[Astronomy subject] The Galaxy Zoo Essay Example | Topics and Well Written Essays - 500 words

[Astronomy subject] The Galaxy Zoo - Essay Example The website has marvellous pictures of different type of galaxies, and it provides information and questionnaire related to the behaviour of galaxies, their shape and color in the space. The GalaxyZoo website provides many interesting facts about the galaxies and the Universe. The database of the website provides an insight into galaxies and its evolution. The database stores about 250,000 samples of galaxies and the members are given a set of questions which are based on pictures of these galaxies. The visitors can take part in the questionnaire, which is based on the images of the galaxies. The visitors to the website have to look at the image and answer the questions based on his/her interpretation of the image. Some of the questions which are being studied are The various researches showed the nature of galaxies such as the information related to the shapes, colours. It was assumed the color of galaxy was red and its shape was elliptical. However, it has been interpreted from the images of GalaxyZoo that one-third of galaxies are red spirals and a larger number of elliptical galaxies are blue -- which are in the process of forming new stars. Earlier it was assumed that galaxies spin in opposite directions but research on pictures found that the two galaxies which are nearby, spin in the same direction, instead of opposite directions. This can be used to interpret the spinning behavior of galaxies. The research on galaxy disks showed the galaxies have larger contraction (bulges) which are central to redder disk galaxies. The research on disk galaxies with smaller central concentration is also significant in this context. In the process of explaining the behavior of galaxies, GalaxyZoo found numerous new things in space which were called Galaxy Zoo peas. Certain blue objects were noticed in some images, which were named Voorwerp by the members of GalaxyZoo. GalaxyZoo is the website which was launched in July 2007. It was based on the data set generated from

The needs of future generations are being met by the current policies Essay - 1

The needs of future generations are being met by the current policies of sustainable development - Essay Example According to the research of Waas, Verbruggen and Wright (2010, p. 631) the concept of sustainability comprises of the initiation of development measures which â€Å"†¦contribute in meeting the needs of the present without comprising the ability of future generations to meet their own needs†. The need for developing sustainable solutions to be implemented across the Arabian Peninsula is most urgent essentially because of legitimate environmental concerns regarding the incidence of air pollution in the region. The primary causes of air pollution specifically in Arabian economies which rely upon the production of oil can be attributed to 1) an increase in population 2) a rise in industrial activity and 3) the extensive use of private vehicles for commute (Ettouney and Saqer, 2012). The discussion and analysis which has been conducted in this paper explicates upon the incidence of air pollution in the urban or metropolitan centers of Gulf States including Umm Alhyman, Riyadh , Dubai, Abu Dhabi and Jeddah. Moreover, the research also proposes a framework for promoting sustainable solutions to combat this issue and advises the respective governments of the Arab States to enforce effective policies to address this crucial issue. The incidence in air pollution measures in Kuwait has been a critical topic of assessment for researchers which aim to establish the extent of the damage which has been caused by related and significant determinants. Moreover, the scope of the examination is also focused upon identifying effective tools and models which can be adapted and executed to identify fundamental trends (University of Queensland, 1993). The research of Ettouney, Abdul Wahab and Elkilani (2009) follows this pattern by launching three comparable yet distinct models to report findings on the level of air pollution in Kuwait and its subsequent health and ecological

Similarities And Differences Between Sport And Fitness Physical Education Essay

Similarities And Differences Between Sport And Fitness Physical Education Essay Throughout this essay I will identify the definition for both sport and physical education, implementing my own interpretation. I will also explain the differences and similarities between them. My research will be based largely on the affect physical activity has on school children. I aim to concentrate my research on the method of teaching PE and sports, introducing both linear and non-linear pedagogy. Finally, I will conclude with my own understanding of my findings and where I feel research should be continued in order to ensure both PE and sports is an active part of every childs life, especially after leaving school. Sport v PE Classifying the definition of sport is not as simple as it seems. Research states, an athletic activity requiring skill or physical prowess and often of a competitive nature, as racing, baseball, tennis, golf, bowling, wrestling, boxing, hunting, fishing, etc. (http://dictionary.reference.com/browse/sport). This is true, however, there is a lot more to it that just skill and competition. Although rules are a major part of sport, making it sound more serious, it can also be fun and entertaining. Physical skill is a key advantage in playing sport, however lets not forget that most sports also require mental skill for strategic planning. The most important aspect of sport is having fun with the added bonus of maintaining a good fitness level. The term sport comes from the old French desport which means leisure. http://en.wikipedia.org/wiki/Sport. Physical Education is Training in the development of and care for the human body; stresses athletics; includes hygiene. http://www.wordwebonline.com/en/PHYSICALEDUCATION. It is a taught course taken during primary and secondary education that encourages psychomotor learning in a play or movement exploration setting. http://en.wikipedia.org/wiki/Physical_education. In the UK, Physical Education classes are compulsory in school until approximately age 16. As well as learning basic sporting skills, the curriculum also pays attention to health and fitness. My first recollection of PE at School was playing pirates in the school gym which involved running around on sporting apparatus being chased. PE is not always being taught the obvious sporting game such as football, hockey, etc. Its aim is to enhance an individuals progress through a variety of activities, which will boost their confidence level; hence my pirate game vastly improved my agility skills. As the student progresses, leaders hip skills are incorporated into the programme as well as being encouraged to be player independent in their decision-making. The most obvious similarity between sport and PE is that they both involve physical activity. Physical health benefits are gained by taking part in regular physical activity, whether that is during school hours (PE lessons), an extra-curriculum activity, or playing for a local club. Research shows that children who participate frequently in physical activity will reduce their chances of acquiring certain ailments such as diabetes and obesity, therefore improving their quality of life. However, other benefits such as affective and social are also gained. Research suggests that affective development is now evident with children. One of the main signs of this is a childs self-esteem that grows stronger when partaking in physical activity. Research show that stress, anxiety and depression, can also be significantly reduced with regular exercise. Probably the most important aspect of both sport and PE is social benefit. Whether you are playing football with a few friends or in a controlle d PE lesson, it is evident that this is a major part of a childs social learning skills. Anti-social behaviour is frowned upon and, to fit in, children tend to conform to the norm. Also, for an introvert child, communication though activity can help dramatically improve their interaction with other children outside of sports and PE and this has a knock-on affect with their affective skills also (Bailey, 2006). However, there may be implications. For example, we are assuming that pupils are enjoying the physical activity and are good at it. What if a child suffers with ability and/or may be teased by other school children for their lack of coordination? This may cause the child to become introvert and depression and anxiety could occur. Although PE has a positive effect for most, this concern needs to be considered carefully when planning PE lessons at school. However, sport is more about being competitive and winning medals and trophies. Although PE can be competitive, teachers introduce fair play; ensuring teams are equally balanced, whether that is by age, sex, and/or ability. However, in sports, the best players are selected for the clubs first team and those with less skill will be placed in a lower performing side. Sport is voluntary and the number of participants can vary from club to club, but the size of group/team can be adapted to suit the requirements of a match. However, PE is compulsory in schools and classes can be vast, this can cause problems for the teacher when applying rules and instructions, especially given that a proportion of children do not want to partake and may be unruly. Within sports there are leagues and competitions, involving officials and a fixture secretary and each club concentrates on one particular sport. However, the chosen activity for a particular PE lesson is usually decided by the teacher and can vary from lesson to lesson. This decision can also depend on the environmental conditions and equipment available to that school. For example, it is difficult for a school in the centre of London to partake in an outdoor adventure activity, as there are no local amenities to support this and some inner city schools dont have the funds to purchase expensive equipment. Linear and non-linear pedagogy The basic skills of PE are learned during a childs school years. This is normally taught using linear pedagogy, a more traditional method. Once the basics are learnt, a pupil may wish to expand on this skill and join a particular sport they excel in. This is where further, more advanced coaching, takes place and in my experience, a more non-linear pedagogy approach is implemented. Linear pedagogy is teacher centred, instructional, technique-based and practiced method. This style is more advantageous in schools than clubs, where, due to enormous class sizes, it is easier for the teacher to maintain control of the class. However, there are problems with this approach. For example, in my school-day experience, in order for skills to be learned, the teacher would use drills to demonstrate a technique and it was a luxury to play a game. This was a disappointment to my peers and me. Tactics were rarely mentioned therefore my decision-making was poor. Non-linear pedagogy leans more towards the Teaching Games for Understanding (TGfU) way of teaching where it is player centred, involving engaging an individual in being encouraged to think for themselves in both tactical and technical aspects (Thorpe and Bunker 1989). Its major advantage it that it is designed to guide players to become independent in their decision-making. For example, a typical training session may involve a short modified game to identify the teams failings. Drill sessions would then take place to strengthen these weaknesses. After the drills, another game would be played to implement the new skill, using their own thoughts. The coach encourages player independence by applying strategies to match an individual players game, therefore improving their decision-making throughout a game (Light, 2006). The main problem with linear pedagogy is that it can be strict and disciplined, almost military style, therefore enjoyment, which should be a major factor, is low on the list of achievements and participating in both PE and sport should definitely achieve this. Lessons become predictable and children tend to pay less attention due to boredom, therefore not much learning will take place. Also, too much structure wont allow those with less ability to achieve the aimed outcome and, instead, may become stressed at their inability to master the skill. This could also damage their confidence. By not allowing children to think for themselves, it reduces their scope of learning and their tactical skills will be limited. Non-linear pedagogy is not without its faults. At school level, it may lack adequate theoretical teaching from a motors learning perspective. Receiving little instruction from the teacher can result in the child not being able to make the correct decision. It is very difficult to measure whether or not the children are learning anything and it can look a lot like chaos (Mack, et al, 2000). Conclusion Taking into consideration the research and my own interpretation, it is encouraging to see that both PE and sports has a positive affect on majority of children. However, my findings highlight the need for schools to reconsider their method of teaching PE. Other less traditional styles should be implemented to enhance the enjoyment of the lesson, which may encourage children to continue their interest in extra-curriculum sporting activities and perhaps join sporting clubs upon leaving school. This will then increase the number of potential elite athletes. Further research needs to be undertaken to investigate the effects of social behaviour in children. For example, how does participating in PE and sports help reduce crime rate? What can the government do to ensure people from deprived areas are given more opportunities to partake in sport? Overall, any type of physical activity should be a part of everyones lifestyle. Although playing sport is more of an individual choice, it is vital that PE remains a compulsory part of the curriculum at schools as this is the grass roots encouragement they require to continue in their enjoyment and progress to playing sport after leaving school. Reference list: http://dictionary.reference.com/browse/sport http://dictionary.reference.com/browse/Physical+education Ones I have not used yet: http://www.tgfu.org/taskforce/index.htm http://www.citejournal.org/vol1/iss1/currentissues/english/article1.htm http://www.suite101.com/content/teaching-breathing-exercises-for-singing-a146136 http://www.questia.com/googleScholar.qst?docId=5002249790 http://www.bmj.com/content/327/7415/592.full

Immanuel Velikovsky :: biographies bio

Correspondence Before the Day Breaks, When I first ran across any of Velikovsky's ideas it was in this online book Before the Day Breaks. In this book Velikovsky writes about his correspondence and conversations with Albert Einstein. I read some of this book before ever reading anything else of Velikovsky, or having any idea of what was proposed in his book Worlds in Collision. Before the Day Breaks is a very well written book, where Velikovsky's main argument is that gravity and inertia are not the only forces acting on the solar system. After Velikovsky published his book Worlds in Collision he has had much difficulty getting anyone in the scientific community to listen to him. There were numerous accounts of unjust behavior towards him from many famous scientist. It is ironic that while many people were ignoring him, he was discussing scientific matters with Einstein. While Before the Day Breaks may not have any substantial scientific impact, it does two separate other things. Provide a good insight to som e of the prejudices of the general scientific community at that time. Give good clues as to what Einstein's personality was like. Background Info. / History 1895, June 10, Immanuel Velikovsky was born in Vitebsk, Russia 1913> studied medicine at Montpelier, France, 1921 Velikovsky received a medical degree at the University of Moscow 1921 moved to Berlin, married, edited a journal called Scripta Universitatis atque Bibliothecae Hierosolymitarum, the mathematical-physical section was prepared by Albert Einstein. This journal played a big role in developing the Hebrew University in Jerusalem, 1924-1939 "Velikovsky lived in Palestine, practicing psychoanalysis- he had studied under Freud's pupil, Wi1helm Stekel in Vienna" quoted from (Short Biography) 1950 published Words in Collision right away it was a NY Times non-fiction #1 international best seller for 7 weeks until the publisher (Macmillan) dropped the book due to opposition to it led by Harvard astronomer Dr. Shapley -This book was about Velikovsky's claims that incidences in numerous independent cultures around the world were not due to terrestrial origin (i.e. comets and planets caused massive disasters) 1960s Velikovsky was considered as quack by most everyone

Key Functions of Education from a Functionalist Perspective

What are the key functions of education from a Functionalist Perspective? Ever since the education system was invented, there have been a lot of ideas and criticisms of how it should work. The most famous sociological groups, functionalists and Marxists, were part of this and still are today. They both think that their views are best for society. Talcott Parsons believes that the education system has three main functions. Firstly it socializes young people into key cultural values such as equality of opportunity, competition and religious morality.Education is said by functionalists (especially Durkheim) to emphasize moral responsibilities in society that people should have towards each other. If these norms were not passed down through generations then there would be a tendency for individualism (where people believe that they are more important than social groups). Citizenship and religious education were introduced as compulsory subjects in schools to see that young people did thi ngs with thought for the society. The second function is to do with the skills that education teaches children, from literacy and numeracy to more job-specific skills.Occupational jobs are becoming more specialized and this in turn will lead to more years in education. The final function of education, according to functionalists is the allocating of roles of young people in society. Examinations and qualifications are said to allocate people for their most suited job. The equality of opportunity took place and so higher talented people are given the most functionally important jobs for the society. Parsons was criticized as he failed to consider that the values transmitted by the educational system may be those of a ruling minority rather than society as a whole.Like parsons, functionalists Davis and Moore saw education as a means of selecting or shifting people for different levels of the jobs market and ensuring that the most talented and qualified individuals are allocated to the most important jobs with high rewards. Society is therefore meritocracy in which people are rewarded for intelligence, ability and effort. They where criticized because the relationship between academic credentials and occupational reward is not close. Income is only weakly linked to educational attainment. There is doubt about the proposition that the educational system grades people in terms of ability.It has been argued that intelligence is so difficult to pin down that school achievement can never equal ‘intelligence’. While Marxists do share many ideas of functionalists e. g. the fact that education prepares us for out acceptance of the values of society they also see how the education system is alienating children. Functionalists, on the other hand, seem unable to see this and believe that the education system can only do well to children by teaching them norms and values. Functionalists where criticized because as Marxists say, education system is not meritocrat ic as there are the influence of class, ethnicity and gender.

Languages and Dialects of Spain Essay

With a population of approximately 45 million Spaniards and 3. 5 million immigrants, Spain is a country of contrasts where the richness of its culture blends it up with the variety of languages and dialects used. Being one of the largest economies worldwide, and the second largest country in Europe, Spain is a very appealing destination for tourists as well as for immigrants from around the globe. Almost all Spaniards are used to speaking at least two different languages, but protecting and preserving that right has not been easy for them; Spaniards have had to struggle with war, ignorance, criticism and the governments, in order to preserve and defend what identifies them, and deal with the consequences (some of which are good and some of which are bad) of dealing with this multilingual society they have. Spanish-Town-Guides, 2002-2011) In Spain there are 17th autonomous regions, the official language spoken in each region is Spanish or Castilian, however, there are three other recognized regional languages used throughout the country (Wikipedia contributors, 2011); Catalan (spoken in Catalonia, Valencian Community, and Balearic Islands), Basque (spoken in Basque Country and Navarre), and Galician, (spoken in Galicia) (Wikipedia contributors, 2011). Distributed throughout Spain there are a variety of smaller groups or regions with their own dialects, most of them Latin derivatives (as well as the main languages); Aragonese (spoken in Aragon, Huesca and Zaragoza), Asturian (spoken in Asturias),Calo (known as the language of the gypsies), Valencian and Mallorquin (Both dialects from Catalan and spoken in Valencia and Mallorca), Extremaduran (spoken in Extremadura), Occitan (also considered as a dialect of Catalan) and Gascon (that is considered a dialect of Occitan) (About. com, 2011). Each region? government has put all the efforts to create laws to ensure that people in all regions speak and practice their own language (Council of Europe, 2011); such is the case of Catalonia which is the region where there have been more efforts to preserve language. In Catalonia, there are no places where natives do not know Catalan or any of the dialects from it, and even foreigners living there must deal with this â€Å"handicap† since, in order to find a job, they need to learn to speak Catalan; otherwise, it will be very difficult to get hired, and social life can be limited as well since veryone around uses Catalan to communicate (Abanco, 1998). Spaniards, especially in Catalonia, Basque Country and Galicia have become very protective of their own languages and dialects, since they outright their extinction during Francoist period, which make them fight to ensure their languages remain being an important part, if not the most important part, of their life and their societies (Wikipedia contributors, 2011). Each region, with a language different than Castilian, is an avid defendant of their language; article 3 of the Spanish Constitution (About the Castilian and the other Spaniard languages) states: â€Å"1. Castilian is the official Spanish language of the State. All Spaniards have the duty to know it and the right to use it. †. â€Å"2. The other Spanish languages shall also be official in the respective Self-governing Regions in accordance with their Statutes. † and â€Å"3.  The wealth of the different linguistic modalities of Spain is a cultural heritage which shall be specially respected and protected† (Cortes Generales de Espana, 1978). This decree has helped to repair the damage caused during Francoist period (in which Spain was under the authoritarian dictatorship of Francisco Franco) from 1936 to 1975, when many of the regional languages were almost lost since they were forbidden; an ironic fact since general Franco was born in A Coruna, one of Galicia? s main cities, where Galician is more used than Castilian to communicate (Eric Solsten and Sandra W. Meditz, 1988). When the civil war ended, in 1975, and, in response to the oppression suffered for many years, some regions (especially Catalonia) began their efforts to preserve and enhance their languages. Thanks to those efforts Catalans can be proud to acknowledge that their languages and dialects are the most well-kept, normalized and preserved in the country, their continuous fight since the very end of war and their pride about using their language has giving them the courage to embrace and protect both, their language and their identity in such way that, in Catalonia, Castilian is limited to those who are foreigners and Catalan to natives. Unfortunately, a very different thing has happened in Galicia and Basque Country; since, by the end of war, the governments of both regions were more concerned about political affairs than preserving languages. In Basque Country, the reason for these lack of protectionism towards language was the persecution Basques suffer during the Civil War, they were accused of terrorism whenever they spoke in their own language; they were hunted and killed for this reason, and all of these actions made them a little afraid of protecting language even years after the end of war. Something similar happened in Galicia, where there were no efforts to maintain language after the war. It was years later that governments started to make efforts to preserve and rescue the language and to normalize it and make it mandatory in each school around the region, but the accurate and pure versions of them got lost with time and what new generations speak today is a mixture of old and new words adapted from the original language, but still it is quite far from the original, unaltered version of each language. The dialects in Spain share, in most of the cases, the same origin (most of the times Vulgar Latin), and the same language (for example Valencian is a dialect of Catalan); it can be thought, then, that communication in a language different than Spanish or Castilian is not that hard, and this is true but not entirely; even though these dialects come from the same sources, they differ greatly from each other; for example, in Catalonia, they use Catalan as well as in Val d? Aran; if an Occitan and a Catalan talk to each other, they will understand most of it but some words are very different, and it will take a bit of an effort to fully understand the language from one region to another. Each one of the circumstances explained above, the civil war, the immigration, the language protectionism and the normalization, are reasons to understand why Spaniards have become tolerant with languages and dialects; they have gone a long way in defending their ideals and their identity; all of the Spaniards and immigrants must pay tolerance in return to the rest of the population and accept everybody else? languages. However, not all Spaniards are sympathetic with this language protectionism, Castilian or Spanish speaking regions, such as Madrid are very less tolerant; they do not understand why one country must be separated more for languages than for borders, and this might be a valid premise, but each region has the right to protect what belongs to it. Languages, in one way, have caused separation among regions because, people consider themselves as Catalans, or Valencians, or Basques, or native of any other regions, more than they consider themselves Spaniards, and many regions are currently fighting for their independence (with no positive results so far) since they aim to be free to use their languages and dialects without being criticized and, also, be able to manage their own resources. There are many implications of having one, two or many anguages or dialects spoken in a same country or region, some of them are negative, such as this search for independence that has caused Spaniards to feel divided, not all of them feel part of the same country and many whish they were not part of the same country at all. Another implication is that communication is limited; even when all Spaniards speak Spanish, it is interesting to realize that they have both languages so acquired that they switch from one to the other in just seconds; this happens particularly with old people. As a woman married to a Catalan and having traveled to Catalonia a couple of times, I had the experience of facing this personally, people are so set in â€Å"Catalan-mode† that one minute they are speaking in Spanish, and the next they are speaking in Catalan without even realizing they change back and, in my particular case, I found myself reminding everyone to talk to me in Spanish; it is an awkward situation because you can also feel like an intruder and is tiring to constantly remind everyone to speak in Spanish, and when they did speak in Castilian, it was hard for me to understand them, since it is quite different from the Spanish or Castilian we speak in Costa Rica. Another negative implication is for immigrants; my cousin moved to Barcelona eleven years ago; she got a scholarship to finish her studies in laws at â€Å"Universitat de Barcelona. The first problem she had to face was the fact that all her lessons were taught in Catalan; and being a native Spanish speaker she felt very frustrated and worried, and it took many years for her to be able to understand Catalan (only understand it because she does not speak it); she is now living there and after she finished college it was very hard for her to find a job, once again the problem was the lack of Catalan; it is very challenging for a foreigner to move there since Catalans are so protective of their language that in order to find a job, people must speak Catalan. The last negative implication, from my point of view, is immigration within the country; my mother in-law was born in Galicia; she learned to speak Galician (the very limited kind of Galician that was spoken during the war) when she was little; and, at the age of nine, with almost her entire primary education finished, her family decided to move to Barcelona searching for a better life, where she had to deal with Catalan (even though during war it was forbidden to use it on the streets). The same problem happens with, for example, people with military positions, they move from one place to another during the entire military service, and they drag their families along with them; children are forced to change from one school to another and from one language to another, and this can cause confusion and frustration reflected on the students’ behavior and performance in school. Even when there are so many negative implications or consequences related to all the languages in a society, there are reasons to believe that there are also positive implications and if there are societies with this kind of structure, it is because it works somehow, no matter the problems involved. In contrast to the negative implications mentioned above, there are many other positive implications of being part of a multilingual society, to mention a few, it can be said that, in the particular case of Spain, their citizens have developed the ability to learn new languages very easily; they not only speak their official language (Castilian), they also speak they regional language (both native like) and this has helped them to develop more their listening skills and aptitude towards new languages; children are born and live in environments filled with language stimuli and learn to communicate effectively in more than one language, making things easier for them to acquire another language. Another example of a positive implication is tolerance, the cross-cultural situation Spaniards live has helped them to be more conscious about their differences and to accept everyone? s believes and culture. The continuous use of languages or dialects to interact with each other is another positive implication, since it has made them to be able to switch languages in a conversation without thinking about it; it comes natural to them since being multilingual is not an issue; it is just their reality. Spain is a multilingual society which has faced several obstacles in the way of preserving and keeping their languages and dialects, this protectionism has led to positive, but also negative consequences and implications for its citizens which, day after day deal with it and adjust to this conditions in order to be a part of the society. As challenging as it can be, Spaniards adjust to each situation in order to fit in; but of course there are also rewards involved, they are capable to appreciate and understand (at least most of them) what a long way each region has come to preserve their identity and they can embrace, and be empathetic with the reasons each region has for such protectionism.

Australian Public Health Practitioners

Australian Public Health Practitioners Introduction Obesity has been a central concern for Australian public health practitioners due to the rapid increase in overweight and obesity in Australian population over the last 30 years (Preventive Health Taskforce 2009). The level of obesity for both males and females in Australia is around 60 percent (Hawley Dustan 2008).Advertising We will write a custom essay sample on Australian Public Health Practitioners specifically for you for only $16.05 $11/page Learn More The primary prevention strategy for obesity prevention is to address multi factors that lead to gaining excessive weight in people, because this problem originates from multi-interrelated complex factors (National Heart, Lung and Blood Institute, 2012). In this essay, three issues with regard to obesity will be discussed. The impact of obesity on individuals and communities will be explored. Then, the risk factors of obesity will be identified. Finally, some primary prevention programs and strategies will be analysed. The Impact of Obesity on Population Obesity may lead to many health problems in all age groups of the society. Obese children have great chance of developping chronic diseases (Veugelers Fitzgerald 2005). High childhood BMI may increase the risk of developing type 2 diabetes, hypertension, let alone coronary heart disease (Falconer, Viner Kinra 2012; Stevens, Trusdale, Wang, Cai Erber 2011). As a result, this supports the claim that obesity in children can be considered as a risk factor for developing chronic diseases in the adulthood (Park, Falconer, Viner Kinra 2012). In addition, adolescents’ obesity may lead to high risk of developing cardiovascular diseases at young adults. Obese young adults and middle-aged adults are more likely to develop chronic diseases compared to non-obese counterparts (Stevens et al 2011). Further, obesity leads to very serious health problems among older people. It has been found that obesity among older people (aged above 70 years) may have only little effect on the potential years of life lost (PYLL). However, obesity may affect their disability adjusted life years (DALY) (Reynolds, Saito Crimmins 2005). Obesity may have some negative effects on the mental well-being. Being obese or overweight may increase the prevalence of psychiatric conditions such as depression, anxiety and stress. Research has also shown that disabled people are more likely to be obese than normal personal due to lack of physical activities.Advertising Looking for essay on health medicine? Let's see if we can help you! Get your first paper with 15% OFF Learn More At the social level, the cost of obesity and obesity-associated problems may increase the country’s economical burden. In 2008, Australia estimated total annual cost of the direct and indirect expenditure on obesity and excessive weight to be 56 billion Australian dollars (Australian Bureau of Statistics 2010). Thus, it is c lear that weight gain is a problem in obesity. Risk factors of Obesity Obesity is a demonstration of energy imbalance in the body. Imbalance of energy occurs due to taking more calories than required (World Health Organisation 2013). In fact, there are many factors associated with living patterns in individuals and communities that may lead to obesity. Those factors can have imbalanced and insufficient diet, screen time and advertisements, lack of access to nutritious food, socio-economic status, work, physical environment and emotional factors. Excessive fat intake results in higher morbidity rates in adults due to high rates of cardiovascular diseases and diabetes. Imbalanced diet and smoking during pregnancy may culminate in obese children (Moll 2014; Kries, Toschke, Koletzko Slikker 2002). A study in Yale School of Medicine and the University of Cologne found that mothers who have high fat diet might have obese children (Moll 2014). Shorter duration of breastfeeding also contri butes to having insufficient child diet, which may lead to overweight children (Tawia 2013; The Department of Health 2013). Family structure may have some effects on weight gain. A study shows that children brought up by single mother or by women with no male partners for longer than two years have higher chances of developing obesity compared to children who are raised by two partners (Schmmer 2010).Advertising We will write a custom essay sample on Australian Public Health Practitioners specifically for you for only $16.05 $11/page Learn More Spending long hours in front of the television or other devices may lead to weight gain. Researchers have found that prolonged viewing time increases food consumption either by having more snakes between meals or by consuming advertised food (Dennison Edmunds 2008). Lack of access to nutritious food and the socioeconomic status can be contributing risk factors for being obese and overweight. Australian Aboriginals f ace the issues of lack of access to affordable and quality nutritious food in their rural and remote Australian areas (Burns Thomson 2006). Thus, obesity rates in Aboriginals are higher than those in non-Aboriginals in Australia (Burns Thomson, 2006). Many people consider work as a contributing factor to weight gain (National Heart, Lung and Blood Institute 2012). Physical environment plays an important role in contributing to gaining weight. A study in California indicates that there is association between obesity and the urban design that does not support physical activity and makes people rely on transportation instead of walking (Lopez-zeting, Lee Friis 2006). Programs, resources and collaborations Several efforts have been taken to reduce obesity in Australians due to its negative impact on people’s health. Smoking in Australia has been reduced successfully through the use of national tobacco strategy, bans on tobacco advertisements (partially), health warnings on toba cco products sold in Australia, high taxation, education to change behaviours, regulations on tobacco products, and disclosure (The Department of Health 2013). Baby Friendly Health Initiative Aim: To increase breastfeeding among women and aim to reduce the associated risk of obesity in children.Advertising Looking for essay on health medicine? Let's see if we can help you! Get your first paper with 15% OFF Learn More Initiative: This is an existing strategy of breastfeeding that has been done through raising mothers’ awareness of the benefits of increased duration of breastfeeding to avoid the associated risk of having obese children (UNICEF 2013). To make this happen, multi sectoral collaborations were involved, such as Australian Feeding Association, Baby Friendly Health Initiatives and Health Care Staff (UNICEF 2013). ODea (2005) shows that breastfeeding approaches could be effectively used to reduce obesity in children. Active After-School Communities Program Aim: To engage active children in safe physical environments to promote their physical activity through playing after school between 3 pm and 5:30 pm. Program: This is an existing program that provides children with recreational safe places to promote children’s physical activity. This is done through the involvement of regional coordinators and local communities in more than 1500 sites around Australia. It is thought that this program has to involve more stakeholders and should be run for more than two days a week to be more effective (Australian Sports Communities 2008). Moodie, Carter, Swinburn, and Haby (2010) argue that the program is cost effective and can be utilised to reduce obesity cases among school-aged children. Outback Stores Aim: To provide aboriginal communities, especially remote ones, with accessible and affordable healthy food by 2015. Such food would make them healthier and reduce the chances of developing obesity. This plan can be achieved through employment of couple of strategies. These strategies will ensure that healthy food will always be available to those communities. It has been noted that this strategy needs to involve more governmental and non-governmental bodies to support its continued success (Outback Stores 2014). Research has shown that the use of the program has significantly improved the health status of aboriginals in Australia (Lee, Leonard, Moloney Minniecon 2009) The NSW Healthy Worker Initiative Aim: Healthy workers initiative aims to promote healthy lifestyles among workers in order to avoid obesity and the associated risks. Program: This is a proposed program. It is collaboration between NSW Health and New Coverwork. In addition, it involves other stakeholders such as business industries, get active behavioural change program and health professionals. This initiative held a forum in 2013 between business and health stakeholders to outline the planned initiative and to get suggestions from the stakeholders. It will commence in July, 2014 (NSW Health Government 2013). Colagiuri (2004) asserts that the NSW Healthy Worker program has the potential to increase the level of healthy living among workers. The Front of Pack Nutrition Labelling Aim: This is a proposed initiative that aim to inform and increase the consumer awareness of the nutritious content of the food bought from retailers. Program: This program aims to label food and bever ages. The number of stars indicates the level of health associated with various products. About nine stakeholders will collaborate on this initiative (The Department of Health 2014). Research has shown that the initiative is based on public health principles, which seek to reduce cases of obesity in the society (Nestle Jacobson 2000). Television initiatives Aim: The proposed initiative aims to reduce the television viewing time. It proposes to use viewing time for educational purposes. Program: The program will help families to schedule their time with less television viewing to go to local recreational areas to do some physical activities (Andreyeva, Kelly Harris 2011; Baker, IDennison, Boyer, Sellers, Russo Sherwood 2007). Another program can target families to educate them on how to develop healthy habits and stay active. For example, television programmes can target women and educate them on the benefits of breastfeeding their children in order to avoid child obesity. There h as been a positive correlation between the chances of developing obesity in children and the amount of time spent watching the television (Dennison Edmunds 2008). In conclusion, the negative impact associated with obesity was identified in this essay. Then, the risk factors were explored. By exploring the risk factors of obesity, numerous programs were identified in order to be used as primary health prevention programs to reduce the prevalence and incidence of the multifaceted risk factors of obesity at the population level. As noticed, this may need to include many health and non-health sectors to resolve the obesity epidemic. References Andreyeva, T, Kelly, IR, Harris, JL, 2011, ‘Exposure to food advertising on television: associations with childrens fast food and soft drink consumption and obesity’, Economics Human Biology, vol. 9, no. 3, pp. 221-233. Australian Bureau of Statistics, 2010, Health, Obesity, cat. no. 80893.3, ABS, Canberra, via AusStats database. B aker, IR, Dennison, BA, Boyer, PS, Sellers, KF, Russo, TJ, Sherwood, NA, 2007, ‘An asset-based community initiative to reduce television viewing in New York state’, Preventive medicine, vol. 44, no. 5, pp. 437-441. Australian Sports Communities, 2008, Helping Kids and Communities Get Active, https://secure.ausport.gov.au/__data/assets/pdf_file/0020/261470/AASCevaluation.pdf Burns J, Thomson N, 2006, Summary of overweight and obesity among Indigenous peoples, healthinfonet.ecu.edu.au/health-risks/overweight-obesity/reviews/our-review Colagiuri, R, 2004, ‘Diabetes as a health promotion focus: a disease for all reasons.-editorial’, Health Promotion Journal of Australia: Official Journal of Australian Association of Health Promotion Professionals, vol. 15, no. 2, p. 95. Dennison, BA, Edmunds, LS, 2008, ‘The role of television in childhood obesity’, Progress in Pediatric cardiology, vol. 25, no. 2, pp. 191-197. Hawley, J Dunstan, D, 2008, ‘ Overweight and Obesity in Australia’, MJA, vol. 188, no. 3, p. 11. Kries, R, Toschke, A, Koletzko, B Slikker, W 2002,Meternal Smoking during pregnancy and Childhood Obesity’, American Journal of Epidemiology, vol. 156, no. 10, pp. 954-961. Lee, AJ, Leonard, D, Moloney, AA, Minniecon, DL, 2009, ‘Improving Aboriginal and Torres strait islander nutrition and health,’ Med J Aust, vol. 190, no. 10, pp. 547-548. Lopez-Zeting, J, Lee, H Friis, R, 2006, ‘The link between Obesity and the built environment , Evidence from an ecological analysis of Obesity and Vechile miles of travel in California’, Elsevier, vol. 12, no. 2006, pp. 656-664. Moll, M. 2014, Pregnant mother’s diet determines baby’s obesity risk, techtimes.com/articles/2955/20140126/pregnant-mother-diet-determines-baby-obesity-risk.htm Moodie, ML, Carter, RC, Swinburn, BA, Haby, MM, 2010, ‘The Cost†effectiveness of Australias Active After†school Communiti es Program’, Obesity, vol. 18, no. 8, pp. 1585-1592. National Heart, Lung and Blood Institute, 2012, Explore Overweight and Obesity, nhlbi.nih.gov/health/health-topics/topics/obe/causes.html Nestle, M, Jacobson, MF, 2000, ‘Halting the obesity epidemic: a public health policy approach’, Public health reports, vol. 115, no. 1, p. 12. NSW Health Government, 2013, The NSW Healthy Workers Initiative, health.nsw.gov.au/healthyworkers/pages/default.aspx ODea, JA, 2005, ‘Prevention of child obesity: ‘First, do no harm’. Health education research, vol. 20, no. 2, pp. 259-265. Outback Stores, 2014, Working with Communities, http://outbackstores.com.au/ Park, M, Falconer, R, Viner, M Kinra, S, 2012, ‘The impact of Childhood obesity on morbidity and mortality in adulthood, A Systematic review, vol. 13, no. 1, pp. 985-1000. Preventive Health Taskforce 2009, Australia: The Healthiest Country by 2020, health.gov.au/internet/preventativehealth/publishi ng.nsf/Content/E233F8695823F16CCA2574DD00818E64/$File/obesity-jul09.pdf Reynolds, S, Saito, Y Crimmins, E 2005, ‘The Impact of Obesity on Active Life Expectancy in Older Americam Men and Women’, The Geronologist, vol. 45, no. 4, pp. 438-444. Schmmer, K, 2010, ‘Family Structure and Obesity in Early Childhood’, Social Science Research, vol 41, no 12, pp. 820- 832. Stevens, J, Trusdale, K, Wang, C, Cai, J Erber, E, 2011, Body Mass Index at Age 25 and All-Cause Mortality in White and African American : the Atherosclerosis Risk in Communities Study’, Journal of Adolescent health, vol. 50, no. 1, pp. 221-227. Tawia, S, 2013,Sustained breastfeeding’, Breastfeeding review, vol. 21, no 1, pp. 22-34. The Department of Health, 2013, Australian National Breastfeeding strategy 2010-2015, health.gov.au/internet/main/publishing.nsf/Content/aust-breastfeeding-strategy-2010-2015 The Department of health, 2014, Front of Pack Labeling Update, https://www.healt h.gov.au/internet/main/publishing.nsf/Content/foodsecretariat-front-of-pack-labelling-1 UNICEF, 2013, Baby friendly Health Initiative, https://www.unicef.org.au/Discover/Australia-s-children/Baby-Friendly-Hospital-Initiative.aspx Veugelers, PJ, Fitzgerald, AL, 2005, ‘Prevalence of and risk factors for childhood overweight and obesity’, Canadian Medical Association Journal, vol. 173, no, 6, pp. 607-613. World Health Organization, 2013, Obesity and Overweight, who.int/mediacentre/factsheets/fs311/en/

Investigate the erosive characteristics of targets using a centrifugal accelerator erosion tester The WritePass Journal

Investigate the erosive characteristics of targets using a centrifugal accelerator erosion tester REFERENCES Investigate the erosive characteristics of targets using a centrifugal accelerator erosion tester ABSTRACTChapter 1: Introduction1.1 Overview:1.2 Erosive wear of pneumatic conveying systems1.3 Project Aim and ObjectivesAim:Objectives:1.4 Project and its scopeCHAPTER 2 LITERATURE REVIEW2.1 Overview2.2 History of wear concept2.3 Basic concepts of erosive wear2.4 Mechanisms of wear test2.5 Factors effecting the erosive wear2.6 Test facilities and conditions2.6.1 Wear Test facilities2.6.2 Test condition for erosive wear impact2.6.3 Centrifugal accelerator erosive tester2.6.4 Glass-blast erosive wear test2.6.5 Measurement of wear 2.6.6 Measurement of solid particle velocity in erosive wear2.7 SummaryCHAPTER 3 METHODOLOGY3.1 Overview3.2 Experimental requirements3.3 Test facilities3.3.1 Centrifugal accelerator tester3.3.2 Description of tabular feeder system3.3.3 Description of Double Disc Velocity meter3.3.4 Tachometer3.3.5 Mechanical sieves3.3.6 Ultrasonic bath for clean the targets3.4 Description of test materials3.4.1 Specimen (Mild steel)3.4.2 Olivine sand3.5 Test conditions for im pacting erosion wear3.7 SummaryCHAPTER 4 Calibrations of Impact Conditions4.1 Overview4.2 Calibration of exit angle of particle jet, particle velocity and speed of the rotating disc:[S2]4.2.1 Calculation of exit angles and particle velocity4.2.2 Calculations of impact conditions of centrifugal erosion tester:4.2.3 Calibration of exit angles of particles, particle velocity, speeds of rotating disc.[S3]4.3 Design of target holders for mild steelChapter 5: Experimental procedureOverview:Procedure:5.1 overview:5.2 Experimental resultsChapter 7 Discussion of Results:6.1 Overview:6.2 Erosion rate with respect to Impact angles:6.3 Erosion rate with respect to velocity of the particle:6.4 ConclusionsCHAPTER 7 CONCLUSIONSCHAPTER 8 Future workREFERENCESRelated ABSTRACT Erosive wear is the phenomenon of removal of the surface of any component basing on different conditions due to high-speed impact of solid, liquid or gaseous particles. It is a common occurrence on most plant and machineries and manufacturing industries. The phenomenon of erosive wear has been studied for many years, and still research is going on the material-related aspects of particle impact erosion. Different laboratory testing methods were used to determine the erosion resistance of all eroded materials. In order to predict the erosive wear rate during the erosion test, some major properties such as effect of erosion parameters, effect of abrasive particle characteristics were investigated. The Aim of the project was to continue the work done by scholars and to investigate erosive characteristics of targets by using a small centrifugal accelerator erosion tester.   The present project focuses on the erosion of ductile materials particularly mild steels as these are used in pneumatic conveyor plants where some of the most severe erosion problem occurs. An experimental process was conducted with olivine sand, mild steel as hitting and target specimens to calculate the erosion rate. During the experimental process a study was made to calculate the specific wear rate and analyse the wear properties under different testing conditions. The report presented gives the detailed description of experimental process along with description of materials and tools used. Also report gives detailed analysis of relations of wear properties and rates of relations. Finally future works which could be possible are discussed in the report. Chapter 1: Introduction 1.1 Overview: Wear is a progressive loss of substance resulting from mechanical interaction between two contacting surfaces, it is a common occurrence on most plant and machineries and manufacturing industries. In 1997, a survey of wear problems and costs in UK industry indicated that a typical average cost due to wear was about 0.25 percent of company turnover [4] [5]. Wear can be abrasion, erosion, corrosion or other chemical reaction, appearance of failed surfaces (e.g. cracking, melting, phase transformation) etc But processes involving erosive wears where there is an involvement of particle size, particle velocity, angle of incidence, and particle distribution are more effective than others. 1.2 Erosive wear of pneumatic conveying systems Erosion involves the mass removed from the surface of any component at different conditions due to high-speed impact of solid particle or a liquid particle. Generally the erosive wear sizes between 5 and 500 microns by causing the particles. (W-1) [3]. Today, many engineering industrial plants are facing the situation of the erosion wear. Phenomenon of erosive wear has been studied for many years, and still research is going on the material-related aspects of particle impact erosion. There is a certain need for the analysis of wear process, before defining the exact problem. As stated earlier wear can be abrasion, erosion, corrosion or other chemical reaction, appearance of failed surfaces (e.g. cracking, melting, phase transformation etc.). The types of wear process will be able to tell what kind of testing is needed to find the wear problem. Sliding friction, erosion testing processes which involve surface fatigue can be modelled at a reduced scale. But processes involving abrasive wears, erosive wear where there is an involvement of particle size, particle velocity, angle of incidence, and particle distribution should be modelled at full scale. This can only happen with an appropriately designed test, and it will be carried out in specially designed erosion testers which involve impact of a stream of particles agai nst a test sample. In order to predict the erosive wear rate during the erosion test, some following major aspects have been investigated (3 progress) [6]. Size and shape of particle Material Properties of the target Impact conditions (Impact angle, impact velocity) Particle concentration on the target. Now a day’s Different laboratory testing methods are used to determine the erosion resistance of all eroded materials. But the main challenge lies in the prediction of correct test conditions which should be adopted during the test. Current project study will involve calibration of test conditions such as particle velocities and impact angles to the targets. The work was mostly concentrated on erosive characteristics of ductile materials used in pneumatic conveyor plants where erosive problems occur most often. As mild steel is a commonly used ductile material in conveyor plants it was chosen as the target material and centrifugal accelerator type erosion tester was used to find the wear characteristics. 1.3 Project Aim and Objectives Aim: The Aim of the project is to continue the work done by those scalars and to investigate erosive characteristics determination of mild steel targets by using a small centrifugal erosion tester.   The present project focuses on the erosion of ductile materials particularly mild steels as these are used in pneumatic conveyor plant where some of the most severe erosion problem occurs. The experiment will be carried out with some of effective erosive wear factors. Objectives: The project has been divided in to several objectives. The main objectives of this project are listed below Calibration of impact conditions on a centrifugal erosion tester Controlling the impact characteristics for pre-set test condition Determination of erosive wear for mild steel targets Relationship between erosion rates for different impact conditions. 1.4 Project and its scope   The main purpose of the project was to determine the erosive wear which is a serious problem in the pneumatic conveyors. Here in this project an attempt was made to calculate erosive wear rate in the mild steel target material using the olivine sand as the eroded material. The results obtained from the experiment can be used for minimising the erosion rate in the mild steel made pneumatic conveyors. Also the work done can be taken as a guideline for several future works in the field of erosive wear.    CHAPTER 2 LITERATURE REVIEW 2.1 Overview Ample of research has been carried out in the area of erosive wear impact on plant and machineries and manufacturing industries. The theoretical concepts obtained from different references such as journals, websites, papers and books which are directly or indirectly related to the project are presented in this chapter. 2.2 History of wear concept Erosive Wear is the concept which is not new to the manufacturing industry, it was first proposed in 17th century. Till 18th century until Osborne Reynolds paper on hydrodynamic lubrication it was not well known in manufacturing industry. In the paper author explained the causes of wear and need for lubrication for the first time. Gradual progress was made from 18th century and now days it has emerged as important factor in any manufacturing industry. 2.3 Basic concepts of erosive wear Removal of material from the surface of the solid body is known as wear. Wear may combine effects of various physical and chemical processing preceding the friction between two contracting materials. obtained result was micro-cutting, micro-ploughing,  Plastic deformation, cracking,  fracture,  welding, melting, chemical interaction(w-2)[11]. Before the start of project it is necessary to know the all basic concepts of wear. Definition of wear coefficient K. (Lb-2) [12]K= Where V=volume worn away L= total sliding distance W=applied load Erosive wear occur due to the impact of number of small particles on the surface of the any mechanical object. Generally erosive wear is caused by the particles of sizes between 5 and 500 microns. Surfaces are impacted by continuous stream of hard particles which is known as particle erosion (11) [3]. One of such major place where erosion occurs is pneumatic conveyors, which may result in punctuation of conveyor bends or dust problem if the bends are penetrated. The main effects of the erosive wear are (2) [13]. Dimensional changes Leakage Lower efficiency Generated particles contribute more wear Erosive wear resistance cannot be estimated only by hardness and characterizing resistance to  Ã‚   penetration. The wear resistance of hard material with equal hardness level can be attributed to their resistance fracture (8) [14]. There are two types of wear which are main reasons for erosion. The first one is due to the repeated deformation during the collision and the other one is due to the cutting action of the free moving particles. The rate of erosion depends on the particle velocity which results in the plastically formed concavity of similar radius of curvature to that of the particle (2)[13]. Repeated deformation during the collision: This type of erosion occurs in the systems in which particles moves at high speeds for example pneumatic fluid bed systems, air mills etc. where the particles move free at high speed and impact on the solid which results in the wear (2)[13].The formula for deformation wear is Where Wd= Units volume loss M= Total mass of impinging particles V= Particle velocity ÃŽ ±= Impact angle K= Maximum particle velocity at which the collision still is purely elastic and ÃŽ µ= the energy needed to remove a unit volume of material from the body by deformation wear. Cutting action of the free moving particles: This type of wear is occurred due to the particle that impinges the component at an acute angle and due to this there is scratching of material from the surface of the component. This scratching of the material is highly influenced by the velocity and the impact angle of the particle (2)[13]. 2.4 Mechanisms of wear test Wear is occurred by mechanical or chemical reactions generally accelerated by friction heating. There are six main wear phenomena which explain only removal of material from the solid surfaces (16) [15]. In many cases, wear is initiated by one of these mechanisms and it may proceed by other wear mechanism, there by complicating failure analysis. Particle contamination can damage systems by causing a variety of types of wear (15) [12]. The following table shows the primary cause of wear for each mechanism (1) [16]. Type of mechanism Primary cause Abrasive wear Particle between adjacent moving surface Adhesive wear Particle and high fluid velocity Fatigue wear Surface to surface contact (loss of oil film) Corrosive wear Particle damaged surface subjected to repeated stress Erosive wear Water or chemical Table 2.1: Different types of wear mechanisms. (1)[16] Finnie in his work Observations of the erosion of ductile metals has made an attempt to clearly discuss the factors affecting the erosion in ductile metals. Also Gwidon W. Stachowiak, Andrew W. Batchelor, GrazynaStachowiak (2004) in their journal Experimental methods in Tribology discussed the mechanism of erosion of ductile metals analytically and experimentally. The analysis was carried out by writing the equation of motion of a single particle impaction on the surfaces, volume for the same was then calculated using the trajectory of particles [18]. Such type of approaches was obviously unsuitable for brittle materials. In the experiment the particle velocity on the surface of the ductile metals were obtained by using high speed double flash light source. The authors mainly concentrated on the calculation of single particle of different sizes and at different angles with which he then calculated for whole of the volume of particles. The authors also explained about the drawbacks th at they came across during the experiment and mentioned about the most unsatisfactory feature of his analysis. It underestimates the weight loss at large angles and, in particular, predicts no erosion at 90 °, and explained the three effects which cause the relative erosion at high angles to be greater than that predicted by the sample theory (9)[17]. 2.5 Factors effecting the erosive wear The numbers of factors which significantly affect the rate of erosive wear were discussed by Dr.Dmitri Kopeliovich in his work Mechanisms of wear in 2009.According to him the factors are (12)[11] Impingement angle: the angle at which a particle hits the surface is very important to erosive wear rate. By the experience it was found that the wear rate was high at an angle of 30 ° for ductile material and 90 ° angle for brittle materials. Impact speed: high speed particles impacts cause more damage than low speed collisions. Particle properties: particle properties were more important in erosive wear phenomenon, sharp and hard particles causes more wear rate. Temperature: High temperatures cause high erosive wear because increase in softness of material in high temperatures Particle flux rate: Particle flux rate is the mass of particles hitting an area of surface per unit of time, which can vary greatly from 100 kg/m^2/s to 10,000 kg/m^2/s. 2.6 Test facilities and conditions 2.6.1 Wear Test facilities The national laboratory in the UK identified over 400 wear testing standards all over the world and American society of lubrication engineers indentified 300 tests that were used in various test laboratories in year of 1973. From these tests some type of tests have slight variation on others, less than 100number of tests are useful to find out the wear problems (15)[12]. As early as Mr. Neale was carried out a survey on wear in 1997 as the result in his survey seven types of wear mechanism were identified, most significant wears were abrasive, erosive and adhesive wear. More than one test method is justified for a particular wear type and more than ten test methods are justified to meet industrial need for seven types of methods (14)[5].There are three major types of erosion testing devices that are used throughout the world for quantifying particle impact erosion against a solid surface (10)[18]. 2.6.2 Test condition for erosive wear impact One of the important tasks of the project was to identify the ideal testing conditions. A journal by B.G Mellor in Surface coatings for protection against wear gives the brief idea of various testing standards. According to Mellor the main equipment that is required to find the erosive wear of the pneumatic bed is the centrifugal accelerator erosion tester. Here in the experiment the different test conditions like using different velocities at different impinging angles are used to find the erosive wear of the component. The investigation is mainly focused on the effect of the particle concentration, effect of progression of wear and the effect of bend radius (3) [19]. The pneumatic conveyor test rig should also be inspected prior to the experiment. The equipment should be set to the conditions that would exactly suit the experiment. Hence, the rotational speed of the screw feeder, the blow tank pressure and the mass flow rate of the air supplied to the conveying pipe all should be adjusted to give a positive experimental result (4)[20].   As mentioned the test rig material is the mild steel on which the experiment is to be performed. The material that is to be used in the experiment which is to be impinged on the mild steel component is the olivine sand abrasives. Olivine sand consists of 98.5% (Mg,Fe)2SiO4, with the balance being made up of traces of metallic oxides. The particles density of the abrasive material should be found out prior to the experiment. The grain size should also be measured and found before the experiment (3)[19]. 2.6.3 Centrifugal accelerator erosive tester The test equipment that is to be used for the determination of the erosive wear for mild steel impacted by olivine sand is the centrifugal accelerator erosion tester. The schematic figure of the centrifugal accelerator erosion tester is shown below (4)[20]. Figure 2.1: Schematic of the centrifugal accelerator type erosion tester (4)[20]. The centrifugal accelerator erosion tester is the testing equipment that is to be used in the experiment in the laboratory. The main parts of the centrifugal erosion tester are feeder, an accelerating rotating disc and a target holding system. The abrasive olivine sand is fed into the central hole of the rotating disc and is accelerated through the several radial ceramic tubes by the centrifugal force and ejected from the end of the tubes. The specimen targets are set for the reorientation relative to the direction of parallel flow by the disc on holders. The edges and back face of the specimens are protected from particle impact to prevent unwanted erosion. The target holder is the main equipment that is used for the change of angle for the particles that to be feed into the system. There are many experiments performed using the same equipment by many researchers which would help the present work with their papers. They clearly explained about the working procedure of the experiment and the methodology and also the result which would be a great reference for the present piece of work (5)[21]. 2.6.4 Glass-blast erosive wear test This test used for determined the wear factors .the glass blast test is consist of carbide nozzle 90mm in length with inter diameter 3mm and it having air injection for particle acceleration. A screw feeder mounted to form a loss in weight, this feeder fed the abrasive into the injector housing. And the object was placed on the adjustable table to control impact angles on the object. The author T.Deng was compared the wear factors using the two wear test and compared the results (6) [22]. The figure 2.2 show below was glass-blast erosive wear test. Figure 2.2:   Glass blast erosive wear test (6)[22] 2.6.5 Measurement of wear The measurement of wear is partly determined by the change of mass occurred in the object. A journal by Gwidon W. Stachowiak, Andrew W. Batchelor, GrazynaStachowiak in Experimental methods gave the brief idea about measurement of wear.   Another problem in the experiment of wear is loss of data when wear is measured over a series of intervals as opposed to continuous monitoring and this monitor shows all worn loss on the object figure 2.3.    Figure2.3: Loss of information when continues wear recording is substituted by periodic measurement (17)[23]. At present there are methods of measuring wear: Detection of change in mass. Measurement of reduction in dimension of a worn specimen. Profilometry of the worn specimen. 2.6.6 Measurement of solid particle velocity in erosive wear Authors A. W. Ruff and L. K. Ives in their paper explained about measurement of solid particle velocity in erosive wear that is being performed in their experiment in the laboratory. Measuring of solid particle velocity is mostly depends on the best erosive testing equipments. Here they have performed the experiment using three different erosion testing apparatus, and explained the working procedure of each of the three different apparatus used. The motion of velocity of particles was determined by high speed photo graphics methods. Also they have shown methods of increasing and decreasing the velocity of particles through motors and transmitted them on transducer output which can be viewed directly on an oscilloscope. As the project is based on experiment the paper would be of great use because the experimental procedure can be useful in many ways (7)[9]. 2.7 Summary The chapter gave detailed literature review of the concept of erosion and its developments over the years. Literature review was very much useful for the proper understanding of the topic and gaps in research. Based on these gaps in research the author proceeded further in project work and the next chapter gives detailed methodologies, equipments and tools used during project work. CHAPTER 3 METHODOLOGY 3.1 Overview This chapter explains about the different testing methods and tools used during the experimental process. Also a brief description of materials and material handling equipment is given. 3.2 Experimental requirements olivine sand was prepared to required sizes: Due to vast availability of olivine sand in the nature it is been preferred in the present project. With the use of sieving machine olivine sand was prepared to required sizes ranging from 45-425 µm. impact velocity and angle were calibrated by double disc velocity meter: The double disc velocity meter was used for calibration of impact angles and impact velocities. The calibration results were used for calculating the erosion rate of the mild steel target at proposed conditions. Setting up of right test conditions: To satisfy the proposed test conditions the correct setup of the experiment was required. The setup process would include setting up the position of the target angle, rotating speed of the accelerating rotating disc and feeding rate of the olivine sand. The erosion characteristics of mild steel were determined at certain conditions: Most of the pneumatic conveyers are designed by specific characteristics conditions , based on this characteristics condition have been choose some specific conditions such as an impact angles 20 °,30 °,45 ° and 90 °Ã‚  Ã‚   and velocity 20,30 and 40 m/sec during this experiment . The main intention was to finding impact angles, impact velocities and size of the material were to determine the erosion rate. Determination of specific erosion rate on mild steel: The specific erosion rates of mild steel target were calculated at different conditions by changing the impact angles and impact velocities, the results were analysed. The highest erosion rate and the least erosion rate of the target were calculated. These results were useful for the predicted models. 3.3 Test facilities There were number of tools used for analysing the test during the experiment which was described below. 3.3.1 Centrifugal accelerator tester Erosion wear test apparatus built by T.deng at the wolfson centre was available for this wear test. Centrifugal accelerator tester which is illustrated in figure 3.1 below consists of a feeder, an accelerator rotation disc and target holding systems. There were two types of feeders to feed the materials into the rotating disc which were vibratory feeder and conical feeder. Conical feeder was used for this present project. The target particles continuously fed to the centre hole of the accelerator rotating disc through special type of funnel, and then from the feeder they travel outwards along the radial tubes in the rotating disk. Material leaves disc at the periphery with tangential velocity equal to disc velocity. Targets are mounted at the points surrounding the periphery of the disc and the specimens are exposed to a series of eroded streams particles from the radial tubes of the rotating disc. Figure 3.2 schematical diagram of centrifugal accelerator tester:   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Figure 3.1: Centrifugal accelerator type erosion tester This method is more advantageous over the gas jet method and well suited to perform the screening tests on many different materials. The specimens were mounted on the holding system which rotates slowly around the accelerator rotating disc but it rotates only in one direction, to eliminate any possible bias associated with specific specimen locations. The maximum numbers of specimens per test have ranged to 30 in different design of rigs. [25] Accelerator rotating disc is one of the most important parts of the centrifugal accelerator tester. Usually the rotating disc diameter varies between 200 and 600 mm. The apparatus shown in figure 3.1 has a disc of 240 mm in diameter and it contains six radial alumina ceramic tubes with an internal bore diameter of 2.6 mm. The erosion centre was placed on rotating disc of 0.24m diameter [25]. The disc was attached to an infinitely variable inverter controlled motor that was driven by V- shape belt drive. The motor requires 220-240 voltage and which has maximum of 2850 revolution per minute. 3.3.2 Description of tabular feeder system In order to obtain a constant mass flow rate of the abrasive particle, a tabular feeder is used to feed the abrasive material into conveyers or into the erosion test rig and serves as an auxiliary machine in coal washing, electric power, sintering plant and building industries [24]. Tabular feeder consist two main parts. 1)   Hopper 2)   Rotating control disc Hopper acts as storage for olivine sand before feeding into the accelerator disc, rotating control disc controls flow rate of material is required. The speed of the rotating disc can be altered using this speed control unit as a result the material flow will change according to the speed of the rotating disc. Figure 3.2 shows the laboratory tabular feeder used for the project work. Calibration of the tabular feeder was achieved by measuring the flow rate of mass of materials. Figure 3.2: Tabular feeder [U1] 3.3.3 Description of Double Disc Velocity meter There are two types of instruments which were used to measure the particle velocity vector in an erosion tester, they are optoelectric velocity meter and laser Doppler anemometer (k89) [10]. The accuracy of the particle velocity measure was low while using optoelectric velocity meter in centrifugal erosion tester. Therefore, a static form of the double–disc velocity meter and displaced wear scar method (R75)[9] were used for calibration test of the particle velocity vector. Static form of double disc velocity meter is used to measure the particle velocity vector and direction of particle travel. The slot on the double disc velocity meter from which continuous flow of eroded particle travels and hits the surface of the target forms a scar on target material. The exit angle of the actual particle jet can be calculated by the following equation. A schematic diagram of double disc velocity meter is shown in figure 3.3. Figure 3.3: Double disc velocity meter 3.3.4 Tachometer Tachometer is a mechanical instrument used to measure the speed of rotating devices. Here in the present experiment it is used for measuring the speed of the accelerating rotating disc. It has the digital display which when placed against the rotating device shows the speed in rpm. The figure of tachometer is shown below. Figure 3.4: Tachometer 3.3.5 Mechanical sieves Sieving is one of the oldest and well-known methods for particle size measurement. Sieve test is a procedure to differentiate the fine material from the course material with the help of a nested column of sieves with wire mesh cloth. Required material is poured into the top sieve which has largest screen openings, each sieve openings in the column are arranged in order of decreasing size, from top to bottom, where it is collected at the base, which is called receiver. The sieve shakes the column, for fixed amount of time, depending on amount of material poured. After the material is finished amount of sand on each sieve is weighed. The weight of sample of each sieve is then divided by the total weight to give a percentage retained in each sieves. Figure 3.5 shows BS Sieves with sieve shaker machine. % Retained =   Ãƒâ€"100 % Where W sieve is mass of retained in sieve W total is the total mass retained in all sieves. Figure 3.5: Mechanical sieves on sieve shaker 3.3.6 Ultrasonic bath for clean the targets An ultrasonic machine is cleaning equipment used for delicate items which uses ultrasound (usually from20-400 kHz) and the appropriate cleaning solvent (sometimes ordinary tap water). This machine can only be used with water but solvent which gives a better cleaning option is always advised to clean the object. These machines are mostly used for cleaning jewellery, lenses and other optical parts, surgical instruments. Ultrasonic machine uses high frequency sound waves to agitate in an aqueous or organic compound. Water is used for normal cleaning of the object where as the solvent is used for more effective cleaning. Figure 3.6: Ultrasonic Targets Cleaner 3.4 Description of test materials 3.4.1 Specimen (Mild steel) Mild steel typically means soft, unhardened steel with low carbon content. Mild steel is the type of steel that contains iron as well as little amount of other elements i.e. 0.18-0.23%Carbon, 0.30-0.60%Manganese, 0.30% Silicon, 0.040% Phosphorous and 0.50% Sulphur. Cheap availability, high stiffness and magnetic property are some of the user friendly characteristics for the vast application of mild steel. Other specifications of mild steel are: Density of mild steel =7.85 g/cm3 (0.284 lb/in3) Young’s modulus = 210,000Mpa (30,000,000psi) Mild steel was taken in 2.5Ãâ€"25Ãâ€"26 mm square specimens and mass of each specimen was measured as approximately 13.34 to 14.90 grams. Figure 3.7: Mild steel target 3.4.2 Olivine sand Olivine sand is one of the most common and easily available minerals in the earth, It has less amount of thermal dilation and is composition of magnesium and iron ortho silicate with chemical formula (Mg,Fe)2SiO4. The density of olivine sand is 3.28 gm/cm3, melting point up to ~1760 deg. C and the crystals present are angular with sharp edges [29] and the product is hard, dense and heavy in nature. It is an abrasive media for sand blasting and water jet cutting services. The main uses of olivine sand are iron ore processing, foundry sands, abrasives, agriculture etc. Chemical Specification of olivine sand [30]: Products Specification MgO 42-47 % SiO2 35-42% Fe2O3 10-13% CaO 2-2.5 % LOI 1.5% Max    Figure 3.8: various size of olivine sand (45~425  µm) 3.5 Test conditions for impacting erosion wear The prominent parameters and their effect on erosion are as follows: 1) Impact angle Impact angle is defined as the angle between the target surface and the direction of striking the solid particle. The variation of erosion wear with the impact angle depends on the characteristics of the target surface material namely brittle or ductile type. 2) Velocity of solid particles Velocity of solid particle strongly impacts the erosive wear. As particle velocity increases there is significant increase in erosion rate. The erosion rate is generally related to the particle velocity using power law relationship in which the power index for velocity varies in the range of 2-4. 3) Particle size and shape of test materials Particle size and shape is also one of the prominent parameter, which impact erosion wear. Many investigators have considered solid particle size important to erosion. The erosive wear increases with increase in particle size according to power law relationship. The effect of particle shape on the erosion is not very well established due to difficulties in defining the different shape features. Generally roundness factor is taken into consideration. If roundness factor is one then the particles are perfectly spheres and a lower values show the particle angularity. Analysis of hitting particle (Olivine Sand) Pneumatic conveyors are mainly used to transport the powdered materials with high speed and various angles. Project work was mainly based on wear erosion of ductile materials in pneumatic conveyors which is caused by powdered particles, hence Olivine sand was chosen as hitting material. Olivine sand is Magnesium Iron silicate which is one of the most common materials found on the earth, Because of its availability and low cost it was chosen in the work, a detailed description of olivine sand was given in section 3.2. One of the important factors in erosion rate of the target material is size of the particle. Hence measuring of size of the olivine sand was the first experimental work which has been carried out. The size of the sand was measured by using BS Sieves; the description of BS sieves was given earlier in the chapter. Steps involved in analysis of sand are as follows: 300 grams of olivine sand was taken and dried before use. The sand was poured through different sizes of BS Sieves which vary from 45  µm to 425  µm.   Ten minutes of vibration with amplitude of 7 Hertz were taken as the standard measurements for the apparatus.   The vibrator which was connected to sieves vibrates whole apparatus then sand follows downward path on the apparatus leaving behind different sizes of grains in each sieve. Amount of Different sizes of sand left behind in each sieve was measured using electronic weighing machine. Calculations related to Olivine sand are as follows: Percentage of weight retained in each sieve is given by dividing the weight of sand in each sieve by total weight of sand. % retained = (W sieves / W total) Ãâ€"100 % Where W sieve is mass of sand retained in sieve W total is the total mass retained in all sieves. Amount of sand left behind in each sieve and percentages of remaining amount of sand were calculated and tabulated. Tabular column was given in appendix 3.1 A graph was plotted with cumulative percentage of total mass of sand retained on Y axis and sieves size on X axis. This graph gives the average size of particle which was to hit the target. Figure 4.1: Cumulative graph for percentage mass of sand and sieve size It can be seen from the graph that a centre line is cutting the cumulative percentage weights of the sand. The point where the line cuts the graph is the average weight of the particle. The average size of the particle was calculated as ≈ 144 µm from the above graph and shape of olivine sand was angular. After size analysis of material, the next stage of the experimental procedure was calibration of impact velocity and angle of the particle .In case of the centrifugal accelerator, the particle velocity is dependent on the rotation velocity of the rotating disc. The range of particle impingement over the surface of a target varies due to the geometry of this type of erosion tester and need to be accounted for. Therefore, some calibrations are necessary to be carried out before the test work starts which include measurement of particle velocity and calibration of the abrasive feeders. 4) Particle concentration for erosive tests Concentration is amount of solid particles by weight or by volume in the fluid. As concentration of particle increases more particles strike the surface of impeller which increase the erosion rate, the concentration of slurries can vary from 2% to 50% depending upon the type of slurry. However, at very high concentrations particle interaction increases and this decreases the striking velocity of particle on the surface. 3.7 Summary This chapter can be considered as the backbone of project work as all the methodologies, description of working equipment, testing conditions and analysis of testing materials were discussed in the chapter. The following chapter discusses about the calibrations of impact angles which is most important in finding the exact test conditions. CHAPTER 4 Calibrations of Impact Conditions 4.1 Overview This chapter gives detailed description of work done during the project work. All the experimental works, results obtained from those experiments, analysis of the results have been discussed the chapter. 4.2 Calibration of exit angle of particle jet, particle velocity and speed of the rotating disc:[S2] The second and most important phase of the experimental work was the calibration of exit angle of the particle, velocity of particle and speed of the accelerator rotating disc. Before calculating erosion rate of target material it is necessary to know the speed of accelerator rotating disc and exit angle of hitting particle at given testing conditions. These can be calculated by calibrating the results obtained after carrying out the experiment with different standard speeds of accelerator rotating disc and various impact angles of hitting particles of the target material. Certain testing conditions were suggested for the experiment which are: Impact angles of the hitting particles at 20 °, 30 °, 45 °, 90 ° of the target material Impact Velocities of hitting particle: 20m/s, 30m/s, 40m/s This stage of experiment was sub divided in different stages: 4.2.1 Calculation of exit angles and particle velocity The exit angle and velocity of the particle was calculated by hitting the target surface with olivine sand. An electric circuit board was taken as target material for this calibration test. The exposed surface of the target was coated blue colour for a better view of particle impact and then it was placed in double disc velocity meter. A detailed description of double disc velocity meter was given in chapter 3. A total of six double disc velocity meters were used for three different angles for more accurate calibrations. The double disc velocity meters were placed in a work holding system where the normal target holders are placed and with desired angles which are 30, 45, 60 degrees respectively. The figure 4.2 shows the work holding system with double disc velocity meters. Figure4.2: Double disc velocity meter on target holding system Figure 4.5:detailed schematic figure of double disk velocity meter with target Different stages of the experimental procedure are described below. Velocity of accelerator rotating disc was fixed to 1500 rpm with the help of tachometer. There was a speed controller for increasing and decreasing the rotating disc speed to obtain desired speed. The double disc velocity meter was located at the position where the normal specimen target holders stand and rotated to a given angle ÆŸr, with respect to the centre of the rotating disc. 500gms of olivine sand was manually fed into the centre of accelerator rotating disc with the help of conical feeder. From the centre of rotating disc the eroded particles (olivine sand) was equally distributed into the six ceramic tubes. By centrifugal force Olivine sand is forced towards target specimens through alumina ceramic tubes. The continuous flow of sand hits the targets with certain angle which is the exit angle of particle (K) forming the impact on surface of the target. The specimen was then removed and cleaned and then photo scanned for further calculations of exit angle and particle velocity. Figures 4.3 show the scanned photo of two test specimen for 30 degrees impact angle on target surface. Figure 4.3: The scan photo of two test specimen for 30 degrees impact angle on target surface. Figures related to other angles and other rotating speeds are shown in appendix 4.1. Exit angle of the particle was calculated by using the following figure. Figure 4.4 geometry of the double disc velocity meter for measuring the particle velocity vector and particle exit angle at the time of testing 4.2.2 Calculations of impact conditions of centrifugal erosion tester: Using photo scanner which can improve the accuracy of measurement from 0.5mm up to 0.01mm, the exit angle of the actual particle jet can be calculated by the following equations, K=cos-1 [sin (60 °-ÃŽ ±)/r Ãâ€" (r+s)] for 30 ° angle K=cos-1 [sin (45 °+ÃŽ ±)/r Ãâ€" (r+s)] for 45 ° angle K=cos-1 [sin (30 °+ÃŽ ±)/r Ãâ€" (r+s)] for 60 ° angle Where, K= exit angle, r= radius of the rotating disc, s= distance between slot and edge of accelerator disc, ÃŽ ±=angle between target centre and particle jet. 1)  Ã‚  1500 rpm -30 °- 1 target From the formula stated above K=cos-1 [sin (60 °-ÃŽ ±)/r Ãâ€" (r+s)] From the reference of figure 4.4 the following values were obtained x= 3.98, y=11.55, r=120mm, s=18.65, ÃŽ ±=19.01 °   k= cos-1 0.723 K=40.73 ° Where X= distance from impact centre to target centre Y= distance from slot to target r= rotating disc radius s=distance from rotating disc to slot centre ÃŽ ± = angle of target holder 2)  Ã‚  1500 rpm -30 °- 2 target   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   From the formula stated above K=cos-1 [sin (60 °-ÃŽ ±)/r Ãâ€" (r+s)] From the figure the values were obtained x= 4.15, y=11.95, r=120mm, s=18.65, ÃŽ ±=19.15 °   Cos k= 0.730 K=40.91 ° The calculations for the exit angles of the particle jet at 45, 60 degrees at a speed of 1500 rpm are shown in appendix 4.2. The experiment was repeated with different speeds of accelerator disc which are 2000 and 2500 rpm respectively. The calculations are shown in appendix 4.2. The quantity of sand was decreased with increasing speeds of accelerator disc, for accurate impact on the surface. Exit angle for each speed of rotation disc was calculated by the formula Exit angle K = Where k1, k2, k3, k4, k5, k6 are exit angles of particle jet. And all the exit angles were tabulated below Position of the Target angle (deg) Exit angles of Particle jet (deg) Accelerator disc speed (rpm) 1500 2000 2500 30 ° Target 1 (k1) 40.73 ° 40.68 ° 42.68 ° Target 2 (k2) 40.91 ° 41.23 ° 41.29 ° 45 ° Target3 (k3) 32.43 ° 32.50 ° 39.42 ° Target4 (k4) 33.55 ° 32.81 ° 40.39 ° 60 ° Target5 (k5) 37.79 ° 37.69 ° 38.53 ° Target6 (k6) 35.78 ° 36.43 ° 37.01 ° Exit angle (K) 36.86 ° 36.905 ° 39.88 ° Table 4.2: Exit angles for various double-disc velocity meters at different angles and speeds The next step was to calculate the particle velocity which was calculated by using the following methodology: Figure 4.5: calibration of the particle velocity For 1500RPM Exit angle K=36.865 ° from above tabular column. Tangent angle (VÃŽ ¸) = ωr Where ω is speed of the accelerator rotating disc r is radius of radius of accelerator rotating disc VÃŽ ¸=18.84m/sec From the Figure 3.4 Cos (K) =VÃŽ ¸/VP Where VP is Particle Velocity Cos (36.865 °) = 18.84/VP VP=23.55m/sec In the similar way particle velocity at different rpm was calculated .the calculation part are shown in appendix 4.3and the velocities are: Particle velocity for 2000 RPM is 31.43m/sec Particle velocity for 2500 RPM is 40.94m/sec. 4.2.3 Calibration of exit angles of particles, particle velocity, speeds of rotating disc.[S3] The next and most important stage of the experiment was calibration of Exit angles of particles, particle velocity, and speed of the rotation disc. A graph was plotted with the help of obtained exit angles; particle velocity for standard conditions (disc velocity 1500, 2000, 2500 rpms, and target angles 30 45 60 degrees) is shown in figure 4.6. Figure4.6: Calibration of exit angles of particles, particle velocity, speeds of rotating disc.[S4]   Calculation of speed of rotating discs, exit angle from the calibration, at proposed impact velocities. With the help of graph, the values of rotating disc speed, exit angles of the particles were found for the given testing conditions. The values of particle exit angle (K) and rotating disc speed are given in the tabular column below. Proposed impact velocities (m/sec) Particle exit angle K (degree) Rotating disc speed (rpm) 20 36.5 1280 30 36.9 1909 40 39.9 2442 Table4.3: values of exit angle and rotating disc speed at impact velocities 20, 30, 40 m/sec. 4.3 Design of target holders for mild steel Target holder is an important device in the experiment which was used to place the target in different required positions. Hence designing of target holders was an important task for any erosive experiment. These target holders contain screws for tightening the specimen in correct position to avoid slips when the test was running. As discussed earlier in chapter 3 mild steel material was used as a target with 25mm square in size and approximately each target was 14.34grams mass. The target was held in a jig which protects the edges and back face of the test specimen. The jig with test specimen was fitted in to a target holder which would be capable of supporting the velocities of hitting particle jets, and can be tilted to different angles required for the test. Generally, there were three types of target holders used to find out the erosion rate of the target, but in the present project the horizontal target holders are used to hold the target specimen to find out the erosion rate. Here the suggested four different impact angle targets such as 20á ´ ¼, 30o, 45o and 90o were taken. For each angle two target holders are taken and the totals of 8 target holders were located on the target holding system for this experiment. The figure 4.1 shows the target in the target holder. As the experiment was conducted at four different impact angles which are 20o, 30, 45 and 90 which are shown in the figure 4.2, 4.3, 4.4, 4.5 schematically. Figure 4.1: target holder    Summary In the chapter discussed the calibrations working procedure for find out the exit   angles and velocities by   related formulas and calculation   which is most important in finding the exact test conditions. Chapter 5: Experimental procedure Overview: The chapter discusses about the experimental procedures which were carried out during the project work. A flow chart is also presented in the chapter which shows the detailed working procedure. Typical photographs of the target surface eroded at different test condition were shown in this chapter. Procedure: Finally the main part of project work was carried out, calculation of erosive wear under specified conditions. From above section, with the help of graph and tabular column it was found that for given testing conditions of particle velocity 20 m/s, 30 m/s and 40 m/s the accelerator speeds are 1280 rpm, 1909 rpm and 2442 rpm, similarly the exit angles are 36.5, 36.9 and 39.9 degrees respectively. The first stage of experiment was carried out for 20 m/s particle velocity and later it is repeated for other particle velocities. But Different quantity of sand was taken when increasing speeds of accelerator disc. Steps involved in the experiment are followed: The apparatus was setup before the experiment. The targets were arranged on target holding system in horizontal position with the impact angle of 20 °, 30 °, 45 °, and 90 °. For more accurate values a total of eight targets were used two for each impact angle position. Target specimens were punched with numbers A1 to A8 for clear identification after the experiment. Before fixing the target materials on holding system they were cleaned with ultrasonic bath using isopropyl alcohol. A detailed description of Ultra sonic bath was given in section 3.3.6. Once the targets cleaned they were weighed using electronic weighing machine which has an accuracy of about 0.1mg. For more accuracy three readings were noted and an average of three was taken as the original weight of target specimen. In the next step the target was arranged at an exit angle of 36.50 and with a centrifugal accelerator disc speed fixed to 1280 rpm and at a particle speed of 20 m/s. The apparatus was all set for carrying out the experiment. Once the apparatus was set up the olivine sand was poured through the tabular feeder for experiment.   But at this instance the issue was how much sand per specific time the feeder should pour. The calibration of tabular feeder gives the rate of feeding for sand. After the calibration was completed the rate of feed should be set for this particular testing condition. This completes all the required set up and requirements for the experiment. After all setup was completed experimental process was started by pouring the sand at a rate of 66.6 g/min. The feeder continuously poured the sand which was approximately 2 Kg in to rotating disc centre for about 30 minutes and the accelerator disc dispatched the sand on to targets. Sand particles which were in line with target materials hit the target and eroded the material from the target. After finish the test, target materials were removed from the target holders. They were again cleaned with ultrasonic bath using isopropyl alcohol also dried and weighed using the electronic balance. The experiment was repeated six times for more accurate results and results were tabulated. Results obtained during the experimental procedure are discussed in the next chapter. A flow chart of experimental procedure is given below: Figure: flow chart describing the experimental procedure The above experimental procedure of the flow chart was used for the other impact condition. The figure 5.2 shows target specimen for 20 m/sec velocity after the test.   30 and 40 m/sec. Velocities figures was shown in the appendix 5.1 Figure5.2: Above figures shows the mild steel specimen after the impact of particles on it at 20o, 30o, 45o and 90o angles and impact velocity 20 m/sec.   Summary Chapter provided the detailed description of experiment procedure for erosive wear test using centrifugal accelerator tester. And also the working procedure flow chart.    Chapter 6 Experimental Results 5.1 overview: This chapter gives the results obtained during the experimental procedure. Detailed tabular columns of results, graphical representations are presented in the report. 5.2 Experimental results Table 4.2 gives the detailed weights of target material before and after the experiment. After measuring target material weights it was time to calculate the amount of eroded material. The amount of eroded material is calculated by deducting the weight of test specimen after the impact of olivine sand from the weight before impact. The specific erosion rate which is amount of material eroded per kilogram of sand was found using a software program designed to calculate the specific erosion rate. The tabular column 4.3 gives the detailed results of amount of eroded material for different angles and weights. Targets    Angle of Targets sand used No. Impact 2 kg 4kg 6kg 8kg 10kg 12kg   remove material (g/kg) specific E(g/kg) A1 20o 0.0003 0.0008 0.0012 0.0018 0.0023 0.0028 0.000233 0.0057 20 ° 0.0057 A2 20o 0.0004 0.0011 0.0016 0.0023 0.0027 0.0037 0.000308 0.0075 20 ° 0.0075 A3 30o 0.0005 0.0009 0.0014 0.0022 0.0027 0.0034 0.000283 0.0069 30 ° 0.0069 A4 30o 0.0004 0.0006 0.0012 0.0020 0.0026 0.0032 0.000267 0.0065 30 ° 0.0065 A5 45o 0.0002 0.0003 0.0011 0.0019 0.0022 0.0030 0.000250 0.0061 45 ° 0.0061 A6 45o 0.0004 0.0007 0.0009 0.0014 0.0018 0.0027 0.000225 0.0055 45 ° 0.0055 A7 90o 0.0004 0.0005 0.0006 0.0008 0.0009 0.0013 0.000108 0.0026 90 ° 0.0026 A8 90o 0.0004 0.0005 0.0006 0.0007 0.0008 0.0012 0.000100 0.0024 90 ° 0.0024 A graph was plotted between the amount of material eroded on Y- axis and amount of sand used on X axis which shows a gradual increase in the material eroded with the increase in amount of sand. Figure : This ends the experimental process which was carried out for the given testing conditions. After the experimental procedure the following values of erosion rate were obtained. Impact angle Specific erosion rate 20 0.0057 20 0.0075 30 0.0069 30 0.0065 45 0.0061 45 0.0055 90 0.0026 90 0.0024 The experiment was again repeated for other testing conditions, the amount of sand used will vary with respect to testing conditions. For   Impact velocity 30m/s Accelerator disc speed 1909 rpm Exit angle 36.90 The results were found as Impact Angle Material Removed Specific Erosion Rate 20 0.000922 0.0225 20 0.001011 0.0246 30 0.001089 0.0265 30 0.001122 0.0274 45 0.001022 0.0249 45 0.001022 0.0249 90 0.000500 0.0122 90 0.000533 0.0130 For Impact velocity of 40m/s Accelerometer speed of 2442 rpm Exit angle of 39.9 degrees the results were found as remove material (g/kg) Specific E (g/kg) 0.001900 0.0483 20 0.001867 0.0474 20 0.001983 0.0504 30 0.002133 0.0542 30 0.002017 0.0513 45 0.002067 0.0525 45 0.001133 0.0288 90 0.001133 0.0288 90 Chapter 7 Discussion of Results: 6.1 Overview: This chapter gives the detailed discussion of results obtained during the experimental process. Variation of erosive rate with respect to various characteristics is discussed in the chapter. From the experiments it was found that erosion rate of the material from test specimen is mainly dependent on two factors; Impact angle of the particle Velocity of the particle 6.2 Erosion rate with respect to Impact angles: A Graph was plotted between impact angles on X axis and Specific erosion rate on Y axis which was shown in figure 5.4.2. This graph has an increase in erosion rate from 20 degrees to 30 degrees of impact angle of target material. This increase was because decline in erosion rate along with increase in impact angle. It can be understood from the graph that as the impact angle of particle increases the erosion rate gradually decreases. This decline in erosion rate is because the number of sand particles hitting target decreases with increase in angle. Figure : 6.3 Erosion rate with respect to velocity of the particle: From the tabular columns 3.4 and 3.5 and 3.6 it can be noted that as the velocity of particle increases the rate of erosion increases. The reason behind this graph is high velocities particles erodes more material. 6.4 Conclusions CHAPTER 7 CONCLUSIONS The project had four objectives to be delivered and which were successfully achieved. The main objective of the project was to investigate the rate of erosion for mild steel targets under specific testing conditions. After conducting series of experiments with olivine sand and mild steel targets, erosion rate for particle speed of 20 m/s, 30 m/s and 40 m/s was calculated. From all the results obtained graphs were plotted to understand the nature of rate of erosion of particles. The graph suggests that rate of erosion increases with increase of particle speed on the target material. Also other graphs plotted between the rates of erosion and impact angle of target suggested that rate of erosion decreases with increase of impact angle of target specimen. Hence the main objectives of the experiment were achieved. CHAPTER 8 Future work The project discusses conditions to avoid erosive wear for mild steel impacted by olivine sand. The vast nature of subject gives the opportunity to carry out the experiment by changing various properties of impact materials and target materials and testing conditions. Some of the experimental works which were not possible to carry out during the present work and would be possible in future are suggested. The next work can be carried out by applying electro static charge to the olivine sand using electrostatic ring sensor equipment. The aim of using electro static ring sensor equipment is to find out charge to mass ratio. Another work that can be suggestible is combination of powder with sand. This is because every powder has its own properties, but when they mix with other materials they lose original properties and adopt new properties. 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