Wavelength Conversion Four Wave Mixing in Silicon Waveguide

Wavelength Conversion by Degenerate Four Wave Mixing in Silicon Waveguide Abstract – Four-wave mixing (FWM) is one of the interesting nonlinearities in optical systems. It is mainly used for wavelength conversion. To investigate the factors that affect the wavelength conversion efficiency, the evolution of Four-wave mixing (FWM) in silicon waveguide is modeled using matlab. The method of modeling is described. The effects of input pump power and waveguide length on the conversion efficiency are investigated.Results show that when propagating along a 0. 048m silicon waveguide, both the input pump power and stroke power decreases, while anti-stroke power increases first and then decreases along the waveguide. It is also shown that for a 0. 048 silicon waveguide, output anti-stroke power is the maximum when the input pump power is 3W. Also, when the input pump power is kept constant, there is a most effective waveguide length for wavelength conversion. Keywords -FWM; model; conve rsion efficiency; input pump power; waveguide length 1 IntroductionFour-wave mixing (FWM) is an inter modulation phenomenon in optical systems, whereby interaction between three waves (two pump waves and a signal wave) produce a fourth wave (idler wave) [1]. This phenomenon can be used for all optical wavelength conversion (AOWC) and entangled photon generation [2, 3]. As extremely small core of si wires produce the nonlinear optical effect even under low optical power, Silicon is used as waveguide in our project for practical wavelength conversion by FWM process with longer waveguide lengths and smaller propagation loss[4].Factors that affect optical wavelength conversion are being studied to enhance the conversion efficiency. It has therefore become important to study FWM in silicon waveguide theoretically to increase the conversion efficiency for further experiment. In our project, FWM matlab to study the factors that affect the conversion efficiency. This paper discusses the fac tors that affect FWM’s conversion efficiency in silicon waveguide. Theoretical treatment is presented in section 2, where FWM in silicon waveguide is described. The method to model FWM in silicon waveguide using matlab is described in section 3.Results are shown in section 4. Results show that both the input pump power and the waveguide length play an important part in the FWM’s conversion efficiency. 2 THEORY The FWM process involves the interaction of four waves (two Pump waves, one signal and one idler wave) as they propagates along a medium. In our project, silicon waveguide is used as the medium. The schematic diagram of FWM in silicon waveguide is shown in figure 1. Here, E represents the electric field of the respective waves and normalized such that power P=|E|^2. Subscripts ‘p’, ‘s’ and ‘a’ represent pump, signal and idler respectively.The superscript ‘f’ represents forward propagating waves. [pic] Figure 1 S chematic diagram of FWM in silicon waveguide . 3 METHODOLOGY The evolution of the three waves along the silicon waveguide can be modeled by the following differential equations [1]. [pic][pic][pic][pic] where Aeff is the waveguide effective core area, ? is the wavelength, ? is the linear propagation loss and ? is the TPA coefficient, ? is the FCA cross section and ? eff is the effective carrier lifetime. h and c follow their usual physical meaning of Plank’s constant and free-space speed of light respectively. k denotes the linear phase mismatch and can be expressed as[pic]. ? is the nonlinear parameter assumed to be the same for three wavelengths and defined as [pic] where n2 is the nonlinear refractive index. To simulate the evolution of the three waves along the silicon waveguide, the above four differential equation are solved simultaneously using Runge-Kutta-Fehlberg (RKF) method [2]. |Parameters |Input-Output simulation values | |? |100/4. 34 m-1 | |Aeff |0. 17? 10^(-12 ) m2 | |? 0. 7? 10^(-11) m/W | |? p |1310? 10^(-9) m | |? eff |1? 10^(-9) s | |c |2. 998? 10^(8) | |h |6. 626? 10^(-34) Js | |? k |0 m/s | |? p |1. 0297? 10-21m2 | |? |2. 43 ? 10^(-11) m/W | 4 RESULTs and discussion . 1 Modelling of FWM in silicon waveguide Given Pp=1W, Ps=0. 001W, Pa=0W and L=0. 048m, Pump power, stroke power and anti-stroke power are drawn with respect to the position in the waveguide. [pic][pic][pic]The figures above show that when propagating in the waveguide, both the pump power and stroke power decrease while the anti-stoke power increases. This is as expected, as the interaction of the pump wave and stroke wave produce the anti-stroke wave. The increase of the anti-stroke power comes from the decrease of the pump and stroke power.It can be seen that, at the end of the waveguide, the pump power is only 0. 26W and the stoke power is only 0. 026W. Both of them decrease 74% of their original power. Both the pump power and stroke power decrease fast at the beginni ng, and then their decrease rate becomes slower when propagating further in the waveguide. This implies that the higher the pump power and the stroke power, the higher the propagation loss. As a result, the anti-stroke power increases fast at the beginning and then its increasing rate slows down. At the length of 0. 42m, the power of the anti-stroke reaches its maximum value which is about 3. 2*10^-5W. Then the anti-stroke power starts to decrease slowly. This may be because when the pump and stroke power is small, the gain of the anti-stroke power is less than its propagation loss. 4. 2 Effects of input pump power on conversion efficiency Given Ps=0. 001W, Pa=0W and L=0. 048m, Pp changes from 0 to 10W with step 0. 2W. The graph of the output stroke power and the output anti-stroke power are drawn with respect to the input pump power. [pic] Figure 2. 1 Output stroke power with different input pump powerThis graph shows that the larger the input pump power, the smaller the output str oke power. This is as expected, as the larger the input pump power, the larger the propagation loss. The output stroke decreases slower when the input pump power is higher. [pic] Figure 2. 2 Output anti-stroke power with different input pump power This graph shows that when the input pump power is less than3W, the higher the input pump power, the higher the output anti-stroke power. This is as expected, as more input power can be converted to anti-stroke power when the input pump power is larger.When the input pump power is larger than3W, the output anti-stoke power decreases with the input pump power. As the higher the input pump power, the higher the propagation loss. When the input pump power is larger than3W, the propagation loss dominates. 4. 3 Effects of waveguide length on conversion efficiency To investigate the relationship between the waveguide length and the conversion efficiency, input power are keep constant, Pp=1W, Ps=0. 001W, Pa=0W, L changes from 0. 001m to 0. 1m wit h step 0. 001m. Output stroke power and output anti-stroke power are drawn with respect to different waveguide length. pic] Figure 3. 1 Output stroke power with different waveguide length This graph shows that the longer the waveguide length, the smaller the output stroke power. This is as expected, as the longer the waveguide length, the larger the propagation loss. The decreasing rate of the output stroke power decreases with the waveguide length. [pic] Figure 3. 2 Output anti-stroke power with different waveguide length This graph shows that when the waveguide length is less than 0. 048m, the output anti-stroke power increases with the waveguide length.This implies that the gain is larger than the propagation loss in the waveguide. When the waveguide length is larger than 0. 48m, the output anti-stoke power decreases with the waveguide length. At waveguide length larger than 0. 048m, the propagation loss is larger than the gain of the anti-stroke power. The output anti-stroke pow er has a maximum value of 4. 5*10^3 when the waveguide is 0. 048m. Thus, the most effective waveguide length is 0. 048m. 5 Conclusion The conclusion serves the important function of drawing together the various sections of the written report.The conclusion is a summary, and the developments of the previous sections or chapters should be succinctly restated, important findings discussed and conclusions drawn from the whole study. In addition, you may list questions that have appeared in the course of the study that require additional research, beyond the limits of the project being reported. Where appropriate, recommendations for future work may be included. The conclusion should, however, leave the reader with an impression of completeness and of gain. AcknowledgmentThe author would like to express her deepest gratitude to A/P Luan Feng and PhD student Huang Ying for their guidance, assistance and advices. The author also wishes to acknowledge the funding support for this project fr om Nanyang Technological University under the Undergraduate Research Experience on Campus (URECA) programme. References The template will number citations consecutively within brackets [1]. The sentence punctuation follows the bracket [2]. Refer simply to the reference number, as in [3]—do not use â€Å"Ref. [3]† or reference [3]† except at the beginning of a sentence: â€Å"Reference [3] was the first †¦Ã¢â‚¬ Number footnotes separately in superscripts. Place the actual footnote at the bottom of the column in which it was cited. Do not put footnotes in the reference list. Use letters for table footnotes. Unless there are six authors or more give all authors’ names; do not use â€Å"et al. † Papers that have not been published, even if they have been submitted for publication, should be cited as â€Å"unpublished† [4]. Papers that have been accepted for publication should be cited as â€Å"in press† [5]. Capitalize only the firs t word in a paper title, except for proper nouns and element symbols.For papers published in translation journals, please give the English citation first, followed by the original foreign-language citation [6]. 1] G. Eason, B. Noble, and I. N. Sneddon, â€Å"On certain integrals of Lipschitz-Hankel type involving products of Bessel functions,† Phil. Trans. Roy. Soc. London, vol. A247, pp. 529-551, April 1955. (references) 2] J. Clerk Maxwell, A Treatise on Electricity and Magnetism, 3rd ed. , vol. 2. Oxford: Clarendon, 1892, pp. 68-73. 3] I. S. Jacobs and C. P. Bean, â€Å"Fine particles, thin films and exchange anisotropy,† in Magnetism, vol.III, G. T. Rado and H. Suhl, Eds. New York: Academic, 1963, pp. 271-350. 4] K. Elissa, â€Å"Title of paper if known,† unpublished. 5] R. Nicole, Title of paper with only first word capitalized,† J. Name Stand. Abbrev. , in press. 6] Y. Yorozu, M. Hirano, K. Oka, and Y. Tagawa, â€Å"Electron spectroscopy studies on magneto-optical media and plastic substrate interface,† IEEE Transl. J. Magn. Japan, vol. 2, pp. 740-741, August 1987 [Digests 9th Annual Conf. Magnetics Japan, p. 301, 1982]. 7] M. Young, The Technical Writer’s Handbook. Mill Valley, CA: University Science, 1989.

Deadly Feasts

Erica Dunyon Directed Readings Deadly Feasts by Richard Rhodes I have to admit, on the opening scene I was really skeptical about reading this book. I really have always hated the idea of cannibalism, so when I was reading and imagining this, in my mind one word came to my attention, â€Å"Disgusting! † Progression into the book, however, received my attention, and I continued forward. I enjoyed reading this book. It was very informative, easy to understand, and easy to read. I learned about various prion diseases and their effect on each species they infect.Deadly Feasts is about spongiform encephalopathies including Creutzfeldt-Jakob disease, Scrapies, Rida, Kuru, and mad cow disease. This book explains the relationships each spongiform disease has in common with each other, as well as their signs and symptoms. Mad cow disease and scrapies are quite similar to each other, and was endemic in Britain when this book was published. Another rare disease occurring in humans known as Creutzfeldt-Jakob disease has then been related to mad cow disease. Creutzfeldt-Jakob disease is one in which eats human brains. Kuru is thought to be another spongiform disease.Kuru was thought to be a result of sorcery. Initially when this disease was discovered, the belief was leaning toward this disease taking on a genetically transmissible role. After much research, it is known that it is a transmissible disease spread by the consumption of infected flesh. The extremely unusual thing about kuru, along with other spongiform encephalopathies, is that it lacks the presence of inflammation. Transmissible spongiform encephalopathies (TSEs) are also known as prion diseases. The infectious microbe in TSEs is a specific protein called prion protein.These prion proteins and proteins of the brain are extremely similar. This may be the reason these proteins are not detected by the immune system which is why they do not cause inflammation. These diseases are unique because they are impo ssible to kill. They have been exposed to virtually everything including, extreme temperatures and radiation, and still have the ability to infect and cause disease. Gajdusek believed that transmission of these spongiform encephalopathies was in the form of protein in diseased dead animals, including sheep and cattle that were fed to other cattle.Rhodes refers to a concept known as industrial cannibalism. This means that the supplements were made from dead cows. Despite the fact that cattle were coming down with a disease that decreases the cow population, supplements were still made with the remaining’s of diseased cattle and fed to other cattle. Transmission of this disease can occur months or even up to decades because the disease can incubate for the allotted time. Britain was responsible for the initiation of research in this epidemic group of diseases. Britain did not inform the public in regards to this disease.They also bought diseased animals for half of the market v alue. The British government banned individuals from feeding animal waste to other animals, in 1989 to limit the spread of these diseases. In addition to limitting the transmission of these diseases, as a safety measure, the FDA prevented industries from feeding cattle protein from dead sheep, cattle, and other susceptible diseased animals. Europe still has increasing cases of the disease, which it infects many various herds and species of animals, supporting that the epidemic disease is able to spread across the species barrier The British government, by making the wrong public health choices, has conducted a frightening natural experiment, allowing a lethal disease agent to spread through the human food supply, exposing the entire British population. † (Rhodes 97) America is trying to prevent the spread of spongiform disease transmission from Britain to the U. S. by manufacturing our own beef and meat products. Unfortunately, it would not be known if the disease has affected our population until it is a point when it might be too late. TSE’s are essentially unidentifiable until they progress to the point of brain damage. † (Rhodes 97) Spongiform diseases are still a known problem in the world, and the protection we give ourselves, or lack of protection is an issue brought up by Rhodes. Rhodes refers that spongiform diseases might be Britain's †new Black Death. † He states that the transmissible spongiform encephalopathies are public health problems and not only clinical. Transmission is controlled by actions of both social and institutional aspects.The term the â€Å"new Black Death† refers to the ease of the transmission of the disease. If the plan for eradication is not carefully planned and executed, transmissible spongiform encephalopathies can be a serious epidemically known disease that can cause many deaths. In conclusion, I recommend Deadly Feasts to all individuals, not necessarily limited to only those interest ed in microbiology. This book gives insight on a former, and always possible, group of diseases that can become epidemic at any time. I believe knowledge is power, so knowing about these diseases only contributes to public safety.

Farewell Speech Essay

â€Å" Every new beginning comes from some other beginnings end. † – Seneca. Middle school ended and now High school has begun. We all go into high school not knowing what to expect. Like if you’ll have the same classes as your best friend, if you’ll have nice teachers, or if you’ll get dumped in a trash can on â€Å"Freshman Friday. † The toughest thing is not knowing which of your friends for middle school will be at your school and which ones won’t be, if your best friend is going to a different school then you. But it’s O. K. high school is a new beginning we get to reconnect with old friends from elementary school and see our friends from last year to. As time goes by and with each of our classes you build new friendships that strengthen as the year goes on. The more you get involved in school the more you get to become friends with more people. I did Cheerleading for school this year and I have no regrets, I made so many new friends because of it they’re like my sisters now. I was also a wrestling manager and that was great I can’t wait to do it again next year, I didn’t only become close with the other managers I also became close with the wrestlers, they’re like brothers now. But no matter how many friends you made in high school you never lose touch with the ones you had in middle school. Every Freshman had those â€Å"Freshman Fears. † Some not as bad others, but everyone has them. Like the fear of â€Å"Freshman Friday† it’s funny because we never actually had that. It’s something they say to scare us†¦. And it works every time. We worry about if we have good teachers or not. Most of them are, but that’s your own opinion. Will we have a lot of our friends in our class? Are they going to have the same lunch as us? We get scared that we’ll get lost in the hall ways, or seniors will run us over. We have so many worries because of what we hear about high school, and that sense we’re the youngest in the school we have the worst teachers. It’s not like that at all in fact this year of high school was great, I wouldn’t change it at all. Yeah, this year wasn’t perfect, there was still drama and fights, but once everyone got past all that this year was really fun. Football games were always fun, everyone went to them and had a great time. Pep rallies are interesting, especially when the seniors and juniors try to win the spirit stick. A lot of people try to make high school sound scary and horrible, but it hasn’t been bad at all. I’ve had a great year and can’t wait to see how the rest of high school will be.

Question 1 Essay Example | Topics and Well Written Essays - 500 words

Question 1 - Essay Example This was also the position of Montesquieu,2 who was concerned with the preservation of political liberty. Theoretically, each branch has unique and particular functions that are suitable to either. The constitution provides the powers of the legislature, which is generally to make laws and to legislate. The executive has the authority to made decisions on administration and enforcing laws, and the judiciary is mandated with interpreting laws and punishing those who break them. The goal of the Constitution is to prevent tyranny by dispersing power so that no one body has a monopoly. An absolute separation of these powers with none overlapping with the other is not practical and would put the government at a standstill. The doctrine does not demand absolute or rigid separation as it is not possible. The Federal Constitution offers a relaxed version of the separation of powers. These roles actually overlap and one power finds itself doing the work of the other in the process of doing its duties. They also cat as checks and balances for each other. For example, the power to make laws belong to the parliament and courts has the interpretative role of the same laws. Courts also checks on the executive by reviewing their decisions and striking them on grounds of judicial review. The executive also interferes with the judiciary as it appoints judges in the judiciary and is clothed with the powers of prerogative pardon. This undermines courts executive powers to prevent interference with their proceedings and to secure enforcement of their decisions. Further, the Senate has a role in appointments and treaties checks on the President. The Congress also has the authority to prevent fraud and abuse of author ity in the other two branches. Therefore, separation of powers is only a theoretical rather than a practical doctrine. From this, it is quite

Hospital Human Resource Department Assignment Example | Topics and Well Written Essays - 1500 words

Hospital Human Resource Department - Assignment Example The paper will have an overall view of the human resource department in a community hospital. Hospital organization hierarchy and structure An organization hierarchy is a form of organizational structure in which every entity apart from one is subordinate to the other. This means that the subordinate departments and sections report to one another within the hierarchy. This ensures that there is a chain of command flowing from the top. The human resource department in community hospital has a hierarchy in which the chain of command flows from the human resource manager. The human resource manager is at the top of the hierarchy given that he/she is the senior most person in the department. He/she oversees the relationship between staff and the organization and establishes the human resources vision. Subordinate to the HR manager are the employee relations manager, compensation and benefits manager and training manager. The training and development manager handles all issues related to recruitment, placements, and selection. Within the same hierarchy exists the employee relations manager who handles matters related to employee grievances and safety issues. The compensation and benefits manager handles issues related to workers’ remuneration, allowances, and incentives. The hierarchy is as shown in the chart below. Fig 1: A chart of Human Resource department’s organizational hierarchy and structure Basic responsibilities of the Hospital HR department The hospital’s human resource department is charged with the responsibility formulating human resource policies, and recruiting and employing staff, training, establishing workers’ remuneration packages and solving any problems related to staffing. This ensures that the hospital meets its personnel requirements and its missions. When formulating new HR policies, the department considers several factors both internal and external to the organization The human resource department ensures that the hospital maintains adequate staff so that no shortage is experienced in the same respect. Staff shortage may affect the hospital grossly to an extent of putting the lives of patients at risk. In so far as staffing is concerned, the department is charged with the responsibilities of recruiting, selecting, and training the employees. The department also offers placement opportunities to trainees and promotion to those staff members that have contributed a lot to the hospital after evaluating the employees (Goyal, 2005). The human resource department of the community hospital ensures that favorable relations exist between employees and managers. It does this by organizing training programs, meetings, and workshops. This has proved beneficial in the hospital as it makes employees feel that they are valued in the hospital and that their contributions in the organization are recognized. The human resource department also ensures that employee’s morale is boosted. This it does b y developing and revising incentive schemes depending on the prevailing situation and considering various factors. The human resource department also ensures that proper procedures and policies are in place for handling employees’ grievances. This goes a long way in avoiding industrial actions including strikes, go slows and litigations as noted by Goyal (2005). Type of department The hospital has a centralized human resource department considering that most of the major decisions are made by the managers. All policies and major decisions a

Leadership, Teambuilding and Communication Assignment

Leadership, Teambuilding and Communication - Assignment Example In this theory, shows that some people have better leadership traits than others. He concludes that there are those people who are born to lead while others were born to be led. Behavioral approach is one other form of traditional leadership style, in this leadership theory, there are three leadership styles that are distinct from each other. Their styles include; authoritarian leadership whereby, the leader maintains strong control over the group at work. In this form of leadership, motivation is by coercion, and there is no free communication between the leader and the staff. Communication comes from the leader only, and the workers are there to follow. In this kind of leadership, there is high productivity but with low self-motivation and autonomy by the workers. Democratic approach is another form of leadership style that is friendlier to the subordinate staff. In the case here, there is free communication from both the staff and the leadership. Decision-making involves everybody in the organization, and the staff seen as a whole and not as a leader. Therefore, it gives room for constructive criticism and autonomy among the employees in the organization. Lastly, there is laissez-faire leadership style, where there is little or no control from the leader (Murphy, 2005). The kind of leadership is so much of the essence in situations with poorly defined problems that need brainstorming to come over the problems. There are a number of leadership theories that include, transformational, cite suggested that leaders have the abilities to groom their followers into better leaders in the future. The grooming is achieved successfully by letting followers have the freedom to control their behaviors.  

Women history Essay Example | Topics and Well Written Essays - 500 words

Women history - Essay Example On the other hand, Ruth Milkman focuses on the issue of gender at work. In this case, the author focuses on the aspect of sexual division during labor. In doing this, Ruth Milkman focuses on the World War II. Milkman indicates that refashioning gender roles remained enormous during World War II. There were expectations in terms of gender roles during this period. Additionally, men and women both played different roles. The fact that both authors focus on women, it means that women remain important in the society. By focusing on women, both authors reflect on the post war period. In fact, the sentiments shared are happenings from the World War II. In writing the quotes, both authors take a critical approach on how certain aspects were conducted during the postwar period. Ruth Milkman and Rickie Solinger conduct an extensive research regarding issues facing women in the past. Additionally, both authors support their thoughts using several quotes. Despite the differences in ideas, both quotes reveal the position of women in the past societies. This means that both authors share similar sentiments regarding women. From Ruth Milkman and Rickie Solinger readings, it is evident that both quotes meet on similar ground. That is, women and aspects surrounding them. In the first quote, Rickie Solinger indicates that women are simply uterus in as much as various organisms support them. Here, the author remains clear regarding women and their personality. In the second quote, Ruth Milkman indicates that women can fill positions meant for men satisfactorily but subject to physical requirements and strengths. Almost similar to Solinger sentiments, Milkman is clear on issues surrounding women. Both authors are clear about roles of women in previous societies. In as much as both authors focus on issues that happened during postwar period, most issues indicated in the readings still happen in modern societies. In fact, the politics surrounding abortion remain

Was the postWorld War II decolonization movement too rushed, Essay

Was the postWorld War II decolonization movement too rushed, especially in Africa' - Essay Example India was completely free and given back to Indians and India became independent of British rule. By 1950, a wave in independence struggle and the need to be free was felt across colonies in Africa and this first began in Benin, where natives wanted to come out of European rule. Very soon, other African nations such as Kenya followed and by 1990, the whole African continent attained freedom from European rule (Hargreaves, 1988). The freedom movement in Africa could be compared with the freedom struggle in India although both could be generalized yet distinct features would be drawn. Whereas in India, the decolonization process developed gradually and took many years and was well planned and carried out, the independence movement in Africa has been considered as rushed and unplanned that left unstable political scenarios and a vacuum in the region. The decolonization process in Africa was a rush for distribution of power and European nations remained apprehensive about the situation that also left Africa in a state of chaos. Following the devastation of World War, France, Britain and Germany, the major colonial powers could not retain their supremacy and control over colonies and nation states so independence from colonial rule was inevitable and showed first in the independence struggle of India. Although the entire African and Asian region followed the Indian example, Africa was not actually prepared to handle independence and chaos resulted from an attempt to end colonial rule almost abruptly. Liberia, Egypt and South Africa were already free nations and Moro cco and Sudan also attained freedom. Benin and later Kenya were however places where initial uprisings took form following the Indian example. However the uprisings in Africa were bloody and not as peaceful as was in India as the European powers initially resisted such uprisings although later had to give in to Africa's demand for independence (Hargreaves, 1988). However when independence in India was more organized, and political powers were distributed evenly, in Africa, chaos resulted with pullout of European powers and there was disruption in political and economic systems, no blueprint or political plan to run the nation states and the tribal and state boundaries were also arbitrary resulting in fights between tribal leaders. As traditions and customs formed an important part of African culture, the change in leadership brought about power struggle between tribal groups and African political leaders. Yet Africa was struggling for its independence just as India did and despite its ill reputation for being a nation characterized by slave trade, it attained its freedom. Although there may be similarities with the freedom struggle in Asia, African nations were markedly showed more disrespect due to cultural attitudes of Europeans and the resistance in Africa was thus tough, forced, unplanned and all of a sudden. In fact some historians have considered the struggle for African independence as unplanned and done as an inspiration of Indian independence so without proper weighing of the advantages and disadvantages of such a struggle. This

Language and Literacy Essay Example | Topics and Well Written Essays - 3000 words

Language and Literacy - Essay Example There seems to be no agreement as to when language was first used by humans. Some estimates date as far back as two million years ago, during the time of Homo habilis, while others date as recent as forty thousand (40,000) years ago, during the time of Cro-Magnon man. What is unarguably clear, however, is that language development is a continuous process affected by several social factors and that most contemporary human languages are a blend of several primitive ones. One main feature of human language is arbitrariness of symbols and sounds. A symbol or sound only needs to be attached to a particular concept or meaning, or even applied to the rules of grammar and becomes a part of the language. For instance, while the word 'nada' is conceptualised to mean nothing in the Spanish language, for Croatian speakers, it means 'hope' (Hudson, 2000). Through the course of this essay, I shall attempt a discourse of the various social factors that come into play in language, within the context of literacy development. In this regard, three students currently undertaking a basic skills "Brush Up Your English" course at Halton College will be used as case studies. After a brief analysis of what has been said and researched on the impact of social factors on language development, I will give a brief account of the backgrounds of the three students in this group, before examining how the duo of region/geography and gender (two main social factors) have affected language development and literacy in these students. Language and Social Factors Sociolinguistics are social sciences that consider the interactions between languages and society as a whole. It is an established body of knowledge that studies language on a social basis. Thus, it involves an interest in interaction, variability and diversity in language (Deumert, 2005). Or as described by Trask (1999), it is "the study of variation in language, or more precisely, the variation within speech communities." (Trask, 1999, p.283). This field of interest only dates back to the 1950s, this perhaps explain why most of the social influences on language development are still not fully comprehended. Within the Sociolinguistics school, there are two broad approaches to language variation; prescriptivism and descriptivism. Prescriptivists tend to be found among the ranks of language educators and journalists, and not in the actual academic discipline of linguistics. They hold clear notions of what is right and wrong and tend to advocate what they consider as 'correct' use of language according to set rules (Hudson, 2000). Describing this school of thought, Thorne (1997) states that "it is associated with formal written and spoken language and is used in dictionaries, grammar books and language handbooks." (p.92). To further buttress this point, Thorne (1997) cited the example of the original version of the National Curriculum for schools' emphasis on Standard English (SE) being taught as "the language of wide social communication and was generally required in formal contexts" (p.138). Descriptivists, on the other hand, do not accept the prescriptivists' notion of "incorrect usage." They prefer to describe such variance as 'non-standard'. Thus, they see Standard English as "only one variety among manylinguistically speaking it can not legitimately be

What is political ideology, and why do you subscribe to it Essay

What is political ideology, and why do you subscribe to it - Essay Example e classic works of Althusser, Mannheim, Freeden and Bell are clarifying this term in terms of its connection to real practices, morphologic structure, and internal classification. So, in a given essay the definition of political ideology is stated and its internal power to influence minds in analyzed. To start with, the very appearance of ideology is caused by human nature. As Althusser (1969) assumed, the fact that human beings use their mental abilities in order to comprehend the world around them creates the very appearance of ideology. As the author summarizes it, â€Å"ideology is a ‘representation’ of the imaginary relationship of individuals to their real conditions of existence† (Althusser, 1969, p. 162). In other words, it is a specific way to imagine reality in general and political conditions in particular. Moreover, materialistic dimension is crucial for Althusser as he refers to the theory of Karl Marx in his determination of ideological thinking. In this case, ideology as a part of certain ideological state apparatus â€Å"always exists in [†¦] its practice, or practices† (Althusser, 1969, p. 162). So, each behavior in society is regulated by the way people appreciate and interpret the world around them. Consequently, their mental con structs impact the reality they live in. Finally, the continuous existence of ideological thinking evokes the fact that some people have more authority than the others. Hence, the phenomenon of ruling ideology appears. In this context, individual can be easily transformed into the agent of ideology by approving certain procedures of interpretation. Actually, each member of society has prescribed identity or â€Å"appointed as a subject in and by specific familial ideological configuration† (Althusser, 1969, p. 176). And so, the horizon of senses which is created by the human thinking on social unequal background enables the very appearance of ideology. Similarly, in the field of political struggle the way of

COMPANY LAW 402 ASSIGNMENT Example | Topics and Well Written Essays - 2500 words

COMPANY LAW 402 - Assignment Example We instituted legal research into this matter with a view of determining the suitability and legality of starting a Picture Framing business in Australia. We believe this goes towards the very crux of your matter. Further, we would like to state that our services can only be of a legal nature on this matter. It is your duty to seek out qualified professionals who will assess the proposed business venture while looking at its location and profitability in order to determine whether it will be a going concern. Due Diligence It would be remise of our duty as consultants if we did not advice you that it is your duty look into the financial and commercial aspects of this business venture. This is because a business wherever it is instituted needs to have a strong financial basis that will see its survival and development. This should be done so as to avoid a situation where you have overlooked the financial aspects of this venture. That would be catastrophic. You should undertake this res earch through professional help. Ownership Before starting on any business, you need to determine whether or not the company structure is right for the particular company, decide what name the company is to assume, its mode of operation, the legal obligations that are assumed by the company, getting the requisite consents and finally registering the company (Commission). As discussed with you a summary of the proposed corporate structure has been prepared. It should be reviewed carefully and approved by your accountant. Australian Law provides for the structuring of any business in four ways. 1. Sole trader: an individual trading on their own 2. Partnership: an association of people or entities carrying on a business together, but not as a company 3. Trust: an entity that holds property or income for the benefit of others 4. Company: a legal entity separate from its shareholders. Sole Trader Looking at the business of a sole trader, one realizes that the same is entered into by one owner. This owner gets the benefit of directly transacting with his clientele thereby creating a trust as between the business and the clientele. The tax obligations related to this business are subject to the personal rates of the business (Government). The only major disadvantage of this enterprise is that the owner is personally liable for the business liabilities of the company. This opens up the owner to lawsuits that are consequent from the company as the company is not a separate legal entity. A sole trader cannot also share the burden of management and costs with any other person (Lawyers). In relation to the Picture Framing business, you both want to be co-owners of the enterprise. This in effect renders this business structure nugatory as far as your proposed enterprise is concerned. Trust The other business enterprise that is provided for in Australia is in the nature of a Trust. A Trust is defined to be a business where the trustee conducts business for the benefit of ce rtain beneficiaries. This in effect means that at all times the trustee can only conduct business that is in the interest of the beneficiaries. The advantages of Trusts are that it minimizes the tax that is levied on the business as the income from the business can be directed at the beneficiary with the lowest income thereby

The Effects of Water Shortages in the Last Decade Essay Example for Free

The Effects of Water Shortages in the Last Decade Essay The effects of water shortages in the last decade. New water purification technologies This oral presentation will be divided into few parts. The first one will deal with how the water supplies available to the people, have gradually decreased in the last decade; statistical data will be presented, together with some pictures and graphs. Also, it will make a projection of what could be the impact of the water shortages in the near future and will examine how devastating the need for drinking water could become if certain measures for retaining it are taken very soon. The next part will be about some of the innovations in the water purifications technologies. The last part will be a discussion, where your questions you will be welcomed and I will also ask a couple of questions. It is quite popular to refer to our planet Earth as the Blue Planet and probably all of us are aware why this nickname is given. That’s because of earth’s surface is 70% covered by water. Unfortunately, only around 2% of this is drinking water and the question are we using this small quantity responsively is getting more and more discussed recently. The shortest answer to this question is â€Å"No†; humanity needs too much fresh water and shortages have become highly noticeable. It’s needless to say that water is crucial for all life on earth. It plays an essential role for our health, economy, food production, and environment. Also, drinking fresh water is a compulsory element of the development of the public health, since 21 of the 37 primary diseases are related to water and sanitation. With the growing world population (over 7 billion so far), water consumption rate doubles every 20 years, a pace that is double the rate of population growth. If population and consumption trends persist, it is estimated that the demand for water will surpass its availability by 56%, and 1. 8 billion people will be living in regions of water scarcity by 2025. This situation is exacerbated by the fact that developing countries, already experiencing water-stress, often have the highest population growth rates—bringing more people into a region that already cannot support them. Here it’s important to explain the terms â€Å"water-stressed countries† and â€Å"water-scarce regions†, given the fact that in the near future they will become part of the geographical description of further more parts of the world. Water-stressed countries are regions with fewer than 1,700 m3 of water per capita per year. People living in water-stressed regions must make painful decisions about using water for personal consumption, agriculture, or industry. Regions with fewer than 1,000 m3 per person per year are defined as water-scarce. Water-scarcity hinders economic development, strains the environment, and drastically limits food availability. The 2009 World Water Development report revealed that nearly half of the global population will be living in regions of high water stress by 2030.

Renewable And Non Renewable Resources

Renewable And Non Renewable Resources Our societys emphasis on green living and the global focus on conservation provide the perfect backdrop for teaching students about fossil fuels. Children are naturally curious about whats going on in the world around them. Now is the perfect time for us, as educators, to capitalize on our students innate curiosity by leveraging current events in the world such as the rapidly increasing prices of gasoline for motor vehicles and the ongoing search for economical and efficient forms of renewable energy to engage students in study about how fossil fuels, natural resources and Provide appropriate vocabulary words. Give students the basic vocabulary words they will need in order to achieve your lesson objectives. Basic vocabulary words for teaching students about fossil fuels would include: fossil fuels, coal, oil, natural gas, renewable and nonrenewable. This module will help the students to learn about the fossils fuel , its importance ,need of its conservation and its harmful effects The teacher may use various skills to decide the complexity level of the content. However teacher may take up the topic as given below- (a)Complexity of content(concrete, Symbolic,Abstract) CONCRETE SYMBOLIC ABSTRACT Natural resources,Destructive distillation of coal, Combustion of fossils fuel Exhaustible and non exhaustible energy resources , Formation of fossils fuel, Harmful effects of caused by fossils fuels Fractional distillation (b) Learning Environment- 1. The chapter may be introduced in class rooms, school lab (bringing sample of different items to the lab) , computer lab (by a power point presentation),Outdoor trip etc. 2.Sequence of the lesson can be taken this way_ Introduction Using concrete or symbolic material for group discussion or the class can be divided into groups or individually students may be engaged in a warm up activity as given in students module. Students wi;ll be asked to make a table and fill that PLASTIC PAPER GLASS METAL WOOD OTHER The possible answers to the questions asked in students module will be- Which column had the longest list? (Answer: It will very likely be plastic.) Which category do you think you depend on most? Why? (Answers will vary.) Where do you think these items come from? (Answer: Everything at some point comes from our natural resources. Paper and wood come from trees, plastics are made from oil, glass is made from sand, and metal is made from ore, etc.) You may also do this as a whole class, instead of individually. You may draw a puzzle with blanks and may ask the students to fill in the blanks to complete the schemetic diagram related to natural resources as shown in students module or show the diagram and ask them to list natural resources 1.2 RENEWABLE AND NON RENEWABLE RESOURCE Teacher may begin the lesson with a small activity of hunting fossil fuel STUDENT ACTIVITY 1 or any other activity or can narrate a story to introduce two categories of natural resources Teacher may involve the students in activities highlighting the depelition of resources as in students module Students Activity 2 DEPLETION OF RESOURCES SIMULATION Through the activity, students will hypothesize that as the next generation comes along, there will be fewer resources available to them and eventually, there could be nothing at all. In addition the number of people using a resource and the amount each person uses are critical in determining the rate at which resources, both renewable and nonrenewable, get used up. Teacher may have a supply of extra popcorn (out of sight of the class) for those students who do not participate directly in the simulation Students will probably eat as much of the popcorn as they can without any thought as to who will come after them. By the time the 3rd generation students are finished, there should be little or no popcorn left. Some of the generation coming next people will therefore have little or none at all. Do not discuss what is happening to the popcorn until all the generations have gotten their popcorn. Some students will begin to realize what is happening. Some students in the 2nd generation may think of the 3rd generation and not take as much. The teacher should just watch and listen without making any comments. Review the definitions of renewable resource, and nonrenewable resource. Relate these definitions to the popcorn simulation. Did any of the students who were part of this simulation think about those who might be eating after them, or were they only trying to get as much popcorn as they could? Assessment, Student Product Each student will turn in their own report after they have gone over the discussion points. Each group of 4 will create a slogan that advocates personal responsibility for resource conservation Teacher may build up the lesson by asking the students to perform another activity in groups comparing renewable and non renewable resources as in students module or may use internet for the students research to compare different energy sources for which the class may be divided into groups and assign different energy resources to be researched and compared to coal energy. Students should include topics of safety, efficiency,environmental impacts and cost. Teacher may involve the students in STUDENTS ACTIVITY 3 to understand symbolically that Coal, oil, natural gas and nuclear fuels will last some day and so they are non renewable resource while renewable source will never finish Assessment: Have students explain the exercise and their findings to the class. Encourage them to discuss what other factors might dictate which energy sources are used by a community, such as environmental impact and the persuasion of special interest groups. What specific factors influence the choices of energy sources in your area? How have local energy costs changed over the past ten years? Use a debate format to discuss factors that might dictate community decisions as stated above. Extension: Encourage students to find out what energy sources are used in other countries. Direct them toward coal-dependent countries (such as the United Kingdom and Germany), as well as countries that do not rely primarily upon coal for their energy (such as Sweden, France, and Japan). Challenge them to find out and compare the energy costs of other countries to that of the United States. Continue with researching 10 years of costs/supply and demand and graph the changes over the 10-year period. Have students compare and contrast the outcomes between the different energy sources. Teacher may share the following facts with students to arouse their interest such as- It took 10 feet of plant matter to make 1 foot of coal. The first oil well in the world was drilled in Pennsylvania, USA. World coal consumption is more than 5.3 billion tons annually of which three quarters are used for generating electricity. The earliest known use of coal was in China. Coal from the Fu-shun mine in northeastern China may have been used to smelt copper as early as 3,000 years ago. The Chinese thought coal was a stone that could burn To run a 100-watt light bulb 24 hours a day for a year we need to use about 714 pounds (325 kg) of coal in coal powered power plant (thermal efficiency of such power plant is typically abut 40%). One liter of regular gasoline is the time-rendered result of about 23.5 tonnes of ancient organic material deposited on the ocean floor. . On August 27, 1859, Edwin L. Drake (the man standing on the right in the black and white picture to the right), struck liquid oil at his well near Titusville, Pennsylvania. He found oil under ground and a way that could pump it to the surface. The well pumped the oil into barrels made out of wood. This method of drilling for oil is still being used today all over the world in areas where oil can be found below the surface. 1.3 COAL Coal is a hard, black colored rock-like substance. It is made up of carbon, hydrogen, oxygen, nitrogen and varying amounts of sulphur. There are three main types of coal anthracite, bituminous and lignite. Anthracite coal is the hardest and has more carbon, which gives it a higher energy content. Lignite is the softest and is low in carbon but high in hydrogen and oxygen content. Bituminous is in between. Today, the precursor to coal-peat-is still found in many countries and is also used as an energy source. Teacher may introduce the concept by giving the students the basic knowledge about coal which they are already familiar of or may ask some general questions about the coal 1.3.1 COAL FORMATION The teacher may plot a story of historical background of coal or give the idea by demonstrating an activity as described in student module-COAL FORMATION ACTIVITY The teacher must arrange the material beforehand. The activity will help in reinforcing Critical thinking ,Cooperative learning The activity may take two class periods over four weeks I f you line your container with plastic wrap before you begin, you can lift the whole formation out when it is dry. T his is a smelly activity. If you have an area where you can put this out of the way and observe it occasionally, you will like it better! Teacher can further illustrate the mining of coal through the activity discussed in students modulestudents activity 4 Chocolate Chip Cookie Mining This activity teaches students about coal and mining. Discuss with the students how coal is excavated . Coal is mined out of the ground using various methods. Some coal mines are dug by sinking vertical or horizontal shafts deep underground, and coal miners travel by elevators or trains deep under ground to dig the coal. Other coal is mined in strip mines where huge steam shovels strip away the top layers above the coal. The layers are then restored after the coal is taken away. The coal is then shipped by train and boats and even in pipelines. In pipelines, the coal is ground up and mixed with water to make whats called a slurry. This is then pumped many miles through pipelines. At the other end, the coal is used to fuel power plants and other factories. 1.3.2 TYPES OF COAL: Types of coal may be introduced to the students by showing them samples of different types of coal and comparing their physical properties through STUDENTS ACTIVITY 5- coal identification activity. This will help students to understand the characteristics of different types of coal and enhance their Critical thinking,Cooperative learning and skill of Comparison and contrast. They will lso understand that the harder coal absorbs more heat. Teacher may discuss with students . Does burning show that peat is the lowest rank of coal? Does the manner of burning of bituminous coal show that it still has volatile material (gas) in it? 1.3.3 COMBUSTION OF COAL Combustion or burning is the sequence of exothermic chemical reactions between a fuel and an oxidant accompanied by the production of heat and conversion of chemical species. The release of heat can result in the production of light in the form of either glowing or a flame. To understand that coal is combustible teacher may perform an activity as stated in students moduleSTUDENTS ACTIVITY- 6 Teacher must arrange for the material before hand . If lignite coal sample is not available, charcoal may be used Students should be motivated to illustrate and describe their observations. Teacher may discuss how coal may be useful because it is combustible and gives off heat. Teacher may take a small sample of the dried plant matter from and hold with forceps. Place sample in the flame of a candle and observe combustion. (This matter can be compared to peat.) Discuss observations. . 1.3.4 DESTRUCTIVE DISTILLATION OF COAL Destructive distillation is the chemical process involving the decomposition of feedstock by heating to a high temperature; the term generally applies to processing of organic material in the absence of air or in the presence of limited amounts of oxygen or other reagents, catalysts, or solvents, such as steam or phenols. The process breaks up or cracks large molecules. Products like coke, coal gas, gas carbon, coal tar and ammonia liquor are formed after the destructive distillation of coal. This helps in producing thousands of distinct chemical compounds. Teacher may demonstrate the pocess of destructive distillation of coal in lab or class as illustrated in students module,and keep the students interest entact . Teacher will discuss different observations about the mixtures collected in the end in test tube and beaker and also explain their uses eith the help of placards or flashcards. 1.4PETOLEUM . Petroleum or crude oil, and natural gas are important hydrocarbons that are found in nature within pores and fractures of rocks. Oil and gas form over millions of years as the result of the decay of marine organisms. These organisms die and collect on the ocean floor. Sediments such as clay and mud are deposited above these organisms. During burial and compaction, the organic matter becomes heated. Hydrocarbons are formed and are forced out of the source rock into permeable beds such as sandstone. As by now the students are familiar with the concept of fossils fuel with its examples and its formation in case of coal the teacher may build the lesson on the previous knowledge of the students with the help of role play Teacher may give students more information about the excretion of petroleum Because oil and gas are not very dense, they migrate upward through the water-saturated rock layers. In some cases, this movement is stopped by overlying impermeable layers of rock such as shale or rock salt and the hydrocarbons are trapped. Then, the oil and natural gas form a reservoir in the porous rock. This type of hydrocarbon accumulation requires a source rock, a reservoir rock, and a cap rock. Most of the worlds reservoirs are in sandstone, limestone, and dolomites. Structural traps are related to folds, faults, or salt domes. When an anticline fold that contains hydrocarbons is drilled, the first material encountered is usually natural gas. This gas often is underlain by oil due to density differences. Water is the densest fluid and is found at the bottom of a reservoir. Secondary recovery methods can be used to increase the amount of crude oil that can be pumped from wells. Presently only about 30 percent of the crude oil in a well can be recovered. However, as oil reserves dwindle, steam, carbon dioxide, and detergents can be used to force out the heavy oil that normally cannot be pumped. 1.4.1 REFINING OF PETROLEUM Petroleum in its crude state consists of various organic compounds that must be refined to form usable products. After giving a brief idea about refining of petroleum and fractional distillation the divide the students into research teams. Each team will research how fractional distillation works, as well as describe one of the major products of fractional distillation. Students may then be motivated to use distillation to separate 2 liquids . The teacher must approve the distillation set-up of the students Misconceptions: Students will assume that the mixture will keep getting hotter and hotter as the water boils. They will not expect the temperature to stay steady until almost all the water has been converted to steam. Students may also think that the melted ice cube is dripping through the foil into the beaker. Teacher needs to clarify their misconception Students should be encouraged to use diagrams and charts to present their information. A rubric is provided for assessing the group work at this stage. A copy of this rubric should be given to students before they start their research so that they are aware of the grading criteria. The objectives of the activity performed are . Students will learn that fractional distillation is the first stage in processing crude oil into usable products. (The other two stages are: Conversion: cracking and rearranging of molecules, and Treatment.) Students will understand how fractional distillation works and what products are produced. They will become aware of how these products are used in their world. Students will familiarize themselves with 8 major products of fractional distillation. Students will be able to perform a simple distillation of liquids modeling the distillation of crude oil. Students will share, display, and explain specific information gathered in their research. Research time will vary based on the availability of computers. Most of the research can be completed in 1 to 2 class periods on the computer. The actual distillation will take one period The activity will help improving the following skills of the students Cooperative learning Student centered learning Communication of information Relevant application to daily life Following Directions Making Connections Mathematics integration Drawing Conclusions Because so many petroleum-based products are found in the home,so teacher may motivate the students to perform a take home activity. To complete the activity, students work with their families to identify six petroleum-based products at home. They write those products on the list. Then they think of one way to help conserve petroleum, by reducing their use of a petroleum product, reusing a petroleum product many times over, or recycling a product so it can be made into something else. They add their conservation idea to the bottom of the list, and have their at-home helper sign the form. When students have completed this short at-home activity, they will bring their list back to school and share it with their classmate. If students are having difficulty completing the project at home, a few minutes could be devoted to the activity in school. 1.4.2 COMBUSTION OF PETROL Teacher may correlate the topic with combustion of petrol in vehicles and explain that incomplete combustion of petrol is dreadful as it produces CO which is suffocating. Students may be motivated to collect data in this regard and analyze and help them to differentiate between the combustion of coal and petrol. 1.5 HARMFUL EFFECTS OF EXCCESSIVE COMBUSTION OF COAL AND PETROLEUM Many non renewable energy resources have detrimental consequences upon the environment. Most people are aware of the greenhouse effect created by carbon dioxide and other greenhouse gases that are released by gasoline-powered vehicles, but this is only one of many serious consequences. Coal plants alone generate hundreds of millions of tons of harmful byproducts, including flue gas, desulfurization sludge, fly ash, and bottom ash. These materials can poison waterways and leach harmful toxins such as arsenic, mercury, uranium, and thorium into the ground and water.. Combustion of these fossil fuels is considered to be the largest contributing factor to the release of greenhouse gases into the atmosphere. Teacher may use powerpoint presentations or vedieosto illustrate the concept 1.6 IMPORTANCE OF NONRNEWABLE SOURCES Fossil fuels are of great importance because they can be burned (oxidized to carbon dioxide and water), producing significant amounts of energy per unit weight. The use of coal as a fuel predates recorded history. Coal was used to run furnaces for the melting of metal ore. . Teacher may introduce the topic with some questions such as What function crude oil serves in our life. Is it something that is really necessary in life? What if it was not available, how would our lives differ? (Students answers will vary). Emind students that Petroleum is the Source of many objects ,e.g. à ¢Ã¢â€š ¬Ã‚ ¢ bandage à ¢Ã¢â€š ¬Ã‚ ¢ glue à ¢Ã¢â€š ¬Ã‚ ¢ plastic bagà ¢Ã¢â€š ¬Ã‚ ¢ bubble gum à ¢Ã¢â€š ¬Ã‚ ¢ golf ball à ¢Ã¢â€š ¬Ã‚ ¢ plastic container or bottleà ¢Ã¢â€š ¬Ã‚ ¢ comb à ¢Ã¢â€š ¬Ã‚ ¢ lipstick à ¢Ã¢â€š ¬Ã‚ ¢ toothbrush and toothpasteà ¢Ã¢â€š ¬Ã‚ ¢ crayon à ¢Ã¢â€š ¬Ã‚ ¢ nail polish à ¢Ã¢â€š ¬Ã‚ ¢ tube of hand creamà ¢Ã¢â€š ¬Ã‚ ¢ elastic band à ¢Ã¢â€š ¬Ã‚ ¢ panty hose à ¢Ã¢â€š ¬Ã‚ ¢ wax paper T ell students that one of the most common petroleum products is gasoline that goes into a car to make it run. Remind students that petroleum-based products can last a very long time. Thats why we should reuse and recycle them whenever we can. For a greater challenge, students could be motivated to write their own Who Am I? questions for different petroleum-based products. When there are enough clues written, each student could read out a clue and ask the rest of the class to guess the product. In the end teacher may guide the students to conserve the fossils fuel -coal and petoleum

An Overview of Butadiene

An Overview of Butadiene 1,3 Butadiene 1,3-Butadiene with its molecular structure of [emailprotected]=CH2 have widely synonym as butadiene,,-butadiene, divinyl, buta-1,3-diene, vinylethylene, vinylethylene, bivinyl, erythrene, biethylene, and pyrrolylene refer to the same physical and chemical properties. It has same Chemical Abstracts Service (CAS) registry number which is 106-99-0, and its Registry of Toxic Effects of Chemical Substances (RTECS) number is EI9275000. As compared to the air, the conversation factor of to 1ppm butadiene is equal to 2.21 mg/m3 in the air. Further important identity and physicochemical properties of butadiene is described as per Table 1. Â   Generally, butadiene was produce during combustion resulting from combustion of organic matters whether it come from natural process or human activities. Among of natural process and human activities, the main contributor of butadiene presence in earth majorly come from human activity which cause high impact to surrounding life and environment. As part of human activities, 1,3 Butadiene being used primarily and commercially in the making of synthetic rubbers and polymers. 1,3 butadiene was produced by complex and specific process as co-product of ethylene during cracking at high temperature (produced C4) at the steam crackers units. The crude C4 that produced from steam cracker units or process then fed to the butadiene extraction units for separation process of butadiene, isobutenes and the other C4s (byproduct called as Raffinate 1) through extractive distillation. The most advanced Butadiene extraction technology is come from BASF NMP Process in which 1,3 Butadiene is extract as per Diagram 1 by utilized N-methyl-2-pyrrolidone (NMP) as solvent. Characteristic 1,3-Butadiene is colourless gas at room temperature with gasoline or mild aromatic odor, highly flammable when exposed to heat and insoluble in water but soluble in ether, acetone, benzene and ethanol. It is very reactive: it may form acrolein and peroxides upon exposure to air, it can react with oxidizing materials, and it polymerizes readily, particularly if oxygen is present. Butadiene is stabilized with hydroquinone, catechol, t-butyl catechol or aliphatic mercaptans1,2. In addition from that, as per GHS-US classification, 1,3 Butadiene is classified and hazard label as per Table 2 and Diagram 2 below: CLASS Hazard Statement Description H220 Flammable Gas Category 1 Exteremly flammable gas H280 Refrigerated Liquefied Gas Contains gas under pressure; may explode if heated H315 Skin Irritation Category 2 Causes skin irritation H319 Eye Irrititation Category 2A Causes serious eye irritation H340 Germ Cell Mutagen Category 1B May cause genetic defects H350 Carcinogen Category 1A May cause cancer Table 2: Classification of 1,3 Butadiene as per GHS-US Classficiation Diagram 2: Hazard label/pictogramns of 1,3 Butadiene as per GHS-US Classficiation Used 1,3 Butadiene is the main raw material to manufacture variety type of rubbers and plastics. It is being used as an intermediate ingredient; monomers in production of polymers, synthetic rubbers or elastomers, and other chemicals. As substitution for natural rubber, Butadiene being used widely in producing synthetic rubbers and polymer which offers numerous advantages in term of improvement in performance, safety and functionality, and lower costs. Over 75% of 1,3 Butadiende was used to produce Synthetic rubber. Synthetic rubber derived from 1,3 butadiene include Styrene-butadiene rubber (SBR), poly-butadiene rubber (PBR), nitrile rubber (NR) and poly-chloroprene(Neoprene). These synthetic rubbers then undergo several others specific process to produce product like: Styrene-butadiene rubber (SBR) and poly-butadiene rubber (PBR) are used in the making of tyres and plastic where able to enhance and increase the resistance of vehicles tyre and plastic towards heat degradation, blowouts, wear and tear. Neoprene or poly-chloroprene is used extensively in manufacture of latex goods which is non-tire application such as gloves, foams, waders and wearsuits. Nitrile Rubber(NR) have variety of end product which mainly used to produce rubber hoses, gasket and seals for automobiles . Remaining 25% of 1,3 Butadiene was used to produce polymers. Polymerd derived from 1,3 include Acrylonitrile-butadiene-styrene (ABS) resins, poly-butadiene polymers, nitrile barrier resins and thermoplastic resins. Among the others, ABS resin was widely used in large volume of thermoplastic resin, containing about 20%- 30% of 1,3 butadiene by weight to produce automobiles part and appliances in automotive industry . Apart from that, 1,3- Butadiene also is used in the production of adhesives for packaging, transporting, or holding food; in components of paper and paperboard that are in contact with dry food; and as a modifier in the production of semirigid and rigid vinyl chloride plastic food-contact articles. Human Exposure The general human exposure can be separated onto two: occupational exposure and non-occupational exposure and describe as per below: 1.3.1 Occupational exposure The highest exposure of butadiene is mainly occurs in occupational settings or workplace area and its surroundings. Potential areas include several industries like: petroleum refinery and operation plant (where the crude C4 cracking process take over and involves butadiene extraction, gasoline production and distribution), distillation and production of butadiene monomer plant, factory or manufacturer of various butadiene based product like synthetic rubber and polymers plant such as tires, gloves and variety injection moulding industries (IARC, 1999). Based from data collected from European Chemical Bereau during 1984 to 1987, the arithmetic means of butadiene concentration at petrochemical and petroleum refinery plant industries area in several location of European countries is ranged from 0.1 to 6.4 mg/m3 Other than that, by refer from survey conducted by occupational hygiene of United Kingdom shows that the mean concentration of butadiene generally below 11mg/m3 with most below 2.2 mg/m3 for butadient production areas while in polymer manufacturer area time-weighted averaged around (4.4 to 6.6mg/m3). Meanwhile at USA in 1985, the arithmetic mean concentration is ranged from 1 to 277 mg/m3 for monomer production plant and 0.04 to 32mg/m3 for polymer production plant. (IARC, 1999; European Chemicals Bureau, 2001). 1.3.2 Non-occupational exposure For non-occupational exposure area, it is obtained that the butadiene mean concentration in ambient air is much lower in ÃŽÂ ¼g/m3 measured than reported in occupational exposure area which measured in mg/m3. Elevation of concentration observed occurs at the vicinity of source like municipal structural fires area, smoking shed or cigarette smoke area, brush and wood fires Butadiene has been widely detected in ambient air but at much lower levels (ÃŽÂ ¼g/m3) than reported in some occupational settings (mg/m3). Elevated concentrations may occur in the vicinity of point sources, such as municipal structural fires, wood and brush fires; cigarette smoking; volatilization gasoline area as well as combustion through vehicle emissions (IARC, 2008). Based on data and study conducted during 1990 and 1994, involvement of 14 cities, rural or towns at Ontario, Canada shows that the results from 1611 samples of outdoor air collected for mean concentration of butadiene is ranged around 0.1ÃŽÂ ¼g/m3 with maximum of 1.7 ÃŽÂ ¼g/m3. (Health Canada, 2000). Dollard et al. (2007) measured butadiene concentrations at rural, urban background (UB), urban industry influenced (UI) and busy-roadtraffic (BR) locations in the United Kingdom from 1993 to 2004. Mean rural levels dropped from 0.39 to 0.02 ÃŽÂ ¼g/m3 between 1995 and 2004; mean UB levels decreased from 0.64 to 0.15 ÃŽÂ ¼g/m3 in 1993-2004; mean UI levels came down from 0.85 to 0.35 ÃŽÂ ¼g/m3 in 1995-2000; and mean BR levels went from 3.3 to 0.57 ÃŽÂ ¼g/m3 in the period 1997-2004. . Human effect Exposure of 1,3 Butadiene can effect human health and the severity can be separated into two, which is acute and chronic. For acute exposure, it can be further split into high doses and low doses. Acute low doses exposure will caused irritation to nose, eyes, lungs and throat. These frostbite injury also may lead to occur through exposure to skin. Acute high doses of exposures will lead to cause damage of central nervous system by showing symptoms to human body such vertigo, general tiredness, distorted blurred vision headache, nausea fainting and decrease pulse rate. Human epidemiological studies has been conducted to identify the Chronic effects to human that cause by exposure to 1,3-butadiene, the result shown the effect to human can cause cancer and cardiovascular diseases. However, due to some limitation and cofounding factors in study of cancer to human due to exposure by 1,3-Butadiene such as simultaneous exposure to syrene and benzene, smoking; the exact causal factors unable to established well. Extensive lab experiment involving animal such as mice and rat has been performed and study to observe relationship of chronic exposure of 1,3-butadiene to cancer. The studies through mice and rat has shown the developmental problems and reproductive effected the animals. Through this study, 1,3-Butadiene has been classified as human carcinogen from EPA and rated as A2; suspected human carcinogen as per The American Conference of Governmental Industrial Hygienists (ACGIH). Further human effect exposed to 1,3-butadiene explain on Table 2. Carcinogenicity to human Based on epidemiological studies conducted shows that high tendancy or risk of leukemia or others cancer to attacked on the lymphohaematopoietic system when chronic exposure to 1,3-Butadiene. This involve three studies on employed workers at 1,3-Butadiene production facility of styrene-butadiene-rubber(SBR) plant where the major exposure is 1,3-butadiene monomer alone. The result of the studies shows the same relation or overlapping cohort population. It was observed in two studies at butadiene monomer facility, overall have slightly excess of mortality from leukaemia while in third study shows decrease in mortality of leukaemia. The increased mortality from leukaemia in one of the monomer industry cohorts was more pronounced among workers who had been exposed at high levels during the first years of production (Second World War). In this cohort, no increase in leukaemia was observed with duration of exposure or cumulative exposure. Based on the study on SBR workers by University of Alabama at Birmingham (USA) considered as very informative data where the study involves in examine the mortality rates of about 17,000 workers through eight facility in Canada and USA. A limiting factor in the evaluations was that the diagnosis and classification of lymphatic and haematopoietic malignancies are very complex and have undergone several changes over the course of time. Although overall mortality from leukemia was only slightly higher in the update of the most recent cohort, a larger increase of deaths from leukemia seen in workers in the most highly exposed from plants and one employee per hour paid, especially those who was hired in early years and has ten years or more jobs. Furthermore, a significant correlation between cumulative exposure of 1,3-butadiene and leukemia deaths observed in this study. A recent analysis shows that the exposure-response relationship for 1,3-butadiene and leukemia are free from exposure to styrene and dimethyldithiocarbamate. Studies with mice showed increased tumour formation in various organs in both sexes at 1,3-butadiene exposures to approximately 14 mg/m3 (females) and 44 mg/m3 (males). This was not observed in rats at exposures up to 2,200 mg/m3, likely due to the crucial role of oxidative metabolism: 1,3-butadiene requires metabolic activation to generate electrophilic epoxides in which important species differences exist (mice are more efficient in the production of epoxide metabolites of butadiene, while rats and humans are more efficient in the hydrolytic detoxification of these metabolites). Many tests on mutagenicity, genotoxicity and mechanism of action clearly indicate that 1,3-butadiene is a genotoxic compound in humans and in experimental animals, requiring metabolic activation to generate electrophilic and DNA-reactive epoxides (epoxybutene, epoxybutanediol and diepoxybutane), one or more of which are considered to be the ultimate carcinogens. Health Effect Description Symptoms Inhalation problem or respiratory irritation Inhalation of 1,3 butadiene gases or aerosols such as mists or fumes generated by the material during handling and normal works can be damaging the human health. Excessive exposures can cause severe irritation to upper respiratory system or central nervous system like nose and throat. 1, 3 butadiene can cause narcotic effects or anesthetic including dizziness and drowsiness, alertness, sleepiness, lack of coordination, vertigo, loss of reflexes and death. Ingestion Drink or food that contaminate with 1,3-Butadiene which the residues of 1,3-butadiene have been found in drink and food container. (McNeal and Breder 1987) Liquid butadiene can cause frostbite to the lips but this unlikely to happen because very low amount of butadiene used in food and drink containers. Eye Person or human can be exposed to the 1,3 Butadiene liquid and gases during manufacture or at occupational area Transient discomfort characterised by tearing or conjunctival redness, pain and blurred vision.exposed to liquid butadiene can cause frostbite if it contacts the eyes and rapidly evaporates. Skin Contact Not to have any skin irritation or harmful to human health in normal condition. It will affected if the person involve in injury or wound In touch with liquid butadiene may cause frostbite and rapidly evaporate. When entry into the blood-stream, through cuts, abrasions or lesions, may produce systemic injury with harmful effects. Chronic As per International Agency for Research on Cancer (IARC), Butadiene is listed as human carcinogen which can directly cause cancer in human. Based on experiments, there is an evident that butadiene can cause genetic defect and may result in toxic effecs to the unborn baby. Cancer ex: leukemia, damaged of cardiovascular system, genetic defect Table 2: Health effect of 1,3 Butadiene to human health Reduce the risk of hazardous In order to reduce risk of hazardous of 1,3butadiene, many precaution and controls shall take in consideration. Separated into two; occupational and non-occupational exposure. 4.1 Occupational The higher human exposure to 1,3 Butadiene is come from occupational environment. Appropriate control can be taking in consideration to reduce the risk exposure by include appropriate engineering controls, hand protection, eye protection, skin and body protection, respiratory protection and environmental exposure control. 4.1.1 A Appropriate engineering controls Appropriate engineering controls : This product must be confined with vapor-tight equipment. With this confinement, vapors should not be released, and local exhaust should be satisfactory. An explosion-proof system is acceptable. Ensure that any venting of material is in compliance with international, federal/national, state/provincial, and local regulations. Hand protection : Wear protective gloves made of PVC. Eye protection : Wear safety glasses with side shields. Wear safety glasses with side shields or goggles when transfilling or breaking transfer connections. Provide readily accessible eye wash stations and safety showers. Skin and body protection : Wear work gloves and metatarsal shoes for cylinder handling. Protective equipment where needed. Select in accordance with OSHA 29 CFR 1910.132, 1910.136, and 1910.138. Respiratory protection : When workplace conditions warrant respirator use, follow a respiratory protection program that meets OSHA 29 CFR 1910.134, ANSI Z88.2, or MSHA 30 CFR 72.710 (where applicable). Use an air-supplied or air-purifying cartridge if the action level is exceeded. Ensure that the respirator has the appropriate protection factor for the exposure level. If cartridge type respirators are used, the cartridge must be appropriate for the chemical exposure. For emergencies or instances with unknown exposure levels, use a self-contained breathing apparatus (SCBA). Environmental exposure controls : Refer to local regulations for restriction of emissions to the atmosphere. See section 13 for specific methods for waste gas treatment. Refer to local regulations for restriction of emissions to the atmosphere. Other information : Consider the use of flame resistant anti-static safety clothing. Wear safety shoes while handling containers. Keep suitable chemically resistant protective clothing readily available for emergency use. Wear leather safety gloves and safety shoes when handling cylinders. Non-occupational Wood burning Take precautions to minimize the amount of smoke released into the home during wood burning. Vehicle engines Make sure vehicle engines are turned off when in an enclosed space such as a garage. Vehicle traffic Minimize time spent near areas of heavy vehicle traffic and avoid living very close to busy roads. Tobacco smoke Families can reduce exposure to 1,3-butadiene by avoiding tobacco smoke, particularly indoors.

Indonesia Essay -- essays research papers fc

  Ã‚  Ã‚  Ã‚  Ã‚  After Indonesia declared independence in 1945 the country’s leader, Sukarno, faced the extremely difficult task of creating a unified state out of Indonesia’s numerous ethnic groups. Also ever since its independence Indonesia’s rulers had to suppress uprisings of muslim groups because it threatened the country’s secular ideology.   Ã‚  Ã‚  Ã‚  Ã‚  The attempts by Indonesia’s leaders to maintain unity and the ways in which the military suppressed separatist movements fueled many of the economic, social, and political problems the nation is facing today. After the tsunami, many of the issues surrounding the nationalist issue resurfaced and might change the nature of the conflict between supporters of Indonesian unity and those seeking independence.   Ã‚  Ã‚  Ã‚  Ã‚  The rebels in Aceh claim that the region was illegally annexed by Indonesia at the time of independence, and a separatist movement has been active there since 1976. During the regime of Suharto the military was given absolute power, and the continuous military presence in the region was marked by brutality towards the Acehnese and mistreatment of suspected rebels. Therefore many Acehnese feel a deep sense of distrust towards Indonesia. Since 2003 Aceh has been under Indonesian military rule and the area was closed off to foreigners as an attempt to isolate the area and crush the separatist movement. Indonesia allowed virtually no foreign presence in Aceh. Many believe that the isolation of the area was an attempt by the government t...

Dickens Social Commentary in Great Expectations Essay -- GCSE English

Dickens' Social Commentary in Great Expectations  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚        Ã‚   Charles Dickens' Great Expectations stands as one of the most highly revered works in all of English literature. The novel's perennial appeal lies in its penetrating depictions of character, rich panoramas of social milieu, and implicit crusades against social evils.1 Dickens used the growth of his characters in Great Expectations, particularly Pip, in relation to others to write about social reform, and most effectively illustrated this by using the first-person narrative style. In Great Expectations, Charles Dickens has written a social commentary using the development of his characters to illustrate his message. In my paper, I will concentrate on three of the main characters, Magwitch, Miss Havisham, Estella, and Joe Gargery. During the time when he lived, Dickens recognized many evils in society. In Great Expectations he focused on the problem of the whole idea of a class in society. It was a social commentary on society. His way to illustrate the solution to the problem of class in society was "to create characters who can get beyond the limitations and divisions of class identifications and see themselves as responsible humans."2 The people who read Dickens' works were often the kinds of people he was attacking. Dickens lived during the Victorian age which was known as the age of social criticism. Great Expectations was Dickens first attack on class in society.3 Dickens did not come right out and preach about social reform in his novels. He uses his rich characters to illustrate the values and morals he is trying to get across. Great Expectations is a novel of social criticism. In Dickens' opinion the two main social evils were selfishness an... ...ornback, 22. 3. Hornback, 4-5. 4. Hornback, 27-28. 5. Charles Dickens, Great Expectations (New York: Dodd, Mead and Company, 1942), 3. 6. Dickens, 395. 7. Dickens, 68. 8. Dickens, 71 . 9. Dickens, 72. 10. Dickens, 72. 11. Dickens, 598. 12. Dickens, 57. 13. Hornback, 25-26. 14. Hornback, 60.          Works Cited Chesterton, G.K. Charles Dickens: A Critical Study. New York: Dodd, Mead and Company, 1906. Dickens, Charles. Great Expectations. New York: Dodd, Mead and Company, 1942. Hornback, Bert G. Great Expectations: A Novel of Friendship. Boston: Twayne Publishers, 1987. Pearson, Hesketh. Dickens, His Character, Comedy, and Career. New York: Harper and Brothers Publishers, 1949. Priestley, J.B. Charles Dickens and His World. New York: Charles Scribner's Sons, 1961.   

The Usage Of A Bandgap Reference Voltage Engineering Essay

A bandgap mention electromotive force is an indispensable constituent of an parallel to digital converter.It is frequently used to provide a mention electromotive force which is compared with others voltages.The bandgap mention used in diverse applications is based on the thought of Hilbiler in 1964 [ 1 ] aˆ‚A bandgap mention electromotive force with low sensitiveness to temperature and supply electromotive force is normally required in parallel or digital circuits. Low electromotive force and low power are two of import design standards in both parallel and digital systems.It been expected that the whole electronics system will be operated down to a individual 1-V supply in near future.The bandgap mention ( BGR ) generators which can be operated under 1-V supply have been widely used in DRAM, falsh memories, analog-digital convertor ( ADC ) and assorted parallel devices.So far many techniques have been proposed to develop electromotive force or current mentions, which can be about independent to temperature and power supply voltage.The bandgap mention is the major design to supply a preciseness electromotive force mention with low sensitiveness to the temperature and the power supply.when CMOS engineerings enter the nano-scale epoch, The demand for battery operated portable equipments will increase.the supply electromotive force has been scaled down from 1.8V ( in 0.18 µm engineering ) to 1.2V ( in 0.13 µm engineering ) , and will drop to merely 0.9V in the following coevals engineering [ 2 ] .In CMOS engineering, the parasitic perpendicular bipolar junction ( BJT ) had been normally used to implement P-N junction of the bandgap reference.But the traditional CMOS bandgap mention circuits did non work in sub 1-V supply voltage.the ground, that the minimal supply electromotive force can non be lower than 1V is constrained by two factors, which is the bandgap electromotive force of around 1.25V in Si, which is exceeds 1V supply.The others factor is the low-tension design of the relative to absolute temperature current coevals cringle is limited by input common-mode electromotive force of the amplifier.These two limitions can be solved by utilizing the resistive subdivision methods, low threshold electromotive force ( or indigen ) device, BiCMOS procedure or DTMOS device.However, those attacks frequently require specialised procedure and word picture which addition fiction cost and procedure stairss. Reference electromotive force generators are required to be stabilized over procedure, electromotive force and temperature fluctuations and besides implemented without alteration of fiction process.The bandgap mention ( BGR ) is one of the most popular mention electromotive force generators that successfully achieve the requirements.regarding the generators, the demand for the low power and low electromotive force operation is strongly increasing the spread of the battery-operated portable applications.A bandgap mention electromotive force is an indispensable constituent of an analog-to-digital converterIt is frequently used to provide a mention electromotive force which is compared with others voltage. A bandgap mention electromotive force with low sensitiveness to temperature and supply electromotive force is normally required in parallel or digital circuits.there are several methods to recognize a temperature independent voltage.the base emitter junction used as a nucleus constitu ent of the bandgap mention is the most popular approach.the general bandgap mention electromotive force mention electromotive force is described by a additive combination of base-emitter electromotive force. Bandgap mention circuit is widely used to supply stable current and electromotive force mentions in parallel circuits every bit good as in assorted signal CMOS circuits.A stable mention circuit should be robust against temperature, power supply and procedure variations.Sub-1-V mention coevals has got importance due to scaling ensuing in shrinking of MOS dimensions and decrease of power supply to minimise power ingestion. owing to follow Moore ‘s Law, it has become needfully of import to diminish the power in the chip.This puts the restraint on the power dissipation of mention generators.the design of this bandgap besides see for low power operation..In traditional BGR circuit, bipolar transistors and one or more resistances are used.BJTs that are used in BGR are in parasitic signifier in CMOS.resistor occupy big country on the bit and hence addition the cost.on bit tolerance of resistances vary from 20 % to 30 % .So, we have to replaced these constituents with MOS transistors t o better public presentation of BGR and to salvage bit area.The combination of different runing parts like subthreshold, additive and impregnation of MOS suppresses the temperature dependance of electromotive force mention.Aims:To set up a dc electromotive force or current that is independent of the supply and procedure and has a chiseled behaviour with temperature. To plan the BGR that independently to temperature and low noise and low electromotive force To plan bandgap mention that can be successfully operated with sub 1-V supply in standard 0.35 CMOS procedure without particular procedure engineering.Problem statementWhen CMOS technologies enter the nano-scales epoch, the demand for battery-operated portable equipments will increase.The supply electromotive force has been scaled down from 1.8V ( in 0.18 m engineering ) to 1.2V ( in 0.13 engineering ) and will drop to merely 0.9V in the following engineering [ 2 ] .in CMOS engineering, the parasitic perpendicular bipolar junction transistor ( BJT ) had been used to implement the high preciseness bandgap electromotive force references.However, the convential BGR generates a 1.25V mention voltage.Its fixed end product electromotive force limited the supply electromotive force and non suited for sub 1-V supply volateg operation.The ground why the conventional CMOS bandgap mention did non work in close 1-V supply voltage.One is that the bandgap end product electromotive force is about 1 .25V [ 3 ] , which exceeds 1-V supply.The others is that the low temperature electromotive force design of the relative to absolute temperature current coevals cringle is limited by the input common-mode electromotive force of the amplifier.These two restrictions can be solved by utilizing the resistive subdivision method [ 4 ] , low threshold electromotive force device [ 5 ] , BiCMOS procedure or DTMOST [ 6 ] . But, those attacks frequently require specialised procedure and word picture which can increase fiction cost and procedure step.However, the bandgap mention working in low supply electromotive force has a higher temperature coeeficient than that of traditional bandgap reference.This resulted in the development of new temperature compensated techniques such as quadratic temperature compensation [ 7 ] , exponential temperature compensation [ 8 ] , piecewise additive curvature rectification [ 9 ] and resistance temperature compensation [ 10 ] .To implement these advanced mathem atical maps with high truth, the development of the low electromotive force bandgap construction requires precision matching of current mirrors or a pre-regulated supply electromotive force, cascade current mirror [ 11 ] , and pre-regulated circuit are good methods to work out this problem.but the minimal supply electromotive force is tradeoff.Scope of work:A typical CMOS execution of a bandgap mention is shown in Fig. 1. The end product mention electromotive force VREF of the traditional bandgap mention circuit can be written as: Equation 1 trad bgr.bmp Figure 1: Traditional/conventional BGR circuit in CMOS engineering where A1 and A2 is the emitter countries of Q1 and Q2, and VT is thermic electromotive force. The 2nd term in ( 1 ) is relative to the absolute temperature ( PTAT ) , which is used to call off the negative temperature coefficient of VEB. Hence, if a proper ration of resistances is kept, an end product electromotive force with lowsensitivity to the temperature can be obtained. In general, the VREF is about 1.25 V, so that the conventional bandgap mention circuit can non be used in low electromotive force application, such as 1 V. Mention electromotive forces and/or currents with small dependance to temperature turn out utile in many parallel circuits. As many procedure parametric quantities vary with temperature, if a mention is temperature-independent, it is normally processindependent every bit good. If two measures with opposite temperature coefficient are added with proper weighting, the attendant measure theoretically exhibits zero temperature coefficient. The construct of the new proposed bandgap mention is that the two electromotive forces ( which are relative to VEB and VT ) are generated by merely one feedback cringle. The two-stage operational amplifier with p-channel input is used in thisnew proposed bandgap mention. The new proposed bandgap mention is shown in Fig. 2, which uses the resistive subdivision R1a, R1b, R2a and R2b to cut down the input common-mode electromotive force of the amplifier.The dimensions of PMOS devices M1 and M2 are the same.The opposition of R1a and R2a is the same, and th e resistanceof R1b and R2b is the same. Following the KCL at the nodesof V1 and V2 in Fig. 2, the mention electromotive force can be expressed as New Picture.bmp Equation 2 Where and.According to equation below: ) /R4 We can expressed equation 2.The point of Vref-conv is indistinguishable to the conventional mention electromotive force in equation ( 1 ) .In order to accomplish sub 1-V operation, the ratio of R1b/ ( R1a+R1b ) is used to scale down the mention electromotive force level.Therefore, the minimal supply electromotive force of the new proposed BGR can be efficaciously reduced to merely. The new proposed BGR mentions can operated under bomber 1V.The whole complete circuit to recognize the proposed bomber 1V BGR is shown below: New Picture ( 1 ) .bmp Figure 2: Complete circuit for new proposed Sub1V So, from the comparing above, I can clearly cognize what I will make on my ain undertaking, what my range of work.From this, i ‘ll go on the new proposed BGR design that already done but I will seek to minimise the supply electromotive force, temperature independent and noise consequence as possible so the BGR will successfully operated in sub 1-V.

Differences in memory management between Windows and Linux Essay

Differences in remembrance focus between Windows and Linux Windows and Linux are two of the just ab divulge commonly utilise operate systems to date. Windows is used more by beginners and everyday information litigateing system users, period Linux is used more by advanced users and is dubbed the hackers operating(a) system. some(prenominal) the operating systems pee their advantages and their disadvantages. This paper ordain be differentiate the two in the operating systems retrospect wariness aspect. Windows manages their virtual repositing in a direct info construction. Each client in the tree is called a virtual address descriptors (VAD). virtual(prenominal) memory descriptors mark each node on the tree as free, reserved, or committed virtual memory. A process organisms with all addresses free which means they croup be committed to memory or be reserved for future use. onward any free address asshole be used it has to first be allocated as reserved or committ ed. Linux uses a relate list selective information structure which is stored in the vm_area_struct structure and defined in .The link list data begins hunting whenever a page is found and records the cast off of address, protection mode, and the direction in which it grows. If the minute of entries becomes greater than 32, Linux bequeath convert the linked list into a tree data structure depending on the new situation. Both Windows and Linuxs memory focus systems riddle the process virtual address office in a similar manner. By using paging, Windows on 32bit systems will affirm access up to a 4GB of standalone ordered address space and physical memory. The top(prenominal) role of the address space is allocated with 2GB of memory for windows kernel-mode, while the lower part is in any case allocated with 2GB of memory for user-mode. While Linux can also access 4GB of physical memory the residuum is the upper part is allocated with 1GB of memory for kernel-mode, while the lower part is allocated with 1GB for user-mode.An important part in any memory management system is the page surrogate system. varlet replacement decides which memory pages to page out when a page of memory call for to be allocated. Windows uses cluster demand paging, which pages are brought in the memory when they are bespeaked. It will also bring one by dint of eight pages in memory concurrently instead of bringing them one by one. Windowspaging system uses a work set concept, which is determined by make out of memory assigned in the current process. It contains pages that are in the main memory which the size of the working set will be altered accordingly. The page replacement algorithmic rule used for Windows is, premier in, First Out algorithm (F.I.F.O). Linux on the a nonher(prenominal) hand uses demand paging so any pages no needed will not be swapped into the memory.Therefore, pages not being used will be avoided and not be read. It will also decrease the amoun t of physical memory and the metre used to swap the pages. Linux also uses reasoned and non-valid bits to identify between pages that are in memory and disk. The page replacement algorithm used for Linux is, Least Recently utilize algorithm (L.R.U). While both Windows and Linux wealthy person their advantages and disadvantages in the operating system. They both have complex memory management systems which fulfills the users need when choosing an OS. With time we can only cypher the complexity of the future memory management systems in both Windows and Linux.ReferencesFelixbytow. (2012, July 08). FAQ/LinkedLists. Retrieved from KernelNewbieshttp//kernelnewbies.org/FAQ/LinkedListsKath, R. (1993, January 20). Managing Virtual Memory. Retrieved from Microsofthttp//msdn.microsoft.com/en-us/ program program library/ms810627.aspxRparrett. (2012, 08 22). About Memory Management. Retrieved from Windowshttp//msdn.microsoft.com/en-us/library/windows/desktop/aa366525%28v=vs.85%29.aspxRusl ing, D. A. (1996-1999). Memory Management. Retrieved from TLDPhttp//www.tldp.org/LDP/tlk/mm/memory.html