Advanced Data Structure Project

CSCI4117 Advanced Data Structure Project Proposal Yejia Tong/B00537881 2012. 11. 5 1. Title of Project Succinct data structure in top-k documents retrieval 2. Objective of Research The main aim of this project is to discover how to efficiently find the k documents where a given pattern occurs most frequently. While the problem has been discussed in many papers and solved in various ways, our research is to look for the novel algorithms and (succinct) data structures among lately related materials and find the one dominating almost all the space/time tradeoff. 3.Background/History of the Study Before we beigin our aim to find a such a succinct data structure, there are a number of fundamental works in our approach. There exist two main among many ideas in classic information retrieval: inverted index and term frequency. (Angelos, Giannis, Epimeneidis, Euripides, & Evangelos, 2005) The inverted index is a also referred to as postings file, which is an index dara structure storing a map ping from content. It is the most utilized data structure in the Information Retrieval domain, used on a large scale for example in search engines.Term frequency is a measure of how often a term is found in a collection of documents. However, there are restricted assumptions for the efficiency of the ideas: the text must be easily tokenized into words, there must not be too many different words, and queries must be whole words or phrases, causing lots of difficulty in the document retrieval via various languages. Moreover, one of the attractive properties of an inverted file is that it is easily compressible while still supporting fast queries. In practice, an inverted file occupies space close to that if a compressed document collection. Niko & Veli, 2007) In further development, people find efficient data structures such as suffix arrays and suffix trees (full-text indexes) providing good space/time efficiency to inverted files. Recently, several compressed full-text indexes have been proposed and show effective in practice as well. A generalized suffix tree is a suffix tree for a set of strings. Given the set of strings D = S(1), S(2), †¦ S(n) of total length n, it is a Patricia tree containing all n suffixes of the strings. It can be built in time and space, and can be used to find all k occurrences of a string P of length m in   time. Bieganski, 1994) Then, we now get close to our original motivation – the Document Retrieval. Matias et al. gave the first efficient solution to the Document Listing problem; with O(n) time preprocessing of a collection D of document s d(1), d(2), †¦ d(k) of total length Sum[d(i)] = n, they could answer the document listing query on a pattern P of length m in time. (Y. , S. , S. , & J. , 1998) The algorithm uses a generalized suffix tree augmented with extra edges making it a directed acyclic graph.However, it requires bits, which is significantly more than the collection size. Later on, Niko V. and Veli M. in their paper present an alternative space-efficient variant of Muthukrishnan’s structure that takes bits, with optimal time. (Niko & Veli, 2007) Based on the background study, we finally move advance to our intensive topic – Succinct data structure in top-k documents retrieval. 4. Research to the Study According to the background study above, the suffix tree is used to minimize the space consumption.In the suffix tree document model, a document is considered as a string consisting of words, not characters. During constructing the suffix tree, each suffix of a document is compared to all suffixes which exist in the tree already to find out a position for inserting it. Hon W. K. , Shah R. and Wu S. B. introduced the first efficient solution for the top-k document retrieval. (Hon, Shah, & Wu, 2009) In order to get rid of too many noisy factors in the large collection, the algorithm adds a minimum term frequency as one of the parameters for highly relevant pattern P. Ho n, Shah, & Wu, 2009) Furthermore, they also developed the f-mine problem for the high relevancy, that only documents which have more than f occurrences of the pattern need to be retrieved. The notion of relevance here is simply the term frequency. In the later study, Hon W. K. , Shah R. and Wu S. B. achieved the study of â€Å"Efficient Index for Retrieving Top-k Most Frequent Documents† by driving the solution derived from related problem by Muthukrishnan (Y. , S. , S. , & J. , 1998), answering queries in time and taking space.The approach is based on a new use of the suffix tree called induced generalized suffix tree (IGST). (Hon, Shah, & Wu, 2009) The practicality of the proposed index is validated by the experimental results. 5. Future Works Since all the fundamental works are settled, our futuer analysis of the â€Å"Succinct data structure in top-k documents retrieval† is mainly based on the most recently accomplishment by Gonzalo N. and Daniel V. (Gonzalo & Dani el, 2012) , a New Top-k Algorithm dominating almost all the space/time tradeoff. . References Bibliography Angelos, H. , Giannis, V. , Epimeneidis, V. , Euripides, P. G. , & Evangelos, M. (2005). Information Retrieval by Semantic Similarity. Dalhousie University, Faculty of Computer Science. Halifax: None. Bieganski, P. (1994). Generalized suffix trees for biological sequence data: applications and implementation. Minnesota University, Dept. of Comput. Sci. Minneapolis: None. Gonzalo, N. , & Daniel, V. (2012). Space-Efficient Top-k Document Retrieval. Univ. of Chile, Dept. f Computer Science. Valdivia: None. Hon, W. K. , Shah, R. , & Wu, S. B. (2009). Efficient INdex for Retrieving Top-k Most Frequenct Documents. None: Springer, Heidelberg. Niko, V. , & Veli, M. (2007). Space-efficient Algorithms for Document Retrieval. University of Helsinki, Department of Computer Science. Finland: None. Y. , M. , S. , M. , S. , C. S. , & J. , Z. (1998). Augmenting suffix trees with applications. 6th Annual European Symposium on Algorithms (ESA 1998) (pp. 67-78). None: Springer-Verlag.

Tourism in Rotorua, New Zealand

I have chosen Rotorua because I think it is a very interesting and important place to New Zealand as a tourist destination and has many distinctive characteristics which include physical characteristics, beliefs, attitudes and what to do in Rotorua. These characteristics are represented in my initial thoughts which are geothermal activity, culture and attractions. I am Rotorua and I am one of New Zealand’s prime tourist destinations. I have many highlights that encourage tourists to come and visit me as a destination. Whether seeking to experience Maori culture, geothermal earth forces, spa rejuvenation, thrills and adventure, or any of the other natural assets such as 16 lakes, some of the world's best mountain biking trails, fantastic trout fishing and myriad forest walking tracks† (Kia Ora welcome to Rotorua, home of the world's highest rafted waterfall, n. d. ). I deliver it all! All of these fun filled and relaxing activities make me a unique destination. I represen t authenticity, energy, fun, culture and learning opportunities. I am home to natural energetic geothermal activity and this is my primary attraction. I have a distinctive smell of sulphur that lets my tourists know they have entered my exquisite boundaries. My key geothermal areas include spectacular geysers, remarkable mud pools and calming thermal pools that have attracted visitors to my region since the 1800’s (Houghton & Scott, 2000). You can experience my relaxing Wai Ora Spa which is the only mud bath complex with therapeutic water and geothermal mud in New Zealand. I have a striking natural landscape that attracts visitors, and it never disappoints. I have a lot of evidence that supports me being a vigorous volcanic region including hissing steam that comes from my roadside vents (Houghton & Scott, 2000). At my many thermal parks I have silica terraces and fumaroles that display striking colours such as red, pink, orange and green (Houghton & Scott, 2000). Some of my breath-taking thermal parks include Te Puia, Wai-o-tapu and Waimangu. Te Puia is known for the famous stunning Pohutu Geyser which erupts up to 20 times a day and reaches heights of over 30m. (Te Whakarewarewa Thermal Valley , n. . ). Wai-o-tapu is a distinctive volcanic area which has a natural bush setting. At Wai-o-tapu the Lady Knox geyser erupts at 10. 15am everyday with heights that reach up to 20metres (Lady Knox Geyser, 2010). The dynamic Waimangu Volcanic Valley has the world’s largest hot water spring and also has the inferno crater which has magical geyser action (Waimangu Volcanic Valley, n. d. ). Many of my tourists that visit Waimangu enjoy walk ing through the peaceful forest passing by mud pools, hot streams and looking down into geothermal craters. My geothermal activity is very important to my destination as it offers authenticity. I am also the homeland of the unique Maori culture that encompasses warmth, spirit and history. â€Å"As wealth and education attainment increase, culture becomes more important as a destination driver† (Yeoman, 2008). This is very important to me as culture is offers a lot to my destination. I comprise many wholesome opportunities to come face to face with Maori culture found in energizing performances and displays and by meeting my people from the Te Arawa tribe. The Te Arawa tribe has now lived on my land for over 600 years. Magical tribal stories relate to their settlement and the developments of their tribe. These are woven into poi, song and haka which are featured in cultural performances. The Te Arawa tribe have guided my visitors as far back as the 19th century when people used to come and visit the historic and unique pink and white terraces at Lake Rotomahana. These were known as the eighth wonder of the world because of the beauty of the natural sinter formations. The pink and white terraces were destroyed in the Mount Tarawera eruption in 1886 that killed 150 people (Mount Tarawera Explodes, 2009). Since the 1930’s the site has been excavated and now thousands of my tourists come and visit my momentous buried village. There are also many night time activities I offer to my tourists that can further their understanding and knowledge of Maori culture. Some of these include the welcoming Matariki, gracious Tamaki Tours and the impressive Te Puia. I also have a thriving arts and craft cultural community. Traditional Maori carving and weaving can be found throughout my gardens and public and private buildings. I also have a community of artists, craftspeople, performers and musicians. My major annual festival and art events include Opera in the Pa, Te Ihi Te Wehi that is a performing arts festival and the Magna Short Film Festivals that include drama and film exhibitions. (What’s On, 2006) These are just many of the breathtaking cultural experiences I can offer tourists as a destination. A key trend in my destination is the development and presentation of the Maori culture and its relevance to my country as a whole. The cultural capital of a destination is how consumers talk about a place (Yeoman, 2008). This is why many people are now coming to my destination as they want to extend their knowledge on Maori culture as it is very important and authentic to New Zealand as a country. My secondary attraction’s includes many fun filled activities. I offer a large range that suits many people from all over the world who seek different experiences. My largest secondary attraction is the Agrodome. It is a world famous and world-class agricultural theme park. Here you can take part in a number of activities such as the sheep show, aqua jetting, farm tours, the swoop, zorb, and various other activities. The sheep show attracts a large number of Asian tourists who enjoy a memorable authentic experience learning about farms and New Zealand history (Agroadventures, 2006). The zorb, swoop and aqua jet attracts those wanting thrill seeking experiences. This is key trend and it emphasizes how diverse my destination is by providing many different opportunities to partake in many unique experiences in one destination. Another one of my very popular attractions is the enjoyable skyline skyrides situated on Mt Ngongotaha. Here you can take in my magnificent views while enjoying a ride on a gondola, go on the luge, try the skyswing or simply dine at the Cableway Restaurant. Skyline skyrides is an amazing attraction that everybody enjoys and it showcases the beauty of my natural landscape. This is a key trend as my natural landscape and its beauty and uniqueness are present throughout my destination. For those who love the outdoors and nature I have two very popular wildlife parks, Paradise Valley Springs and Rainbow Springs Wildlife Park. At Paradise Valley Springs you can relax and take in the fresh air as you stroll through the park. I have various animals that my visitors can get close to including lions, deer, angora goats, donkeys and emus (Welcome to paradise, n. d). Also here at Paradise Valley Springs I have a freshwater spring called Te Waireks, also known as sweet water. You can drink this pure water straight and it is very cleansing. As a destination I believe I am very interesting, diverse and unique and have many characteristics that are appealing. These include both physical and cultural characteristics that offer a wide range of variety that suits everybody. I believe that I don’t disappoint and everybody should come and visit me. I am a very captivating destination that offers authenticity and beauty, while providing many different cultural and learning opportunities to my trusty visitors. I have chosen the logo, â€Å"Rotorua, I offer it all!!! †Ã¢â‚¬ . I have chosen this slogan because I think it is important to tourism branding as it shows how diverse Rotorua is and how many different experiences it offers.

A Reluctant Product of Therapy

Like many pediatricians and other adults who spend most of their time around children, she used false enthusiasm to cover up her other emotions. And also like many other adults who make spending time with children their jobs, she lived under the assumption that children were unable to see through this falsehood, and that children would somehow find this enthusiasm entertaining, or comforting, or relatable. But every time she smiled at me, the skin on her face bunching up under her cheeks and forehead to make room for her unnaturally large grin, I would cry. Because instead of her smile being reassuring, it confirmed to me that something was wrong. Not only that something was wrong, but that something was wrong with me. Her name was Ann, and she was one of my physical therapists. For three or four one-month spouts between the ages of three and twelve, my mother dragged me to her twice a week to undergo some new-wave quack therapy called Tomatis, a treatment in which I wore enormous headphones and listened to high-pitched opera music for hours on end, which, the doctor claimed, was supposed to cure everything from ADD to depression. At times I have convinced myself that all the time I spent with Ann was pointless. She was a board-certified torturer. And who was I for living through this? I was the glorious survivor, who was able to outlast her condescension and her misreading of my abilities, and through a philosophy of self-reliance and emotional fortitude, let my suppressed intelligence and charm blossom! It was, at least, easier to believe this. However, I have come to realize going through therapy as a child increased my success in social and academic spheres as an adult. I have to admit now that as a child I was slow to learn to read. I remember sitting in my 1st grade classroom with my paper reading exercise book, which had shorter words than everybody else’s, stumbling through â€Å"The Cat and the Mat†. My mild cerebral palsy was also something visible; I have home videos of me running like a duck on the soccer field, my right foot making a ninety-degree angle outward with each step. Perhap s I was just a late-bloomer for reading, and my cerebral palsy magically disappeared when I matured. But more likely, it was the many hours I spent in therapy that propelled me to be a good student, if not an exceptional athlete, as a young adult. My physical therapist, Skippy forced me to my physical limits on the treadmill, even though my limit might have been fifteen minutes on the lowest speed. I learned to take sports, and many other aspects of my life, seriously, not covering them up with shoulder shrugs and sarcastic jokes. My reading tutor Erin nurtured me to love reading, putting an MM on the bottom of every page I read correctly. The pleasure of candied bribery turned into actual enjoyment as I was able to move up from such boring books as â€Å"The Cat and the Mat† into riveting classics such as Harriet the Spy. Now reading has not only turned into one of my favorite free-time pleasures, but is also one of my major academic strengths; being able to read well and un derstand words has allowed me to write good research papers for history and to understand complex concepts in my biology textbook. Even Ann, while I was listening to that terrible music, engaged me in games of Scrabble Jr. and checkers, fostering my competitiveness and love for solving puzzles. Therapy is a gift I have learned to appreciate; many of the things I consider part of my unique trademark – my love of reading, my love of puzzles, my frankness and sincerity learned in defiance to the tyranny of fake smiles – were a result of therapy. Therapy made me who I am.

Collecting Information and Forecasting Demand Essay

Collecting Information and Forecasting Demand - Essay Example The last component is the model of marketing which refers to the model that is followed by an organization and its marketing team in developing and implementing marketing plan in order to increase the sales and awareness of an organizations goods and services. One of the most important part of the marketing intelligence system is internal records of the system and these records are essential as they help in identifying and differentiating between those marketing process that are operating in an effective and efficient manner and those systems that are ineffective and inefficiently operating. Example of one such record are the sales invoices of an organization and these sales invoices help in depicting the sales level of different products and services of a company (Kotler, 2012). If the sales invoices depict that the sales of a particular good and service has declined, the information can be useful in identifying the reasons that led to the decline and can even help in identifying so lutions to increase

Organizations going through Change Research Paper

Organizations going through Change - Research Paper Example These aspects are presented in Intel Corporation (2011) and Jones, Watson, Gardner, & Gallois (2010). In Intel Corporation (2011), the rationale for change is informed by the need to match Intel’s enterprise architecture with the current market demand for semiconductor chips. On the other hand, Jones, Watson, Gardner, & Gallois (2010) address change in the light of communication challenges in the21st century. The role of Intel in enhancing the welfare of the communication industry is highlighted. The commonality between the two publications is that they both evaluate the sources and impacts of organizational change. However, while one is based on the internal operations of the corporation, the other focuses on the entire industry. Organizational change for Intel is influenced by technology, operation processes, and architecture subject to the desired level of creativity and innovativeness (Ilozor, Peter, & Graham, 2012). In this respect, Intel uses diverse rationales for internal change, while the industry rationale for change is communication-based. Therefore, the use of single or multiple rationales in assessing the need for change depends on the specific operations undertaken by the

Humanities Assignment Example | Topics and Well Written Essays - 750 words

Humanities - Assignment Example The gods represented in the poem make their actions based on unknown hasty and premature decisions. As a result, the cause of the flood remains unclear: â€Å"Then came the flood, sent by gods intent.† (15). On the contrary, the Bible gives a definite answer: the cause of the flood was the immoral behavior of the people (Gen. 6.5). In other words, in the epic of Gilgamesh, the deadly flood was the result of a whim of the gods, while in the Bible - a punishment for sin. God of the Bible could not accept the immoral behavior of people since it offended His divine plan, and He deliberately decided to destroy mankind. In the poem, there is no explanation as to why Utnapishtim had an opportunity for salvation, while the Bible explains why God chose Noah to be saved: â€Å"Noah was a just man and perfect in his generations, and Noah walked with God† (Gen. 6.9). For this reason, God of the Bible did not regret His decision, while the gods of the poem began to regret their acti ons, blaming Enlil that he did not punish the sole culprit of his anger. The Inferno by Dante is a world masterpiece of medieval literature. This literary work is linked with both ancient heritage and the ideas of Christian Catholicism to convey the most important religious issues that existed in Western Europe in the Middle Ages. This work is characterized by a special vividness of images that have been used by Dante to realize his goals. In The Inferno, the poet portrayed his journey to the afterlife. In general, The Inferno is based on Christian mythology as well as on the doctrine of heaven and hell (Raffa 2). The hero visits various fantastic places: Hell, which has nine circles, Purgatory, and Heaven. Dante sees the amazing wonders, meets with the angels, the righteous, the souls of sinners, God, Lucifer and his minions, as well as the heroes of ancient myths. The moral sense of Dante’s travel

Take home Exam Essay Example | Topics and Well Written Essays - 750 words

Take home Exam - Essay Example Please utilize the space that you feel is necessary to fully answer the questions. You are encouraged to use the materials provided in class and on Blackboard: 1. On a Sunday night, an 8th grade student shares via Instagram, a drawing, crude but clear suggesting a specific teacher should be shot and killed. The students in the school then shared the picture with other students and it went viral. By Monday morning, all of the students were discussing the threat in classes and many students did not come to school or called their parents to go home for fear of what might occur. Can the student be suspended for this form of speech? Explain your answer including an analysis of the legal standards and applicable case law. According to the Education Centre and other various advocacies dealing with state student discipline, they argue that in this kind of case, students should be suspended from school or even expulsion regardless of age and are not obligated by state statute or regulations for alternative provision of education to those students chased away from schools. This will serve as a discipline action and an example to other students who think to come up with those types of illegal ideas. 2. Student is texting in class and the teacher takes his phone and turns it into the office. Later that day, the principal learns that the student has been bullying other peers via social media. The principal searches the student’s phone and opens his social media applications finding teasing statements posted in response to other student’s tweets on Twitter. The principal suspends the student for bullying. Was the search of the cell phone justified? Explain your answer including an analysis of the legal standards and applicable case law. The teacher searching the cell phone was a legal action because he or she had a reason. He/she wanted to know the information,

SMART criteria Essay Example | Topics and Well Written Essays - 750 words

SMART criteria - Essay Example The motion detectors shall be installed to sense whenever there seems to be activity in the room. This will avoid instances of switching on light in an empty room. Whenever there is motion in the room the switching system shall be in standby mode. Light detectors shall then be engaged when the level of light reduces which shall turn the lights on. Motion detectors shall be the primary switching control to put the switching system on standby mode. The motion detector shall be installed by using laser technology to enable sensory of even the smallest movements within a room (Fraden, 267). The light detectors will be the secondary switching level turning on the lights when low levels of light are detected in the occupied room. Measurability The progress of the project shall be based on the set timetable for the plan. Each step in the installation of the switching system shall be analyzed before going forward to the next step. The first step has been laid down as wiring the house. This w ill be done to ensure the circuit is well placed and in the desirable manner. This step is expected to consume the most time as it involves a lot of physical work. The goals of the plan shall be measured against the time laid down for the expected progress. The installation of the circuit should adhere to the installation standards (Linsley, 144). These include the wiring safety codes and the color codes used internationally. Other national standards shall also be applied in measuring the suitability of the installation of the systems. Comparing the setting of the switching system with the set standards shall provide a platform for measuring the conformity to standards. This will ensure that the end product not only works perfectly, but is also safe and conforms to set standards. Attainability The need to install the switching system arises from the desire to switch off unnecessary light. The aim of installing this new system will be to ensuring regulation in the amount of wasted en ergy. Providing a proper control to the usage of light shall immensely reduce the costs incurred from energy related bills. Evidence exists to show that this method can be able to save up to 25% of the energy consumption, reducing energy costs by a similar margin (Klaus D. John, 97). This regulation will occur by providing a system that allows for usage of light only when necessary. The number of lights left on overnight shall also be minimized by using this system. If an individual leaves a room without switching the lights off, the timer shall automatically switch the lights off. This occurs after motion detectors fail to detect any activity in the room. Excess lighting in the rooms shall also be reduced by the light sensors as they control the amount of light allowed into a room at any time. Realistic The proposed system provides an avenue for saving a lot of energy costs. This shall translate into reduced energy bills for the house. The installation of this system is viable as a way of relieving the owners of the house from the high costs of electricity and lighting. Achievement of this shall be through efficient management of the lighting by using switching system that is automated (Reed, 245). The system continues to be employed in many establishments like hotels, and desirable outcomes have been realized. If the same system is utilized within the scope of this house, similar results can also be realized. This lighting system can immensely reduce the time taken by people moving round to switch lights in places

Corporate Culture and Performance Essay Example | Topics and Well Written Essays - 500 words

Corporate Culture and Performance - Essay Example While organizational values relate to employees, profit, customers, stakeholders, community, and the like, individual goals will relate to fairness, honesty, trust, respect, quality, and cooperation. These are precisely the values that are inherent in the organizational values statement. Alone, these organizational values are far too general and open to interpretation. It is easy to forget the particular and complicated nature of human moral experience (Kotter, 2003). Thinking about and discussing the ethical implications of a goal is more practical and valuable than using a list of values or ethical models. Acting on the ethical implications is even more valuable. Ethical action in modern organizations is the relentless effort to make values a part of the goal-setting equation. Where the managers go wrong, however, is in expecting more from these values than they can deliver. it s organizational culture reflects unique industry requirements and customers' expectations. Each application deals with the realities of a particular goal and how to accomplish it. It is possible to say that new changes will be influenced by old principles of work and will need a new set of principles for further change. In this case, corporate culture is the real foundation on which organizational ethics is built.

Cross-cultural and HR Practice (Module is Human Resource Management) Essay

Cross-cultural and HR Practice (Module is Human Resource Management) - Essay Example Both the issues involved in the particular research, i.e. organizational culture and HR have been extensively investigated in the literature. In this context, it has been found by Schuler et al. (1998, 159) that HR management practices applied in the particular countries should be based on the following criteria: â€Å"a) the business structure, b) the legislative and employment relationship context, c) the patterns of HRM competence and decision-making and d) the national culture†. On the other hand, the study of Sims (2002) referred especially in the value of HRM programs applied within a particular organization. According to the results of this study â€Å"human resources involve HRM programs aimed at developing HRM strategies for the total organization with an eye toward clarifying an organization’s current and potential problems and developing solutions for them; They are oriented toward action, the individual, the global marketplace, and the future† (Sims, 2002, 3). The above assumptions are supported by the views of Jackson et al. (1995, 237) who noticed that HRM is most commonly consideredâ€Å"as an umbrella term that encompasses: a) specific human resource practices such as recruitment, selection, and appraisal; b) formal human resource policies, which direct and partially constrain the development of specific practices; and c) overarching human resource philosophies, which specify the values that inform an organizations policies and practices†. At a next level, Kesler et al. (1997) mentioned that there are three basic processes which define the formulation of particular types of HRM practices in firms of all industrial sectors. These processes are the following ones: â€Å"a. aligning organization, b. developing capabilities, c. managing performance† (Kesler et al., 1997, 30). In other words, the role of HRM is considered to be crucial to the formulation of the organizational culture

Nickel and Dimed Essay Example for Free

Nickel and Dimed Essay Ehrenreich speaks about the working class poor in her book Nickel and Dimed. She discusses many issues that are affecting the working class poor including health problems, lack of resources, lack of security and lack of adequate financial resources to live on. She continues to maintain that there should be a higher minimum wage and that one should be able to work for minimum wage and live on that amount of money. In order to do her research for this book, Ehrenreich agreed to live like the working poor. She worked at various places of employment including a small locally owned restaurant where she was a waitress; Merry Maids where she worked as a maid; and Wal-Mart where she worked as a store associate and all were negative experiences in her opinion. Capitalism is the idea that the economy of a given country should be run completely by the people of the country and that the government should not be involved in any way. Capitalism relies heavily on the idea that if the people were to control the wealth rather than the government than more human needs would be met. The people would also be in control of the ways of producing wealth and therefore wealth would be available to more in theory. Another principal idea in capitalism is the idea of land ownership. In capitalism those who own land would be able to sell their land to whomever they please or even sell the rights to use the land as an ongoing marketable property. The government would not produce fair market value for products either, the price of products would solely be based upon the market value which would be based upon supply and demand and a free price structure. I agree with Ehrenreich that there needs to be a lot of structural changes in our society. The only way to truly change the system is for everyone to be on board. I once heard a friend state that there should be a one house rule, meaning until everyone in the country has one house, no one should be allowed two. I feel strongly that the work that Ehrenreich did was important to those whom she was involved with as well as opening up the world of the working class poor to which many people have a hard time understanding. There were many things that I learned while reading the book Nickel and Dimed. I learned many things about what it would be like to be less fortunate than I am. There are many things that could happen to improve the system that involves us. The structural changes that were involved in the book included restructuring the minimum wage system, the way that the working class poor is able to afford basic human needs and that there needed to be changes to the health care for these people as well. Some structural changes that need to occur in order for there to be a better life for the working class poor including livable wages. It needs to be mandated and regulated by our government that the wages that someone earns are enough money to properly care for a parent and a child. Yes this could make it hard for a single parent with more than one child but for them to be at a wage where there was the ability to pay for themselves and one child would still be a vast improvement on what there is today. The wages need to allow a person to be able to provide housing, transportation, food and clothing. The problem with many low income families is that they get to a point where they have to choose between two of their needs. Take for instance in the book the young woman who was unable to afford to feed herself when she was pregnant as paying all of the bills was reliant upon her. She was working very hard as a pregnant woman for Merry Maids and working to ensure that there was a way to take care of an ill relative. This should not happen in our country where so many people are so fortunate. No one should have to go without food and set structural changes and better enforced regulations on pay would advance the quality of life for many who are a part of the working poor. Having wages that one can easily live on is very important. There are many things that could benefit the people of the working class poor if they were able to make enough money to survive on a month to month basis, rather than struggle. Some other structural changes that need to be made are issues with housing. It is sad to think of the fact that so many people in the US are homeless. The homeless in our country are not all unwilling to work. For instance just the other day I saw on Oprah a story about a middle class family with three children who were now homeless after being laid off and losing their home. Some of the structural changes that need to be made with housing are the way that people are able to find places to rent when they have little or no income through no fault of their own. I am not saying that there should be a way for people to just get free housing for everyone but rather that those who are in these situations and have worked hard and are simply laid off because of a bad economy are able to find a way to keep housing. The regulations made on housing and the way that housing is available to the working class poor needs to change as well. Another structural problem that needs to change is the lack of health care for those who fall in the working class poor. There is adequate health care through Medicaid if you don’t make money or if you only make little money. However someone who is working full time makes too much money to qualify for Medicaid alone. The person has to pay a co-pay in order to be able to get their Medicaid and usually they have a spend down to meet as well. A spend down is money that is out of pocket prior to any Medicaid benefits kicking in. The problem with this is that those who are working full time and earning only minimum wage are not making enough money to cover the cost of housing, food and their medical. Having a better and more readily available health care system for all is something that is important as many things that end up costing more lately could be prevented by having adequate regular medical exams and check ups. I am not even saying that there should be free national health care but rather that there are some ways that the availability of health care should be improved for all people. My suggestion would be a program that uses the social security numbers in order to offer free services to the American people. This would be like yearly physicals, generic prescriptions at reduced costs, yearly eye exams and reduced eye wear and yearly dental exams and reduced dental procedures. The charges should be based on a sliding scale fee with the person submitting income and monthly bill verifications. Another thing that could be done in order to make sure that employees are getting adequate health care is that the government could place regulations on companies about health care. The government could impose a percentage of an employee’s salary that a company could charge for health insurance and the government could limit the number of part time employees that companies have in comparison to how many full time employees have and if the company fell outside of those guidelines then they would have to offer health insurance to their part time employees as well. These are all simple things that would not cost the employers much more money and they are all things that could really benefit the entire working class poor in the long. Simple regulations have the ability to make the biggest changes in our economy. Another way that the government could regulate the medical insurance problems for the working class poor is to regulate the amount of money that can be employed for such health care services as a continuation in the direction that we are headed in currently is only going to raise insurance costs and make the availability of insurance to all even further out of reach. By having some set regulations for the cost of health care and the cost of health care insurance the government could easily help the working class poor to be able to better provide adequate health insurance for themselves. In the book Nickel and Dimed the author thoroughly explores the working class poor and their lifestyle. The author looks at the fact that without structural changes there will never be a better life for this entire class of people. These people will continue to struggle on a monthly basis, will continue to face homelessness, hunger and inadequate health care if there are never any changes made to the structural system that is indeed causing the problems for the worker. The system could make many simple changes that could greatly affect how these people, the working class poor, live their lives. These simple regulations and easy changes could make the world of difference to someone who is not as fortunate as others as this class of people would not have to go hungry again. Also it would greatly reduce the number of severely ill people who were unable to get early detection for major medical problems because of a lack of resources. Capitalism would allow the working class poor to be able to have control of more wealth and to control more of the terms of wealth that was available to them. It would give everyone an equal chance to be able to get some type of wealth system in place.

Christmas present Essay Example for Free

Christmas present Essay This passage shows that everyone around the table knows the goose is cheap but is all-thankful of how it looks. This here shows that they really make the best of what they have. Many different ways Victorian reality was different including infant mortality which Dickens talks about through Bob Cratchit son Tiny Tim, whose the smallest of the house at sits on Bob Cratchit arm. Tiny Tim hasnt got much and is crippled but he is still a blessing to the Cratchit family. He is warm-hearted and has innocence. He told me, coming home, that he hoped the people saw him in church, because he was a cripple, and it might be pleasant to them to remember upon Christmas Day, who made lame beggars walk and blind men see. Tiny Tim hear is thinking about others and not himself, this goes to show he hasnt got much, and is a cripple but is still in the Christmas season. Which shows that Tiny Tim is very selfless. Through all of this experience Scrooge is silent all the way through and this shows the reader that he is very ashamed. This is confirmed when the Ghost of Christmas present says the words that Scrooge had said. Scrooge hung his head to hear his own words quoted by the Spirit, and was overcome with penitence and grief. The reader starts to realise that Scrooge is changing and feeling sorry for what he had said, and wishes he could take it all back. Scrooge is starting to truly find out the nature of the Christmas season. But he still hasnt fully got it yet; he has still got more to come. On the journey to other places, which were celebrating Christmas, Dickens uses a number of long sentences to build up tension and to describe places. And now, without a word of warning from the ghost, they stood upon a beak and desert moor, where monstrous masses of rude stone were cast about, as though it were the burial-place of giants; and water spread itself where over it listed or would have done so, but for the frost that held it prisoner; and nothing grew but moss and furze, and coarse, rank grass. Dickens uses a sentence structure where there are many sub co ordinate clauses first in the sentence before the main clause. This is used to build up tension and describe places they are the ghost and Scrooge are going to visit. Dickens gets Scrooge to go to these places because Scrooge needs to change his selfish ways, and by showing him how poor and rich people celebrate their Christmas and they are both alike. The next and last place Scrooge goes to is his nephew. His nephew is sympathetic to him but the rest arent so easily quick to accept his new ways. I am sorry for him; I couldnt be angry with him if I tried. Who suffers by his ill whims! Himself, always. Here he takes into his head to dislike us, and he wont come and dine with us. Scrooges nephew feels sorry for him being so selfish and tries to justify his selfish ways to the rest of the family. I have no patience with him, observed scrooges niece. Scrooges nieces sisters, and all the other ladies, expressed the same opinion. Apart from Scrooges nephew they havent got time for Scrooge and his selfish ways. By watching his own family he realises and finds out what people think about him, the truth about his behaviour. Then he realises that other people are very important to him. Family is important! A Merry Christmas and a Happy Year New Year to the old man, whatever he is! Even though Scrooge is selfish and has a solid cold heart, his family still love him and still wish him a Merry Christmas and a Happy New Year. To conclude, by Scrooge hearing this, going from door to door, following all the ghosts back through his life helps him to change his selfish ways and antics. Which helps to live and good and prosperous lifestyle, and start to find out what the Christmas season is all about.

Effects of Material on Braking Abilities

Effects of Material on Braking Abilities Abstract: The most important utility in our lives as of today is automobiles, there is a lot of research and development is going in every section of the automobile field to give the safest possible vehicle to the world. One such is Brakes section; this is very important part in every vehicle, though we have most accurate and efficient brakes now-a-days, but they fail at the extreme conditions of heat , vibrations , high frequencies etc., this project is mainly concentrated on the aspects which are causing adverse affect to fail and create unusual   disturbances in the brakes. One such is brake squeal, an unwanted sound which is caused due to the vibration of the brake pads against the disc generating the high pitch noise. There are few other problems which leads into the high frequency problems, vibrations, tear in the brake disc etc. Here in this project a detailed study of disc brake is taken into account by considering with two different materials cast iron and aluminium alloy. The performance of brake is studies using normal stress analysis, vibration analysis and thermal analysis. The main problem of squeal can be due to the combination of vibration in brake set-up from callipers to the brake discs. And can also due to the uneven surfaces of the brake disc which causes due to the improper heat dissipation in the brake disc, all this problems are kept into consideration and this analysis are carried out for brake disc with two different materials as mentioned. A simple change in the design of brake disc has also been done for the maximum heat dissipation and this design also studied in this extreme conditions. And these two type brake disc are compared in all its possibly calculated attributes and the best one is concluded. Introduction: An automobile is a creation of history when they started and now it has become a crucial part of the world. Automobile is a wheeled motor vehicle used for transporting passengers, good etc. There has been a lot of improvement in the automotive field in all ways from the past few decades. The main aim of the automotive department is to provide safest vehicle from its design to the material used for each component. Every single thing is decided on basis of the effect of it on the human lives. The vehicles we use are very efficient when compared with older generation vehicles, the safety increases with the development and technology. But there are few problems which are yet to be solved. One such is about brakes, as we know BRAKES are the most important part in the every moving body, we have seen very drastic improvement in the methods of braking system. In olden days the brakes were handled by hand and now we have disc brakes and hydraulic brakes.   But the whole concept of brakes is working on same principle of kinetic energy is converted into heat energy. We find brakes very commonly used in cars, bikes, aeroplanes, automated machines etc. Brake is a device which decelerates the vehicle or machine by converting its kinetic energy into other form of energy, which will bring the vehicle down to the rest. We have disc brakes now which require very less amount of effort and time to stop the vehicle due to its accuracy and sensitivity; this are widely used in vehicles now-a-days. The drum brakes were used for very long time and we use even now, these were also very efficient brakes but due to the very common issues of changing the brake pads very often due to the short hand braking or improper usage, this has been replaced by disc or hydraulic in few machines. But we have found very common issues in disc brakes due to the brake rotor and brake pads. Due to the high friction while short braking we get unwanted noise brake squeal, though it doesnt have much effect on the performance of the vehicle, but it may fail the brake due to the tear o f brake disc or brake pads. A detailed study of each problem will be studied in further report taking disc brake system. History of Brakes: Invention of brake has started with the automated machines; brakes came into light mainly when the motorised wheeled vehicles came into existence. Brakes were not only used in the vehicles, these are used in other machines as brake lever to stop the motion rotor and so on. It has been an essential part of the moving systems. Brakes have developed a lot from first generation vehicles to present time. Early braking systems used steel rimmed wheels to stop the vehicle, which consists of curved wooden block designed to bear against the steel tire when operated by a single leverage system from the driver seat. But the brake shoe used was normal way of braking either in the horse drawn vehicle or steam locomotive. In 1895 Michelin Brothers move a step ahead to replace the steel rimmed wheels with the pneumatic rubber tire to come out with a new braking system as the brake shoes were no longer satisfactory.   A new method of braking system was required in those times as two early devices attempted to apply the friction force to the axle or to drum on axle or transmission shaft were not efficient as wanted. One method was use of wooden block inside a flexible contracting metal band which when pressed together would tighten the drum causing friction between the drum, which is connected to the wooden block and w heel, then the vehicle gets slow down. The other method was inner wheel or brake drum which will add an external contracting band to bear against the drum to bring the vehicle to rest. In 1899 Daimler started cable operated braking system; a cable was wound around a drum and attached to the chassis, so that when the cable is tightened when car was moving forward, the rotation of drum will increase the tightness and grip of cable, so that it will reduce the amount of force required to pull the cable-lever on the pedal to stop the moving vehicle. This brake system worked well but still the braking efficiency was less, the added efficiency called servo assistance is still an important factor in drum brakes even today. The external brake was vulnerable to the atmospheric conditions like weathering and to un-even roads which caused a rapid loss of efficiency and wear of the brake shoe lining and on few times automatic brake use to happen due to the drum expansion. To overcome all these problems an internal shoe brake was developed were the expanding the brake shoes were placed the inside the brake drum, mainly to protect from the dust and weather. Originally early brakes were operated by mechanically, i.e. the transformation by mechanical system was used to expand the brake shoes against drum by the drivers effort applied on the brake pedal. It works by pressing the brake pedal, which make cam to rotate by a lever connected to pedal, which forces the shoes to come on contact with the brake drum. And springs attached to both of the brake shoes to retain the original position when brakes are released. As the early brakes use to operate on lever supported cables and linkage system of fixed rods, equalising the same amount of brake pressure on the wheels has presented many problems , which were solved when hydraulic system was introduced, which used fluid to transfer the force applied to the brake pedal. In hydraulic braking system the set-up of cylinders and pipe lines forms a closed system which is filled with fluid. The pressure generated in master cylinder will transmit equal force to the each wheel cylinder and then equal pressure is applied to all brake shoes. This hydraulic system is used with the disc brake as well. Disc brake is more efficient braking system which was used mostly sports car when introduced but now it has been a very common system in passenger vehicles. It has a disc and a calliper is attached to it which can be operated mechanically, hydraulically, pneumatically, electromagnetically. Types of brakes: The brakes are broadly explained as using friction, pumping or electromagnetism. But one brake system can also use more than one principle. As the project is based on the disc brake we will look forward only to discuss about the frictional brake. Frictional brakes: These types of brakes are mostly rotating devices with a stationary pad attached with a rotating surface. These types of brakes are widely used even now in modern automotive braking system. Basically this are developed from band brakes to drum brakes then to the disc brakes. Band brakes: A simple type of brake, works on a principle that a band is wrapped round the rotating drum. When a force is applied on the lever, the restraining torque is found from the difference in tension between the two ends of the belt. The principle of operation of the band brake is same as for belt drives. This is external type braking system, as we see in picture the brake shoe are mounted on the drum. Ref: http://school.mech.uwa.edu.au/~dwright/DANotes/brakes/intro/intro.html Drum shoe brakes: This type of brake usually mean the brake shoe is mounted to press the inside surface of the drum. Two brake shoes are connected with a calliper set-up; it has lining on it which will create a frictional force when pressed towards the moving surface of the vehicle. These types of drum brakes are still used in modern cars due to the some cost and engineering benefits. These are applied to the rear wheels of today cars. Ref: http://school.mech.uwa.edu.au/~dwright/DANotes/brakes/intro/intro.html Disc Brake: these most widely used brake of these days, A disc is mounted on the wheel or axle and brake pads are placed within the jaws of the calliper, this is give the necessary friction when it will grip on the brake disc. Ref: http://static.howstuffworks.com/gif/disc-brake3.jpg Characteristics of brakes: Brakes are described on basis of several characteristics as Peak force: The maximum force obtained to decelerate the vehicle is called peak force. Few times this can be more than the traction limit of tires, then the wheel gets skid Continuous Power dissipation: As we know that the brakes get hot in use and get fail when the temperature gets too high, the maximum amount of power that dissipates through the brake without failure is the continuous power dissipation. Fade: Due to the over heat of the brakes the surface of the brake pads or disc get fade which will cause decrease in the effectiveness of brakes. Few times even cooling will have big effect on to fade. Power: when a very less force leads to the braking force, which is higher than the other brakes in similar class then its stated as powerful brake, which is due to the sensitivity of the brake system. Durability: Friction brakes have the lining which has wear surfaces, these to be renewed periodically.   Like brake shoes, pads or brake disc. Even if wear surface due to brake shoe generates high peak force this will lead to wear quickly. Weight: In some circumstances brakes are often mounted on wheels, this can disturb the traction significantly. Here weight means brake itself or an additional support structure Noise: generally brakes create some minor noise when applied, but sometimes create a high pitch noise called squeal or grinding noise. Principles of braking system: Brakes work on simple principle to slow down the moving vehicle by applying an external force, it may use more than one component; directly or indirectly several components effect on the momentum of the moving vehicle. Various types of process are used for braking effect. Frictional brakes are most commonly used these days, these works on the simple mechanism of changing the kinetic energy into the heat energy, which is done by only factor friction. Friction is created when a stationary brake pad grips on the moving brake disc with a force applied. This type of braking system is also used in the disc brakes; the stationary brake pads rub on the disc rotor which moves relatively in its own axis. Basic laws of braking system: Braking system can be explained by two simple Newton laws; which will explain the whole concept of the braking system As we know that the Newtons second law The net force on an object is equal to the its mass times its acceleration and points in the direction of the acceleration F = m* a The law is used to find out the net force required by brake pads to bring the moving vehicle to rest, tough there are many other factors to be considered for calculation of brake force which will be discussed further. It can also be explained through Newton first law Every object remains at rest or in motion in a straight line at constant speed unless it is forced to change its state by an external force if we check this law, an external force (brake force) is required to change the state of the vehicle (motion to rest). As this law explained the evaluation of the brake force and system of braking, a further law explains how the brake force will stop the vehicle. Law of thermodynamics: Energy can neither be created nor be destroyed; it will be converted from one form of energy to other form. This explained the frictional force (brake force) is converted into the heat energy. Factors considered while Braking: There are many factors to be considered for the high braking efficiency and performance; here we will see the few important factors which have a more effect on braking efficiency. 1. Condition of disc rotor: An uneven disc or ruffed disc rotor will decrease the braking effect; it has to be very well maintained as few a times due to dust and weather a extra layer is formed on the disc surface which will have a negative effect on the braking concept. Or wear of disc rotor due to overheat. 2. Pressure on brake rotor: A sufficient amount of brake pressure is to be maintained to get enough frictional force to stop the vehicle. If less pressure is applied it will directly affect the brake efficiency as force acting on the two rubbing surface will become less. 3. Contact surface: The area of contact between the brake pads and disc rotor should be more then the high friction is obtained. If lining of brake pads or surface of disc rotor is uneven then area of contact will be less, which will affect the brake efficiency. 4. Tyres: The design of tyre also have a normal affect on the brake efficiency, the more the contact of tyre to the road surface the good will be the braking system. Worn tyres will have less braking action and will not allow vehicle to stop the required point and may also skid, braking action is found high in new tyres due to its more contact with the road surface. There are other factors which also play an crucial part in brake efficiency like aerodynamics, heat dissipation, weight of body etc., Causes of failure: The most commonly found causes for the brake failure are 1. Oil or grease on the brakes will cause failure as it interferes with the friction. If we found oil in brakes mean the oil seal has failed and is why oil is leaking. 2. Overheat of brakes to great degree, which will develop a hot spot on the rotor and drums. This spots will resist the friction from brake shoe and pads, therefore braking power is lost and brake fails. 3. Brake squeal which indicates the tear in the brake pads, by the time the brakes start making a grinding sound, they would have worn out past the pads to rotors. This will require to change more than just brake pads for new one, which will increase replacement cost as well. 4. Improper wheel alignment or disturbance in the steering system will also lead into the failure of brakes. Even if the mass of vehicle will get out of its range due to extra load will cause a brake failure due to the uneven load distribution. DISC BRAKE Introduction: Disc brakes came into existence in 1890s in England. But due to the poor state of roads and dusty conditions the disc and pads use to get rust and get wear, so the system got non-viable at that time. But later it was fully adopted in 1950s with new innovations in the previous design. Many companies started using it in their cars as it was better when to compared with drum brakes, the main reason as it has overcome the brake fade problem by providing the resistance to the brake components and overall performance is better when compared with drum brakes.   Disc brakes become popular in sports cars due to its braking performance. Now it has been common in commercial vehicles as well, as its used at front of the vehicles, as the front brakes perform most of the braking effort. Components: A disc brake assembly consists of a 1. Cast-iron disc (disc rotor) that rotates with the wheel. 2. Calliper assembly attached to the steering knuckle (operated mechanically or hydraulically). 3. Friction materials (disc pads) that are mounted to the calliper assembly. Operation: (Hydraulically powered) Disc brakes prove to be efficient when compared with drum brakes even the working principle is same for both systems. The basic principle of braking system The kinetic energy is converted into heat energy   When brake pedal is pressed, the hydraulic pressure is applied on the piston; it pushes the brake pad to get in contact with the disc. As the pressure increases the calliper pushes the outside pad to get in contact with the disc. Due the friction generated between pads and disc will create the braking force as the pads gets in contact fully with the disc rotor. But if we study the disc brakes widely, it shows that it does not use the much of the friction between the lining and rotor to increase the braking power as drum brakes does, they likely cause a pull between them. Disc brakes have constrained self-energizing action, there has to be sufficient hydraulic pressure to get the required braking force. The braking force can be increased by changing the size of calliper piston. Even less heat dissipation occurs as the friction surface is exposed to the air, which also reduces the braking fade.   Design of disc rotor: generally disc rotors are either solid or ventilated. The ventilated type disc rotor has cooling fins in the middle of the disc to ensure good cooling. Proper cooling ensures longer pad life and it also prevents fading. Some ventilated rotors have spiral fins which allow more air flow and better cooling. These fins are mounted on side of the vehicle and directional. Spiral fins are used in the front of the vehicles as front brakes take most of the braking action as more heat generates. Ref: https://pontiworld.com.au Design of calliper: The calliper are used as floating calliper or fixed calliper design, and these are mounted on the axle or attached to the wheel. Floating calliper type: The calliper are used as floating calliper or fixed calliper design, and these are mounted on the axle or attached to the wheel. this type of calliper requires less parts than the other type and its also less in weight and economical. Based on requirement it consists of one or two pistons. The piston is either side of the calliper. Hydraulic pressure from the main cylinder is generated and the piston thus press the brake pad towards the disc, then instantly an equal hydraulic pressure is generated at the other side and right brake pad pushed towards disc rotor and vehicle stops due to the braking force. Fixed calliper type: The calliper are used as floating calliper or fixed calliper design, and these are mounted on the axle or attached to the wheel. This type of calliper design has piston on both sides of the calliper, which provides the equal force to each brake pad. These fixed calliper types can set-up either one or two pistons on each side. The two pistons can generate a more braking force and a compact design, as these absorb and dissipate more heat, due to its size and weight. This design is capable for greater number of hard stops of short brakes without the effect of brake fade. Materials used for component: The material used for disc rotor plays an important role in braking force. The material should be tuff enough to stand on high pressures and high friction forces. Generally cast iron is used for disc rotor commercially, but ceramic discs are used for high-performance vehicles and heavy automobiles. Recent study shows that aluminium alloys also do a great job as disc. Now we will discuss in detail about the commonly used materials cast iron and aluminium alloys. Cast iron: Grey cast iron alloy is used for the manufacturing of disc rotor; it has superior properties and various advantages over other materials, as it best suitable for manufacturing and machining when compared with other materials which lead to the graphite lubricating the cut and breaking the chips. It contains 2.5%-4% of carbon and greater than 2% of silicon.   This material has good wear resistance and galling which leads to self lubricating due to the graphite flakes. The graphite microstructure of grey cast iron allows less shrinkage. The silicon percentage in the grey cast iron makes the material corrosion resistance and increases its fluidity when casting which also makes material easy to weld. Compared with other alloys of the cast iron, grey cast iron has low tensile strength , the good point about this material is the shock and impact resistance is almost doesnt exist. Here we will see the properties of the grey cast iron for ASTM 60, Tensile strength 62.5 Kpsi Compressive strength 187.5 Kpsi Shear modulus of rupture 88.5 Kpsi Modulus of elasticity ( Tension ) 20.4 - 23.5 Mpsi Modulus of elasticity ( Torsion ) 7.8 - 8.5 Mpsi Endurance Limit 24.5 Kpsi Brinerll Hardness 302 H_b Specific heat 447 j/kg deg Ref: http://www.engineershandbook.com Characteristics of Grey cast iron: Wear resistance: Grey cast iron works as excellent resistance to sliding friction wear, it is widely used for manufacturing of sliding components, most of the automobile components are made up of this item, its all because of the low coefficient of friction, resistance to the galling it has which is due to the effect of graphite flakes . This will help the disc rotor to withstand for high friction forces. Thermal conductivity: The important merit of grey cast iron is its high thermal conductivity, due to its flake graphite structure, heat dissipates occurs in material with good rate. This will increase the cooling of the disc rotor Machinability: Due to the ferrite graphite structure, grey cast iron is simplest and easiest alloys for machining and casting. This will make easy to get the typical designs of the disc rotor with spiral and fins Damping capacity: Grey cast iron has high ability to absorb vibration energy and also damping vibrations, which is due to the high percentage of the graphite flakes it has in it. It also has great property to resist high frequency vibrations. This will help disc rotor Aluminium Alloys: Aluminium is the important alloy of aluminium alloys, were the other metals are copper, silicon and magnesium. It has less tensile strength and low melting pointing. It has good casting characteristics due to its great levels of silicon (4-13%) in it. It is widely used as disc rotor due to its corrosion resistance.   But this is quite expensive when compared with cast iron. Though is in light in weight, has good electrical and thermal conductivity. It does also can be recyclable. All these properties brought a change in many industries to change their traditional materials i.e., aluminium alloys. Characteristics of aluminium alloys: Light weight: The best part of this material is its light in weight, actually its one third of steel in weight, due to its specific weight of 2.7 g/cm3. The more the energy consumed by aluminium the high will be the load capacity of the vehicle.   This will decrease the vibrations and also increases the brake efficiency due to its light weight. Properties of the aluminium alloys: Density 2600-2800 kg/m3 Melting point 660 deg Elastic modulus 70-79 Gpa Poisson's ratio 0.33 Tensile Strength 230-570 Mpa Yield Strength 215-505 Mpa Percent Elongation 10-25% Thermal expansion coefficient 20.4 -25.0 10-6 /k Thermal conductivity: its used in most of the high conductivity line like power transmission, it has twice of the copper in the properties, and its a good conductor of heat and electricity. This will increase the heat dissipation of the disc rotor. Ductility and recyclability: Due to the lower density and melting point, the material is considered as ductile, this will help to the complicated design, as we need in the disc rotor with spiral fins and groves for the air dissipation. Recyclability is also one great factor of aluminium as it consumes only 5% of the energy to melt it, and it doesnt affect its original quality of aluminium. Corrosion resistance: This is the main factor which made it to select for disc rotor manufacturing. It has a natural property of corrosion resistant as it surfaces form an oxide coating on it. While using as disc rotor further surface treatments like lacquering and anodising are done to increase its resistance towards corrosion. Major problems with Disc Brakes: The disc rotor of Disc Brakes is more exposed to the air, due to which there are very frequent chances of getting damaged. Usually this damage of disc rotor is explained in four common ways warping, cracking, rusting and scarring. Few a times the damage takes the disc into the unsafe area then the new disc is replaced with damaged ones. But sometimes using simple machining and other process this damages can be overcome. As scratches or damage on disc rotor can be removed by removing the thin layer on the disc on lathe machine if after that the thickness of the disc falls in the safe dimensions for the braking force. Warping: This is caused due to the excessive heat of the friction area of the disc rotor, due to excessive shorthand braking, uneven cooling of disc may also causes warping. If braking pads get into contact of disc excessively this will lead to warping after certain times, this warping is most commonly found in the racing cars as brakes are used very frequently due to speed and used at high gear times. There are few methods which can avoid the warping, braking at lower gear which will help to reduce the braking load on the brakes, and less heat is generated. The more the braking load, the more the heat generated and more the chances of improper cooling to take place. Changing the disc design with more fins can few times avoids warping. Improper installation of disc rotor may also leads to the warping as only the overwhelmed disc will come in contact with the brake pads. Cracking: This is found mainly in the drilled disc. Cracking occurs mostly around the edges and holes of the disc, due to the uneven expansion in severe environments. As the uneven expansion take place and the braking load varies every time the brake is applied which will lead to the cracking. And in several situations the disc will fail and no possible repair can be done. Even cracking can be overcome by maintaining proper the cooling of the disc and proper heat dissipation. If cracking is become severe then there might be a chance to replace the disc rotor. Rusting: This is found in the vehicle which are not used for period of time, the regular use keeps the friction area clean, but when not in use the friction area and slots get rusted and it reduces the braking power, due to which the strength of the disc also falls down and at this conditions disc should replace with new one. Scarring: Scarring occurs if something hard gets in contact with the disc while moving, which forms a hard spot on the disc, which reduces the braking power and weakens the brake. Generally this happens when the brake pad service life come to end and still its attached to the brake set-up then the steel support of the brake pad get in contact with the disc which creates a hard scratch. These scratches will form black slots when a vehicle come in use, and reduces the structure strength. This can be avoided by regular checking of brake pads checking life of the friction layer, machining the disc to remove the layer on surface of disc which removes the scratches. There are few phenomenal problems which has been a challenging task in braking department like brake squeal, brake judder and brake dust. These problems can be dangerous when they get on excessively. Change of design, material, brake assembly setup all these have been checked extensively to find out the perfect solution for these problems, this project is undertaken based on this problems. Lets discuss in detail about these problems and what are the methods being simplified to overcome it. Brake Squeal: squeal mean noise, this brake noise is a vehicle system problem due to the regularity and severity. The noise generated is mainly because of brake and suspension components together. This is not considered as the main problem to the vehicle were performance is the initial objective, but its not so proper for the road use. This noise is mainly between the pad and disc during the braking. But squeal can also be combination of disc, calliper and brake pads. To avoid squeal under the braking condition is not so possible, if we are assuming brake to absorb very high energy inputs. Actually this brake squeal came into account when front wheel drive and metallic brakes arrived. These metallic pads are harder than asbestos counterparts, and thus more squeal is observed if there are more irregularities and roughness on the rotor surface or if you found looseness between the pads and callipers. Few types of calliper designs are more noisier, if the pads of this callipers are not fitted so tightly and the calliper itself move around when brakes are applied. The more the brakes play the more are the chances of noise. Fixing the squeal problems in wrong way can lead to the squeal more worse. Brake squeal also occurs due to vibration of brake pads towards the disc rotor when vehicle is moving at low speed, this may not affect the braking performance much but will lead to the replacement of brake pads, this is very common problem which most of the vehicles are facing now.   Lot of methods are used to reduce the level of noise,   simple methods like having chamfers to the linings, applying grease between the pads and calliper, adding the brake shim between   the brake back plate and brake pads etc., these may help in some way to reduce the noise. Ref: http://www.aa1car.com/library/bsqueal.htm While using the methods to reduce the brake noise, have to assume the vehicle suspension system which acts more on the braking system, but at the end the squeal is avoided by trial and error method. Although we see an efficient improvement in understanding the actual reason for the brake squeal, it has been difficult to solve it. It was easily verified through the design and study to overcome the squeal, but it was different case practically. The failure was mainly caused because of the dynamic behaviour of the braking system and due to the gap between braking components. The easiest way was using high temperature Effects of Material on Braking Abilities Effects of Material on Braking Abilities Abstract: The most important utility in our lives as of today is automobiles, there is a lot of research and development is going in every section of the automobile field to give the safest possible vehicle to the world. One such is Brakes section; this is very important part in every vehicle, though we have most accurate and efficient brakes now-a-days, but they fail at the extreme conditions of heat , vibrations , high frequencies etc., this project is mainly concentrated on the aspects which are causing adverse affect to fail and create unusual   disturbances in the brakes. One such is brake squeal, an unwanted sound which is caused due to the vibration of the brake pads against the disc generating the high pitch noise. There are few other problems which leads into the high frequency problems, vibrations, tear in the brake disc etc. Here in this project a detailed study of disc brake is taken into account by considering with two different materials cast iron and aluminium alloy. The performance of brake is studies using normal stress analysis, vibration analysis and thermal analysis. The main problem of squeal can be due to the combination of vibration in brake set-up from callipers to the brake discs. And can also due to the uneven surfaces of the brake disc which causes due to the improper heat dissipation in the brake disc, all this problems are kept into consideration and this analysis are carried out for brake disc with two different materials as mentioned. A simple change in the design of brake disc has also been done for the maximum heat dissipation and this design also studied in this extreme conditions. And these two type brake disc are compared in all its possibly calculated attributes and the best one is concluded. Introduction: An automobile is a creation of history when they started and now it has become a crucial part of the world. Automobile is a wheeled motor vehicle used for transporting passengers, good etc. There has been a lot of improvement in the automotive field in all ways from the past few decades. The main aim of the automotive department is to provide safest vehicle from its design to the material used for each component. Every single thing is decided on basis of the effect of it on the human lives. The vehicles we use are very efficient when compared with older generation vehicles, the safety increases with the development and technology. But there are few problems which are yet to be solved. One such is about brakes, as we know BRAKES are the most important part in the every moving body, we have seen very drastic improvement in the methods of braking system. In olden days the brakes were handled by hand and now we have disc brakes and hydraulic brakes.   But the whole concept of brakes is working on same principle of kinetic energy is converted into heat energy. We find brakes very commonly used in cars, bikes, aeroplanes, automated machines etc. Brake is a device which decelerates the vehicle or machine by converting its kinetic energy into other form of energy, which will bring the vehicle down to the rest. We have disc brakes now which require very less amount of effort and time to stop the vehicle due to its accuracy and sensitivity; this are widely used in vehicles now-a-days. The drum brakes were used for very long time and we use even now, these were also very efficient brakes but due to the very common issues of changing the brake pads very often due to the short hand braking or improper usage, this has been replaced by disc or hydraulic in few machines. But we have found very common issues in disc brakes due to the brake rotor and brake pads. Due to the high friction while short braking we get unwanted noise brake squeal, though it doesnt have much effect on the performance of the vehicle, but it may fail the brake due to the tear o f brake disc or brake pads. A detailed study of each problem will be studied in further report taking disc brake system. History of Brakes: Invention of brake has started with the automated machines; brakes came into light mainly when the motorised wheeled vehicles came into existence. Brakes were not only used in the vehicles, these are used in other machines as brake lever to stop the motion rotor and so on. It has been an essential part of the moving systems. Brakes have developed a lot from first generation vehicles to present time. Early braking systems used steel rimmed wheels to stop the vehicle, which consists of curved wooden block designed to bear against the steel tire when operated by a single leverage system from the driver seat. But the brake shoe used was normal way of braking either in the horse drawn vehicle or steam locomotive. In 1895 Michelin Brothers move a step ahead to replace the steel rimmed wheels with the pneumatic rubber tire to come out with a new braking system as the brake shoes were no longer satisfactory.   A new method of braking system was required in those times as two early devices attempted to apply the friction force to the axle or to drum on axle or transmission shaft were not efficient as wanted. One method was use of wooden block inside a flexible contracting metal band which when pressed together would tighten the drum causing friction between the drum, which is connected to the wooden block and w heel, then the vehicle gets slow down. The other method was inner wheel or brake drum which will add an external contracting band to bear against the drum to bring the vehicle to rest. In 1899 Daimler started cable operated braking system; a cable was wound around a drum and attached to the chassis, so that when the cable is tightened when car was moving forward, the rotation of drum will increase the tightness and grip of cable, so that it will reduce the amount of force required to pull the cable-lever on the pedal to stop the moving vehicle. This brake system worked well but still the braking efficiency was less, the added efficiency called servo assistance is still an important factor in drum brakes even today. The external brake was vulnerable to the atmospheric conditions like weathering and to un-even roads which caused a rapid loss of efficiency and wear of the brake shoe lining and on few times automatic brake use to happen due to the drum expansion. To overcome all these problems an internal shoe brake was developed were the expanding the brake shoes were placed the inside the brake drum, mainly to protect from the dust and weather. Originally early brakes were operated by mechanically, i.e. the transformation by mechanical system was used to expand the brake shoes against drum by the drivers effort applied on the brake pedal. It works by pressing the brake pedal, which make cam to rotate by a lever connected to pedal, which forces the shoes to come on contact with the brake drum. And springs attached to both of the brake shoes to retain the original position when brakes are released. As the early brakes use to operate on lever supported cables and linkage system of fixed rods, equalising the same amount of brake pressure on the wheels has presented many problems , which were solved when hydraulic system was introduced, which used fluid to transfer the force applied to the brake pedal. In hydraulic braking system the set-up of cylinders and pipe lines forms a closed system which is filled with fluid. The pressure generated in master cylinder will transmit equal force to the each wheel cylinder and then equal pressure is applied to all brake shoes. This hydraulic system is used with the disc brake as well. Disc brake is more efficient braking system which was used mostly sports car when introduced but now it has been a very common system in passenger vehicles. It has a disc and a calliper is attached to it which can be operated mechanically, hydraulically, pneumatically, electromagnetically. Types of brakes: The brakes are broadly explained as using friction, pumping or electromagnetism. But one brake system can also use more than one principle. As the project is based on the disc brake we will look forward only to discuss about the frictional brake. Frictional brakes: These types of brakes are mostly rotating devices with a stationary pad attached with a rotating surface. These types of brakes are widely used even now in modern automotive braking system. Basically this are developed from band brakes to drum brakes then to the disc brakes. Band brakes: A simple type of brake, works on a principle that a band is wrapped round the rotating drum. When a force is applied on the lever, the restraining torque is found from the difference in tension between the two ends of the belt. The principle of operation of the band brake is same as for belt drives. This is external type braking system, as we see in picture the brake shoe are mounted on the drum. Ref: http://school.mech.uwa.edu.au/~dwright/DANotes/brakes/intro/intro.html Drum shoe brakes: This type of brake usually mean the brake shoe is mounted to press the inside surface of the drum. Two brake shoes are connected with a calliper set-up; it has lining on it which will create a frictional force when pressed towards the moving surface of the vehicle. These types of drum brakes are still used in modern cars due to the some cost and engineering benefits. These are applied to the rear wheels of today cars. Ref: http://school.mech.uwa.edu.au/~dwright/DANotes/brakes/intro/intro.html Disc Brake: these most widely used brake of these days, A disc is mounted on the wheel or axle and brake pads are placed within the jaws of the calliper, this is give the necessary friction when it will grip on the brake disc. Ref: http://static.howstuffworks.com/gif/disc-brake3.jpg Characteristics of brakes: Brakes are described on basis of several characteristics as Peak force: The maximum force obtained to decelerate the vehicle is called peak force. Few times this can be more than the traction limit of tires, then the wheel gets skid Continuous Power dissipation: As we know that the brakes get hot in use and get fail when the temperature gets too high, the maximum amount of power that dissipates through the brake without failure is the continuous power dissipation. Fade: Due to the over heat of the brakes the surface of the brake pads or disc get fade which will cause decrease in the effectiveness of brakes. Few times even cooling will have big effect on to fade. Power: when a very less force leads to the braking force, which is higher than the other brakes in similar class then its stated as powerful brake, which is due to the sensitivity of the brake system. Durability: Friction brakes have the lining which has wear surfaces, these to be renewed periodically.   Like brake shoes, pads or brake disc. Even if wear surface due to brake shoe generates high peak force this will lead to wear quickly. Weight: In some circumstances brakes are often mounted on wheels, this can disturb the traction significantly. Here weight means brake itself or an additional support structure Noise: generally brakes create some minor noise when applied, but sometimes create a high pitch noise called squeal or grinding noise. Principles of braking system: Brakes work on simple principle to slow down the moving vehicle by applying an external force, it may use more than one component; directly or indirectly several components effect on the momentum of the moving vehicle. Various types of process are used for braking effect. Frictional brakes are most commonly used these days, these works on the simple mechanism of changing the kinetic energy into the heat energy, which is done by only factor friction. Friction is created when a stationary brake pad grips on the moving brake disc with a force applied. This type of braking system is also used in the disc brakes; the stationary brake pads rub on the disc rotor which moves relatively in its own axis. Basic laws of braking system: Braking system can be explained by two simple Newton laws; which will explain the whole concept of the braking system As we know that the Newtons second law The net force on an object is equal to the its mass times its acceleration and points in the direction of the acceleration F = m* a The law is used to find out the net force required by brake pads to bring the moving vehicle to rest, tough there are many other factors to be considered for calculation of brake force which will be discussed further. It can also be explained through Newton first law Every object remains at rest or in motion in a straight line at constant speed unless it is forced to change its state by an external force if we check this law, an external force (brake force) is required to change the state of the vehicle (motion to rest). As this law explained the evaluation of the brake force and system of braking, a further law explains how the brake force will stop the vehicle. Law of thermodynamics: Energy can neither be created nor be destroyed; it will be converted from one form of energy to other form. This explained the frictional force (brake force) is converted into the heat energy. Factors considered while Braking: There are many factors to be considered for the high braking efficiency and performance; here we will see the few important factors which have a more effect on braking efficiency. 1. Condition of disc rotor: An uneven disc or ruffed disc rotor will decrease the braking effect; it has to be very well maintained as few a times due to dust and weather a extra layer is formed on the disc surface which will have a negative effect on the braking concept. Or wear of disc rotor due to overheat. 2. Pressure on brake rotor: A sufficient amount of brake pressure is to be maintained to get enough frictional force to stop the vehicle. If less pressure is applied it will directly affect the brake efficiency as force acting on the two rubbing surface will become less. 3. Contact surface: The area of contact between the brake pads and disc rotor should be more then the high friction is obtained. If lining of brake pads or surface of disc rotor is uneven then area of contact will be less, which will affect the brake efficiency. 4. Tyres: The design of tyre also have a normal affect on the brake efficiency, the more the contact of tyre to the road surface the good will be the braking system. Worn tyres will have less braking action and will not allow vehicle to stop the required point and may also skid, braking action is found high in new tyres due to its more contact with the road surface. There are other factors which also play an crucial part in brake efficiency like aerodynamics, heat dissipation, weight of body etc., Causes of failure: The most commonly found causes for the brake failure are 1. Oil or grease on the brakes will cause failure as it interferes with the friction. If we found oil in brakes mean the oil seal has failed and is why oil is leaking. 2. Overheat of brakes to great degree, which will develop a hot spot on the rotor and drums. This spots will resist the friction from brake shoe and pads, therefore braking power is lost and brake fails. 3. Brake squeal which indicates the tear in the brake pads, by the time the brakes start making a grinding sound, they would have worn out past the pads to rotors. This will require to change more than just brake pads for new one, which will increase replacement cost as well. 4. Improper wheel alignment or disturbance in the steering system will also lead into the failure of brakes. Even if the mass of vehicle will get out of its range due to extra load will cause a brake failure due to the uneven load distribution. DISC BRAKE Introduction: Disc brakes came into existence in 1890s in England. But due to the poor state of roads and dusty conditions the disc and pads use to get rust and get wear, so the system got non-viable at that time. But later it was fully adopted in 1950s with new innovations in the previous design. Many companies started using it in their cars as it was better when to compared with drum brakes, the main reason as it has overcome the brake fade problem by providing the resistance to the brake components and overall performance is better when compared with drum brakes.   Disc brakes become popular in sports cars due to its braking performance. Now it has been common in commercial vehicles as well, as its used at front of the vehicles, as the front brakes perform most of the braking effort. Components: A disc brake assembly consists of a 1. Cast-iron disc (disc rotor) that rotates with the wheel. 2. Calliper assembly attached to the steering knuckle (operated mechanically or hydraulically). 3. Friction materials (disc pads) that are mounted to the calliper assembly. Operation: (Hydraulically powered) Disc brakes prove to be efficient when compared with drum brakes even the working principle is same for both systems. The basic principle of braking system The kinetic energy is converted into heat energy   When brake pedal is pressed, the hydraulic pressure is applied on the piston; it pushes the brake pad to get in contact with the disc. As the pressure increases the calliper pushes the outside pad to get in contact with the disc. Due the friction generated between pads and disc will create the braking force as the pads gets in contact fully with the disc rotor. But if we study the disc brakes widely, it shows that it does not use the much of the friction between the lining and rotor to increase the braking power as drum brakes does, they likely cause a pull between them. Disc brakes have constrained self-energizing action, there has to be sufficient hydraulic pressure to get the required braking force. The braking force can be increased by changing the size of calliper piston. Even less heat dissipation occurs as the friction surface is exposed to the air, which also reduces the braking fade.   Design of disc rotor: generally disc rotors are either solid or ventilated. The ventilated type disc rotor has cooling fins in the middle of the disc to ensure good cooling. Proper cooling ensures longer pad life and it also prevents fading. Some ventilated rotors have spiral fins which allow more air flow and better cooling. These fins are mounted on side of the vehicle and directional. Spiral fins are used in the front of the vehicles as front brakes take most of the braking action as more heat generates. Ref: https://pontiworld.com.au Design of calliper: The calliper are used as floating calliper or fixed calliper design, and these are mounted on the axle or attached to the wheel. Floating calliper type: The calliper are used as floating calliper or fixed calliper design, and these are mounted on the axle or attached to the wheel. this type of calliper requires less parts than the other type and its also less in weight and economical. Based on requirement it consists of one or two pistons. The piston is either side of the calliper. Hydraulic pressure from the main cylinder is generated and the piston thus press the brake pad towards the disc, then instantly an equal hydraulic pressure is generated at the other side and right brake pad pushed towards disc rotor and vehicle stops due to the braking force. Fixed calliper type: The calliper are used as floating calliper or fixed calliper design, and these are mounted on the axle or attached to the wheel. This type of calliper design has piston on both sides of the calliper, which provides the equal force to each brake pad. These fixed calliper types can set-up either one or two pistons on each side. The two pistons can generate a more braking force and a compact design, as these absorb and dissipate more heat, due to its size and weight. This design is capable for greater number of hard stops of short brakes without the effect of brake fade. Materials used for component: The material used for disc rotor plays an important role in braking force. The material should be tuff enough to stand on high pressures and high friction forces. Generally cast iron is used for disc rotor commercially, but ceramic discs are used for high-performance vehicles and heavy automobiles. Recent study shows that aluminium alloys also do a great job as disc. Now we will discuss in detail about the commonly used materials cast iron and aluminium alloys. Cast iron: Grey cast iron alloy is used for the manufacturing of disc rotor; it has superior properties and various advantages over other materials, as it best suitable for manufacturing and machining when compared with other materials which lead to the graphite lubricating the cut and breaking the chips. It contains 2.5%-4% of carbon and greater than 2% of silicon.   This material has good wear resistance and galling which leads to self lubricating due to the graphite flakes. The graphite microstructure of grey cast iron allows less shrinkage. The silicon percentage in the grey cast iron makes the material corrosion resistance and increases its fluidity when casting which also makes material easy to weld. Compared with other alloys of the cast iron, grey cast iron has low tensile strength , the good point about this material is the shock and impact resistance is almost doesnt exist. Here we will see the properties of the grey cast iron for ASTM 60, Tensile strength 62.5 Kpsi Compressive strength 187.5 Kpsi Shear modulus of rupture 88.5 Kpsi Modulus of elasticity ( Tension ) 20.4 - 23.5 Mpsi Modulus of elasticity ( Torsion ) 7.8 - 8.5 Mpsi Endurance Limit 24.5 Kpsi Brinerll Hardness 302 H_b Specific heat 447 j/kg deg Ref: http://www.engineershandbook.com Characteristics of Grey cast iron: Wear resistance: Grey cast iron works as excellent resistance to sliding friction wear, it is widely used for manufacturing of sliding components, most of the automobile components are made up of this item, its all because of the low coefficient of friction, resistance to the galling it has which is due to the effect of graphite flakes . This will help the disc rotor to withstand for high friction forces. Thermal conductivity: The important merit of grey cast iron is its high thermal conductivity, due to its flake graphite structure, heat dissipates occurs in material with good rate. This will increase the cooling of the disc rotor Machinability: Due to the ferrite graphite structure, grey cast iron is simplest and easiest alloys for machining and casting. This will make easy to get the typical designs of the disc rotor with spiral and fins Damping capacity: Grey cast iron has high ability to absorb vibration energy and also damping vibrations, which is due to the high percentage of the graphite flakes it has in it. It also has great property to resist high frequency vibrations. This will help disc rotor Aluminium Alloys: Aluminium is the important alloy of aluminium alloys, were the other metals are copper, silicon and magnesium. It has less tensile strength and low melting pointing. It has good casting characteristics due to its great levels of silicon (4-13%) in it. It is widely used as disc rotor due to its corrosion resistance.   But this is quite expensive when compared with cast iron. Though is in light in weight, has good electrical and thermal conductivity. It does also can be recyclable. All these properties brought a change in many industries to change their traditional materials i.e., aluminium alloys. Characteristics of aluminium alloys: Light weight: The best part of this material is its light in weight, actually its one third of steel in weight, due to its specific weight of 2.7 g/cm3. The more the energy consumed by aluminium the high will be the load capacity of the vehicle.   This will decrease the vibrations and also increases the brake efficiency due to its light weight. Properties of the aluminium alloys: Density 2600-2800 kg/m3 Melting point 660 deg Elastic modulus 70-79 Gpa Poisson's ratio 0.33 Tensile Strength 230-570 Mpa Yield Strength 215-505 Mpa Percent Elongation 10-25% Thermal expansion coefficient 20.4 -25.0 10-6 /k Thermal conductivity: its used in most of the high conductivity line like power transmission, it has twice of the copper in the properties, and its a good conductor of heat and electricity. This will increase the heat dissipation of the disc rotor. Ductility and recyclability: Due to the lower density and melting point, the material is considered as ductile, this will help to the complicated design, as we need in the disc rotor with spiral fins and groves for the air dissipation. Recyclability is also one great factor of aluminium as it consumes only 5% of the energy to melt it, and it doesnt affect its original quality of aluminium. Corrosion resistance: This is the main factor which made it to select for disc rotor manufacturing. It has a natural property of corrosion resistant as it surfaces form an oxide coating on it. While using as disc rotor further surface treatments like lacquering and anodising are done to increase its resistance towards corrosion. Major problems with Disc Brakes: The disc rotor of Disc Brakes is more exposed to the air, due to which there are very frequent chances of getting damaged. Usually this damage of disc rotor is explained in four common ways warping, cracking, rusting and scarring. Few a times the damage takes the disc into the unsafe area then the new disc is replaced with damaged ones. But sometimes using simple machining and other process this damages can be overcome. As scratches or damage on disc rotor can be removed by removing the thin layer on the disc on lathe machine if after that the thickness of the disc falls in the safe dimensions for the braking force. Warping: This is caused due to the excessive heat of the friction area of the disc rotor, due to excessive shorthand braking, uneven cooling of disc may also causes warping. If braking pads get into contact of disc excessively this will lead to warping after certain times, this warping is most commonly found in the racing cars as brakes are used very frequently due to speed and used at high gear times. There are few methods which can avoid the warping, braking at lower gear which will help to reduce the braking load on the brakes, and less heat is generated. The more the braking load, the more the heat generated and more the chances of improper cooling to take place. Changing the disc design with more fins can few times avoids warping. Improper installation of disc rotor may also leads to the warping as only the overwhelmed disc will come in contact with the brake pads. Cracking: This is found mainly in the drilled disc. Cracking occurs mostly around the edges and holes of the disc, due to the uneven expansion in severe environments. As the uneven expansion take place and the braking load varies every time the brake is applied which will lead to the cracking. And in several situations the disc will fail and no possible repair can be done. Even cracking can be overcome by maintaining proper the cooling of the disc and proper heat dissipation. If cracking is become severe then there might be a chance to replace the disc rotor. Rusting: This is found in the vehicle which are not used for period of time, the regular use keeps the friction area clean, but when not in use the friction area and slots get rusted and it reduces the braking power, due to which the strength of the disc also falls down and at this conditions disc should replace with new one. Scarring: Scarring occurs if something hard gets in contact with the disc while moving, which forms a hard spot on the disc, which reduces the braking power and weakens the brake. Generally this happens when the brake pad service life come to end and still its attached to the brake set-up then the steel support of the brake pad get in contact with the disc which creates a hard scratch. These scratches will form black slots when a vehicle come in use, and reduces the structure strength. This can be avoided by regular checking of brake pads checking life of the friction layer, machining the disc to remove the layer on surface of disc which removes the scratches. There are few phenomenal problems which has been a challenging task in braking department like brake squeal, brake judder and brake dust. These problems can be dangerous when they get on excessively. Change of design, material, brake assembly setup all these have been checked extensively to find out the perfect solution for these problems, this project is undertaken based on this problems. Lets discuss in detail about these problems and what are the methods being simplified to overcome it. Brake Squeal: squeal mean noise, this brake noise is a vehicle system problem due to the regularity and severity. The noise generated is mainly because of brake and suspension components together. This is not considered as the main problem to the vehicle were performance is the initial objective, but its not so proper for the road use. This noise is mainly between the pad and disc during the braking. But squeal can also be combination of disc, calliper and brake pads. To avoid squeal under the braking condition is not so possible, if we are assuming brake to absorb very high energy inputs. Actually this brake squeal came into account when front wheel drive and metallic brakes arrived. These metallic pads are harder than asbestos counterparts, and thus more squeal is observed if there are more irregularities and roughness on the rotor surface or if you found looseness between the pads and callipers. Few types of calliper designs are more noisier, if the pads of this callipers are not fitted so tightly and the calliper itself move around when brakes are applied. The more the brakes play the more are the chances of noise. Fixing the squeal problems in wrong way can lead to the squeal more worse. Brake squeal also occurs due to vibration of brake pads towards the disc rotor when vehicle is moving at low speed, this may not affect the braking performance much but will lead to the replacement of brake pads, this is very common problem which most of the vehicles are facing now.   Lot of methods are used to reduce the level of noise,   simple methods like having chamfers to the linings, applying grease between the pads and calliper, adding the brake shim between   the brake back plate and brake pads etc., these may help in some way to reduce the noise. Ref: http://www.aa1car.com/library/bsqueal.htm While using the methods to reduce the brake noise, have to assume the vehicle suspension system which acts more on the braking system, but at the end the squeal is avoided by trial and error method. Although we see an efficient improvement in understanding the actual reason for the brake squeal, it has been difficult to solve it. It was easily verified through the design and study to overcome the squeal, but it was different case practically. The failure was mainly caused because of the dynamic behaviour of the braking system and due to the gap between braking components. The easiest way was using high temperature