Phase Transformations in Metals

It follows that some of the parent phase volume disappears. * Transformation reaches completion If growth Is allowed to proceed until the equilibrium fraction Is attained. Two types of Nucleation 1 . Homogeneous: nuclei of the new phase form uniformly throughout the parent phase. 2. Heterogeneous: nuclei form preferentially at structural inhomogeneous, such as container surfaces, grain boundaries, insolvable impurities, dislocations, etc. Homogeneous nucleation: solidification of a pure material, assume nuclei of solid phase form In the interior of the liquid phase.There are two contributions to the total free energy change AC that accompany a solidification transformation 1 . The volume free energy Agave – which is the difference in free energy between the solid and liquid phases. Agave will be negative if the temperature is below the equilibrium solidification temperature. The magnitude of its contribution is the product of Agave and the volume of the spherical nucleolus (4/ 3 aorta ) 2. Surface free energy y: energy comes from the formation of the solid-liquid phase boundary during the solidification transformation. Is postlude; the magnitude of this contribution Is the product of y ND the surface area of the nucleus (nor) * the total free energy change GAG Is equal to the sum of these two contributions: GAG=4/3 aorta GAG_v+rattrap y * In a physical sense, this means that as a solid particle begins to form as atoms in the liquid cluster together, its G first increases. If this cluster (embryo) reaches a size equal to the critical radius, r*, then growth will continue with the accompaniment of a decrease In LEG. An embryo with a radius greater than Is called a nucleus.A critical free energy occurs at the maximum of the curve, which corresponds to the activation energy needed for the formation of a stable nucleus. Critical radius of a stable solid particle nucleus: ) Activation free energy required for the formation of a stable nucleus: ) This volume fre e energy change is the driving force for the solidification transformation, its magnitude is a function of temperature. At the equilibrium solidification temperature (or melting temperature) Tm, Agave Is O, and with decreasing temp It becomes Increasingly more negative.Agave temperature decreases meaning, nucleation occurs more readily at temperature below Tm The number of stable nuclei n*(having r>r*) is a function of temperature as well: 1 ) changes in T have a greater effect on than on he denominator. As T is lowered below Tm the exponential term decreases such that the magnitude of n* increases *another important temperature dependent step in nucleation: the clustering of atoms during short range diffusion during the formation of nuclei. The influence of temp on the rate of diffusion: high temp increases diffusion.Diffusion is related to the frequency at which atoms from the liquid attach themselves to the solid nucleolus, VT. Thus, low temp results in a reduction in VT. The nuc leation rate N is the product of n* and VT Heterogeneous nucleation has a lower activation energy than homogeneous because he surface free energy is reduced when nuclei form on the surface of preexisting surfaces. Growth occurs by long range diffusion consequently, the growth rate G is determined by the rate of diffusion, and its temperature dependence is the same as the diffusion coefficient (recall chapter that diffusion increases as temperature increases).Most phase transformations require some finite time to go to completion, and the rate is important in the relationship between heat treatment and the development of macrostructure * for solid systems the rate is so slow that true equilibrium structures are rarely achieved, equilibrium is maintained only if heating and cooling are carried out at SLOW unpractical rates. *for other than equilibrium cooling Superimposing: cooling to below a phase transition temperature without the occurrence of the transformation Superannuating: hea ting to above a phase transition temperature without the occurrence of the transformation

Proposal to Write a Research Paper on Climate Change Mitigations

To Write a Paper on Climate Change Mitigations - Research Proposal Example The economy is affected due to the reduction of agricultural outputs that are caused by soil degradation and loss of other resources that are of economically important. People’s social lives are affected by climate change. For instance, when there are floods some people are usually relocated and others left homeless. Many people develop skin cancer due to global warming that is caused by climate change (Department of Ecology State of Washington, 2009). My readers will be the environmental and business students in my school. I have chosen them since they know about the impacts, causes and the mitigations of climate alteration. They also think that atmospheric change is a serious issue and solutions have to be found. In my research, I will use several sources like books and articles to find information about climate change. I will also interview people in our school and my neighborhood using questionnaires about the climate change issues. I will use the following as one of the s ources to study on my research topic. This topic meets the standards for a relevant topic in my future career. Firstly, I have sufficient interest in the topic. As a business and environmental enthusiast, I have realized that mitigating climate alteration effects will bring positive effects to the social and economic aspects in our country. I am deeply interested in the mitigation measure that other environmentalists have practiced. Secondly, the topic meets standards since it can be searched quickly. A computer search in the library has shown numerous sources accessible on this topic. Moreover, our college library has a wide array of possible sources that I believe will produce a unique project. For my project, please allow me to research the ways of mitigating climate change. If you have ideas concerning the changes on this topic, please notify me.  

Including Children with Disabilities in Early Childhood Education Research Paper

Including Children with Disabilities in Early Childhood Education Programs - Research Paper Example Further, the differences between children with disabilities or developmental delays and other children are difficult for teachers to deal with (Openshaw 45). However, an inclusive early childhood classroom benefits both normal children and those with disabilities. The former learn acceptance, tolerance and helpfulness, while the latter benefit from the dynamic environment, particularly when they receive supplementary help to overcome any setback caused by their disability. Social workers, special education teachers, speech therapists, and others can provide immense support. Thesis Statement: The purpose of this paper is to investigate the inclusion of children with disabilities in early childhood education programs. Early Childhood Education Optimizing children’s potential through early education depends to a great extent on the environment in which they learn, whether at home, in day care, or in a nursery school classroom. In an inadequate environment, children’s poten tial will not get developed, resulting in quickly widening gaps in achievement which become increasingly difficult to overcome. Example of a model program in America for preschools targetted at low-income children is Head Start. It has offered a helping hand to the nation’s neediest families and children through provision of pre-academic skills, social skills, preventive medical and dental care; and teaching families about nutrition. Head Start also provides child care services otherwise unavailable to low-income parents, and gives nutritious meals and snacks to the preschoolers. It is one of the several early education schemes that ensure that children from lower economic groups get support and preparation for formal schooling (Kennedy 3). The aim is towards equity among all children for reaching their potential and fulfilling their dreams. Short-term beneficial outcomes of the Head Start program are that â€Å"children benefit from improved health and nutrition, and from b eing in a safe and nurturing environment† (Currie 233). Some medium-term benefits of the early education program include the prevention of children being placed in the special education track, and reduced incidence of grade repetition in early grades. Potential cost savings are extensive, because special education is significantly more expensive than regular schooling, and those children who enter special education are more likely to stay in that track. Monitoring of the children’s progress is necessary at every step. Inclusion in Early Childhood Education The concepts of inclusion and exclusion of children with disabilities in relation to the general early education classroom, renders disabled children as ‘different’ from their non-disabled counterparts. Inclusionary discourses are based on the ‘humanness’ of disabled children, where they are not perceived as ‘the other’ as compared to children in the general education classroom. The concept of humanity emphasizes disabled children being ‘like us’. On the other hand, exclusionary approaches to early education believe that regular teachers and early childhood centers are not responsible for the education and care of disabled children (Purdue, Ballard & MacArthur 47). Early childhood education that incorporates inclusion of disabled children, or excludes them is a concept that is a part of a wider social context where there may be

China's growth contradicts the links between democracy and growth Essay

China's growth contradicts the links between democracy and growth. Discuss - Essay Example Alongside democracy, capital and labor are some of the critical factors considered to have a significant effect on economic growth in the long run. There have been misconceptions that China’s economic growth is linked to the fact that China is a one-party state that upholds the authoritarian form of government. These mistaken views have influenced other countries to believe that authoritarian rule contributes hugely to economic growth, although China’s growth is tied to liberalization of political and economic reforms, which have led to reduced authoritarianism. China’s growth contradicts the links between democracy and growth China’s growth contradiction with democracy has brought about complication in the fact that the world’s richest countries attribute their success and growth to existence of democracy in their systems. The belief that economic development are linked to democracy is getting weaker as authoritarian regimes like China are proving that they have the capability of achieving economic growth without putting any efforts on political democracies. However, it remains a fact that high per capita income in democratic states has a significant effect in achieving stable and increasing economic growth. Over the last twenty-five years, China's has maintained tremendous economic growth with rigid political aspects that have remained closely tied to authoritarian form of governance. This stagnation in political reforms has negated the concept of economic growth, resulting in educated citizens who later pressure the most authoritarian governments to allow for democracies in which they themselves can exercise control over political situations for the benefit of the entire country. Claims that democracy does not contribute to economic development arise with respect to government’s function of representing the common needs of all the citizens. Different requirements, views, and opinions of different citizens necessitate the government to function independently and represent the collective views of all citizens other than needs of a few individuals. Democracy existence is said to be a hindrance to the independence a government in fostering economic growth and effective citizen representation. The government is given the responsibility of collecting taxes and putting the revenue into productive use with respect to aggregate preferences of citizens. Therefore, democracies may become obstacles for government’s rational functionality; however, multiparty systems in voting in governments may represent rational preferences that meet a variety of conditions to a limited proportion. Moreover, democracy may reflect a system of governance that meets requirements of citizens but does not foster aggregate preferences such as economic prosperity. However, autonomy of the government in countries like China only infringes on political freedom and not economic freedom. Lack of political freedom is depicted by the single party governance where the government places independent emphasis on liberalization of foreign and private investment. Usually, authoritarian governments that have liberalized their economies are statistically proved to economically

Tort law Essay Example | Topics and Well Written Essays - 2000 words

Tort law - Essay Example The following sections of this assessment are specifically going to focus on the relevant statutes that can be inferred when negotiating for a settlement as well as remedies. Case list and relevant statutes Briefly outline any cases/statutes you have researched in this area which are relevant to our client’s claim. This should be more than just a bulleted list. Basically, tort law commonly refers to a civil wrong not arising from a contract and in the case of negligence, everyone has a duty of care owed to the neighbour (Capiro Industries vs. Dickman 1990). Cooke (2010) suggests that a remedy can be given in the form of compensation where the plaintiff can prove beyond reasonable doubt that the defendant owed duty of care in the event of injury. Thus, in case of tort law, specific duties apply to everyone and are imposed by the law. According to Terry & Giugni (2009), there are four elements of the tort of negligence that have to be proved by the plaintiff and these include th e following: there is need to prove that the defendant owed the plaintiff a duty of care, the defendant breached that duty by falling below expected standards, the defendant’s conduct caused the plaintiff to suffer physical or economic harm (causation) and the harm suffered by the plaintiff was reasonably foreseeable (remoteness). Under common law, duty of care must be observed whereby the breach of such duty, causation of damage, remoteness of damage and the defences would be taken into account as illustrated in the following cases below. Facts The case of Murphy v Brentwood[1991] 1 A.C. 398 can be used to establish the duty care owed by the contractors in the construction industry. Issue Were defendants negligent? Rule They were negligent because they did not take into account safety precautions when constructing the house. In our case, we did not constantly check the state of condition of our buildings. Analysis The court found that the engineers as well as contractors wer e negligent when they failed to take necessary measures to ensure that they construct a solid foundation of the house. In the case of Blyth v Birmingham Water Works Company, the facts are as follows; the defendants installed a fire plug near the plaintiff’s house that leaked during a severe frost, causing water damage and the jury found the defendant negligent, and the defendant appealed. Issue Were the defendants negligent? Rule Defendants can only be negligent when they fail to do what a reasonable person can do. Analysis This was an accident caused by natural causes. The case of Bolam V Friern 1957 also illustrates a case involving negligence but the court ruled in favour of the doctor because he was acting within his profession. In most cases, for a claim to be successful, the four elements mentioned above have to be proved. The Occupiers’ Liability Act (OLA) 1957 is mainly concerned with the duty care owed to the occupiers of a building and these can be classified as employees or visitors. They ought to take into consideration the risk of danger that may prevail. On the other hand, the employer is liable for breach of his duty if he fails to provide his employees with safety as well as safe equipment to use (Wilson and Clyde Coal Co Ltd v English [1938 ] AC 57 (HL) 141). This also includes a duty to

Theory integration on 3 terrorism cases Term Paper

Theory integration on 3 terrorism cases - Term Paper Example The theories on terrorism are also too varied, such as to defy an integrative understanding of the phenomenon. This paper will therefore explain the orthodox and non-orthodox theories on terrorism, applying these to three known cases of terrorism. Analytical discussion will try to show that the hypothesis is valid and relevant. Orthodox terrorism theories Terrorism is a highly debatable issue. Its complexity emanates from the primeval nature of man to sow lethal violence against his kind. It is estimated that the 18th century French Revolution gave impetus to modern terrorism that led to the upsurge of contemporary terrorism with its state, interstate and global dimensions. Thus far, orthodox theories on modern terrorism have been used to understand cases of terrorism, but these have been subjected to debates. In an in-depth analysis, Jason Franks opened up a discussion of the Orthodox Terrorism Theory or theories, proposing a more comprehensive non-orthodox understanding of the phen omenon which be applicable in the many years to come. For Franks, the Orthodox Theory is capable of answering the questions what makes up terrorism and how it can be countered. However, he notes that the Orthodox Theory fails to adequately answer why it happens. ... o coerce and intimidate governments to accept political, religious or ideological objectives, and secondly in defence of the terrorist act as when Hezbollah leader Sheikh Fadlallah described terrorism as â€Å"fighting with special means against aggressor nations in religious and lawful warfare against world imperial powers.† ( Kramer n.p.). The situation shows that it is difficult to establish a sound foundation for research and policy on terrorism. This may also suggest that resolving the phenomenal rise of terrorism may continue to meet difficulties in the times ahead. To be fair, the Orthodox Theory on Terrorism has merits. It comprises the western model of understanding terrorism along the human ideals of liberty, rule of law, and democratic life in society. It is also a practical concept in dealing with acts of terrorism as threats to state authority. The Orthodox Theory has laid down three useful themes on terror acts, namely (a) Functional, as embodied by the Theory of Provocation, or the belief that terrorism aims to provoke a response from a repressive state by means of strategies that will radicalize citizens against government (Laqueur 72) (b) Symbolic or the explanation that terror acts have image- value under the idea of â€Å"terrorism in theatre† (Jenkins 132), and (c) Tactical as terrorists use strategies along short-term objectives such as hijacking, as well as long-term objectives to advancing the broader cause of revolution. In spite of merits derived from the Orthodox understanding of terrorism, Franks perceives that this approach needs to be improved owing to the new terroristic environment which has pushed terrorism beyond the state into interstate and global boundaries. The alternative terrorism theory Improving on the orthodox theory, Franks

No namecan the writer make a name for me Essay Example | Topics and Well Written Essays - 2750 words

Marks and Spencer as One of the Biggest Retail Companies - Essay Example In April 2004, the prospect of the company seemed blurred. The brand of the Marks and Spencer got a great push back and lost its confidence due to the consecutive decline in sales and continual negative PR. The company has started to lose public faith and love and the fear has taken over by Philip Green of Arcadia Group was on the threshold. Rejecting the offer of Mr. Green, Mr. Stuart Rose has restructured the company through promoting its brand and has formulated a method of treatment, which worked in a significant way for the M & S to get back its health. (Thompson, Neal, Threadgould and Trillo, June 30, 2006: 3-4) There were different thoughts on the vulnerability of the company. Analysts told that decline of sales of the company in a continuous basis and lack of enthusiasm for change was mainly responsible behind such weakness whereas the journalist reported that the company listed itself in one of the worst performers among the 100 companies. Besides the customers were also not satisfied with the product of the company. The garments of the company were believed to be old-fashioned. People thought the company might have fallen in the vicious circle of loss. Fall in sales of the M & S in one way led to falling in share price and in another way led to negative captions producing the negative impression in the market. These movements caused to loss of confidence over the company by the customers for the purchase and also by the investors to invest. In this situation when Mr. Green came with his proposal to acquire M & S, the senior team of the company including the new Chief Executive of the company, Mr. Stuart Rose and the Executive Director for Marketing, Store design and Development, Mr. Steven Sharp has formed a new plan regarding the business of the company and successfully crush the proposal of Mr. Green.