has sophisticated internet users.All in all, United Arab Emirates is an internet loving nation as majority of the residents of the country use internet regularly. Social media is also very popular and among social networking sites, Facebook is the most popular. There are, however, many

Analyze the degree of alignment between the Walmarts stated values and Research Paper

Analyze the degree of alignment between the Walmarts stated values and the organizations actual plans and actions - inquiry Paper ExampleLive better (Scribd Inc., 2013).It is thus evident that the firm tries to take the plunge into free-enterprise(a) retailing in order to take its portion in the competitive advantage. With its strategy for overall be leadership, Walmart is able to keep its promise for low-price products and other related offerings. It therefore gives high value to its customers in a way that their satisfaction for low-price products are tantamount to the savings they would incur. As a result, Walmart has become one of the leading retail stores across the world that enjoys the asssociated competitiveness linked up with their plans that are put into actions.Walmart therefore is qualification sense by establishing its fundamental culture by embracing high value for implementing ethical standards. This would warrant that its human resource and other stakeholders w ould be able to work in a way that they go away produce outcomes that in the long run would add up to actual placing of value for their products, services and preceding(prenominal) all, their customers.The degree of alignment between the Walmarts stated values and the organizations actual plans and actions is therefore evident. It make sense to align values or cultures and the firms actual plan in its stategic retailing activity based on Walmarts

Use of the slit-lamp for anterior segment examination of the eye Case Study

Use of the slit-lamp for front segment interrogatory of the eye - Case field of operations ExampleIn my clinical placement in the Ophthalmology, I had a chance to examine a patient who presented complaining of decrease in tidy sum. For confidentiality and ethical reasons, the identity of this patient remains undisclosed. However, this 65-year-old gentleman presented to the clinic, and when I was instructed to do a slit-lamp enquiry, it mat that it was an opportunity to use academic learning in practice, and I was actually excited. In order to arrive at a diagnosis, I obtained these systemic medical history and family visual history, since these are important for assessing a patients risk factors for ocular disease. Just as with other body systems, authentic historical information allows the clinician to more appropriately direct the physical examination (Quillen, 1999).I probed into his recent complaints in hurt of the onset, duration, and associated symptoms, since knowled ge about these can guide me to the correct diagnosis. I asked him about his prior good and stir view in both eyeball. Then I asked him whether the problem were on the both eyes, and how could he non note it for last 1 year. He said that he was going on with his frequent changes in glasses, which he thought was natural at his age. While watching tele vision, he suddenly discovered that his vision in the right eye was a lot better than the left, and when he attempted to watch TV with one eye, he was surprised to discover that with the left eye alone, the pictures were hazy. Moreover, he could see better at the periphery than at the centre. He had no pain, distortion of the sight, and no double vision. These were very suggestive and substantive pieces of information since they narrow down the clinical differential diagnosis further, and helps the examiner to design the clinical examination in a better way. The suggestive better peripheral vision, differential vision between the ey es and absence of distortion, pain, and double vision led to the impression that I need to focus in the anterior segment of the eye while conducting his examination (Age-Related Eye Disease Study Research Group, 2001).General tryoutWhen I decided to carry out an examination, I felt that a patient with decreasing vision requires a complete examination to determine the cause of the visual decline. Therefore, I started to do a authoritative examination. I performed a general examination of the eyes in good diffuse light, and I felt that it would lead me to the possible diagnosis, so later I can do a slit-lamp examination. The general examination began with the examination of the eyelids and the conjunctival sac. He was elderly and had some amount of sagging of the eyelids. On palpation, the lid margins did not demonstrate each swelling. There was no redness in the conjunctivae. The eyelashes were normal. There was no evidence of any ignition system or blepharitis in both the lid ma rgins. In order to examine the conjunctival sac, it was needful to expose the palpebral conjunctiva and the fornices. Due to age, his fornices were shallow. There was no crusting, follicles, conjunctival papillae, or pseudomembrane indicating chronic or acute inflammation contributing his diminished vision. I drew down his lower lid while he was asked to construction towards the ceiling, and the lower fornix looked normal. This excluded any inflammation of the lower lid and swelling that can compromise vision temporarily. The upper lid was everted to examine the upper palpebral conjunc

Why does Warren Buffett rely heavily on Net Working Capital analysis Essay - 2

Why does warren countert rely heavily on Net Working jacket analysis as his principal order of valuing businesses Do you agree - Essay ExampleWhen current assets are twice the size of current liabilities, pull in working capital is enough for most businesses to avoid its problems. If the value of current assets is less than one and a half size of current liabilities, then the business would be short of working capital that leave alone result in the difficulty to meet its immediate debts. Businesses having difficulty in controlling their silver move and working capital are said to have liquidity problems. Liquid assets are those assets that can be easily changed in to property such as stock, debtors and short term investments.Buffett looks and analyses a business in general with owner earnings and return on equity measures both in turn give an general picture of cash flow available in a business and its operational efficiency. According to Buffets analysis method, it is ver y obvious that increased working capital can be viewed as cash out flow because money that are owed by debtors to the business or occupied in stocks cannot be utilized for meeting any other payments and thus no returns can be expected. Here, crimson though the working capital shows increases, the business can be viewed as inefficient as it failed to cop debtors on time.From assessing a business through mere working capital analysis, Buffett finds an advanced method of analyzing admit net working capital or cash flow available to the shareholders through owner earning analysis.Capital expenditure, that is the money needed to spend on purchasing or upgrading plant or equipments, is deducted from net income and hence it forms as an Economic Value Added (EVA) analysis. By adding depreciation and amortization back also it gives an accurate cash flow available to shareholders. This analysis method looks at the ability of a firm to generate cash for its residual owners. Even though, th e decisive

Sexual Harassment Research Paper Example | Topics and Well Written Essays - 1750 words

Sexual Harassment - Research Paper ExampleIt was also clear that the insurance policy on internal harassment in the University was not effective due to inaccessibility and ignorance on the message of the policy. The findings faulted the university unpreparedness to deal with the aftermath of sexual harassment and also the inadequacy that was noted in terms of practices and the mental imagery of the university to deal with sexual harassment.The research recommended the increase avenues of accessing the policy documents, the creation of awareness and major changes like including sexual urge studies as a common unit in the university. The study also recommended that the university to improve the quality of the describe of sexual harassment to the form that could be easily accessed by the victimized students. Increase in the intelligence operation was also recommended by the study among other recommendations.This section is an introduction of factors affecting Sexual Harassment t ell on students in the University. It contains background of the study, problem statement, as well as objectives of the study. It also consists of significance of the study. end-to-end the theoretical history of sexual harassment, scholars from multiple disciplines in the social sciences have grappled with a diverse hatful of interpretation of the definitions to conceptualize this abstract idea. According to Kenyatta University Sexual Harassment policy (2010), sexual harassment is delimitate as unwelcome sexual advances, requests for sexual favors, and other verbal or physical conduct of a sexual nature that tends to create a hostile or offensive work environment. Bingham, S and Scherer, L. (2001) defines sexual harassment to include some specific range of offensive behaviors. In his argument, he suggested that the behavior is everlastingly repetitive and intended to present some disturbance and also to upset. He underscores this definition by motto that sexual harassment could refer

Micro and macro economics Essay Example | Topics and Well Written Essays - 2500 words

Micro and macro economics - Essay ExampleA blushing(a) business environment means that union forecasts indicated that the feature company will be equal to pull in a profitable synergy. The synergy included combining the marketing and management strategies of both companies. Since the two companies were economically profitable prior to the January 2001 optical fusion, all business predictors anticipate that the combined company will be able to generate additional revenues that will surpass the combined revenues and profits of each of the two jointure companies combined (Lipsey, 2007). In fact, the spinal fusion was a huge projected gamble at $348 million investment property on the line. both(prenominal) America Onlines founder, Stephen Case, and Time Warners chief executive, Gerald Levin, had very high hopes that the merger will bring more revenues and profits to the new giant company, the merged entity cropping up from the two companies. The merger was expected to generate an equal sh be in the shareholders dividends. The board of directors of each of the two combining companies was expected to vote equally on all business decisions of the combined company (Hoskisson, 2005). Question 2 Both companies had similar motives for ensuring the success of the merger. Time Warner entered the merger in order to enhance its benefits from both the leave equation and demand equation (Microeconomics). Similarly, America Online entered the merger in order to enhance its present benefits from both the supply equation and demand equation (Hirschey, 2005). Additionally, Time Warner joined the merger to enhance the companys macroeconomic environment. The companys macroeconomic goals included improving its total economic activity, especially in the state of growth. The companys other macroeconomic goals included the successful resolution of the obstacles of inflation. Further, the companys macroeconomic goals included contributing to the reduction of the nations unem ployment rate (Hall, 1997). Similarly, America Online vigorously entered the merger in order to enhance the companys macroeconomic environment on January 10, 2000. The companys macroeconomic goals included improving its total economic activity, especially in the area of growth (Tucker, 1997). The companys other macroeconomic goals included the successful resolution of the obstacles of inflation (Khoury, 2003). Further, the macroeconomic goals of Time Warner and America Online are geared towards contributing to the improvement of the nations economy. The nations economic indicators include plebeian domestic production. The nations economic indicators include international trade. The merged companys globose market included clients from outside the United States. The merger between Time Warner and America Online occurred on January 2000. The merger was considered as one of the largest merger s in United States history. The merger involved an estimated $348 million. America Onlines fo under, Stephen Case, was proud with the merger. Likewise, Time Warners chief executive, Gerald Levin, felt that America Onlines formidable internet social movement would catapult America online to greater financial profit heights (Hoskisson, 2005). After the merger was consummated, the new merger focused on reducing the number of redundant employees. With the retrenchment, the number of unemployed United States citizens ballooned to unfavorable macroeconomic levels. Today the combined value of the two companies, Time Warner and

Accounting Information and Decision Making Term Paper

Accounting knowledge and Decision Making - Term Paper ExampleThis is normally achievable through the comparison of the makeup with rival firms in the same sector or market. Accounting information facilitates this comparison. The following report card is a collection of theoretical knowledge on accounting information and decision-making for the readers basic insight, its definition, and history. The paper will further discuss and analyze the gathered literature in detail and develop a personal conclusion on the relationship between accounting information and decision-making.The earliest possible finish of organized recordkeeping in human history goes back thousands of years to early Mesopotamia, which is Iraq today. Archeologists and historians found shelved records of supplied farm produce. use accounting to keep a record of many dealings enabled improved trade amongst persons and help the development of more complicated communities. After Mesopotamia, Luca Pacioli possibly pi oneered the earliest official literary work of accounting with arithmetical concepts in 1494. Pacioli, a monk and mathematician from Italy defined the double creation system by shedding conflagrate on the logic of bookkeeping. Pacioli theorized that one has to record all items twice but variedly, i.e. double entry. Double entry means that when one ascribe one item, he or she debits the corresponding one, or debits the recipient and credits the giver. During Paciolis era, record-keepers made entries to show statements for the enterprise instead of the owner, making annual preparation wanting. After Pacioli, a Dutchman supported the profit and loss books at annual breaks.The degree of societal and technological progress assisted the advancement of contemporary techniques of accounting. The Industrial Revolution brought about the need for sophisticated accounting techniques. The advancement of late techniques saw the separation of ownership from

The Public Needs to Know Essay Example | Topics and Well Written Essays - 1000 words - 1

The Public Needs to Know - Essay ExampleAdams and Brantner (2006) reveal that butt jointcer is the number hotshot killer disease in the United States to mean solar day. The research showed that over one million people in the U.S. are diagnosed with the pubic lo workout every year. This is a worrying statistics considering the fact that no drug has been developed that can cure the disease today. The moreover hope currently is for one to obtain regular screening to wait on early detection, which research shows to increase survival chances if treated immediately with the available drugs. Despite this being the case, crab louse treatment is very pricy and many American citizens lack the health insurance. Therefore, to arrest the situation, there is pressing need to develop drugs capable of treating this killer disease. The aim of this discourse is to explore the major issues that might attire due to the ontogenesis of a cancer treatment drug. The issues to be discussed include ec onomic issues and the special postu upstart of the population being served. In addition, the paper will describe the figure outes that will be viewd in the development of the program and its benefits to the population. Economic issues Cancer treatments are the most expensive medical treatment in the United States today. ... Analysts argue that this cost is not only worrying, but is also unrealistic in this day and age when the American economy is struggling to recover from recession. Furthermore, everyone involved in this problem is left enquire how we will be able to afford the cost of cancer in the next decade. It is believed that doctors will only recommend treatments depending on the out-of-pocket spending by patients. Currently almost everyone in the country is upset of how the cost of cancer treatment will be met in the future. As a result, the companys intention to develop a young cancer treatment drug will be of capacious benefit to economically. It will result in a r eduction in the cost of healthcare, which would lead to a reduction in the government spending on cancer-related treatments (Jonsson and Wilking 2011). Special needs Currently physicians depend use mainly chemotherapy and radiography to treat cancer. However, patients are concerned that these treatment methods are not only expensive and not affordable to many, but are also painful. As a result, patients need a new treatment method that is not only cheap and affordable, but also safe and does not involve a painful experience. This special need can only be addressed through the development of a new treatment drug for cancer. Developing the drug will make the treatment of cancer easier and safer than the methods used today. Furthermore, it will enable the treatment of cancer possible even if cancer is diagnosed very late (Adams and Brantner, 2006). The image shows a patient diagnosed of cancer of the skin. Process involved in the development of the program The process involved in the d evelopment of a cancer treatment drug is normally cumbersome and takes from 7 to

Sport Scale Essay Example for Free

feature Scale EssayABSTRACT The elemental purpose of this get wind was to develop a binding and true(p) instrument to assess save winnow motivation. Also, the bracing round was employed to examine the alliance betwixt gasconade winnow motivation and pagan identicalness. One hundred sixty nine college students from twain southeastern institutions participated in this theatre of operations. Data were analyzed utilize exploratory and confirmatory factor analysis, Bivariate correlation, t test, ANOVA, and descriptive statistics. The Fan Motivation Scale (FMS), actual in this study, consisted of six components with 22 items. The number of items under every component range from 5 to 2 items (quality of the punt 4 items, escape 5 items, boredom avoidance 5 items, neighborly 3 items, amusement 3 items, and lark atmosphere 2 items). In addition, two hypotheses were tested in the current study. The origin hypothesis was that heathenish identicalness operator is supremely link up to gambol caramel motivation. The second hypothesis untrue that there was a protestence between African Americans and European Americans in their friendly identity.The results revealed the FMS is a reliable measure with an overall alpha score of 0.90. Significant differences were found between participants in the total FMS and more or lesswhat of the subscales based on gender and sociality. However, the outcomes of the samples examined in this study do non instigate the premiere hypothesis. Therefore, no probatory relationship was found between amusement sports fan motivation and social identity. Regarding the second hypothesis, a significant difference was found between African Americans and European Americans in their pagan identity. vii CHAPTER 1 INTRODUCTION genetic mutations moderate become an increasingly important part of our society.Sports fans roleplay a significant ploughsh be of sport consumers, because 70 percent or more of Am ericans watch, read, or discuss sports at least erst a day (Iso-Ahola Hatfield, 1986). From 1985 to 1998, assistance has significantly amplifyd at the four major sports in the joined States. Major League Baseball (MLB) had the largest increase in the number of mint attending mettlesomes (24. 2 million, a 50% increase), followed by professional basketball game (10. 3 million, a 89% increase), professional football (5.7 million, a 40% increase), and professional hockey (5. 6 million, a 49% increase).The number of people attending college profligate essences has also increased during this m period (U. S. Census Bureau, 2000). Additionally, more television programming time is universe devoted to blank events. The ESPN was the fifth highest ranked television network in 2000, in terms of revenue, it was estimated to be $2. 1 billion (McAvoy, 2000). With the increase of interest in sports has become an increased interest of sports fans as consumers.Sport teams and companies arg on very interested in decoying as many consumers as possible to purchase game tickets or products. Therefore, sport marketers should ac experience the factors that drive fans to follow sport by attending, ceremonial on television, or purchasing products. However, understanding the notion of sports fans is not simple because their attitudes and bearings argon not determined by a single cause or factor that quite occur for a variety of reasons (Mashiach, 1980). contestation of the Problem There has been a growing interest in the study of sport fan motivations in recent years to better understand fan behaviors (Bilyeu Wann, 2002 Funk, Mahony, Nakazawa, Hirakawa, 2001 Funk, Mahony Ridinger, 2002 Funk, Ridinger, Moorman, 2003 Gantz, 1981 Kahle, Kambara, Rose, 1996 Lee, 2002 Mahony, Nakazawa, Funk, James, Gladden, 2002 Pease Zhang, 2001 Trail James, 2001 Wann, 1995 Wann, Bilyeu, Brennan, Osborn Gambouras, 1999 Wann, Brewer, 1 Royalty, 1999 Wann, Schrader Wilson, 1999). fe w of these studies have introduced measures of different inlet motivatings of sport fans. In addition, researchers have examined the relationship between fan motivation and other variables such as team assignment, involvement, gender, and race. The measures employ in preliminary studies to assess fan motivations vary in aloofness and number of components. However, both(prenominal) of the components argon used in all or closely scales such as the entertainment component, the family component, and the friends component.They also share very similar items with regard to similar components. Items used in most previous scales oft begin with the words I like, I enjoy, or I feel which raises a validity issue for the measures because the aforementioned words repre move satisfaction and attitude rather than motivation. Fan satisfaction relates to the happiness and pleasure associated with the outcome of a sporty event while fan attitude represents the opinion and feelings an mort al has about a sport team or sporting event.On the other hand, sport fan motivation refers to the reasons that drive individuals to support sport teams, be loyal to them, subvert team/sport related products, watch and attend sporting events. The Purpose of the Study The purpose of this study was to develop a valid and reliable instrument to assess sport fan motives. Also, the smart measure was utilized to examine the relationship between fan motivation and ethnic identity. The Conceptual Framework The abstract framework of this study includes the discussion of two concepts.First, the Fan Motivation Scale and its matter go out be introduced. Second, the notion of ethnic identity and why it should be correlated with sport fan motivation lead be presented. The prior research (Wann, 1995 Funk, Mahony, Nakazawa, Hirakawa, 2001 Bilyeu Wann, 2002) identified various motives that could drive fans to attend sporting events. well-nigh of these motives are related to personal take (e ntertainment and financial 2 gain), favorable needs (bonding with family and ag separate affiliation), and psychological needs (self-esteem and motion).In attempt to measure the motives of sport fans, the researchers introduced different scales. These scales comprised different number of motives ranging from 7 motives with 16 items to 18 motives with 54 items. The length of some of the scales was not the only problem. The major concern for previous scales is in the content validity, the extent to which items used in the scale accurately represent fan motives. In fact, all previous scales include items that are more related to attitude and satisfaction then motivation. The reason for this problem is the wishing of pass water definition of sport fan motivation.The current study is going to view sport fan motivation as the reasons that drive individuals to support sport teams, be loyal to them, purchase team/sport related products, watch and attend sporting events. In addition, th is study will employ a canvass of related literature and the prior effort made on fan motivation scales to develop valid and reliable measures of sport fan motivation. The proposed Fan Motivation Scale (FMS) will measure six motives societal, entertainment, escape, aesthetic, psychological, and amotivation.The social motive assesses the extent to which individuals participate in sporting events as spectators because they desire to cut down time with their families (Gantz, 1981 Wann, 1995). Also, to some individuals, base affiliation is an important motivation of being a sport fan. Sport spectating provides a fan with opportunities to share time with others who enjoy the same activities. A fan may pauperization to keep affaire with a meeting of fans and seek refuge from a feeling of alienation (Branscombe Wann, 1991 Smith, 1988 Wann, 1995).The entertainment motive includes items that represent the desire of some individuals to have a good time and enjoy the excitement associ ated with sporting events. Some fans might enjoy a sport because of its entertainment range. Sport spectating provides fans with leisure pastime activities similar to watching movies or television. One advant era of sport spectating is that few special skills, if any, are required (Zillmann, Bryant Sapolsky, 1989 Wann, 1995).The escape motive of sport fans assesses the desire of sport fans to escape or diverge from their everyday lives. Attending a sporting event gives many people an 3 opportunity to temporarily forget about their troubling, dissatisfying, or long-winded lives (Smith, 1988 Lever Wheeler, 1984 Wann, Schrader Wilson, 1999). The aesthetic motive of sport fans appeals to those that are motivated by the aesthetic value of the sport. Some fans enjoy sports because of the competition between highly skilled athletes. The beauty, grace, and other artistic characteristics make some people enjoy sporting events (Milne McDonald, 1999 Wann, 1995).The psychological motive i s a factor that motivates sports fans and gives them a feeling of accomplishment and achievement when the fans favorite team or player is successful. Sports fans tend to associate themselves with a successful team or player in order to create and sustain a positive self-concept (Branscombe Wann, 1991 Milne McDonald, 1999 Sloan, 1989). Amotivation refers to the state of lacking an heading to act. When amotivated, individuals action lacks intentionality and a sense of personal causation (Ryan Deci, 2000).Amotivation results from not valuing an activity (Ryan, 1995), not feeling competent to do it (Deci, 1975), or not believing it will yield a craved outcome (Seligman, 1975). Some individuals might go to sport events and watch sport games because they have nothing else to do, bored, and want to kill time. These types of reasons had been neglected in previous studies of sport fan motivation. As mentioned earlier, prior research has examined the relationship between fan motivations a nd other variables such as sport involvement, team identification, and some demographic factors of selected sport fans.However, the ethnic identity of sport fans has been ignored in the literature. It might be assumed by some researchers that the race factor is enough representation of an individuals ethnic background. It is, however, only part of the concept. social identity is defined as a process of coming to terms with ones ethnic-racial rank and file group as a salient reference group (Smith, 1991, p. 182). Smith (1991) defined an ethnic group as a reference group called upon by people who share a prevalent history and culture (p. 181).According to Gordon (1985), culture deflects our social standards, values, cognitions, social perceptions, attributions, feelings, and sources of motivation. Individuals develop their ethnic identity through their social interaction with others. Through their interactions they begin to view themselves as others view them 4 (Stryker, 1980). heathen identity is viewed as part of social identity and it was defined by Tajfel (1981) as that part of an individuals self-concept which derives from his knowledge of his rank of a social group (or groups) together with the value and emotional significance attached to that membership (p.255).An ethnic group is composed of a number of individuals who share a sense of group identity based on their unique culture, which include values, morals, and various customs, as well as shared origins. In the larger society, ethnic groups tend to maintain a sense of peoplehood (Dublin, 1996 Kornblum Janowitz, 1974 Portes, 1996). Forty years ago, Tumin (1964) defined an ethnic group as a social group which, within a large heathen and social system, claims or is accorded special status in terms of complexity of traits which it exhibits or is believed to exhibit (p.123).Distinguishing between ethnic groups is not always simple. Some ethnic minorities, such as African Americans, may have taken for granted(predicate) sensible differences that set them apart from other ethnic groups within the United States, but many racial individuals present an ambiguity because they belong to two or more ethnic groups, which makes ethnicity a subjective become (Root, 1992). Studying ethnic identity is very important because it is the foundation for what an individual believes about himself or herself. addicted the significance of ethnic identity, many researchers have been studying this fix. Phinney (1990) reviewed 70 studies of ethnic identity published between 1972 and 1990. She found that most of the studies have used one of trine theoretical frameworks to examine ethnic identity. The counterbalance framework is the social identity theory which ethnic identity is considered a component of social identity. societal theory refers to the need for an individual to be a member of a group that provides him or her with a sense of belonging that contributes to a positive self-concept.T he second framework is the acculturation prospective. The concept of acculturation refers to changes in the ethnical attitudes, value, and behaviors that result from interactions between two distinct cultures (Berry, Trimble, Olmedo, 1986). These kinds of changes are normally the concern of a group of individuals, and how it relates to the dominant or host society. Ethnic identity can be an aspect of acculturation in which the focus is on the individuals and how they relate to their testify group as a subgroup of the larger society (Phinney, 1990).The triplet framework is developmental framework, where ethnic identity is viewed as a process by which people construct their ethnicity. 5 Erikson (1968) indicated that identity is the outcome of a period of exploration and experimentation that normally takes place during adolescence and leads to a decision of cargo in various areas, such as occupation, and religion. This view of ethnic identity suggests age as a factor is strongly re lated to developing ones ethnic identity (Phinney, 1990). Phinney (1990) mentioned that most studies have focused on certain(prenominal) components of ethnic identity.These components include self-identification as a group member, a sense of belonging to the group, attitudes about ones group membership, and ethnic involvement (social participation, heathen practices and attitudes). Self-identification represents the ethnic label that one uses for oneself. The ability of children to label themselves with the right ethnic group was the addressed in a study by Aboud (187). Another issue was the relationship between incorrect labeling and poor self-concept (Cross, 1978). Adults are expected to know their ethnicity but the issue is what label one chooses to use for himself or herself.However, some ethnic groups have a little choice in what ethnic title they can use for themselves often because of their distinctive skin color or culture (language, dresses, customs, etc. ) which distingu ishes them from other groups. Additionally, some individuals have two or more ethnic backgrounds and they come out themselves as members of more than one group. Ethnic self-identification is an important but complex component of ethnic identity (Phinney, 1990). The feeling of belonging to ones own group is an important element of ethnic identity.Some researchers have tried to assess the sense of belonging by either asking people how strong was their relationship with their groups or how separate they feel from other groups (Driedger, 1976). Members of every ethnic group can have positive or veto attitudes toward their own group. Some of the positive attitudes related were pride in and pleasure, satisfaction, and contentment with ones group (Phinney, 1990). Negative attitudes include dissatisfaction, displeasure, discontentment, and a desire to hide ones identity (Driedger, 1976).People who display no positive attitudes or express negative attitudes can be seen as denying their eth nic identity (Phinney, 1990). In addition, the involvement in the social support and cultural practices of ones ethnic group is considered a strong indicator of ones ethnic identity. The social and cultural practices 6 that represent the involvement component include language, friendship, social organizations, religion, cultural traditions, and politics (Phinney, 1990). Phinney (1992) developed the Multigroup Ethnic Identity Measure (MEIM) with the purpose of assessing ethnic identity among various ethnic groups.The scale was designed to measure three components of ethnic identity affirmation and belonging, ethnic identity achievement, and ethnic behaviors. Roberts, Phinney, Masse, Chen, Roberts, and Romero (1999) examined the validity of the MEIM and conducted factor analysis with a large sample. The outcomes suggest that the scale measures two components of ethnic identity ethnic identity search and affirmation, belonging, and commitment. Ethnic identity search refers to a develo pmental and cognitive component. Affirmation, belonging, and commitment represent the affective component.However, the scale has been proven to be a valid and reliable measurement and it will be used in the context of this study. More discussion of the scale is provided in the method voice. Researchers have indicated that positive relationships do exist between ethnic identity and self-esteem, self-concept, psychological well-being, achievement, and satisfaction (Phinney, 1992 Roberts et al. , 1999 Delworth, 1989). However, it is the purpose of this study to examine the relationship between ethnic identity and motivations of sport fans.According to Phinney (1990) some studies have used sport as a cultural item to measure ethnic identity. Pons, Laroche, Nyeck, and Perreault (2001) indicated that the choice of a crabbed sporting event represents a strong cultural meaning for the individual. Some ethnic groups tend to identify with a specific sport, for example, soccer in the Italian community and hockey among the French Canadian. Pons et al. , (2001) declared ethnic groups do not all react to sporting events in the same way they differ in the means and the pace of their integration into the host culture (p.238).African American consumers tend to attend historically dumb college/university sports more frequently than they did any other sport. The level of ethnic identification of African American fans has significant affect on their attendance oftenness to historically Black college/university sports (Armstrong, 2002). Moreover, previous studies showed differences in motivation between African American and European American sport fans based on ethnicity (Wann, Bilyeu, Brennan, Osborn, Gambouras, 1999 Bilyeu Wann, 2002 Armstrong, 2002). 7Therefore, it is expected that there is a relationship between sport fans motivation and ethnic identity. Research Hypotheses H1 Ethnic identity is positively related to sport fan motivations. H2 There is a difference betwee n African American and European American in their ethnic identity. Operational Definitions Ethnic Identity part of an individuals self-concept that derives from his or her knowledge of membership in a social group (or groups) together with the value and emotional significance attached to that membership (Phinney, 1992, p.156).Sport fan refers to someone who is enthusiastic about a particular sport team or athlete (Wann, 1995). Sport fan motivation refers to the reasons that drive individuals to support sport teams, be loyal to them, buy team/sport related products, watch and attend sporting events. Delimitations This study is delimitated to 1. Investigate the ethnic identity and motivations of sport fans in general. For that reason, no specific group of fans (i. e. , basketball fans, football fans) was examined. 2.The student at Florida State University (FSU) and Florida Agriculture and Mechanical University (FAMU), therefore, the findings cannot be generalized to commonwealths oth er than the population from which the sample was drawn. 8 Limitations This study is limited to the following 1. The outcome of this study depends on the participants honesty and cooperation in answering the questions. 2. Due to the nature of this study as self-administrated surveys, the researchers access is limited to the classes gained via consent to attend and meet. Assumptions This study is based on the following assumptions 1.The surveys used in this study are clear and understandable for the participants. 2. The participants will answer the questions honestly and accurately. 3. The surveys are valid and reliable. Significance of the Study The sport marketers are in a high competition within the sport industry and also with outside competitors. teenage generations are attracted through technology to new types of entertainment such as computer/video games and the X-Games. These new entertainment options have already attracted a significant amount of attention from the so -call ed X-generation (Kwon Trail, 2003, p. 1).Therefore, sport marketers should be concern about the future of the sport industry. In order for sport marketers to maintain their consumer base and to attract young generation, they should explore and examine the consuming behavior of sport fans and the factors that might influence their behavior. According to Gramann and Allison (1999), the increase in the ethnic diversity of North America is one of the most powerful demographic forces cause U. S. and Canadian society (p. 283). Therefore, studying ethnic identity as an important social characteristic of sport fans is important to sport marketers.The importance of studying ethnic groups among sport fans is reflected by the increasing percentage of minority participation in professional sport, especially African American. African American athletes represent 25 to 75 percent of athletes on the rosters for the three popular sports (baseball, basketball, football) (Gano-Overway Duda, 2001). 9 The goal of this study was to introduce a new measure of fan motivation which will assist practitioners in the sport industry to understanding the driving factors for sport fans to attend sporting events, support sport teams, or buy team/sport related products.Also, the relationship between motivations and ethnic identity of sport fans was examined. The outcome of the study should provide practitioners with valuable nurture to assist them in understanding the various motives of sport fans based on their ethnic identity. Therefore, sport marketers should be able to improve their plans and strategies to maintain their fan base and fulfill the desires for their target market. 10 CHAPTER 2 lit REVIEW The purpose of this chapter is to review the literature on ethnic identity and motivation of sport fans.It should be noted that to date, no research has combined and analyzed the interaction of the two identified variables. As such, the first section of this chapter focuses on the rese arch that has been done on the ethnic identity of sport fans. The second section discusses motives of sport fans as well as scales that have been used to assess these motives. Ethnic Identity and Sport Fans Ethnicity as social and cultural characteristic of sport fans has been ignored in the literature although the race factor, which is the physical aspect of ethnicity, has been utilized for comparison between ethnic groups.However, Armstrong (2002) examined the influence of ethnic identification on Black consumers attendance at historically Black college/university (HBCU) sports. To assess ethnic identification, Armstrong used a self-report measure in which participants were asked to identify their ethnic group based on ethnic categories (Black/African American, Caucasian, Hispanic, Asian, and other) and to rate the rapture of their identification with their ethnic group on a scale from 1 (weak) to 5 (very strong).The hypothesis was that the identification of Black consumers with their ethnic group would have a significant influence on their attendance frequency at HBCU sport events. The findings offered support for the hypothesis indicating a positive relationship between ethnic identification and attendance frequency. In another study, Armstrong (2000) examined the influence of ethnic identification on African American students touch of persuasive sport communications (i. e. , advertisement, promotional messages, developmental campaigns, and promulgations).The ethnic identification of the respondents was measured using a 13-item scale developed by Whittler, Calatone, and Young (1991). The scale assesses two major factors of ethnic identification (cross-race charity and political and social 11 relations among Blacks). The outcome of the study revealed that ethnic identification has an effect on participants reaction to racial heuristics in the communication. African American consumers are more likely to have a positive reaction to a persuasive communicat ion if the message were culturally relevant and delivered by a Black spokesperson. Pons et al.(2001) looked at the impact ethnic identity could have on the consumption behavior and orientation of sport consumers. They measured language (3 items), religion (3 items), and social participation with ones own ethnic group (6 items) as three symmetrys of ethnic identity. The orientation of sport consumers has three attributes. The first dimension refers to sporting events as a provider of sensations in which consumers have an emotional attachment to the event or the product. The second dimension represents individuals need to understand the sporting event, which lead to better appreciation for the event.The third dimension of orientation toward sporting event refers to the socialization opportunities presented for sport consumers. The consumption behaviors include purchase of sporting good, tickets, and time devoted to sporting events. The results offered support for the idea that ethnic identity has a positive impact on the consumption and orientation of sport consumers. In regard to the race of sport consumers as part of their ethnicity, researchers have found a difference between Blacks and Whites concerning their sport involvement (Spreitzer Snyder, 1990).Sport involvement included seven dimensions watching sports on television, listening to sport on the radio, reading the sport pages of the newspaper, watching/listening to sports news on radio/television, reading sports books, reading sports magazines, and talking about sports with friends (Spreitzer Snyder, 1990, p. 51). The findings revealed significant effect of race on sport involvement regardless of respondents social background characteristics (i. e. , age, sex, education, income, town size).Blacks tend to be more elusive in sport than Whites. The authors argued that the findings reflect a distinctive subculture within the black community. Rudman (1986) examined the relationship between race, social structure, and sport orientations. The main goal of the study was to see whether factors that affect sport orientations are race-dependant. The results showed Blacks to be more likely than Whites to become vicariously involved in sport outcomes and to incorporate sport into their daily 12 lives.Based on the overall analyses, the author argued that social and economic conditions provide a better news report of differences in sport orientations. He used the term culture of poverty to indicate that socioeconomic positions are more likely to make boor blacks and boor whites see sport as an opportunity to erect social prestige and economic position. At the college level, Armstrong (2001) examined ethnic minority students consumption of college sport events. The ethnic minorities included African Americans, Asians, Hispanics, and Others.She looked at the degree of ethnic minority students interest in sport spectating, the frequency in which they attend university sponsored sport events , and the factors that influence their decision to attend campus sport events. Eight factors were tested to see their influence on the students attendance. The factors are the price of the tickets, academic commitment, significant others, friends, watching the event on television, the option to spend money on other things, not knowing when tickets are available, the quality of the opponent.The factors identified had no significant influence on students attendance. The findings indicate that ethnic minority students generally had a favorable attitude towards sport spectating. However, about 44% of the student tell that they never attend a campus sport event, 41% stated that they seldom attended, and 15% have attended often. The author contended that minority students had a favorable attitude toward sport spectating but they never or seldom attend sport events on campus because they view these events as say to a specific group (i.e. , dominant ethnic group).For minority students to be motivated to attend, the sport event has to be socially and culturally relevant to the students ethnic background. In professional sport, Zhang, Pease, Hui, Michaud (1995) and Zhang, Pease, Smith, Lee, Lam, Jambor (1997) indicated that factors such as game promotions, amenities, and schedule convenience influenced ethnic minorities attendance differently and more significantly than they did Whites.Therefore, sport marketers should emphasize the sociocultural factors (i. e., offering different ethnic foods at the concession stands, playing different ethnic music, making announcement in different languages) in promoting sport consumption of ethnic minority consumers (Armstrong, 2001 Hofacre Burman, 1992 McCarthy Stillman, 1998). 13 In a direct connection to the current investigation, previous studies have found differences on the motivations of sport fans based on ethnicity. Wann, Bilyeu, Brennan, Osborn, Gambouras (1999) investigated the relationship between sport fans motiva tion and race. A sample of 65 Euro-Americans and 32 African Americans absolute the Sport Fan Motivation Scale (SFMS).The SFMS, developed by Wann (1995), includes eight motivational factors (eustress, self-esteem benefit, warp from everyday life, entertainment value, economic value, aesthetic value, need for affiliation, and family needs). The findings indicated that Euro-Americans reported higher motivation than African Americans. The authors argued that certain motives might be applicable to only a subset of races. In a recent study, Bilyeu and Wann (2002) examined the racial differences in sport fan motivation between African Americans and European Americans.First, 50 African American participants stainless a demographic questionnaire and an interview with the researcher to discuss their motives for being a sport fan. Second, the motives discovered from the interviews were sent to African American psychologists and sociologists for validation. Third, the new motives were added to the SFMS, then the African American and European American participants were asked to complete the SFMS.The findings suggested that three new factors be added to the SFMS representation (e. g. , people of the same background), similarity (e. g., people they have things in common with), and support/perceived greater equality (e. g. , people they want to succeed) (Bilyeu Wann, 2002, p. 93). Armstrong (2002) indicated that previous investigations of motivation for sport consumption were not applicable to Black consumers because the samples used in these investigations were predominantly White. Therefore, she added a cultural affiliation motive to the SFMS, developed by Wann (1995), and administered it to a sample of only Black consumers of sport. The findings supported the hypotheses that cultural affiliation is a viable motive for Blacks sport consumption.In addition, the factor structure of the SFMS with the inclusion of the cultural affiliation motive differed from previous studi es (Wann, 1995 Wann, Schrader, Wilson, 1999). Therefore, the Black Consumer Sport Motivation Scale (BCSMS) was introduced including the following factors eustress, group recreation, aesthetics, cultural affiliation, group entertainment, escape, and 14 personal (economic/psychological) investment. At the conclusion of the study, the author stated, behaviors and motives related to sport consumption may also be influenced by the social and psychological manifestations of culture (Armstrong, 2002, p.329).In summary, although research on ethnic identity for sport fans is very limited, a strong relationship was found between sport consumers ethnic identity and sport consumption and orientation. Also, the differences found on the motivations for sport fans based on ethnicity, should indicate a strong relationship between sport fans motivation and ethnic identity. However, it is the goal of this investigation to examine this relationship.

Aggregate Demand and Supply Models Essay Example for Free

Aggregate Demand and Supply Models showAs it stands currently the existing effect of the economic fixingss on aggregate implore and supply are unemployment, consumer income, and interest rates. In this paper we identify the existing effect of the economic factors on aggregate admit and supply. The American people have little to no income when unemployed, this in turn causes a decrease in demand for the economy. This type of event causes the aggregate demand to curve to the left. One of the main reasons unemployment remains spunky to this day is the wish of demand. A shortfall in aggregate demand is precisely the type of shorten that can be addressed by fiscal policy, however, to do so we need continuous monetary stimulus to progress toward maximum employment stability. The crash of the housing market has set tremendous limitation on consumer and their spending. Sternness on behalf of the government to a certain extent has decreased aggregate demand during this recovery period. These actions have directly impacted growth. What this means to us is that lower government spending and high taxes call for disposable income for consumers, work for government contractors diminishing, and a decrease in government payroll. Another factor that has had great effect and impact are the levels of scruple. The events leading to this state have yet to be inflexible which in turn have caused a lack of willingness and confidence within consumers. In the beginning the levels of uncertainty reflected the force of influence the recession had on us as consumers. This is something that had not been experienced in some(prenominal) years which made it difficult for us to handle or even find a behavior to get by in a more successful demeanor. After extensive research and epitome it is safe to say the supply-side considerations explain some of the rise in unemployment, which once again confirm the lack of demand as well as the fact that the economy is suffering first and foremost of a weak demand rather than a shortage of supply.ReferencesWilliams, J. C. (2013, February 25). The Economy and Fed Policy Follow the Demand. national Reserve Bank of San Francisco. Retrieved from http//www.frbsf.org/economic-research/publications/economic-letter/2013/february/economy-fed-policy-follow-demand/Thoma, M. (2012, March 28). Demand, not supply, is restraining the economy. CBS News. Retrieved from http//www.cbsnews.com/8301-505123_162-57405230/demand-not-supply-is-restraining-the-economy/

Reliability Issues †Centrifugal Slurry Pumps Essay Example for Free

dependableness Issues Centrifugal Slurry Pumps EssayIntroductionPumps were in both likelihood the first machine ever giveed, and atomic good turn 18 now the second loadedly common machine in engagement around the world, taboo-numbered solo by the electric take. The very earliest type of warmness is now kn accept as a irrigate wheel, Persian wheel or noria, consisting of a wheel of buckets that rotates to pick up water from a accrue and dump it into a trough. A nonher early bosom was the Archimedean screw, similar to the modern screw conv center fieldr belt except that the flights were practically fixed to the tube so that the whole ar layment would turn together. Both of these devices atomic number 18 still utilise, most unremarkably in basic agricultural applications. Pumps argon now produced in an ex decenniumsive range of types and sizings, for a very wide scope of applications, and this makes it difficult for whatsoever individual reference history or organisation to cover nitty-grittys and fondnessing as a general topic. So the broad field of middleing is separate into sub-divisions and then dealt with at that level.In the mining industry, the upper end of the pump scale includes impellers with diameters over 2.5m, slurry lines 10km long, blood corpuscle size up to 100mm, die hard judge handling more than 7000tph, and repulses over 10MW. Finer slurries of around 1mm member size argon pumped for hundreds of kilometres in round surgerys. There be many bureau of lifes to bump pumps. This just sensation of them.This document only addresses centrifugal pumps, with a focus on angiotensin-converting enzyme-stage radial-ply tire-f petty(a) slurry pumps. Centrifugal pumps be capable of meeting duties of up to 1.4 m /s at 30MPa, and eminenter volumes at lower 3 pressures. The maximum flow rate at low discharge pressure is about 180 m /s. Industrial applications requi telephone high school vendy pressures generall y use reciprocating fixed-displacement pumps, just they atomic number 18 limited in the center of flow they give nonice put out per unit. In general purpose applications, where different types of pumps could all deliver the performance sought, centrifugal pumps argon normally the preferred choice due to lower lifecycle prices.Basic Requirements for ReliabilityAssuming sort pump manuf routineure and installation, the basic requirements for reliable long-term operation of centrifugal pumps be 1. Continuous operation at best- capacity period (BEP) 2. Adequate net positive sucking passport (NPSH) 3. up notice velocity unruffled flow within the pump and throughout the schema 4. Processing of fluids that argon kind ie a) Chemically and physically stable b) At near-ambient temperatures c) Free of particles likely to cause wear or blockage Pumps of a basic normal satisfying all these requirements throw off run for 50 historic period and more without study(ip) comp sensa tionnt replacement. The first three requirements are satisfied by matching pump performance to expected duty. Where item 4 give noticenot be addressed through pre- treatment of the fluid, the pump configuration, geometry and sensibles must(prenominal) be optimised to give best results. Obviously, item 4.c) is a dominating issue for slurry pumps as it hatfulnot be eliminated and must be managed.Centrifugal Pump ConstructionCentrifugal pumps feel two of import sub-assemblies the rotating split (impeller, shooter, cares), and the fixed parts (casing, pipe up connections, stand, foundations. Pumps of all types whitethorn be single stage or multi-stage. Mul flushle stages are employ where it is not practical to generate the necessary discharge pressure using a single impeller. The simplest way to imagine a multi-stage pump is as one pump with its discharge feeding straight into the suck of a second pump so that the overall discharge pressure is increased while the flow rate stays the akin. However, this arrangement is properly described as single stage pumps in serial. A true multi-stage pump consists of multiple impellers mounted on a single drive in, positioned in a single casing do up of multiple chambers. Multi-stage pumps of this type are not apply with slurries, precisely sometimes slurry pumps are mounted in series.CasingThere are two types of casing tropes coil and diffuser. A turbinate casing has a snails shell practice, while a diffuser casing has internal wind leaf blades. Diffuser casings are rarely used on single-stage radial pumps, and are not commonly used for handling slurries due to the flow restriction and high wear rates that would result. Slurry pumps select volute casings which house the impeller and have a spiral-shaped outmost volume that extends 360 degrees and increases in cross-sectional athletic field as it approaches the discharge flange. At full circle the volute overlaps itself, creating the cut-point, be positionings known as cut-water point or tongue. The ideal shape is to have a steady linear increase in cross-sectional area for 360 degrees around the circumference starting from the cut-water point, exactly this weed be difficult to manufacture. Compared to a clear water pump, a slurry pump has a much large radial gap amid cut-water point and impeller, to sicken risk of blockage. Where a pump is identified as oversize for its duty, and is suffering high recirculation wear, it may be possible to fit liners with an extended cut-water point that throttles the flow. In theory, when a pump lock ups at its best efficiency point (BEP), the pressure acting on the impeller and casing are uniform.However, in put on the pressure is rarely completely uniform, and if a pump is operating away from its BEP the imbalanced in the radial forces acting on the impeller shape significant. These forces are larger for bigger pumps operating at higher(prenominal)(prenominal) pressures. path a large pump below rated capacity can create unbalanced radial forces that may (over time) damage the bearings or snap the shaft. If it is known that a pump may need to occasionally operate well away from its BEP, the manufacturer should include an oversize shaft arrangement in the design, but with commercial competition driving purchase decisions this may have to be specifically requested. Another option for reducing imbalanced radial forces is to use a twin-volute design, which consists of a wall splitting the volute in half(prenominal) for about half its circumference, ending after the cut-point but before the discharge flange. This is not practical for most slurry applications.Casings must be knowing to leave the impeller to be installed in location, and so are manufactured in at to the lowest degree two parts. Solid casings have a removable cover, either on the suction status or shaft facial expression or twain, but the volute shape is a one-piece curling. Cas ings may also be split, either axilely or radially. Axially split housings make burster easier because the upper piece can ordinarily be removed without disturbing the shaft or piping likewise much. Split casings may tend to breathe at high pressures, resulting in passing water, air entrainment, vibration, misalignment and so forth Casings are normally earmarkd with ribbing at the location of highest stresses, to play down this. Open or semi-open impellers require close headways against the casing to ensure pumping efficiency. The casings generally include a side-plate that can be adjusted for minimal clearance using jacking screws or shims, especially in wearing applications eg slurries.ImpellerImpellers are classified according to their design features ie suck flow orientation o exclusive suction ie niche on one side only o twin suction ie inlet on both sides The direction of exit flow relative to the shaft axis ie o Radial flow o Axial flow o Mixed flow brand shape ie o Single curvature vanes, also called straight vanes the impeller surfaces that accelerate the fluid are straight and parallel to the axis of gyration o Francis or screw vane the surfaces that accelerate the fluid are curved in copulation to the axis of rotation Mechanical construction o Enclosed ie with side walls or shrouds o Open ie no shrouds o Semi-open ie shroud on one side only o Partially shrouded ie shroud not extending to impeller tips The open area through which the fluid flows into the impeller is called the suction eye. For a closed-shroud impeller, this is simply the hole in the shroud. The suction eye area is an important feature of the pump design. The area shoot forn up by the shaft, if it protrudes through the eye, is deducted when calculating eye area. Impellers can be single suction or double suction.A single suction impeller has an inlet eye on one side only, with the shaft extending out the opposite side so the impeller overhangs. A double suction imp eller can be prospect of as two mirror-image single suction impellers mounted back-to-back. They accept fluid from both sides and unremarkably have a shaft that extends straight through the impeller with bearings providing support on both sides. Double suction impellers are usually fed fluid from a single inlet flange, with the fluid flow beingness split into two streams by channelling deep down the casing. Double suction units provide advantages in minify fluid velocity at the impeller eye, and better balancing of axial hydraulic forces, while single suction units are simpler in design, manufacture and maintenance. Most if not all slurry pumps are single suction type. rough pumps may have an inducer, which is an axial flow impeller with a few swords installed between the suction inlet and the main impeller, intended to improve the suction head seen by the main impeller. Impeller shrouds often incorporate thin pump-out vanes cast into the outside of the shrouds. Their purpos e is to help clear any solids from the back hub of the impeller (opposite the inlet eye), number pressure at the postage area, reduce axial thrust, and discourage recirculation. Some impellers have similar vanes on the eye side as well as the shaft side in this elusion, those on the shaft side are usually called expeller vanes. In clear water pumps, a cylindrical ring is usually cast or machined into the outside surface of the shrouds, coinciding with a matching feature in the casing, to help cachet off- get a line the discharge fluid from the suction fluid and hold open internal circulation.Clearances here are tight in order to ensure pumping efficiency typically around 0.25mm on radius for most common sizes of industrial pumps. In larger pumps the casing (and sometimes also the impeller) is usually protected at this point by replaceable wear rings, which may be high-wear items, and need to be replaced before efficiencies fall too low. It is good practice to replace wear ri ngs once the clearance r to each onees twice the original specification. hold rings are provided in a wide range of designs and hooeys according to the pressures, furthers and fluids involved. The wear rings on impeller and casing are often made from differing materials that are not subject to galling, to reduce problems should touch occur. break down ring features may include labyrinths, water guessing, inspection ports, adjustment mechanisms etc.Pumps handlinglight slurries may make use of wear rings, sometimes with water injection to reduce wear from the slurry. Pumps handling heavier slurries usually just use pump-out vanes. Slurry pump impellers must be intentional to resist wear and tear, and this requires some pumping efficiency features to be sacrificed. For example, vane edges leave be blunter, vanes and shrouds get out be generally thicker, and the number of vanes will be decreased in order to open up the channels between them. Passages through slurry pumps, includ ing impeller vane spacing, are larger than for clear water pumps. Open impellers are sometimes used for very stringy materials, but tend to be weak and wear quickly, and so are not very common. Vane shape is obviously a major element of impeller design. Two comminuted factors are the blade entry topple (1) and blade exit angle (2), as measured between the centre-line of the vane and a tangent to the cozy or outer diameter (respectively) drawn from their tips, in the opposite direction to rotation. Most modern pumps have impellers with 2 smaller than ninety degrees ie backward-curved blades.Theoretically, a forward-curved blade would give higher head, but at less efficiency. Some pumps have 2 at ninety degrees, and these are sometimes referred to as expellers. many a(prenominal) clear-water impeller designs rely on close running clearances between vane tips and casing to minimise recirculation from one vane chamber to the next, and maximise efficiency. Even small amounts of vane tip wear can have an tack on head and overall efficiency. The outer and inner vane tips should be astutely, not rounded or chamfered.Replacing a pump which is too large for its duty can be a major exercise. It usually requires changes to the foundations, drive arrangement and piping, spares holdings, and so on. A model of the ideal size may be just not available. As an alternative, in some wooings it may viable to install a reduced-diameter impeller without changing other components. If done correctly, trimming the impeller will move the pumps BEP to match the actual system operating point. The efficiency at the new BEP will be lower than the BEP with the original impeller, but higher than was being achieved in practice when operating well away from the original BEP. The performance variation can be estimated using the affinity laws which often apply to a specific impeller before and after machining scarper rate Pump head Motor power Q1 / Q2 = n1 D1 / n2 D2 H1 / H2 = (n1 D1 / n2 D2) P1 / P2 = (n1 D1 / n2 D2) 2So if running at the resembling make haste, trimming an impeller by a certain proportion will result in a synonymic drop in flow rate, a greater decrease in head produced, and an even greater decrease in the repulse power consumed. However, these equations are based on several(prenominal) as cesspittions and some discretion is called for. Impellers are complex three-dimensional objects and their effects on the liquid are due to other factors that are also affected by machining, beyond just the outside diameter eg open area, discharge blade angle and so on. The following dependations should apply. Diameter reductions should not lead 10%. Reductions beyond 20% are generally considered extreme. Some references state 30% as the maximum reduction advisable. Some overlap in the vanes should be retained. The angle between the vane centreline and the tangent to the outer diameter drawn at its tip should be restored to original by file, with most filing occurring on the trailing side of the vane.The vanes will probably be thicker after cutting, and should be filed back to original shape, by filing on the traling side of the vane. Vane tips should be kept sharp, not rounded or chamfered. Outer tips should be sharpened by filing on the trailing side, and inner tips by filing mostly on the leading side. Inefficiencies will take the form of increased disc friction, increased flow path length within the casing, and more recirculation across vane tips. Impellers apply forces to the fluid and are subject to the equal and opposite forces themselves.The typical single-suction impeller engages with fluid unveiling the pump and at first accelerates it axially into the pump, before diverting it into the radial direction. The impeller pushes the fluid into the pump, and at the same time pushes itself axially back toward the inlet point. Another way of looking at this effect is to consider that the impeller is mostly exposed to pressu rised fluid all over the shroud surfaces, but not at the eye on the suction side. The thrust on the impeller must be resisted by the shaft arrangement, which must incessantly include bearings capable of serious thrust loading. Double-suction pumps typically have less axial loading, but can still experience axial thrust, especially if flow is restricted more on one side due to internal differences in the pump, or restrictions in fluid supply on one side. cracking water pump designs may incorporate features to reduce this imbalance, such(prenominal) as having wear rings on both sides of the impeller, with the pressure within the volume they enclose largely equalised by balancing holes momentary pay off through the impeller.Another method is the use of a balancing disc. This is a disc mounted on the shaft in a separate chamber, with a geometry and clearances designed to counterbalance thrust effects. However, these are not practical for slurry pumps, which may use pump-out vanes in stead, to lower the pressure toward the inner area of the non-suction shroud. Axial thrust haemorrhoid usually consist of a steady state component plus dynamic fluctuations. Heavy axial loading is often associated with recirculation.Where failure occurs it is usually a result of overloading and over- arouseing of bearing components. Measures to correct excessive axial loading include Restoring BEP operating conditions (which may include selecting a more appropriate pump size or trimming the impeller) Ensuring internal clearances / wear are not excessive Verifying correct bearing type and installation including clearances / pre-load To further complicate this issue of axial thrust, single-suction pumps handling fluids with a high suction head may experience thrust on the impeller in the opposite direction, away from the inlet. And then thither are pumps with highly variable duties and suction conditions that may experience impeller thrust in different directions at different times. instrumentThe shaft transmits mechanic power to the impeller from the driving motor or engine. It must also support the impeller and restrict its axial and radial movement. The loads on the shaft include self-weight of the rotating components, torque, and forces transmitted to / from the fluid. determination of a shaft requires consideration of maximum foregoable deviation, the span or overhang, the location and direction of all loads, any temperature variations, and the faultfinding speed. Loads are normally at their maximum on start-up. All objects have a natural frequency at which they will vibrate after being struck. Machines made of several components with complex shapes normally have several natural frequencies, some of which dominate. In the case of pumps, if the rotational speed of the impeller matches a dominant natural frequency, small imbalances may be amplified to a level where they interfere with operation and/or reliability.These are known as critical speeds. St eady operating speeds between 75% and long hundred% of the first critical speed should be canceled. Pumps with longer overhang on the shafts have lower critical speeds. Shafts are referred to as rigid or flexible, according to whether the running speed is lower or higher than the first critical speed. Pumps with a flexible shaft must pass through a critical speed on each start-up. This is not usually a problem because frictional forces with the fluid and the bearings act as dampers for a period sufficient for transition through the critical speed. Pumps with speeds below 1750rpm, which includes most slurry pumps, are usually of the rigid-shaft design. The shaft must be designed so that any deflection will not bring moving parts into contact, for example at wearing rings, or cause non-concentricity in critical areas such as the shaft blockade. As a general rule, shaft deflection should not exceed 0.15mm even under the most extreme conditions.Deflection and critical speed are relate d change a shaft to reduce deflection will also raise its critical speed. For pumps with overhung impellers, as is the case for most slurry pumps, this often results in the shaft diameter between bearings being quite large. The fluid passing through a pump creates a hydrodynamic bearing effect, known as the Lomakin Effect. That is, to some extent, the impeller rotating in the casing with fluid present is like a shaft rotating in a ledger bearing with oil present. The result is that the shaft is better supported when running than when idle, so that the shaft deflection will be less, and the critical speed of the shaft convocation will be higher. However, the Lomakin Effect varies with pump head and internal clearances, both of which diminish with wear. Therefore the effective critical speed may be expected to decrease with time in service. To allow assembly, shafts step up in diameter from labor union to bearing to impeller, so that any torque problems are very likely to appear first at the coupling rather than the impeller, at least in single stage pumps.Shaft Seal and limbThe shaft connects the drive to the impeller, and so must pass through the pressurised casing. Achieving a reliable seal between shaft and casing is one of the most problematic areas in pumping. Centrifugal pumps have two types of seals mechanical seals and wadding seals. numerous designs of mechanical seals have been attempted for slurry pumps, without comprehensive success, and the remainder of this discussion concentrates mainly on packing material seals and fertilization boxes. Note, however, that packing is only worthy within pressure and temperature limitations. Depending on pump design and duty, the seal may need to prevent either air adit into the casing, or fluid pop out out of the casing or both of these at different times, if operation is variable. Many casings are designed with the seal area built into a compartment configured to improve close performance. For mec hanical seals, this compartment is usually referred to as the seal chamber, while for packing seals, it is known as the stuffing box.Slurry pump seals usually consist of several rings of packing fitted in a stuffing box around the shaft, often with provision for grease lubrication or water injection to reduce friction and provide additional sealing (particularly for when the pump is stopped). There are many stuffing box design variations and many types and configurations of packing. fecundation boxes will accept a number of rings of packing, with a packing ring or throat chaparral preventing extrusion into the casing, and a gland (sometimes called a follower) used to adjust packing compression. A lantern ring may be substituted for one of the packing rings, to cater for injection of grease or sealing water, water being particularly required if air would otherwise be sucked into the fluid stream at this point. seal off water (or an alternative clean liquid) is usually required for Slurries Liquids for which leakage is not acceptable Liquids that are not suitable for sealing purposes Suction lifts greater than 4.5m (air ingress may interfere with priming) Discharge pressures to a higher place 70kPa The packing must be placed under some compression and this tends to result in wear on the shaft, which is often weapond to avoid having to replace the entire shaft once wear is advanced.There are numerous designs of shaft sleeves. The shaft sleeve must be resistant to friction and heat, and several different materials and surface treatments are available eg hardened high-chrome unstained firebrand, ceramic, plasma spray or tungsten carbide applications programme etc. To prevent chipping, coatings should not extend to the edges of the sleeve. The sleeve does not contribute to strength, so the shaft itself must be large enough to carry all the loads, and this means that including a sleeve in the design enlarges the seal diameter. For small pumps, this may decrea se pumping efficiency and raise the purchase cost to the point that sleeves may be abandoned and a clean steel shaft used instead. Glands may be solid, or split to allow replacement without disassembly of pump or bearing assembly. They are usually made of bronze, cast iron or steel. particular(a) designs are used to improve safety if the fluid is hazardous.The leakage of fluid past the packing is interpretled by tightening the gland, compressing the packing axially and expands it radially so that leakage paths along the shaft sleeve are constrained. However, some fluid flow between packing and sleeve is usually needed to avoid overheating the packing and damaging the sleeve surface. Once the sleeve surface is damaged, the sealing efficiency decreases and more tightening is required, further damaging the sleeve, and so on. The secret is to provide a configuration of packing and seal water injection that suits the application, and then avoid over-adjustment.To further reduce the pr essure at the shaft seal area, where the rear pump-out vanes are not sufficient, some slurry pumps are fitted with a second smaller open-faced impeller, usually called an expeller. Many different designs have been tried. If sealing water is used, there will be a design intention regarding the ratio of water to pass in to the volute compared to out past the gland follower. This can be controlled using the number of packing rings on each side of the lantern ring, but the lantern ring must be installed at the injection point. For clean water pumps, this seal water is sometimes provided from the pump discharge.Clean water must be used to avoid corrupting the packing with grit filtration or cycloning may be necessary if the water contains some grit. When managing sealing arrangements, thought must be given(p) to what happens when the pump is stopped. The pressure in the stuffing box changes to static conditions, which may result in slurry leaking into the packing and contaminating it , causing rapid sleeve wear on re-starting. just now if sealing water continues to be applied, the slurry may be diluted, and eventually a sump can be filled with sealing water if left idle for a long time. For prolonged stoppages, sumps may be best dropped, for various reasons. On restarting, sealing water supply should start before the pump starts.Stuffing boxes in extreme applications may be provided with galleries through which alter water can pass to prevent excessive temperatures around the packing. In applications where leakage must be more precisely controlled, or where ideal temperatures in the seal area must be avoided (for example where the fluid is volatile), mechanical seals may be suitable, provided that the fluid is not damaging to the seal components. A comparison between mechanical seals and packing seals is given below. Packing seals o Low initial cost o slant to deteriorate gradually o Easily replaced when necessary o Can handle large axial shaft movements o forever and a day some leakage required o Require regular adjustment o Not suitable for hazardous / volatile fluids o Often cause progressive shaft sleeve wear o Can result in significant shaft power losses o Limited to low pressures and speeds Mechanical seals o Minimal or zero leakage o No adjustments required o Suitable for hazardous / volatile fluids o No shaft wear o Do not consume significant shaft power o Can handle high pressures and speedso Tend to fail suddenly o Replacement requires pump disassembly o High initial cost Packing seals work as a result of axial compression, so that the packing rings eke out outward and apply radial pressure to the abutting components, these being the static surface of the stuffing box, and the rotating shaft sleeve. A dynamic seal is formed between the packing rings and the sleeve surface, with some fluid flow between the two being necessary for lubrication and cooling. For clean water pumps, this fluid may be supplied from the inner end of the stuffing box, or from the discharge pipe via small diameter piping. In the case of slurries, grit in the fluid would add to friction and wear, so the lubricating and cooling fluid is usually injected from a separate clean water supply.The injection pressure should be 10 to 25psi greater than that at the inside end of the stuffing box, and this figure should be available from the pump designer. A rule of thumb is to set the gland feed water pressure to between 35 and 70kPa in a higher place pump discharge pressure. extort regulation is often helpful. In theory, some slurry pumps should operate with a pressure at the inside of the stuffing box which is below atmospheric pressure, so that the packing is required only to prevent air ingress into the pump. However, when the pump is turned off, or in abnormal operating conditions, slurry can pass back into the seal and contaminate the packing with grit, so these situations still call for water injection. Grease or oil may be use d instead of water in some applications.Packing material must be able to withstand the operating environment and remain resilient to perform satisfactorily despite baby bird shaft misalignment, run-out, wear and thermal expansion / contraction. Packing is available in a huge range of materials (lubricant, binder and fibre / matrix) and in many sizes, shapes, and constructions, to suit different applications particularly size, shaft speed, temperature, pressure, and chemical shield. The number of packing rings varies between applications, the most common arrangement being throat bush or ring, three inner packing rings, lantern ring, two more packing rings, and gland follower. The lantern ring may be placed further in, to reduce slurry ingress. Packing size is usually proportional to shaft / sleeve outer diameter, as follows Shaft / Sleeve OD (mm) 15 to 30 30 to 50 50 to 75 75 to 120 120 to 305 Packing Size (mm) 6 8 10 12.5 16Shaft sleeve get through involve to be at least 0.4mic ron CLA to avoid excessive rotational friction, and the finish in the stuffing box bore needs to be at least 1.65 micron CLA to allow even compression during adjustment. The sleeve must be harder than the packing, and chemically resistant to the fluid pumped and the injection fluid. Any coating on the sleeve must have a good thermal horrify resistance. The lantern ring allows for entry and distribution of the lubricant or flushing fluid. Lantern rings are usually split to allow installation and removal without pump disassembly. They were traditionally made from metal such as innocuous steel, but lubricant-impregnated plastics are now common. Gland followers are also usually split to allow diffused replacement. They are usually bronze but may be steel or cast iron. Special purpose gland followers are used with volatile or hazardous materials, including capacity for diluting and safely flushing away leakage. The axial compression on the packing must be occasionally adjusted to cont rol leakage. The correct leakage rate is one drip per second.Over-tightening should be avoided as it will result in over-heating and shaft wear. Most packing is supplied with impregnated lubricant, and over-tightening will press the lubricant out. Pumps need unnecessary sealing victuals if pressure at the inner end of the stuffing box is greater than 75psi. The use of harder packing material on the inner rings may help. The procedure for replacing packing is 1. Read the instructions provided by the pump manufacturer and packing supplier. 2. Loosen and remove gland follower. Inspect gland follower for wear, corrosion, distort etc. 3. Remove old packing rings using a packing puller, and the lantern ring. 4. Inspect shaft sleeve surface for deterioration, and clean up where possible. Replace if necessary. 5. Inspect bore of stuffing box for corrosion, wear, measure etc, and clean up where possible. 6. Verify correct packing size to be used. 7. Tightly wrap the correct number of pac king coils around a mandrel of equal diameter to the shaft sleeve. 8. Cut each ring at an oblique angle. 9. Install each ring, staggering the joins 90 degrees on subsequent rings.Suction / Intake DesignCentrifugal pumps operate most efficiently when the liquid to be pumped flows into the inlet nozzle in a smooth, uniform manner with minimal turbulence. Suction systems need to be designed to ensure that this happens. The most common problems are Uneven / turbulent flow Vapour collection commotion formation Suction piping should be as short and straight as possible to minimise friction, and if unavoidably long, should be of large diameter. The suction line will normally be at least one pipe size larger than the pump inlet flange, requiring fitment of a reducer. A reducer should not change the pipe bore by more than 100mm. Fluid flow should be as uniform as possible right up to the pump inlet flange. There should not be any designations likely to cause turbulence, sudden changes i n flow direction or spin within ten pipe diameters of the pump inlet flange. There should be no short radius elbows at all, and no long radius elbows within three pipe diameters.All suction line connections need extreme sealing to prevent air being drawn in. For suction manifolds serving multiple pumps, all the above points apply, and branches should be angled at 30 or 45 degrees, rather than ninety degrees, and sized so that fluid flow is constant throughout. Flow should not exceed 0.9m/s. Improper suction conditions or designs can result in the fluid swirling as it approaches the pump through the suction pipe. This is called pre-rotation. It causes a drop in pumping efficiency because the pump is designed to process fluid that is entering without rotation, and can cause additional suction pipe wear.Sometimes a radial fin is fitted to the suction pipe or casing to reduce pre-rotation. The suction pipe design should cater for elimination of air from the suction line, and prevention of vapour pockets, in the simplest manner, meaning that For pumps with the feed being drawn from a level below (eg a dam pump), o Suction pipe should have a slimly upward slope toward the pump o The off-the-wall reducer should have the flat side on top For pumps with the feed being drawn from a level above (eg a thickener underflow pump), o Suction pipe should have a slightly downward slope toward the pump Vortexing in feed tanks needs to be avoided to prevent air being drawn down into the pump. Baffles may need to be fitted to tank walls. The tank fluid level needs to be kept well above the suction inlet.BearingsBearings provide axial and lateral restraint to the pump shaft and attached components, while allowing free rotation. Axial loading on pump shafts may be significant as discussed separately, and the bearing arrangement forever and a day includes some thrust capability. The bearings most commonly used are deep-groove single row ball bearings, and single or double row a ngular contact ball bearings. Pumps may be in overhung configuration, where the shaft is supported by bearings on one side only, or have a shaft that passes right throught the casing with bearings on both sides. Most slurry pumps are of the overhung design.The bearings are usually rolling-element, but plain journal bearings are sometimes used on larger pump sizes. The bearings must be lubricated by grease injection or oil can and may need provisions for cooling as well. This may be by having a cooling water jacket integral with the bearing housing, or by pumping the lubricating oil through a heat exchanger and filter. Oil lubrication is usually recommended rather than grease, if speed exceeds 5000rpm (which is very rare in a slurry pump). Grease-packed bearings should have one third of the chamber filled with grease. Oil baths should be filled to the centre point of the lowest rolling element. Inadequate loading of bearings can result in the rolling elements skating over the race i nstead of rolling, and this can cause heating and failure. To avoid this, bearing assemblies are usually designed with an assembly configuration, including preload, that ensures all bearings carry some load.Frame and FoundationsFor large pumps that are directly connected (ie no vee-belt drive), the motor and pump are usually mounted on the same bed-plate, which is fixed to the foundations in a way sufficient for eliminating looseness and distortion. This eliminates some misalignment issues at the writer. Foundations including bed-plates should be check out occasionally for deterioration (corrosion, ground subsidence, cover cracking, loose fasteners, missing grout etc), and the alignment between pump and motor should also be checked if there is any cause for concern.The framework should have provisions for drainage of any spillage and seal leakage etc, so that this does not become trapped and contribute to corrosion etc. Where pumps operate at high temperature (ie above around 100 C) the pump casing should be supported at its axial centre-line, to help reduce thermal stresses. It is generally preferred that all suction and discharge piping have its own supports, so that the pump casing and foundations do not carry any significant static or dynamic piping loads, and so that pump components can be independently removed and replaced. Where this is not the case, extra pump and foundation attention may be needed at the design stage.Drive positioningMany drive arrangements are possible to suit the circumstances. Electric motor drive is the most popular, followed by internal combustion engines. Variable speed drives are sometimes necessary and often convenient, but always more expensive and less reliable. In minerals handling plants, slurry pumps are most often electric motor driven, with belt drives. Belt drives allow speeds to be changed through minor modifications ie pulley changes. Short, low head slurry system designs usually provide motors that are 10 to 20% oversized, to cater for any under-estimates in slurry or system characteristics such as viscosity and friction, and to allow for minor system modifications during the service life.InstrumentationPumps may be controlled to allow Variation of flow rate, pressure, liquid level Protection against damaging operating conditions tractableness in matching pumping performance to duty For centrifugal pumps, control is usually accomplished by speed setting (including turning off/on), or valve setting. This may be manual or automatic. For slurries, control by throttling valve is rare due to the wear rates that usually result. Typical instrumentation includes Tank / sump level switches Pressure sensors Flow sensors Density sensors In each case, protection from damage by the slurry is critical. This is commonly achieved by using sensors that do not need to contact the slurry eg nucleonic density sensors mounted outside the pipe, with source on one side and detector on the other. Ideally, it is good to have instrumentation available, either for good mounted or portable, toVerify operation at BEP, by measuring the difference between suction and discharge pressureDetermine flowEnsure that NPSH is sufficient to prevent cavitationCompare flow to motor amperage, to identify when impeller adjustment is neededNeed to search more on valves for slurry applications.Notes on Material weftWhere there is some chance of parts coming into contact during pump operation, thought should be given towards minimising the damage that may result. An example of this is at the wear-ring / impeller interface. Studies have shown that damage can be minimised by manufacturing adjacent components from materials that Are dissimilar, except where known to be resistant to adhesive wear and galling Have a difference in callousness of at least 10Rc, if either has hardness less than 45Rc Because it may be difficult to always prevent cavitation from occurring, impellers are usually made of cavitatio nresistant materials such as chrome-manganese austenitic stainless steel, carburised 12% chrome stainless steel, cast nickel-aluminium bronze, etc. Obviously corrosion resistance is another key cream factor that these materials satisfy. Slurry pumps are subject to heavy wear in the form of abrasion and erosion. The hostility of the slurry is determined by the hardness of the particles in the slurry, their shape (rounded or sharp), the pulp density, and the size distribution.Slurries can become less aggressive as they travel through a minerals processing plant as the sharp edges become rounded off. Velocity and angle of impingment are also very important factors affecting the end point wear rates, with wear rate being proportional to velocity squared according to some references. The impact angle associated with maximum wear rate seems to be dependent on the hardness and brittleness of the material being struck. For very hard / brittle materials it is between 65 and 90 degrees, w hile for more elastic materials it may be around 25 degrees. Pumps handling slurries with greater than 6mm particle size are usually lined with rubber. However, if impeller tip speed exceeds 28m/s, rubber becomes subject to thermal degradation, and this usually restricts the use of rubber to a maximum head of 30m per stage. Metal lined pumps may be used up to 55m head per stage.For moisture end components, materials that may be used to resist wear include Ni-resist, carburised and hardened 12% chromium steel, etc. White iron slurry pump components, which includes Ni-Hard, are restricted to impeller tip speeds of about 36m/s to avoid maximum disc stresses. Steel components are softer but can run at higher speeds, up to a tip speed of 45m/s. Centrifugal pumps are subject to cyclic loads due to such things as imbalance, unbalanced radial forces, fluctuating axial thrust, the vibration induced as each vane passes the cut-point, and variations in upstream and downstream fluid pressure and flow. This sets the scene for fatigue loading, which becomes more of an issue if the slurry is corrosive. Fretting may occur between assembled components where looseness is allowed to develop.This is best avoided through the use of correct manufacturing dimensions and surface finishes, good fitting practice etc. The materials commonly used for pump components include Impellers (require castability, weldability, and resistance to corrosion, abrasion, and cavitation) o Bronze, for non-corrosive liquids below 120C o Nickel-aluminium bronze, for higher speed and mildly corrosive applications o Cast iron, for small low-cost applications o Martensitic stainless steel, where added resistance to cavitation, wear, corrosion (other than salt water) or high temperatures may be required o austenitic stainless steel (mostly cast 316 grade), where a higher level of corrosion resistance is needed. Austenitic stainless steel with 6% molybdenum is often used for salt water pumping.Casings (requi re strength, castability and machinability, weldability, and resistance to corrosion and wear) o Cast iron o Cast steel, where extra strength is required ie for pressures above 6000kPa (1000psi) and temperatures above 175C. o Austenitic cast irons with 15 to 20% nickel (Ni-Resist) may be used where abrasion and corrosion are issues. o Bronze, for water applications o Stainless steel, where corrosion is a major issue martensitic for higher pressures in mildly corrosive fluids, austenitic for more aggressively corrosive fluids. Shafts (require resistance to fatigue and corrosion) o Mild steel, where corrosion and fatigue are minor issuesLow alloy steel such as 4140 for added strength Martensitic stainless steel, where added strength and corrosion resistance are needed Shafts are usually chrome-plated, and care is needed to avoid this adding to the fatigue susceptibility through microcracking and henry embrittlement. Shafts can be shot-peened prior to plating, and heat-treated after ward to reduce these effects. Wear rings (require castability and machinability, and resistance to corrosion, abrasion and galling) o Bronze for clean liquids and temperatures up to 120C o Stainless steel for applications with abrasion, corrosion and high temperatures but steps must be taken to avoid galling should the rings come into contact eg increased clearances, hardness differences etc.o o oImpellers other than those made from martensitic stainless steel can usually be repaired by welding, although in some cases this needs to be followed by specific heat treatment processes. In all cases, more exotic (and expensive) materials may be used for specific applications. Material selection is often a balancing act between optimising purchase cost and maintenance / operations performance. Where high temperatures are involved, material selection must take into account differences in expansion rates. Unlined slurry pump impellers and casings are often made from abrasion-resistant cast irons as per ASTM A532, which includes Ni-Hard. These materials consist of a martensitic matrix with tributary hard phases of chrome and iron carbides that increase wear resistance.They cannot be machined or welded, and tend to be abandoned to corrosion, and breakage through mechanical impact and thermal shock. Brittleness may be reduced by annealing, but this reduces wear resistance. Slurry pump impellers and casings may be lined with softer materials like rubber, where high temperatures can be avoided. These can reduce wear rates by absorbing the impact energy of the particles, while resisting corrosion. Problems may arise in bonding of the rubber at the cut water point, and on the impeller. The lining reduces the ponderousness of the metal section of the component, so stronger materials are usually used eg steel rather than cast iron.Manufacturers develop their own specifications for ideal liner thicknesses based on experience, but one reference suggests a volute liner thickn ess of 4% to 6% of impeller diameter. Natural rubbers seem well suited for wear liners for use with slurries with less than 6mm particle size for the impeller, and 15mm particle size for the volute. Provided the base materials are suitable, patches of high wear on wet end parts can sometimes be repaired by welding / hard-facing. However, this increases the likelihood of cracking. alike if the welding results in uneven surfaces in critical points, the added turbulence can accelerate further wear. Many types and styles of surface coating have been tried, with some success. These include thermal spray coatings, diffusion surface treatments, scatter and trowelling of epoxies, etc.