apanese Cinema and Western Audiences

Japanese Cinema and Western Audiences: Why a Foreknowledge of Japan's Social, Cultural and Historical Background Is a Necessity in Order to â€Å"Properly† Appreciate Japanese Cinema and Western Audiences: Why a foreknowledge of Japan’s social, cultural and historical background is a necessity in order to â€Å"properly† appreciate Japanese Cinema. Discuss the claim that Japanese cinema cannot be properly understood by Western audiences without a wider understanding of Japanese history, culture and society. In this essay I intend to prove that a foreknowledge of Japan’s social, cultural and historical background is a necessity in order to â€Å"properly† appreciate Japanese Cinema.With reference to films such as Ugetsu Monogatari and Tokyo Story, my aim is to use my illustrative examples, analysis and references to scholarly sources to clearly show that in order to â€Å"properly† understand Japanese Cinema, a foreknowledge of Japanese histor y, culture and society is a definite requirement a western audience. The concept of world cinema has become commercially a genre. This genre creates the concept of the ‘other’; this is because it is other to what a western audience is used to (which is Hollywood or European cinema). It is also categorized as â€Å"third cinema†, with â€Å"first cinema† being Hollywood.This grouping normally means that the film is in a foreign language (non-english), it is culturally specific to the culture that produces it and is pre-occupied with culture and history or specific social and political ideas. These forms of categorization alone are evidence that western audiences consider Japanese cinema outside of their understanding of traditional cinema. To begin the argument we can relate to one significant theorist. Donald Richie moved to Japan during the occupation in order to study Japanese films, in order to gain an understanding of the Japanese national character, t o assist in defeating the Japanese military forces.In his long stay in Japan, he familiarized himself with Japanese theatre, art, culture, cinema and society. This allowed him to play the role of â€Å"mediator† between Japanese cinema and the west† Without Richie’s knowledge of Japanese culture, history and society, his appreciation for Japanese cinema would be sparse. Fumiaki Itakura commented on Western audiences â€Å"Japaneseness† was invented just one hundred years ago, and were based on cultural nationalism. They are not likely to understand the ideology of this â€Å"Japaneseness. † It is clear that Japanese cinema is too culturally specific for a western audience to ‘fully’ appreciate.Kenji Mizoguchi’s films have been put forward by critics and scholars as perhaps the most culturally specific Japanese films. His film â€Å"Ugetsu Monogatari† (1953) is a Jidai-geki film, (a period drama) for which he has become rec ognised as an auteur. Themes revolving around wealth, family and spirituality play a main role in the film. Freda Freinberg described the film as â€Å"Totally other to the world we knew† in relation to western audiences. The geisha dance scene would be completely disregarded by a western audience. Firstly her singing is very culturally specific, and is a Japanese form of chanting.According to Leger Grindon in reference to the â€Å"Realms of the Senses† , the geisha functions as a sign of the Japanese forbidden, and the surrender of emotions in replacement of sexual passion. Genjuro has left his wife, and is being seduced by Lady Wakasa. The camera work is very insignificant to how the dance is portrayed. The camera stays at a mid-shot whilst she performs, only following her movement. The dance is a Japanese traditional dance, it’s very slow paced, as she dances she waves a fan. During this scene the attention is never on Genjuro. We can see in back ground of t he shot that he is hypnotised by her dancing.Mizouchi wants the audience main focus to be on the dance. The traditional dance and song of this scene is very culturally specific, a western audience would not be able to â€Å"properly† appreciate it without a foreknowledge of Japanese Culture. The most significant part of this scene is the voice of her father. A low chant begins to accompany Lady Wakasa singing, this shocks the mistress and stops her from singing. The camera is still only focused on Lady Wakasa, the audience don’t see where the voice is coming from. The camera then pans slowly to their statue.Lady Wakasa falls to Genjuro using very exaggerated and expressive movement. This is inspired by traditional Kabuki theatre, which a western audience wouldn’t appreciate without foreknowledge. Lady Wakasa claims that it’s the voice of her late father. He is expressing his happiness for his daughter. These strong spiritual and religious themes are commo n in Japanese culture. Buddah, evil spirits, the omen, ghosts and after life are all common themes of Japan’s beliefs of spirituality. Leger Grindon comments on religion that â€Å"in few cultures is it taken seriously and as it as much a part of daily life as in Japan. This scene would be disregarded, and not ‘properly’ appreciated by a western audience, without a further insight to Japanese culture. Lady Wakasa’s spirit is used as a representation of Japan’s past. Genjuro is seduced by a spirit, this is a representation of being seduced to return to their fugal past. i Here Mizoguchi is using form to represent the past. A understanding of Japanese History is significant when viewing Japanese Cinema. In â€Å"Ugetsu Monogatari† there is a lot of narrative revolved around Tobei, who longs to be a Samurai, as it is a respected role society.The samuri status has also been criticized in â€Å"Life of Oharu†, as Oharu is disgraced by her family due to falling in love with a Samurai, which leads to her fate of prostitution. In â€Å"Ugetsu Monogatari† Tobei’s spots a famous general’s vassal behead his lord. Mizoguchi’s use of camera work means that the beheading is hidden from the shot. The main focus is not on the camera work and editing, (as it does in Hollywood) instead the camera work works around the action. Long takes and wide shots allow the action to tell the story. This gives the impression that we are viewing the scene in real time.Critic Freda Freiberg stated that â€Å"Mizoguchi is one of the masters of the long take. † A long take, pans out from the vassal as he begins to walk away. Dues to Tobei’s desperation to become a samurai, he kills the vassal and steals the head. To a western audience the idealisation of the samurai would not be understood without a wider understanding of Japans history. This means that an audience could not ‘properly’ apprec iate the film without a foreknowledge of Japans history. Yasujiro Ozu has been considered by David Bordowell as â€Å"quintessentially Japanese† . His films are made up of small domestic stories, shot mainly in interior sets.Unlike the Hollywood system, Ozu prioritised space over narrative. i In his film â€Å"Tokyo Story† (1953), he directly confronts the idea of where Japan is going after the war, in terms of national identity. He effectively documents a Japanese life at this time, and touches on the idea of society changing through their past, present and future. Tokyo Story really deals with three generations passing through life, but mostly with the generation that is passing out of it. The scene when the grand parents arrive at the house, they enter wearing traditional Kimonos and bow when greeting.This juxtaposes with their son who is dressed in a suit. Already we can see the grand father and the son playing representation of the changing generations: the grandf ather representing the past, and his son of the present. In another scene, the grandson is pictured studying English as a desk, wearing a baseball cap. This representation, as small as it is, shows the future for Japan and where it is headed. Baseball is an American sport that was adapted by the Japanese during the occupation. Also, by sitting the boy at a desk, Ozu is making a statement about what Japan’s future holds, in this he is relating to westernization.Relating to westernization is a common idea in Japanese films. For instance Seijun Suzuki’s â€Å"Tokyo Drifter† features night clubs influenced by western music, and even involves western characters in one of his scenes, making a statement about Japanese westernization. All of these representations would mean nothing to a western audience without foreknowledge of Japans social traits. In a later scene feature the grand father and his friends, he says â€Å"young people today have no backbone, where is th eir spirit? † He is touching on younger generation having no ambitions, and how times are changing.Ozu’s films commonly deal with role reversals, mostly between generations. As example the scene where the grandmother wishes to spend time with her grandchildren, we can see that the mother has little control over her son. He spins around in his chair and kicks his legs about as his mother tries to convince him to accompany his grandmother. At the end of the scene the mother (Fumiko), gives in and leaves her son to spin in his chair. In the case of the grandparents, their children are to preoccupied with their own lives to spend time with them, instead they send them away to a spa.These are two examples of how roles have been reversed, with younger generations gaining the most control. This is a representation of where Japan is headed, and that it’s in the hand of the younger generation. Without a previous understanding of the Japanese social state, a western audien ce would not be able to ‘properly’ appreciate the film to it’s fullest. Women’s status in society is commented on in the film, how their roles are changing. Noriko is seen working a desk job, she lives by herself and is only dependant on herself. She is seen throughout the film in a skirt and shirt, rather than the traditional Kimono.This is stating how women’s roles are changing. However Noriko appears to be clinging on the memory of her late husband. The grandmother asks of her to move on from the memory of her son, and find another partner. Socially, Japanese have presented a hierarchy with the male above the female. This is a dominant theme in â€Å"Ugetsu Monogatari† and â€Å"Life of Oharu†(1958) women are left in ruins because their man has abandoned them. In â€Å"Tokyo Story† it presents a modern picture of women in society, and show that although their roles may have changed, they still are classed below men.Noriko is still dependant on her husband, even after his death. Kishi Matsuo commented on women’s role in society â€Å"comparing today with the Ginkgo and Nara periods, I don’t find much difference, women have always been treated like slaves. † Without a wider understanding of Japanese society, the representation of women would be misunderstood. What the analysis of Mizoguchi’s â€Å"Ugetsu Monogatari† and Ozu’s â€Å"Tokyo Story† has clearly shown is that it is entirely right to claim that Japanese cinema cannot be properly understood by Western audiences without a wider understanding of Japanese country’s history, culture and society.Japanese cinema is too culturally specific that a western audience wouldn’t be able to ‘properly’ appreciate it. Japanese history, culture and society are all commented on throughout Ozu and Mizoguchi’s films. The content of this essay has explained that what is being commented on is too complex for a western audience, meaning they could not ‘properly’ appreciate these films, and Japanese cinema overall.

Globalization Process

Globalization is the process which unites nations, societies and traditions through a worldwide system of communication, transportation and trade. Globalization is usually used as an easy way of spreading the technologies, production, and communication across the globe. It also involves the flow of thoughts and technologies. Due to globalization, regions are coming closer to each other. Globalization is not only modernization but it is the amplification of global social affairs which connect different locations in such a manner that local activities are bent by activities happening miles away (Steger, 2010).Thus, globalization has very strong economic, governmental, educational and social dimensions. According to ‘Malcolm Waters’ in his book ‘Globalization’, globalization is defined as, â€Å" the intensification of world- wide social relations which link distant localities in such a way that local happenings are shaped by events occurring many miles away a nd vice versa. This is dialectical process because such local happenings may move in an obverse direction from the very distanciated relations that shape them.Local transformation is as much a part of globalization as the lateral extension of social connections across time and space† (Waters, 2001, pg. 5). Globalisation is the way by which people, companies and government of different nations integrate and interact with each other. The process of globalisation has effects on the cultures, atmosphere, governmental systems, economic developments, wealth and on individual’s physical comfort in nations all around the globe.Globalisation is the process by which normal life around the globe is noticeable by calibration of communication, transportation, financial activity, Ecological and social interdependence. Globalisation has many positive effects opening up gaps of opportunities and economic prosperity to the developing countries but globalisation also has a harmful side w ith negative effects. In this assignment, I will discuss few positive and negative effects of globalisation.According to researchers and intellectuals, modern age led to the foundation of globalisation but most scholars say that globalisation is not new and its origin can be traced back to the early civilization. For centuries, people have been trading to each other at great distances. Third millennium B. C. was the ancient form of globalisation. At that t time the trade link was among Sumerian civilization and Indus valley civilization. After that era, there were many events where trade connections were made connecting several countries like, Greece, Egypt, Roman Empire, India, etc.The attractiveness of the trade links led to the expansion of different trade routes. In 19th century, industrial revolution took place which was a significant time in the record of globalisation (Boudreaux, 2008). This was the period when Muslim dealers and Jewish started going to different locations al l around the globe to sell a variety of products which led to the combination of thoughts and customs. This revolution led to improved trade and business dealings. Due to enhanced goods and colonization, many nations all around the world became the customer of European market.However, the period of pre globalisation came to an end after World War 1. The effects of conflict were very adverse which led to the Great Depression. The time between 1850’s and 1940’s witnessed the acceleration of worldwide set of connections and cultural flows, dominated by European powers. By the mid of the nineteenth century quick developments in communication and transportation technologies like, radio, telephones, railways, shipping, telegraphy, etc took place. Globalisation has a comparatively new thought and idea that the world has been implementing.There are many positive effects of globalisation which are very advantageous for everybody in all countries. Globalisation has been the most successful affluence and anti-poverty movement in modern history. Following mentioned are some of the positive effects of globalisation on so various demographic segments of society. The most noticeable positive effect of globalisation is the improved and better quality of goods due to global competition. ‘Customer is the king’ approach to production has led to the improved quality of goods and services.Because Domestic companies have to struggle out foreign competition, they are bound to lift their standards and customer satisfaction levels to survive in the market (Stiglitz, 2007). When an international brand comes in a new country, it comes in travelling on some goodwill and concern which it has to survive up to. This establishes competition and ‘survival of the fittest’ situation in the market. Due to globalisation, various companies have entered into the developing countries and therefore generated employment for the citizens.This factor has given an opportunity to invest in the rising market and tap up the talent available there. Globalisation increases job opportunities as new firms start functioning in different countries; hence it increases living standards of people (Suarez & Qin, 2004). Usually there is a lack of capital in developing countries which obstructs the growth of domestic companies and so employment. In such cases globalisation plays an important role in obtaining profitable employment opportunities. Globalisation greatly affects the global economy and the impact of foreign trade on economy is very immense.Comparative benefit has always been a factor even in the history. Trade has been institutionalised due to globalisation (Bhagwati, 2007). Globalisation has improved free trade among nations and has improved liquidity of capital permitting investors in established countries to invest in undeveloped countries. It brings foreign exchange to the countries due to the increase in foreign trade. Globalisation is very favourable for the 3rd world countries as it results in economic development. It also improves the global economy by increasing GDP.Trade between nation’s increases as it provides freedom to the global marketing exchange of goods and capitals. Established countries can invest in developing countries and positive competition increases hence, improving businesses. It has been asserted that globalisation increases the productivity and living standard of people. With the manifold positive effects, globalisation also has its negative side. Few of its negative effects are listed below. The most significant negative effect of globalisation is the disappearance of several cultures.The cultures of the countries that are economically powerful are more dominant than others. There is a great risk of spoiling of the cultural values of developing countries due to overseas investments and foreign citizens working from developing countries, changing the attitude, lifestyle and mind-set of t he existing developing nations due to foreigners (Stilitz, 2003). Since international community is growing, more population have become unaware of social, moral and ethical values which are diverse in defining group. Hence, globalisation damages small cultures which are in danger of being destroyed.In order to save the cultures, small nations and developing countries should promote their cultural values and standards. Such nations should keep practicing their culture, so that young generation will be aware of all the customs and traditions. For instance, in developing country like ‘India’, many foreign companies and organizations operates and foreign trade is very immense, but the cultural values and tradition of people living there are still the same as Indians promote and practice their culture in every walk of life.Due to globalisation, more and more companies invest on developing nations, which economically is very beneficial for the countries but significantly affe cts environment by polluting it and escaping easily from weak developing countries regulatory rules and regulations. Many products and manufactured goods produced by various companies are not eco-friendly and thus, increase pollution. It also increase the risk of transporting diseases like Swine flu, Bird flu etc. unintentionally between countries as individuals from all around the world travel more often after globalisation.Many international powerful committees should be made in order to control and alert such companies and corporations who are responsible for polluting the environment and if they do not take action, then such corporations should be banned. This will help in decreasing the production of non eco-friendly products by creating awareness at the educational level and informing individuals with their negative effect. In today’s world, most of the corporations are aware of this negative effect and therefore, manufacture eco-friendly products which are healthy and recyclable.The last major negative effect of globalisation is the complexity of competition. Due to globalisation, international trade between the nations has started to remove limits. This condition of companies has resulted in steady competition with the national competitor, as well as the international competitors. Thus, businesses want more thorough and demanding competitive environment in order to continue stability and progress. Expansion of monopole corporations and channel between manufacture expenses are the chief effects of this tough competition in businesses (Eriksen, 2007).Developing and small nations choose to use overseas resources for their development, but instead, it disposes the equality and stability. Small corporations should focus on research and development. They should lower the manufacturing cost and should improve the quality of the manufacturing product, by using local goods hence, saving the cost of trade. Being a local company, they can understand the ma rket better than the foreign companies. By doing this local companies in developing countries will be able to gain most of the market share and will be able to compete with the foreign companies.In the conclusion, it can be said that globalisation develops better relations among nations and helps in eliminating negative perceptions for the people. Global problems and issues can be solved by discussions. Foreign trade and tourism leads to social benefits which increases migration between the countries and provide chances to live and earn abroad. This results in the decline of cultural barriers and helps in improving the relationships among nations. But with all the positive effects it also has its share of disadvantages and is sometimes unfavourable for the countries that are undeveloped and weak.

Knowledge and Organizational Learning Essay

The emerging importance of social media was not one that has taken the corporate world by surprise. By empowering people with the sensibility that their voice matters and can make a difference, social media technologies have altered forever how people communicate and the way companies conduct their business. The success of Web 2. 0 lies primarily in the network effects which creates a sense of community. With the implementation of effective social media strategies, many global brands have won the hearts of their customers simply through staying connected and relevant. As such, this essay will explore how social media when managed strategically in an organisation, can be used to improve its ability to share knowledge across space and time, support innovation, aid problem solving and build social capital. Some case studies of organisations excelling through their social media platform will be discussed and evaluated. It must be noted however, that social media in all of its glory can act as a double edged sword when it is not used appropriately. Improving knowledge sharing Knowledge could be defined as ‘actionable information’ that allows one to make a more informed decision and provide an effective input to conversations and innovation at organisation levels (Jashapara, 2011). It enables one to act more effectively and aid in the ability to better predict future outcomes. A major challenge in organisations today is fostering a knowledge sharing culture. Whereby explicit knowledge is somewhat easy to codify and stored, the sharing of tacit knowledge remains rather equivocal. Through communities of practice which connects people through shared mutual interest and expertise in a specific discipline, organisations are now able to foster the kind of knowledge sharing culture they aspire (Burk, 1999). These social and professional networks create a virtual platform for employees to share relevant experiences and best practices, as well as identify knowledge gaps in their learning. As the ‘bite-size’ information is now readily accessible, learning and knowledge sharing becomes more convenient and easily assimilated. Yammer, an enterprise social networking tool is used by over 200,000 companies and more than 80% of Fortune 500 companies for internal communications and knowledge sharing (Customer Success). Launched in 2008, it drew inspiration from Facebook and Twitter where it features social networking as well as mircroblogging with a secure and private network. Designed for company collaboration, file sharing and exchange of knowledge and information with other users within their organisation or pre-designated groups, Yammer has successfully removed geographical barriers and creates immense knowledge sharing opportunities. It is imperative to note that there are two internal cultural forces that impacts learning and effectiveness in organisations (Jashapara, 2011). In an organisation culture with strong forces of cooperation, it is an ideological organisation where employees are more inclined to share knowledge and expertise. Conversely, if the forces of competition are dominant, it may create silos mentality whereby there is unwillingness to share knowledge in order to gain a competitive advantage (Holst & Fields, 2010). Despite having the various technologies in place for knowledge sharing, there must be interpersonal trust between employees in order to facilitate the exchange of knowledge (Lucas, 2005). Affect-based trust which is built on mutual care and concern between employees is a predominant factor as to one’s willingness to share tacit organisation knowledge. It is found that individuals who were friends were more inclined to share personal and tacit knowledge with one another (Epsein, 2000). The tacit knowledge transfer is characterized by interpersonal relationship as well as long-standing working relationship which will motivate an individual to act in ways that benefit the other (Smedlund, 2008). Hence, with trust and a culture to share, the silo mentality of an organisation will be diminished and they will reap the benefits of knowledge sharing. Supporting innovation Innovation is the ongoing process of discovering new products for the customers or improving work process and efficiencies (Jashapara, 2011). It is no longer a question whether an organisation should pursue innovation but rather, it is a prerequisite for achieving a competitive advantage and success in many industries today. Innovation spurs motivation and efficiency within an organisation and though effective innovation management, it can increase market share through existing markets and capture new markets as well (Potecea & Cebuc, 2010). Customer experience will be enhanced with improved product quality and with wide range of choices made available to them. Innovation prevails in organisations with flexible and adaptive structure, a culture of trust and knowledge sharing and led by a committed management team who are motivated to promote organisation learning (Dasgupta & Gupta, 2009). Through the use of effective social media strategies, an organisation now has more platforms share ideas, gather feedback and innovate on product offerings and customer experience. One prime example is Starbucks’ own version of a social network portal, ‘My Starbucks Idea’ where it is an avenue for customer to share their own Starbucks related ideas (My Starbucks Idea). Inaugurated in 2008, it leverages on desire for engagement and interaction in social network by giving users the ability to share and vote for ideas and check on the outcomes of their suggestions. Through this platform, Starbucks is able to hear directly from their customers and act upon the ideas thereby cultivating and creating great consumer value and community. My Starbucks Idea’ is complemented with Starbucks Blog, ‘Ideas in Action’ which features contributions by various Starbucks employees who shares on the implementation of the ideas given by users through the ‘My Starbucks Idea’ site (Ideas In Action). Ultimately, through the use of social media, Starbucks is clearly prioritising their communication with customers and this creates an e ven greater sense of loyalty to know that their ideas are valued and implemented. It gives customers the empowerment to be involved in part of the decision making process and the ability to shape the future of Starbucks. Aid problem solving The emergence of problem-finding and problem-solving approach highlights the importance of identifying problems to solve, seizing opportunities and overcoming the challenges in organisations (Nickerson, Yen, & Mahoney, 2012). Through the multiple channels of social media, organisations can now connect with customers and hear first hand of their experiences and address problems instantaneously. A good example of an organisation leveraging on social media to aid problem solving is Best Buy, the world’s largest consumer electronics retailer (About Best Buy). Through the years, they have provided customers with exceptional choice, unbiased advice and trusted support for their technology needs. Galvanised by the influence and power of social media, Best Buy created a feed on Twitter called Twelpforce to provide solutions for customers (Dunn, 2010). Those who are having technical problems are able to post it on Twelpforce and a team of Best Buy associates or other Twitter users can post solutions or suggestions. By monitoring the feeds, Best Buy’s management are able to hear unbiased customers’ feedback on their products and assist them in real time. Twelpforce also presents the opportunity for new sales as individual choices are largely influenced and made on the recommendations and advocacy of others (Cunningham, 2012). Electronic word of mouth is especially powerful as the people in an individual’s social network are usually deemed as a trustworthy source of information (Curran, O’Brien, & O’Hara, 2011). Through Twitter and other social media platforms, Best Buy demonstrates their commitment to rejuvenate and refine their customer experience, and at the same time, drives value and innovation to create a more positive and connecting world. Building Social Capital Social capital refers to the active connections and network of relationships between people: the trust, mutual understanding and shared values which binds them together and facilitate coordination and cooperation for mutual benefit (Cohen & Prusak, 2002). It is the glue that promotes knowledge exchange and innovation hence, an essential strategy for organisations to gain competitive advantage in the markets which they operate. However, the development of social capital does not relegate the importance of investing in human capital in organisations (Cummingham, 2002). Huppi and Seemann (2001) phrased it appropriately that â€Å"human capital resides in the people; social capital resides in the relationships among them†. Using social media, organisations can connect with each other more readily and establish a network of community and relationships without any geographical boundaries. This is exemplified by Accenture, a global consulting and technology services and outsourcing company with circa 259,000 employees (About Accenture). They have created a Knowledge Exchange that is integrated with thousands of communities of practice which enables geographically and spatially dispersed employees to share ideas and collaborate more effectively. Residing on a Microsoft SharePoint platform, it features a wide social network with â€Å"people profiles† with biographies, photos and resumes as well as individual’s interests and skill sets. The Exchange also contains blogs, wikis, market insights and e-learning where sharing ideas and knowledge is evident and encouraged. Through The Exchange, company research revealed positively that there was a 42 percent increase in employees’ engagement and collaboration activities. Top collaborators are recognised with â€Å"celebrating performance points† and rewarded with badges that appear on their people profiles (Zielinski, 2012). Risks of Social Media With the many positive benefits of using social media in organisations, there are inherent risks involved when it is not managed effectively. One risk organisations face on social media platforms is the sharing of information. While it is a good medium for employees to share knowledge and ideas, it could be misused when confidential information and intellectual property are leaked. Most employees are aware of the implications of responding unthinkingly to emails however, the same degree of care and forethought are not always applied to social media sites. Thus, there is a danger that an individual may divulge confidential information mindlessly without realising that it is cast in stone and stored online indefinitely (Everett, 2010). While the decision to post videos, photos, thoughts and experiences on social networking site is entirely personal and â€Å"private†, a single act can spark a fire and create far reaching unimaginable consequences for an individual as well as organisations. A passing comment could end up being misinterpreted and a thoughtless prank filmed could easily go viral online affecting the reputation and profits of a company. An infamous example is the Domino’s Pizza debacle in 2009 whereby two Domino’s employees posted unappetizing videos on YouTube. The gross act of tampering with food damaged the company’s reputation severely and cut into nationwide profits. The only saving grace in this debacle is the company CEO, Patrick Doyle who posted another video in response and gave a well-worded apology and took full responsibility. Apart from the risks involving employee’s improper use of social media, social media presents an opportunity for disgruntled customers and competitors to assail a company’s reputation and start a public relations crisis. Instead of a traditional complaint email viewed only internally, unhappiness about a particular product or service standards can be viewed by potentially everyone in the world through social media. This is aggravated by the sharing functions on social media sites like Facebook whereby one may share another person’s unpleasant experience with their ocial contacts even though it may not have affected him. ‘United Breaks Guitars’, a YouTube video created by Dave Carroll in July 2009 is an example of how a customer can use social media to voice his unhappiness. In the song he blamed United Airlines for breaking the neck of his $3,500 guitar, caused by careless baggage handling and unreasonable policies. As the claim did not occur within the standard 24-hour time frame, it was deemed ineligible. 50,000 views were generated just within 1 day and it grew to 8 million by March 2010. It currently has more than 12 million views with popular shows like ‘The Checkout’ on ABC featuring it. Even though United Airlines did finally offered a $3,000 compensation for the damage made to his guitar, the damage done to the reputation and public relations of United Airlines is estimated to have cost them $180,000 within four days of the song been published. Another risk associated with social media is malware and account security. With most of the time spent on social networking sites, it makes their users ideal malware targets. Typical attacks take advantage on the trust relationships between users and their social contacts and try to trick users into giving up sensitive information which can be exploited for financial gain (Everett, 2010). By clicking on links sent by trusted friends, one might be susceptible to malware infection from drive-by downloads which steals information and might give attacker total access and control of the computer. This is especially disastrous for organisation whereby confidential information and trade secrets may be infringed. By not engaging in social media could be a risk in itself for organisations as nowadays most brands and companies are being discussed online. It is essential for an organisation to have a voice in these conversations, monitor and react timely to negative comments. With the risks involved, an organisation should develop a sound corporate policy on the usage of social media and educate employees of the role they play. The IT department needs to regularly update it security protection and firewall to mitigate any malware attacks or unsecure networks. Conclusion Social media presents a wonderful opportunity for organisations to leverage and share knowledge with each other despite geographical boundaries. With effective management, it promotes social capital where trust relationships can be built and creates a platform of engagement and collaboration. Social media platforms enable organisations to listen to the voices of customers and innovate and act upon the ideas given. By doing so, they gain customers’ loyalty and trust which is important to their success. Lastly, social media allows employees and customer to share their problems and receive suggestions and solutions by other users in real time. However, it is imperative to note that not all is good with social media as it can have disastrous impact on a company if it is not managed effectively. Social media does have a powerful amplifying effect. But just like any technology, it can be used for good or evil.

Assignment4 Assignment Example | Topics and Well Written Essays - 1750 words

Assignment4 - Assignment Example Saxophones are a common instrument in the contemporary society. Thus, the instrument can be found in musical classes or other Jazz sessions. The shiny nature of the instrument portrays it as an artistic masterpiece that arouses varied feelings on musical players. The instrument was originally intended for military and classical musical purposes. Owing to the versatility of the instrument, musicians in other genres around the globe are now playing the saxophone. Consequently, musicians in the avant-garde, classical, jazz, and pop and rock are playing the saxophone. The instrument can sound wild and poignant or smooth and stifling (Stewart et al., 5). The instrument can seamlessly blend into any joint, be it jazz big bands or orchestras. Moreover, the saxophone blends into the ensemble rock band solos or jazz quartets. Musicians in the contemporary world are trying to stretch the instruments into accommodating virtually every genre of music. Thus, the saxophone is steadily finding novel purpose in many genres of music. The design features of the saxophone depict an exceptional work of art. The design features appear attractive from the outward look to the inner features that create sound. The saxophone is a wind instrument of the nature of a conical bore. The instrument has a varying that increases from one end to the other (Hippe, 40). Thus, the instrument begins with a single diameter in one end that expands proportionately to the lowermost end of the instrument. By contrast, cylindrical instruments such as the clarinet, maintain uniform diameters in the whole length of the instrument. The varied design features of the saxophone have inner functionalities besides the outward looks. Conical bore instruments characteristically produce mellower and warmer qualities of tone compared to cylindrical instruments. Although saxophones are typically constructed using brass, plastic, gold and silver can also be utilized in the construction (Hippe,

Managing change Essay Example | Topics and Well Written Essays - 4000 words

Managing change - Essay Example The different steps associated with change management programs have been put forth by various researchers. Out of them the most prominent model is the eight step managing process of change as proposed by Kotter (1996) (Todnem, 2005, p.370). The process begins with the creation of a sense of urgency in the organization, i.e., major changes necessitate a sense of motivation among relevant people who can sense a potential crisis in the organization. This can arise due to lost markets, reduced profits, and entry of competitors, lost customers or even unacceptable products and services. Such aspects lay down the foundation for change requirements in the organization. This is followed by putting together of a guiding team or a group of enthusiasts who would recognize the indispensability and value of the change. The third step requires creating a vision and a strategy which requires motivating people, giving them a direction and aligning their efforts and processes. Vision gives employees the depiction that each one involved carries and evokes on a regular basis to ensure that the course does not get deviated. The next step is to communicate the vision to all subjects concerned. It is crucial to spread the change message across the organization through repetitive activities through as many channels as possible. Empowering people is the next step in which barriers and obstacles to the change are removed in order to remove hindrances which discourage people to take up the change. Following this step is to create momentum for the change by consolidating the accomplishments and allowing and enabling further changes. The final step is to implant the new approach into the culture of the organization (Tcherpokov, 2006, p.1-2). The change process was initiated in British Airways on account of consistent financial losses over a period of time, shrinking of the cabin crew, diminishing profits, diminishing share of the market, technological changes and cultural changes. The aim of the change process was to enhance organizational efficiency, reduce costs through restructuring of the organizational structure and strategy. The company’s mission and idea for the change process was communicated across all levels of the organization on a repetitive basis so as to ensure its acceptance and absorption into the system. Moreover, as per the steps put forth by Kotter (1996), British Airways implemented the change process by empowering individuals in the organization to actively participate in the change. This was achieved through training of staffs in the desired direction such as to make them efficient not only to participate in the change but also develop the changed culture throughout the organizational hierarchy. The idea was to bring about the productivity and performance improvement through the people. Only after the idea for the change was inculcated into the organizational culture, it could be implemented successfully. When the changed processes, norm s, activities were completely ingrained into the culture of the organization the results were seen to be long lasting and a new culture was successfully developed in British Airways (Tcherpokov, 2006, p.2). Reference Tcherpokov, M. (2006). The Eight-stage Managing

Socialist Feminism and Bifurcation Personal Statement

Socialist Feminism and Bifurcation - Personal Statement Example Here I would make it absolutely clear that when I said sociology for women that did not mean a sociology exclusively for women rather " it means a sociology that addresses society and social relations from the standpoint of women situated outside rather than within the relation of ruling" (Smith, "The Every day" 46). Let us talk in a little detail about the genesis of my theory. During the experiences of my own life and work, I had noticed that male of the society has defined roles and status of a woman in it. The feelings and experiences of woman do not get priority even in the conceptualization of her own ideology. Women are viewed more as an object rather than human, they are just the 'other' and are forced to see the world from a male point of view. So I say. "There is a disjuncture between how women experience the world and the concepts and theoretical schemes by which society's self-consciousness is inscribed" (Smith, "The Conceptual" 13). The women see and experience the world in which they live by not their own experiences but as in perspectives of the rule framed and theories propounded by men for them. As a result, women are kept in confusion and remain deprived of self-discovery. I observed that "Our images of how we should look, our homes, our lives, are given shape by the work of peo ple in academia, in television, radio, newspapers, and other organizations forming the 'ideological apparatuses' of the society'" (Smith, "The Every day" 17). These relations of the ruling are made up of texts and ideology. The texts are what presented to us, woman, by a government organization, other institutions, popular media who tell us how we should look, manage home and such everyday matters, we shape our lives around the ideology presented in these various texts. The ideologies created by these ideological apparatuses and real experiences do not correlate and thus create chaos in women/s life. The ideology is created by the male in such a way that complete domination and authority remain with them.

Week 5 Discussion Questions Essay Example | Topics and Well Written Essays - 500 words - 3

Week 5 Discussion Questions - Essay Example The reason that total quality can positive influence the sustainability initiatives of a company is because the implementation of total quality leads to continuous improvement through an organization. For example if a company is spending too much on electricity bills the total quality system of company will identify the deficiency so that the manager can implement alternative solutions to remedy the situation. Lowering energy usage is a sustainability practice can help the environment because it reduces the dependency of petroleum derivatives and helps decrease the CO2 emissions the business activity of a company generates. A common practice of total quality system is the use of benchmarking. Benchmarking involves selecting a demonstrated standard of performance that represents the very best performance for processes or activities very similar to yours (Heizer, et al. 1996, p.84). The use of benchmarking can help improve sustainability by imitating environmentally friendly practices other companies are implementing. If a manager learns that another company with compatible operation implemented a process that allows the use of recycle water in the manufacturing line benchmarking that practice can help achieve greater sustainability. A sustainability plan positive impacts internal stakeholders in a variety of ways. A sustainability plan can help improve the working condition of the employees of the company. For example if the company has manufacturing processes that are releasing toxic gases a sustainability plan can identify that deficiency in order to apply alternative solution to fix the problem. Once implemented the employees quality of life at work and long term health is going to improve. Another potential improvement that a sustainability plan can provide to the employees is improving the temperature and moisture levels of a facility in order create greater comfort for the

Organizational behavior Essay Example | Topics and Well Written Essays - 2000 words - 2

Organizational behavior - Essay Example ous responsibility on its shoulders as regards any issues be it legal, environmental or technical and fulfills the requirements with utmost diligence. Even when the whole world was reeling under sustainability issues in 2008, this company reported net profits. In this journey, of late, it was faced with the issue of technical competency. It could not sustain change and management of configuration of IT management on an enterprise-wide basis. The issues could be both external and internal. To analyze the external issues, a more detailed PESTLE analysis would be result fetching. (Anon., 2009) - 1 Economic Factors: The whole world was reeling under economic depression due to collapse in global demand in 2008. However, this company has managed its sales and profits successfully through multi-level customer and supplier collaboration. Social Factors: There was a sharp rise in the employee turnover in the year 2006 to5.8%. It gradually decreased in the next years and in 2008, the turnover was only .7%. In the mean while there were also recruitments. As such, while 3,24,875 were employed in 2006. The same number has now risen to 3,69,928. The important point to be noted here is that the company also increased its sales targets and greater transparency aspects on technical fronts. So, sufficiency of this employed work force could be an issue on the amount of work done by them. Technical Factors: The firm was unable to catch up with the modern generation technology due to non-reproducibility of developers’ projects in its branches worldwide. Control of employees in all these units became a major issue. Even compliance to legal issues on deadlines was very difficult. As such, it has undertaken a drastic change in IT configuration. (Anon., 2009) - 2. Legal Factors: As an international brand compliance to legal issues was always required by the organization. However due to non- integrated IT systems, understandability of the reports was always a question. This became a

Pascal and the Probability Theory Research Paper

Pascal and the Probability Theory - Research Paper Example His father introduced him to Mathematics when he was 15 years old. Despite this fact, he had started making discoveries in geometry as early as 12 years. Come 1939, his family moved to Rouen after his father was appointed a tax collector. His creativity was exhibited at this point, whereby; he was able to invent a calculator so as to make his father’s work easier during his day to day endeavors. Later in 1647, Pascal conducted and wrote about experiments concerning vacuums, but many scientists disregarded the existence of vacuums. For instance, the great French philosopher Rene Descartes visited Pascal for 2 days and disagreed with him concerning the vacuum. In a letter Descartes wrote to Huygens after this encounter, he asserts that â€Å"Pascal had too much vacuum in his head†1. This did not deter him from pursuing mathematics and science; in 1653, he published a treatise on the equilibrium of Liquids. Pascal later invented â€Å"Pascal’s Triangle†, a tr iangular array of numbers which solves mathematical problems. He would later become interested in probability after a gambling question was projected to him. In correspondence with another great scientist Fermat, they were able to solve the problem of points; how to divide stakes in a game of dice if the game is incomplete. Pascal almost lost his life in 1654, and this affected him psychologically to the point of being a staunch Christian. Even after setting the ground for the theory of probability, Pascal quit Mathematics to pursue a quieter Christain life in a monastery in Paris. He never married. He succumbed in 1662 to malignant stomach ulcers. Introduction Even from an early age, Pascal was curious about natural occurrences, and he formulated experiments to study these occurrences. Pascal studied fluids, pure and applied sciences, pressure and machines, among other scientific principles. While still a teenager in 1642, Pascal had begun ground-breaking work on calculating machin es. At first, his attempts failed, but he finally managed to invent the mechanical calculator three years later2. This simply shows that Pascal was able to invent scientific principles from an earlier age. However, one of Pascal’s greatest invention is in the field of Mathematics is the â€Å"Theory of Probability†, a theory that is centered on estimating and calculating the chance of doing something. For example, if 6 men are playing dice, what is the chance that each of them can win the game? And if at all two are eliminated, what is the chance that each of the remaining four will win the game? Probability centers on such occurrences. The theory of probability was advanced so as to prove the fact that chance can be mathematically calculated accurately. Various facets in the modern world apply probability. This is not just in mathematics courses, but it is also applicable in the practical courses like genetics, quantum mechanics, kinetic theory of gases, industrial qu ality control and insurance.This paper dwells on the history of the probability theory, and how Pascal contributed to this theory, and how his findings were shaped by other great scientists who were also researching on the theory. Pascal’s involvement with probability dates back to 1654 when another scientist, Chevalier challenged him to solve a puzzle which at that time was known as â€Å"the problem of points†. This problem had been posed in the late 1400s and no one had managed to solve it for a period of 200 years. The problem was that; how the stakes of a chance game should be divided

Land Pollution Essay Example for Free

Land Pollution Essay Land pollution, in other words, means degradation or destruction of earth’s surface and soil, directly or indirectly as a result of human activities. Anthropogenic activities are conducted citing development, and the same affects the land drastically, we witness land pollution; by drastic we are referring to any activity that lessens the quality and/or productivity of the land as an ideal place for agriculture, forestation, construction etc. The degradation of land that could be used constructively in other words is land pollution. Land Pollution has led to a series of issues that we have come to realize in recent times, after decades of neglect. The increasing numbers of barren land plots and the decreasing numbers of forest cover is at an alarming ratio. Moreover the extension of cities and towns due to increasing population is leading to further exploitation of the land. Land fills and reclamations are being planned and executed to meet the increased demand of lands. This leads to further deterioration of land, and pollution caused by the land fill contents. Also due to the lack of green cover, the land gets affected in several ways like soil erosion occurs washing away the fertile portions of the land. Or even a landslide can be seen as an example. Causes of Land Pollution Below are the sources of land pollution: 1. Deforestation and soil erosion: Deforestation carried out to create dry lands is one of the major concerns. Land that is once converted into a dry or barren land, can never be made fertile again, whatever the magnitude of measures to redeem it are. Land conversion, meaning the alteration or modification of the original properties of the land to make it use-worthy for a specific purpose is another major cause. This hampers the land immensely. Also there is a constant waste of land. Unused available land over the years turns barren; this land then cannot be used. So in search of more land, potent land is hunted and its indigenous state is compromised with . 2. Agricultural activities: With growing human population, demand for food has increased considerably. Farmers often use highly toxic fertilizers and pesticides to get rid off insects, fungi and bacteria from their crops. However with the overuse of these chemicals, they result in contamination  and poisoning of soil. 3. Mining activities: During extraction and mining activities, several land spaces are created beneath the surface. We constant hear about land caving in; this is nothing but nature’s way of filling the spaces left out after mining or extraction activity. 4. Overcrowded landfills: Each household produces tonnes of garbage each year. Garbage like aluminium, plastic, paper, cloth, wood is collected and sent to the local recycling unit. Items that can not be recycled become a part of the landfills that hampers the beauty of the city and cause land pollution. 5. Industrialization: Due to increase in demand for food, shelter and house, more goods are produced. This resulted in creation of more waste that needs to be disposed of. To meet the demand of the growing population, more industries were developed which led to deforestation. Research and development paved the way for modern fertilizers and chemicals that were highly toxic and led to soil contamination. 6. Construction activities: Due to urbanization, large amount of construction activities are taking place which has resulted in large waste articles like wood, metal, bricks, plastic that can be seen by naked eyes outside any building or office which is under construction. 7. Nuclear waste: Nuclear plants can produce huge amount of energy through nuclear fission and fusion. The left over radioactive material contains harmful and toxic chemicals that can affect human health. They are dumped beneath the earth to avoid any casualty. 8. Sewage treatment: Large amount of solid waste is leftover once the sewage has been treated. The leftover material is sent to landfill site which end up in polluting the environment. Effects of Land Pollution 1. Soil pollution: Soil pollution is another form of land pollution, where the upper layer of the soil is damaged. This is caused by the overuse of chemical fertilizers, soil erosion caused by running water and other pest control measures; this leads to loss of fertile land for agriculture, forest cover, fodder patches for grazing etc. 2. Change in climate patterns: The effects of land pollution are very hazardous and can lead to the loss of ecosystems. When land is polluted, it directly or indirectly affects the climate patterns. 3. Environmental Impact: When deforestation is committed, the tree cover is compromised on. This leads to a steep imbalance in the rain cycle. A disturbed rain cycle affects a lot of factors. To begin with,  the green cover is reduced. Trees and plants help balance the atmosphere, without them we are subjected to various concerns like Global warming, the green house effect, irregular rainfall and flash floods among other imbalances. 4. Effect on human hea lth: The land when contaminated with toxic chemicals and pesticides lead to problem of skin cancer and human respiratory system. The toxic chemicals can reach our body through foods and vegetables that we eat as they are grown in polluted soil. 5. Cause Air pollution: Landfills across the city keep on growing due to increase in waste and are later burned which leads to air pollution. They become home for rodents, mice etc which in turn transmit diseases. 6. Distraction for Tourist: The city looses its attraction as tourist destination as landfills do not look good when you move around the city. It leads to loss of revenue for the state government. 7. Effect on wildlife: The animal kingdom has suffered mostly in the past decades. They face a serious threat with regards to loss of habitat and natural environment. The constant human activity on land, is leaving it polluted; forcing these species to move further away and adapt to new regions or die trying to adjust. Several species are pushed to the verge of extinction, due to no homeland. Other issues that we face include increased temperature, unseasonal weather activity, acid rains etc. The discharge of chemicals on land, makes it dangerous for the ecosystem too. These chemi cals are consumed by the animals and plants and thereby make their way in the ecosystem. This process is called bio magnification and is a serious threat to the ecology. Solutions for Land Pollution 1. Make people aware about the concept of Reduce, Recycle and Reuse. 2. Reduce the use of pesticides and fertilizers in agricultural activities. 3. Avoid buying packages items as they will lead to garbage and end up in landfill site. 4. Ensure that you do not litter on the ground and do proper disposal of garbage. 5. Buy biodegradable products. 6. Do Organic gardening and eat organic food that will be grown without the use of pesticides. 7. Create dumping ground away from residential areas.

Tribological Audit Of Rolling Element Bearings

Tribological Audit Of Rolling Element Bearings 1. INTRODUCTION: In the current scenario, conservation of material and energy is very much important. As the principal cause of material wastage is wear, any reduction in wear leads to savings. Friction is the main cause of wear which leads to energy dissipation and damage to equipments. [1] Friction occurs when one surface drags upon another surface. The magnitude of frictional force depends upon the interaction of mating surfaces. All surfaces consist of minute asperities and depressions even though the surface has high degree of finish. From close observation it is clear that frictional force is produced due to the distortion of the micro asperities when one surface slides over the other. As most of the surfaces are elastic up to a limit, the original shape is regained afterwards. In extreme cases the asperities get removed due to plastic flow of materials. [4] This process of removal of material from one or both of two surfaces in contact is known as wear. [6] Lubrication is the most effective me thod to lower the friction and to control wear and tear. Lubrication is the process of interposing a solid liquid or gaseous lubricant in between two surfaces in relative motion in order to decrease wear and tear. [6] Tribology is the science of interacting surfaces in relative motion and of related subjects and practices. [5] Tribology is derived from the Greek word Tribos which means rubbing. It deals with relative motion of the bodies, friction, wear and lubrication. The motion of the bodies includes sliding, rolling, spinning, bouncing or combination of these. [5] The written history of tribology is as old as about five thousand years. In olden days itself people were concerned about friction and the ways to reduce it. Assyrians used rollers made of wood to move massive stones. [2] Later carts are developed as rolling friction is less than sliding friction. Although the ways to reduce friction was highly concerned from the olden days itself, the word tribology was introduced in 1966. [5] The minimum film thickness in tribological machine elements was in the order of 10 µm to 100 µm at the start of the century. Later advance in the tribology led to the development of components with film thickness up to 1 µm. The thickness is further reduced to 0.1 µm by the end of the century. In short, tribolo gy in the important factor in design of machine elements and selection of lubricants. [5] 2. ROLLING BEARINGS: Invention of wheel led to minimise the effort of moving an object as rolling friction is less than that of sliding friction. Even though rolling motion produces less friction, man was seeking different ways to decrease the rolling friction. This led to the discovery that bearing based rolling motion consumes less power. Hence it was implemented in all rolling systems including complex machine mechanisms. In earlier periods the roller bearings was not able to compete with the hydrodynamic sliding bearings as it cannot meet with the endurance characteristics of the other. The roller bearing was universally accepted in the 20th century by the development of superior bearing materials and advanced techniques. This helped to manufacture roller bearing assemblies with extreme accuracy and long life. The competition among the manufacturers increased in early 1970s which led to a sudden increase in the production of high quality products at relatively low costs. [2] Rolling bearing includes all types of bearings to permit minimum friction between two moving surfaces relative to one another. The main application of roller bearing is to rotate a shaft relative to some fixed or oppositely rotating structure. It also allows relative linear motion of a fixture in a fixed direction provided by a stationary shaft. [3] Usually a bearing consists of two steel rings each of which consists of a hardened raceway. The hardened steel balls or rollers roll in these raceways. These rolling elements are usually held in an angular spaced structure which is called separator or retainer. [2] ball.gif Figure 1- Ball Bearings [7] There are different types of roller bearings based on their analysis of operation. A brief description on various types of bearings is explained below. 2.1 BALL BEARINGS: 2.1.1 Radial Ball Bearings: Radial ball bearings are the most popular rolling bearings. This type of ball bearings has an inner and outer raceway grooves in between the balls are inserted. The grooves have curvature radii of about 53% of the size of the ball diameter. The inner groove is concentrically fixed inside the outer groove and the ball bearings are present in between the grooves. The bearings are separated uniformly. A cage is used to maintain the separation. Deep groove ball bearings have the capacity to carry more loads as it is having large ball diameter. It can carry radial as well as thrust loads. Seals are present to keep the lubricant in and protect from external dirt. [2] Figure 2- Radial Ball Bearings [8]radial-bearings.jpg 2.1.2 Angular Contact Ball Bearings:406px-Angular-contact-ball-bearing_single-row_din628_type-b_120.png Angular contact bearings are designed to withstand heavy thrust loads or a combination of both thrust and radial loads. The ball bearings have a contact angle which does not exceed 40 degrees. Single and double row ball bearings are usually used depending upon the nature and magnitude of force to withstand. In this type of ball bearings, the outer raceway is the part of a sphere. The load applied on the outer raceway is minimised as the balls do not conform well into it. By using large balls the load on each ball can be minimised. This type of bearings can be used in applications where the parallelism of shaft and the housing are not exact to each other. [2] Figure 3- Angular Contact Ball Bearings [9] 2.1.3Thrust Ball Bearings: thrust-ball-bearing_din711_ex.png Thrust bearings are those bearings having a contact angle of 900 which can withstand thrust loads. These types of bearings are meant for high speed applications. The thrust bearings are mounted on spherical seats to obtain high degree of alignment ability. These bearings cannot be used to hold any radial loads. [2] They are mainly used in automotive, marine and aerospace applications. These increase smoothness and help in noise reduction thereby reducing friction in the attached part. Small size, reduced friction and long life are the main advantages of thrust bearings. [10] Figure 4- Thrust Ball Bearings [11] 2.2 ROLLER BEARINGS: Roller bearings are used in applications where the bearings have to support very high loads. Rollers are used in these bearings instead of balls. In these roller is cylindrical in shape and so line contact is formed between rollers and raceways. This spreads the load out a large area. Hence they have more load supporting capability. [12] They supply more fatigue endurance than ball bearings. Also the cost of manufacturing is high. These bearings consist of two concentric raceways which consist of rollers in between the two. To increase the load carrying capacity, cylindrical bearings with two or more rows of rollers are constructed. Different types of roller bearings include needle roller bearings, tapered roller bearings, thrust roller bearings and spherical roller bearings. [2] Roller-Bearing.jpgLB_OP_Linear_Motion_Bearing_250x250.jpg Figure 5- Roller Bearings [13] Figure 6- Linear Motion Bearing [14] 2.3 LINEAR MOTION BEARINGS: Linear motion bearings are the recent products developed in order to provide free motion in one dimension. In machine tool slide ways, very high friction is developed. Linear motion bearing consists of balls which carry the loads laterally in a particular direction and hence wear and tear can be minimised. They provide smooth, precision, guiding surface. The rolling element of a linear bearing rides over it thereby reducing friction. [15] 3. TRIBOLOGICAL FACTORS: Tribology deals with friction, wear and lubrication. The two key factors related to tribology are interacting surfaces and relative motion. It is clear that tribology is concerned with two surfaces in relative motion which are adequately close to one another. Usually a poor tribological interface is designed and then various lubricants are used to lower the friction between the surfaces. The most acceptable way is to design a better interface which includes the selection of a good lubricant also to minimise the friction and wear to the lowest. [5] Various tribological factors are to be taken into consideration while taking a situation. The important tribological factors include: Material Surfaces Lubricants Operating Conditions [5] 3.1 MATERIAL: The initial step to be taken while designing a product is the material selection. There are various factors which are taken into consideration while selecting the material. For tribological point of view the following factors are to be given importance before material selection. Basic Mechanical Properties Friction Wear Resistance Compatibility [5] 3.1.1 Basic Mechanical Properties: The basic mechanical properties of the material such as elastic modulus, Poissons ratio, yield stress, hardness, fatigue resistance, ultimate tensile strength and thermal conductivity are to be analysed. [5] Also the availability and cost of the material are also taken into account. Based on these observations the best material suitable for the manufacturing of bearings is selected. The selection of material used for bearings is to be done carefully based on standard specifications. The material plays an important role in the performance of the bearings. This affects the overall performance of the machinery also. The selected material is used to manufacture the load bearing parts of the bearings like raceway grooves and balls or rollers only. Retainers and cages are made from some other soft materials with desired qualities. [17] 3.1.2 Friction: Friction is the resistance offered by two interacting surfaces in relative motion. The degree of friction is denoted by coefficient of friction  µ. [6] Friction occurred during sliding is known as sliding friction and which occurred during rolling is known as rolling friction. The main factors which cause friction are adhesion between surfaces, surface hardness, asperities etc. [6] 3.1.2.2 Laws of Friction: There are different laws of friction which are applicable to dry friction between interacting surfaces. The first and second laws were put forward by Leonardo da Vinci and third law was introduced by Coulomb. [6] The first law of friction states that force required to initiate or sustain sliding FT is proportional to FN, the normal force. [6] Thus FT ÃŽ ± FN or FT =  µ.FN [6] Where  µ = Coefficient of friction The second law of friction states that the friction force FT is independent of the apparent area of contact Aa [6] The third law of friction states that friction is independent of sliding speed. [6] It was found that the first two laws of friction are obeyed in almost all experimental conditions. Lubrication systems can be used to lower the friction developed within the bearings. Friction in bearings depends upon the viscosity of lubricant and shear rate. Self lubricated bearings are widely used as it offers only very low friction. [20] 3.1.3 Wear: Wear can be termed as the material loss or volume loss from the surface of the materials in contact. [21] The main types of wear occurring on material surfaces are adhesive wear, abrasive wear, fatigue wear, corrosive wear. The local pressure at the asperities becomes extremely high when the normal pressure is acted upon the mating surfaces. When the pressure exceeds a certain limit, the asperities deform plastically until the area of contact increased sufficiently to withstand the load. The wear produced due to adhesion process has been explained by Archard equation. Wad = K [22] Where Wad = wear rate K = wear coefficient F = normal load H = hardness of softer material When two dissimilar materials slide over one another, the softer material gets scratched away. Thias type of wear is called as abrasive wear. Fatigue wear occurs when a rotating shaft is subjected to reversal of bending stresses. Corrosive wear is due to the reaction of the material surface with the environment or an external agent. [6] Wear occurs in ball and roller bearings due to corrosion, shock loading of fatigue. Atmospheric agents like dirt and girt are the other external factors which are responsible for wear. [4] 3.1.4 Compatibility: Alloys are usually selected as bearing materials. Alloy is a solid composition consisting of two or more metals and elements in fixed proportions. The two alloys which are used to manufacture the bearings are Chrome Steel and Stainless Steel. Steel is an alloy of iron and carbon. [17] Various other elements like silicon, manganese, phosphorous, sulphur, chromium and molybdenum are added in chrome and stainless steels in order to increase the strength, hardness and corrosion resistance of the alloys. [18] Carbon is used in the alloy to form cementite structure and to formation of pearlite, spheroidite, bainite, and iron-carbon martensite. This improves hardenability of the alloys up to 0.65%. Wear resistance is increased up to 1.5%. Toughness of the alloy reduces and the brittleness increases when carbon is added. Manganese increases the hardness penetration of steel. Chromium is added to increase hardness, toughness and wear resistance to steel. Silicon acts as the deoxidiser during the manufacturing process. [19] 3.1.4.1 Chrome Steel Chrome steel is one of the widely used alloys to manufacture bearings. It is used mainly in high load bearing applications as this material is capable of withstanding very high loads. The machinability of the material is as high as highly finished, less noisy bearings are obtained. Also the life of the bearings is also very high. Under test conditions, the Rockwell hardness of the material is observed as 60 64 C. This material is used in applications where corrosion is not considered. [16] The constituent elements in the chrome steel are given in the table 1. 3.1.4.2 Stainless Steel The standard material used for the bearings is 400 series Martensitic Stainless Steel. This type of steel is highly resistant to corrosion and hence stainless steel bearings are used in applications where corrosion is to be taken into account. It is having less load withstanding capacity when compared to chrome steel. There are three types of 400 series Stainless Steel suitable for making bearings. These materials are developed by manufacturers to be used for certain specific applications. [16] 3.1.4.2.1 DR Stainless steel This material is highly resistant to corrosion and is used in applications which deal with highly corrosive medium. The material can be precisely machined so as to obtain high degree of finish to the surface of bearing. This helps in smooth, low noise operation of the bearings. The Rockwell hardness of the material is observed as 58 60 C. [16] The chemical composition of the material is given in table 2. 3.1.4.2.2 AISI 440C Stainless Steel AISI 440C Stainless Steel is highly resistant to corrosion and is easily available. But it is not widely used now a day when more modern materials are developed. The Rockwell hardness of the material is 58-60 C. [16] The chemical composition is given in table 3. 3.1.4.2.3 ES1 Stainless Steel: This material is highly resistant to corrosion and has high machinability. Thus highly finished surfaces can be produced. The material is having a Rockwell hardness number of 58 60 C. [16] The composition of the material is given in table 4. 3.2 SURFACE: Surface quality of the materials is one of the major tribological factors which determine the efficiency of the product. [4] Surface finish decides the amount of friction and wear of the material. Surface texture and conformity are the terms which are to be given importance. 3.2.1 Surface texture: The surface of the material is the part which interacts with the environment. The surface may not be highly finished due to several reasons. It may be due to the imperfections caused during manufacturing, due to external agents or due to loads acting on the surface. The deviations observed on the surface can be mainly classified into three which includes roughness, waviness and error of form. [23] Roughness is the surface irregularities which consist of rises and valleys. This creates an uneven surface pattern. Waviness is the small ups and downs on the surface which is having less amplitude that of roughness. These may be caused due to work piece deflections, vibration or heat treatment. Error of form is the slight deviations from the nominal shape. [6] The surface profiles can be traced by using different apparatus like Abbott profilometer, Tomilson surface finish recorder and Talysurf surface finish recorder. [4] 3.2.2 Conformity: Conformity is the degree of agreement between the surfaces. [5] An interface consisting of two plates is said to have high conformity. Journal bearing is an example for high conformity material. An interface consisting of a plate and a ball is said to be having low conformity. Ball bearing is an example for low conformity material. Conformity is an important factor which is to be considered as it has an important role in determining the pressure, shear stress and temperature in the interface. [5] Figure 7- Surface Texture [23] 3.3 LUBRICANTS: Lubrication is the technique employed to reduce wear by the interposition of a solid, liquid or gas between the two surfaces which come into contact with one another. It was a persistent problem for man for centuries from the day he used to move materials. Friction consumes and wastes energy whereas wear leads to the damage of the equipment which are undesirable and it has to be avoided at any cost. Every moving part of machinery is subjected to friction leading to wear and tear which has to be avoided. Lubrication plays a vital role in avoiding the friction between mating surfaces. The history of lubricant begins thousands of years before. It was found that the ancient Egyptians used lubricants to avoid friction in the wheels of chariots. [24] In ancient times lubricants were of animal, plant and marine origin. Later mineral oils were started to use as lubricant. The new science of lubrication based on hydrodynamics came in 1880s. [24] Lubricants are of solids, liquids and gases but liquid lubricants are widely used. These include mineral oil, synthetic oil, grease, vegetable oil and water. Lubrication is done by applying a thin film of lubricant between the surfaces in contact. [6] Thus undesirable problems like friction, wear, noise and vibrations can be reduced to a very high extent. 3.3.1 Viscosity: Viscosity of a lubricant is the main characteristic which is taken into account before selecting it for a specific application. Friction, heat generation, film thickness and load carrying capacity depend upon the viscosity of lubricant used. Generally viscosity can be stated as the hindrance of the fluid to flow. But based on lubrication, viscosity is the measure of ability of fluid to maintain lubrication at specific operating conditions. [24] 3.3.2 Lubrication Regimes: Lubrication can generally be classified into four different regimes based on the thickness of the fluid film in between the surfaces in contact. They include: Hydrodynamic Lubrication Boundary Lubrication Mixed Lubrication Elastohydrodynamic Lubrication 3.3.2.1 Hydrodynamic Lubrication: image8.jpg Figure 7- Hydrodynamic Lubrication [25] In hydrodynamic lubrication, a fluid film is formed in between the two surfaces in contact. Thus one surface floats on the other and there occurs no direct contact between the surfaces. In microscopic level the surfaces of the materials consist of asperities. In normal condition without lubrication, the asperities are in direct contact with each other. When one surface slides over the other, the asperities get deformed producing friction and hence wear. Hydrodynamic lubrication helps avoid the friction as there is no direct contact between the surfaces. The viscosity of the lubricant helps to increase the fluid pressure in between the surfaces. Thus the lubricant layer holds the surfaces apart. As the lubricant layer formed is thicker than the surface roughness of the material, one material slides over the other without damaging the surface. It is observed that the thickness of the film is more than 1 µm. [24, 25] The surface is separated apart by hydrostatic lift. A fluid flowing over a surface immediately takes the speed of the surface. Similarly when the fluid moves in a converging gap, the pressure increases and the surface is lifted. [25] 3.3.2.2 Boundary Lubrication: Boundary lubrication is a type of lubrication in which the surface roughness of the material is same as that of the fluid layer thickness. Thus when one surface moves upon the other, the asperities comes into contact. When load is applied the asperities gets plastically deformed which leads to friction and wear. As friction is not desirable different methods are also adopted to reduce friction in this type of lubrication. This includes the use of various additives to the lubricants. The additives are classified according to the surface action exhibited on the material surface. They are mainly of three types. Physically absorbed layers Chemically absorbed layers Chemical reaction layers 3.3.2.2.1 Physically adsorbed layers: When the lubricant is applied, it forms a layer on the material surface. The weak intermolecular force called van der Walls force exerted by the layer of the lubricant helps to attach to the surface. This layer lubricates and allows the other surface to slide over the other without causing friction. As the lubricant is not undergoing any chemical reaction, the process is reversible. The bonds formed by van der Walls force are weak and it can be removed. The main disadvantage of the physically adsorbed lubricants is that they have a temperature limit above which the lubricant melts. 3.3.2.2.2 Chemically adsorbed layers: Chemically adsorbed layers are those formed due to the chemical reaction with the surface material. Chemisorption is a type of adsorption in which the molecules are hold tight by the valence force of the molecules of the lubricant. The bonds created are stronger than the physically adsorbed layers. Usually chemically adsorbed lubricants form long chain fatty acid molecules, which has high affinity to metal surfaces. Fatty acid additives like stearic and oleic acid forms chemically adsorbed layers. The typical thickness of the boundary film is about 3 µm. As chemical reaction takes place in the interface, the adsorbed layer can be removed only under extreme conditions like high temperature, vacuum or by using some chemical treatments. [26] 3.3.2.2.3 Chemical reaction layers: Chemical reaction layers are formed by the reaction of additives in the lubricant with the surface of the material on which it is applied. In this adsorption is not taking place, instead a chemical reaction that bonds the lubricant and the material occurs. Thus the layers formed are permanent. The main disadvantage of physisorption and chemisorptions is the temperature limit above which the lubricant gets ineffective. In this type of reaction the working temperature is not a factor. Hence this type of lubrication is used in high speed and high load operating systems as high temperature is developed in these cases. Zinc dialkyl dithiophosphate (ZDDP) is widely used as an additive to produce effective chemical reaction films. [24] 3.3.2.2 Mixed Lubrication: Mixed lubrication has the features of both hydrodynamic lubrication and boundary lubrication. In hydrodynamic lubrication the contact surfaces are separated apart by the pressure of the lubricant interposed between the surfaces. Hence there will not be any contact between the two surfaces in motion. But in boundary lubrication, one surface rests on the other. When the surface moves the asperities gets plastically deformed which causes friction and wear. Mixed lubrication acts between the two extremes of hydrodynamic and boundary lubrication. In mixed lubrication regimes a fluid film layer is developed where contact takes place between the asperities of the surfaces. Thus a slight deformation is formed while sliding occurs which is highly desirable. The film thickness ranges from 0.05 µm to 0.1 µm. [25] 3.3.2.3 Elastohydrodynamic Lubrication: Elastohydrodynamic lubrication is a type of lubrication which brings together hydrodynamic lubrication, hertzian contact and change in viscosity with pressure. In this method of lubrication, the surface is modified to minimise friction. Elastohydrodynamic lubrication is used in applications where low conformity and highly loaded tribological interfaces are present. Roughness of the wearing surface is taken into consideration in this lubrication. Roughness is taken as the average of high and low points of the surface which is called as the centreline average. [27] A non conformal contact can produce pressure to a very high level. When the pressure increases it directly affects the viscosity of the lubricant. In normal conditions the viscosity of the lubricant is less noticeable but during elastohydrodynamic lubrication the viscosity increases which makes the lubricant act as a semi solid. This creates a thin film of oil in between the mating surfaces. [25] 3.4 OPERATING CONDITIONS: Operating conditions are the main aspect to be taken into account while designing a mechanical component including bearings. There are different factors which comprises the operating conditions. Load Relative Motion Temperature Environment 3.4.1 Load: The load applied on each ball and roller is to be determined to manufacture the bearings which can operate at the desired applications without failure. In order to calculate the load deflection relationship is to be developed for roller element contacting raceways. In almost all the applications the outer or inner raceways is in steady state rotation. The speed of the rotation may not be large enough to affect significantly the distribution of the load equally on each roller or ball elements. The rigidly supported bearing is subjected to radial load which may lead to deflection. The radial deflection at any rolling element is given by ÃŽ ´ÃË† = ÃŽ ´r cos ψ  ½ Pd [2] Where ÃŽ ´ÃË† = radial deflection r = ring radial shift ÃŽ ¨ = angular location Pd = diametral clearance Thrust load and roller bearings are also subjected to thrust loads which are distributed equally among the rolling elements. The thrust load can be calculated using Q = Fa / Z Sin ÃŽ ± [2] Where Q = thrust load Fa = applied load Z = number of rollers per row ÃŽ ± = contact angle 3.4.2 Relative Motion: Relative motion is the motion of either one or both surfaces with respect to each other. There are different forms of relative motion depending upon the style of motion. They include sliding, rolling, spinning and bouncing. Sliding refers to the smooth movement over a surface maintaining the contact between each other. Rolling is the movement by revolving within the axis. Spinning is the rotation of a material within its axis. Bouncing is the rebounding due to an impact. Chance for sliding occurs in the rolling bearings due to thrust loads. Bouncing may occur due to sudden fluctuation in loads which may lead to destruction of bearing material. 3.4.3 Temperature: Operating temperature is a factor which is to be taken into consideration for the smooth functioning of the bearings at load conditions. Temperature rise may occur in the bearings during operation which may be due to different reasons. One factor which causes the rise in temperature is the application of excess load. If excess load is applied, the material may not be designed to withstand that much high load. So it may lead to failure. Another reason for the temperature rise is the absence of lubricant. The lubricant should be interposed to the surfaces in contact. If it fails to continuously supply the lubricant to the surface, friction is produced which results in gradual rise in temperature. Various coatings are also used to overcome temperature extremes. 3.4.4 Environment: Nature of environment is the feature which can influence the efficiency and life of the bearings. There are different agents which affect the operating conditions of the bearings which may be harmful. These include contaminations like dust, wear particles, air, water, process fluid etc. Insulations are to be provided to avoid exposure to these external agents. This can be done by using seals or coatings. 4. CONCLUSION: The various tribological factors are to be considered while designing rolling bearings. This tribological audit looks for the different factors which affect the performance and life of the bearings. The major tribological factors found include material, surface, lubrication and operating conditions. Different solutions are available which can be applied to each factor to lower the friction. Material should be wisely selected which can be easily machined to obtain highly finished surfaces and should possess the strength to withstand the loads applying on it. The material should be selected according to the application. Surface texture and conformity of the material is to be carefully observed as the surface finish is one of the major factors which cause friction. Lubrication plays a major role in the performance of the equipment. Right method of lubrication is selected. Elastohydrodynamic lubrication forms the film with minimum thickness which is the most desirable in bearings. Operat ing conditions affects the performance and life of the bearings which includes contaminations like dirt, wear particles, water, corrosive process fluid etc. Proper measures are to be taken to avoid exposure to these agents. From this audit it is clear that we have to take care of the tribological factors and select the most suitable ones to obtain maximum performance and life to the rolling bearings.

The Reactor Design Project Engineering Essay

The Reactor Design Project Engineering Essay The project objective was to optimize three different adiabatic ammonia reactor configurations with respect to reactor performance in order to produce 800 tonnes of ammonia per day, or the molar equivalent of 0.5447 kmol s-1 of ammonia. The optimizations in reactor performance involved primarily, minimizing the catalyst volume and secondarily, maximizing the catalyst lifespan, as well as ensuring the final operating conditions were stable. Due to the absence of a cost function, the reactor could NOT be optimized with respect to cost minimization. Three different reactor types were considered, namely a single plug-flow reactor, a dual interstage cooling reactor and a dual cold-shot cooling reactor. Temperature, pressure and fraction of ammonia in the feed stream were found to have the greatest effect on the resultant catalyst volume. Using MATLAB, it was found that the minimum volumes were 9.61 m3, 3.94 m3 and 4.78 m3 for a single stage plug-flow, an interstage cooling configuration and a cold shot cooling reactor configuration respectively. The interstage cooling reactor allowed for a 59% decrease in total catalyst volume when modified from the single stage design, but required an increase in inlet feed temperature of 115K and 2 additional heat exchangers. The cold shot cooling method allowed for a 50.2% decrease in reactor volume from the single stage design, requiring a 75K increase in feed temperature. 1. Introduction 1.1. Background Ammonia synthesis (also known as the Haber process) is one of the most widely applied chemical processes in the world; in 2009, the total worldwide production of ammonia exceeded 133,000 metric tonnes 1, this is second only to the worldwide production of sulphuric acid. Most of the ammonia produced is used in the manufacture of fertilisers (such as ammonium nitrate), ammonia is also used in the manufacture of nitrogen-based polymers such as nylon. Another noteworthy use of ammonia is as the starting reagent for the manufacture of nitrogen-based explosives such as nitroglycerin. The reaction which generates ammonia is exothermic and equilibrium limited: N2 + H2 is in equilibrium with NH3 ΆHR (298K, 1atm) = -46.11 kJmol-1 [Eqn. 1] In the early 20th century, Fritz Haber discovered that in order to obtain a significant yield of ammonia, the reaction required both high pressures and low temperatures (in accordance with the van t Hoff-Le Chatelier principle). It was known that the rate at which N2 decomposed in the reaction was very slow (N2 is thermodynamically more stable than NH3); therefore a very efficient catalyst was required in order to facilitate ammonia formation. Nowadays, the catalyst used in most industrial ammonia reactors is usually a porous form of enriched iron. Catalysts are expensive, but they present a good trade off; reactors are able to produce sufficient amounts of product at lower, more manageable temperatures and pressures. 1.2. Design objective The overall objective was to design a continuous fixed bed plug-flow process to meet the companys daily ammonia production demand of 800 tonnes per day (exclusive of any ammonia in the feed). The primary design objective was to try to minimize the catalyst volume the process required in order to meet the production requirement. The design also had to be considered safe to operate and had to operate at conditions that were considered to maximize the lifespan of the catalyst; these two were considered as secondary objectives. The preliminary design of the reactor considered a single-stage adiabatic bed with a bed cross-sectional area of 2.0 m2. The final designs involved two different two-stage systems; one implementing interstage cooling and the other implementing cold-shot cooling. Reactor performance and sensitivity were analysed by observing the effects of altering specific operating and design variables. The cost function for the process was not known, therefore it is important to note that the reactor could not be optimized with respect to cost, however the design could be implemented such that the reactor performance was greatly improved. For example, minimizing the required catalyst volume (and hence minimizing the reactor volume) will reduce the construction cost of the reactor. However this may come at the expense of greater operating and maintenance costs and, in the case of two-stage systems, may result in additional construction costs (interstage cooling requires heat exchanger(s) to be built). The investigation will only allow qualitative suggestions to be made as to which specific design aspects contribute to the generation and/or reduction of costs. 1.3 Safety The reactor operating conditions should be stable; such that small disturbances will not lead to thermal runaway (which has important implications for safety). Other than that, there are no large risks involved with operating the ammonia reactor, provided that good process control is implemented by the operator. 2. Kinetic theory and types of reactor configurations 2.1. The kinetics of ammonia synthesis and its implications on reactor design Ammonia synthesis involves a single exothermic, reversible reaction between nitrogen and hydrogen. For reversible reactions, the conversion corresponding to thermodynamic equilibrium at the chosen operating conditions cannot be surpassed. Since the reaction is exothermic, the activation energy (which is only temperature dependent) of the backwards reaction is greater than that of the forward reaction. Therefore an increase in temperature causes a rise in the rate of the reverse reaction which is greater than the rise in the rate of the forward reaction thus decreasing the maximum attainable conversion but decreasing the required catalyst volume. On the other hand, operating at a lower temperature increases the maximum attainable conversion, whilst reducing the total reaction rate and increasing the required catalyst volume. With regard to pressure, the effect is the opposite; increasing the pressure causes a greater rise in the rate of the forward reaction compared the backward react ion and vice versa. Designing a reactor producing ammonia therefore requires a compromise between keeping temperatures sufficiently high such that reaction rate remains significant whilst obtaining a respectable conversion of ammonia. Similarly, the pressure should be great enough so as to maintain a significant reaction rate, but not so high as to cause the reactor to deviate from safe operation. In order to minimize catalyst volume (and meet the primary objective), it is desirable to operate at the maximum forward rate of reaction at each cross-section across the reactor; thus maximizing the average forward rate across the reactor, this allows the desired extent to be met with the minimum catalyst surface area and hence with the minimum catalyst volume. In order for this to occur, each cross-section in the reactor must be operated at the unique pressure and temperature required to achieve maximum rate for a particular extent, i.e. the reactor moves along the locus of maximum reaction rates. This is unfeasible in this investigation since there is no temperature or pressure control implemented across the reactor (the reactor is adiabatic and WSHAFT=0); and even so, maintaining specific pressures and temperatures at each point along the reactor is practically unfeasible in itself; as each point in the reactor would require its own heat exchanger and pressure control system. Therefore for exothermic reversible reactions (without heat removal), the temperature increases along the length of the reactor and the rate vs extent profile will always have a characteristic maximum because the temperature along the reactor increases due to the heat released by the reaction, causing the net production rate to increase up to a certain extent before the reverse reaction starts to become significant. As the rate of the backwards reaction tends to increase further and temperature rises, the overall reaction rate will eventually reach zero at equilibrium. 2.2. Brief description of the Plug-Flow Reactor (PFR) A plug-flow reactor is characterized by fluid flowing through one end of the reactor and out the other, whilst satisfying the assumptions of plug-flow. The assumptions state: Fluid properties and flow rate remain constant across any cross-section of the reactor. The flow is orderly, with no element overtaking or mixing with fluid ahead or behind, (i.e. the residence time is the same for all fluid elements). The above assumptions tend to hold true where there is turbulent flow (Re >105), ensuring good radial mixing, and if the ratio of reactor length to diameter of the reactor is large (ratio à ¢Ã¢â‚¬ °Ã‚ ¥ 50), where lateral mixing may be neglected 2. Figure 1: An illustration of a plug-flow reactor 3 2.3. Brief description of Interstage Cooling Interstage cooling, also known as intercooling, is a multiple reactor design suitable for exothermic reversible reactions. Heat exchangers are used to cool the output of each reactor before being passed on to the next reactor, allowing for a greater possible conversion to be achieved in each successive reactor. This process can be replicated for an indefinite number of reactors until the reactor temperature is too low for reactions to occur or until the decrease in catalyst volume is not worth the additional cost of construction and complexity of operation. This project considers only the case where two reactors are used. Figure 2: An illustration of a dual reactor interstage cooling system4 2.4. Brief description of Cold-shot Cooling Cold-shot cooling reactor designs are similar to that of interstage cooling, but allow for elimination of the intermediate heat exchangers by injecting cold feed directly into the outlets of each reactor. This addition cools down the outlet stream of the reactor and also has the effect of decreasing the composition and conversion of the flow into the subsequent reactor (corresponding to the path from point b to c in Figure 3 below). Figure 3: An illustration of a dual reactor cold-shot cooling system 5 The flow diagram of two cold-shot reactors illustrates the lack of heat exchangers as compared to interstage cooling, as well as the splitting of the initial feed stream by the splitting fraction alpha, ÃŽÂ ±, which is the fraction of the fresh feed used as the coolant. The extent of reaction remains constant after mixing (which can be proven by a mass balance). 3. Mathematical model Derivations of differential equations All the assumptions of plug-flow mentioned above were applied in the construction of the equations below; the reactor was also assumed to operate at steady state (there is no mass hold up due to the catalyst). All other assumptions are mentioned in the derivations. It should be noted that rNH3 is defined as (rNH3 generated rNH3 consumed) and is measured per unit of catalyst volume; hence the equations specify the volume of catalyst VC and not the reactor volume VR. 3.1. Change in catalyst volume with respect to the extent of reaction: Mass balance on ammonia: [Eqn. 2] The extent of reaction can be defined as: [Eqn. 3] Equations 2 and 3 were combined to obtain the following equation: Since , the equation above was rearranged to give the initial catalyst volume gradient: [Eqn. 4] 3.3. Change in temperature with respect to the extent of reaction: Figure 4: An illustration of the cross section of a plug-flow reactor An energy balance across an infinitesimally small cross section of the catalyst bed gave: Shaft work (W), changes in kinetic energy and changes in potential energy were neglected: The equation above was divided by the cross-sectional area of the tube, A: where Q denotes the heat transfer by conduction. In the equation below, the enthalpy change upon mixing was neglected (a perfect solution was assumed). It was also assumed that the gases in question were ideal and hence their enthalpy was independent of pressure, the energy balance then took the form: [Eqn. 5] is the standard heat of formation of compound. i denotes each species present. Recalling that for a tubular reactor, and : does not have a negative sign as rproduct is calculated as the main subject) [Eqn. 6] The heat of reaction was simplified as shown below: [Eqn. 7] Equation 7 was substituted into Equation 6 which was then substituted into Equation 5: [Eqn. 8] The chain rule was used to combine and : Since the reactor was assumed to be adiabatic, Q = 0: [Eqn. 9] 3.4. Change in pressure with respect to the extent of reaction: The chain rule was used to find using the formula for , bed cross-sectional area A and since A dl = dVC. Substituting the components of the three terms above, we get the initial pressure against extent gradient formula: [Eqn. 10] 4. Simulation theory and strategy 4.1. Main simulation objectives Regardless of the design used, these objectives are overarching and apply to all three reactor types: The first two bullet-points define what is meant by optimizing the reactor: Minimizing catalyst volume; Operating temperatures and pressures are limited by safety considerations (preventing thermal runaway), material construction and catalyst degradation conditions. These degradation conditions are specified by actual limits set by ammonia process operators in industry: these are above 823 K and above 300 bar 6; Interstage and cold-shot cooling designs are only dual reactor designs. The derivation of the required total extent for all simulations is as follows: The MATLAB coding incorporating the required data and was used to solve the differential equations described earlier in the mathematical model for the outlet temperature, pressure and catalyst volume; all the assumptions applied in the mathematical model were thus applied in the coding, unit consistency was also maintained in the programming. 4.2. Single stage simulation strategy It is clear that a plug-flow reactor can take advantage of concentration profiles present in the reactor in order to minimize the total catalyst volume. Near the desired extent, adiabatic plug-flow reactors (running exothermic reversible reactions) operate ideally somewhere between the equilibrium line, where the rate of the forward and backwards reaction are equal, and the optimum line, which is a curve connecting the maximas of all the different rate curves, also known as the locus of maximum rates. Figure 5: A graph displaying the variation of forward rate with extent It is opted to run the reactor under conditions such that the inlet rate is exactly equal to the outlet rate where the reactor exits at the desired extent of 0.5447. The rin = rout condition limits the maximum average rate by a small amount but provides a greater amount of kinetic stability in the event of a disturbance; a small increase in the inlet temperature may push the reaction closer to equilibrium whilst a small decrease in the inlet temperature will decrease the outlet rate slightly but still allow the reactor to operate in a region of higher rates. The locus of rin = rout is found between the optimum line and the equilibrium line. As shown in Figure 5, this condition also means that the region of maximum reaction rate is taken advantage of; i.e. the rate in the reactor is always greater than or equal to the inlet rate. Therefore, although the temperature increases along the reactor, the forward rate is kept as high as possible. As the extent of reaction increases across the reactor for a fixed set of inlet conditions, it is expected for the surface area of catalyst to increase; if more product is generated, more catalyst is required to facilitate this generation. There is a limit in the MATLAB coding such that the catalyst volume decreases whilst the reaction extent continues to increase; the code is such that results after this point are treated as erroneous and are not used, thus the code finds the inlet conditions needed to achieve the maximum possible extent for an adiabatic reactor. To apply the simulation strategy, a MATLAB program was created to find the inlet conditions which satisfy the rin = rout condition for a desired final extent (0.5447 in this case). A separate program was also created to vary operating and design conditions individually and examine their effect on the catalyst volume. Graphs of the locus of maximum reaction rate, locus of rin = rout rates and the equilibrium curve were constructed using the desired inlet conditions determined from the single stage simulation. 4.3. Interstage cooling simulation strategy The overall reaction follows the adiabatic operating curve (it may not necessarily be a straight line due to the pressure drop across the reactor). It was desirable for the reaction to end at the same point as in the single stage simulation (with the same final extent); where the rate at the outlet of the second reactor lies on the rin = rout line for the desired extent. It was also desirable for the rate at the exit of the first reactor to be equal to the rate at the entrance of the second reactor; so that the reactor can continue onwards from the same rate in the second reactor (and maintain the average forward reaction rate). For this code, there was no condition that the rate at the inlet of the first reactor must equal the rate at the outlet of the first reactor (and likewise for the second reactor); since it was unfeasible to make the rates equivalent at all the inlets and outlets. Instead it was specified that rate1 OUT= rate2 IN and that rate2 OUT = rate OPTIMIZED SINGLE STAGE OUT. The extent in the first reactor (and therefore in the second reactor) had to be specified for each set of results. If the extent was too high, the outlet of the first reactor would be very near equilibrium whilst if it was set too low the outlet of the first reactor would be reached before the maximum rate had been obtained; therefore a degree of overshoot past the maximum reaction rate was desirable; the program ensured that there was a degree of overshoot past the maximum reaction rate in both reactors before validating a result. The locus of maximum reaction rates (from the single stage optimization) was used to determine the feed temperature for which the rate is a maximum at the start; this temperature was roughly 790K (located graphically). Above this temperature, the region of maximum reaction rates was not utilised at all; and the maximum extent achievable (using the gradient of the operating line) at equilibrium was roughly 0.28. This specified the minimum extent of reaction in reactor 1. If the feed temperature were too low, the first reactor would perform similar to a single PFR, defeating the purpose of having two reactors. Thus a moderate extent range of 0.3 0.4 was chosen for the first reactor as it was unworkable to put an excessive production load on either reactor. In order to apply this strategy, a program was used to specify the inlet conditions to the second reactor; the program moved along the operating curve using the initial conditions obtained in the single stage reactor up to the desired extent in the first reactor. This gave the inlet rate to the second reactor as well as the flow rate, temperature and composition of this stream. Following this, the rate1 OUT = rate2 IN condition was used to acquire the inlet and outlet temperatures and pressures of the first reactor and its volume. Lastly, the inlet conditions to the second reactor and the remaining extent were used to calculate the volume of the second reactor. The combined volumes and degrees of cooling between the reactors were compared for the chosen range of extents. 4.4. Cold-shot cooling simulation strategy Figure 6: A graph displaying the variation of extent with temperature for a cold-shot system The rate identity rin=rout used to optimize the single PFR was used in the cold-shot cooling reactor design. With reference to Figure 6, optimization was achieved by ensuring that the reaction moved from points aÆ’Â  bÆ’Â  cÆ’Â  d , with the following rate identities; ra = rb and re = rd. The second reactor would operate along the path that the optimum single PFR would operate on (e Æ’Â   d). By adhering to the above conditions, there were three variables left to define, namely alpha (ÃŽÂ ±), initial feed temperature Tini and the interstage extent ÃŽÂ ¾1. Fixing alpha and Tini would automatically define ÃŽÂ ¾1 and outlet temperature of the first reactor as the rates at points a and b must be the same. This optimized the first reactor for the given inlet conditions. By constructing enthalpy and mass balances on the mixing point of the outlet from the first reactor with the cold stream, the inlet temperature into the second reactor was determined, thereby finding outlet conditions of the second reactor, should it achieve the required extent of 0.5447 kmol s-1. Finally, in order to ensure that total optimization had occurred for the specified alpha and temperature, the difference in rates at points e and d was confirmed to be as close to zero as possible. Several iterations would be required to home in on the best inlet temperature for a given extent. The temperature of the feed used for cooling, Tf, was 298K; significantly lower than the temperature of the fluid exiting the reactor. This imposed an upper limit on the split fraction ÃŽÂ ±, beyond which the feed temperature into the second reactor would be too low for reactions to operate at an acceptable rate; catalyst volume would need to be larger to counter this effect, meaning optimization would not achieved. Therefore, by varying ÃŽÂ ± for 50 equal intervals from 0.01 to 0.5, and finding the 50 corresponding Tini values that satisfied the above stated rate identities gave the optimum reactor for each value of ÃŽÂ ±. The best cold-shot reactor specification was easily deduced from the setup which had the smallest overall catalyst volume. Results and Discussion 5.1. Single Plug-flow Reactor 5.1.1. Varying the ammonia composition in the feed Figure 7: A graph displaying the effect of ammonia feed mol % change on catalyst volume The composition of ammonia in the feed was changed while keeping the molar feed rate constant. (Change ratio: 4% decrease in NH3 = 1% increase in N2 + 3% increase in H2, etc). Figure 7 shows that decreasing the ammonia fraction from the original 8 mol % (while increasing the reactant mol %) lead to a significant drop in catalyst volume required. The greater concentration of reactants favoured the forward reaction, increasing the rate of formation of ammonia, leading to a smaller catalyst volume. When the ammonia fraction was too high (à ¢Ã¢â‚¬ °Ã‚ ¥0.16), the initial concentration of reactants was insufficient to achieve the required extent. Also, as the partial pressure of ammonia increased in the reactor, a greater proportion of the catalysts active sites became blocked and the forward rate decreased, increasing the required catalyst volume 7. It was decided to keep the mol % of ammonia in the feed at 8% in subsequent simulations; although the lowest mol % of ammonia in the feed produces the minimum catalyst volume, it is impractical for this to occur since ammonia is normally recycled in industrial reactors 8. 5.1.2. Varying the reactor cross-sectional area Figure 8: A graph displaying the effect of cross-sectional area on catalyst volume Figure 8 shows that increasing the cross-sectional area reduced the catalyst volume, but this reduction was more significant only at the smaller area values. Increasing the area increased the number of catalyst pellets available at the reactor cross-section; therefore a greater reaction rate was initially facilitated as the volume increased. However, the inlet flow was fixed, and beyond a certain area, the flow into the reactor did not utilise the additional pellet area at the cross section; and thus the catalyst volume was less affected. The cross sectional area for the remainder of the investigation was kept at 2m2 because the increase in cross-sectional area above 2m2 does not justify the relatively minimal reduction in catalyst volume. 5.1.3. Variation of catalyst voidage Table 1: Displays catalyst volumes for different values of catalyst voidage Voidage 0.7 0.6 0.5 0.4 0.3 Vc at ÃŽÂ ¾ = 0.54466 (m3) 23.4642 23.4877 23.5399 23.6728 24.1043 Voidage is the ratio of the catalyst volume to the reactor volume. A larger voidage means a higher catalyst pellet density, thereby allowing a smaller catalyst volume. However, increases in voidage past 0.4 did not contribute to any further significant decrease in catalyst volume. For the purpose of subsequent simulations, the voidage was kept to the original 0.4. 5.1.4. Variation of catalyst diameter Table 2: Displays catalyst volumes for different values of catalyst diameter Catalyst Diameter 0.011 0.009 0.007 0.005 0.003 Vc at ÃŽÂ ¾ = 0.54466 (m3) 23.5881 23.6209 23.6728 23.7675 23.9954 It is seen from the data that varying catalyst diameter had a negligible effect on the catalyst volume, suggesting that although the surface area of each catalyst pellet increased, the number of catalyst pellets decreased, and thus the overall catalyst area did not change significantly. It was decided to stick to the original catalyst diameter provided. 5.1.5. Varying temperature and pressure Figure 8: A graph displaying the effect of inlet temperature on catalyst volume for different isobars As the temperature was increased, a decrease in the catalyst volume was observed. At lower pressures, the gradient of the graph (the change in VC with inlet T) was much higher and therefore inlet temperature was more effective at reducing the catalyst volume at lower pressures. This has some implications with respect to cost; if the inlet temperature is increased, there is an electricity cost associated with operating the reactor at this higher inlet temperature, but there is also a saving due to the reduction in catalyst volume. Figure 9: A graph displaying the effect of inlet pressure on catalyst volume for different isotherms As inlet pressure was increased, the catalyst volume decreased. As discussed in the theory, the increase in pressure favoured the forward reaction, thereby increasing the reaction rate per unit volume of catalyst. However, the capital costs spent on reactor materials able to withstand the high pressures have to be taken into consideration in addition to the greater maintenance cost of the catalyst bed (since a higher pressure reduces the longevity of a catalyst). 5.1.6. Results of single stage simulation Table 3: Displays the specifications and feed conditions the optimized single PFR Feed Composition Cross sectional area (m2) Catalyst Diameter (m) Voidage Extent Temperature (K) Pressure (Bar) N2 H2 NH3 In Out In Out 0.23 0.69 0.08 2 0.0007 0.4 0.5447 624.2 796.0 300 298.6 It can be observed that the pressure drop throughout the reaction was rather insignificant compared to the total pressure in the reactor. The optimization values from the single stage plug-flow reactor were essential for designing dual reactors that utilized interstage or cold-shot cooling as the second reactors were designed to follow the reaction path taken by the single stage PFR. The optimum single stage pressure of 300 bar was also the optimum pressure used for the subsequent simulations; the maximum operating pressure tolerable is 300 bar according to the catalyst degradation conditions specified in the simulation objectives. 5.2. Interstage Cooling Figure 10: A graph displaying the extents of reaction for different temperatures. The interstage path for ÃŽÂ ¾1 values of 0.3, 0.34 (optimum), and 0.4 are displayed along with the locus of maximum reaction rates, the equilibrium curve and the locus of rin = rout. Results were obtained for 10 extents between 0.3 and 0.4; these are displayed in the appendix. From the graph above, it can be seen that for all three extents; 0.3, 0.34, 0.4, the reaction in the first reactor moved past the locus of maximum rates and the locus of rIN = rOUT and then approached the equilibrium curve, thereby maximizing conversion. The outlet stream was then cooled to a point along the path taken by the volume minimizing single PFR. The graph thus shows that performance optimization occurred in the interstage cooling design as catalyst volumes in both reactors were minimized. The range of chosen extents for the first reactor, 0.3 0.4 kmol s-1, also proved to be robust, providing well performing reactors with small catalyst volumes (where all reactors had a combined catalyst volume less than half of that of the single stage reactor). Volume reached a minimum of 3.94 m3 when the extent was fixed at 0.34 kmol s-1 with an inlet feed temperature of 737.1K. 5.3. Cold-shot Cooling Table 4 Conditions and results for the optimum cold-shot system Extent Achieved Temperature (K) Catalyst volume (m3) 1st 2nd 1st 2nd In Out In Out Vr1 Vr2 0.2958 0.2489 699 795.769 717.172 796.407 1.523 3.254 (Vc 1 Vc 2 = 1st 2nd Catalyst volume respectively) Figure 11: Catalyst volume minimizing temperatures at specific alpha values During simulation of the cold-shot cooling reactor design, it was deduced that the range of ÃŽÂ ± was restricted from 0.01 to 0.38, beyond which the bulk of the reaction would occur in one of the two reactors, making the other redundant. Optimally, ÃŽÂ ± should be somewhere between the limits of the range; for ÃŽÂ ± = 0.19 and feed temperature at 699K, a minimum overall volume of 4.78 m3 was achieved. It is seen from the graph above that as ÃŽÂ ± deviates from 0.19 and tends towards 0, the first reactor behaves more like a single PFR. The same happens to the second reactor as ÃŽÂ ± tends towards the ÃŽÂ ± upper limit. Increasing the initial feed temperature causes ÃŽÂ ± to increase in order for optimization to occur, while a decrease would bring about the opposite effect. This is because a larger fraction would be required to cool the output from the first reactor to achieve optimization should the reactor operate at a higher temperature. The contrary is true; with a larger ÃŽÂ ±, the initial feed temperature cannot be too low as excessive cooling of the second fraction would occur. 6. Conclusion It can be concluded that the investigation w