Investigating electric potential Essay Example for Free

Investigating electric potential EssayA graph of V against 1/d gives a straight line with positive slope from x=0. 05m. It shows that the electric potential measured by the test is inversely proportionate to the distance of the probe from the surface of the sphere. Discussion A volt m or a CRO cannot be used to measure the electric potential at a point in the air because both instruments draw a small current to produce a deflection and this will disturb the electric field. With no flame, the probe may acquire an induced charge and thus affect the field around it, altering the potential at the beset. Therefore, a flame probe is used.It produces positive and negative ions which discharge the needle so that the needle becomes uncharged due to neutralization. Since the needle is now neutralized, its potential is the same as the original potential. Sources of flaw When measuring the distance of the probe from the centre of the sphere, a piece of string with a mass attached was dr opped from the sphere for locating the zero mark of the meter ruler. This may not be accurate as the sting may not be vertically below the centre of the sphere Precautions 1. The wire which connects the needle and the electroscope cannot touch the bench or any other earthed conductor.This is to prevent charge leakage. 2. The charged sphere must be well away from the walls and the bench gratuity as the induced charges on these objects will upset electric field. Conclusion Between two parallel plates the electric potential remains continual at constant distance from the metal plates the electric potential is proportionally to the distance from the earthed plates Around a charged sphere the electric potential remains constant at constant distance from the centre of sphere the electric potential is inversely proportionally to the distance from the surface of sphere

Mutual Fund Project Essay Example for Free

Mutual Fund Project EssayThe stemma employs a passive solicitude investment approach. It is a low cost way to gain diversified exposure to the equity market in the United States.The fund invests in calciferol of the largest companies in the United States. The companies span many different industries and the fund accounts for about 75% of the United States stock markets value. VFINX measures the investment return of large-capitalisation stocks. The most obvious risk is the volatility that comes with its full exposure to the stock market. The mutual fund portfolios composition is made up of 99. 45% stocks and . 55% cash. The expense ratio for this mutual fund is . 17%. This is the annual fee that shareholders are charged.It expresses the percentage of assets deducted each fiscal year for fund expenses, including 12b-1 fees, circumspection fees, administrative fees, operating costs, and all other asset-based costs incurred by the fund. For the Year-to-Date (ytd) rankings in its category, VFINX ranked in at 24 according to Yahoo Finance. Over the last 10 years, the fund has performed in direct correlation to the SampP 500 being that it is an index fund and there is a beta of 1, meaning that whatever the SampP 500 does, the fund will do as well.VFINX is a good choice if an investor is seeking a mutual fund that offers the stability of large, established companies and the long exposure of a fund that holds both value and growth stocks. Fidelity Magellan Fund (FMAGX) has ridden the ups and downs over the years of the markets roller coaster. The fund has at peace(p) through many changes over the years and star of the most important key factors to the funds performance has been related to the way it was managed. The fund currently has assets totaling 14. billion and its portfolio consists of growth and value stocks across the capitalization spectrum from around the world and the United States.The fund keeps about 20 percent of the holdings in foreign stocks . It is one of the worlds most known actively managed funds and has finally found some stability due to its newest manager, Harry Lange. In 2008, during the financial crisis, the management chose to stay aggressive instead of investing defensively and incurred a bad loss, which lead to the changes in management. FMAGX is classified as a large growth fund and is ranked 24 in its category according to Yahoo Finance. The 3-year beta is 1. 7, which means that it bears more risk than investing directly in the SampP 500, that this also means that it could provide heftier returns. The mutual fund portfolios composition

Biological Conservation And Its Importance Environmental Sciences Essay

Biological conservation And Its Importance Environmental Sciences EssayThe irreversible loss of the earths diverse biological imaginations is given major splendor today. The quick resources atomic function 18 primarily threatened by habitat degradation and loss, habitat fragmentation, overexploitation, and species invasions (Groom Carroll, 2006 Mittermeier Bowles, 1993) which near experts believed we are now confronting the sixth major extinction in history. The assorted natural resources or bio transition, as defined by the Convention on Biological Diversity, is the variability among living organisms from all sources including, inter alia, terrestrial, marine and different aquatic ecosystems and the ecological complexes of which they are part this accepts diversity within species, between species and of ecosystems (CBD, 1992).The planets biological diversity basically gives abide by to our complaisant and economic life. We use the living universe as a resource for fo od supply, an energy source, a source for recreation, a major source of raw materials for medicines, and a natural resource for industrial products. It is a source of many of our current medicines (e.g., 25% of all pharmaceutical prescriptions in the US contain active ingredients from plants and 3000 antibiotics more than(prenominal) as penicillin are derived from microorganisms, (WRI/IUCN/UNEP, 1992). Further much, people are estimateing to the natural world as an escape and as a means of maintaining their sanity, especially in the industrialized nations. All of this translates into unsloped economics as advantageously, as the growing industry of ecotourism and otherwise temperament-based forms of recreation (e.g., fishing, hunting, hiking) becoming ever more popular. Worldwide, nature tourism generates some $12 one jillion million annually (Lindberg, 1991) and it is likely to grow even more rapidly in the tropical countries, where it is already a major foreign exchange e arner for some(prenominal) countries. Moreover, Pearce et al. (2007) categorized the economic values or benefits of biodiversity into four general components First, its contrisolelyion to ecosystem functions which include watershed regulation, nutrient cycling and microclimate mediation, the provision of global services such as climate regulation and carbon sequestration, and evolutionary processes. Second, the commercial and use values which involve the harvesting use and marketing of particular biodiversity commodities, such as timber, bush meat and medicinal plants. Third, non-use values which reflect the peoples willingness to pay for biodiversity saving regardless of the uses made of biodiversity. Motivations for non-use value vary some flightiness of stewardship, some nonion of Natures remediate to hold up, a concern to leave an as situated for future generations, aesthetics, and so on. Fourth, its contribution to ecosystem resilience derived from aggregated diversity i.e. from the aggregated value of genetic diversity within species, species diversity and ecosystem diversity.The diversity of nature not only offers us a vast power of choice for our current needs and desires. It withal enhances the eccentric of nature as a source of solutions for the future needs and challenges of mankind. The earths genes, species, and ecosystems are the products of over 3 billions of evolution, and are the basis for our survival. Humans depend on other organisms for food, medicines, and raw materials. Our survival is tied to the health of the ecosystems we live in. The diversity of life ensures that living things will be able to adapt to a future, which is certain to be full of change. In very basic terms, in order to adapt to a changing environment, the raw materials of nature as well as sympathy itself require genetic, species and ecosystem diversity. Daly Cobb (1989) emphasized this point when he said that the diversity of nature increases the likelihood that at least some species will survive and give give birth grow to new lineages that will replenish the earths biodiversity.Living things likewise prevail an intrinsic value and a beauty that is considerable and without which our life would be poorer. All these things make the maintenance of biological diversity vitally important to humankind, coming from the opportunities it provides humanity to adapt to local and global change.Biological resources now face serious repercussions over payable to pervasive human activities. Species are becoming extinct, ecosystems and ecosystem types are lost and the remaining populations and species are losing their diversity. Thus, everyone is convinced about the importance of biological conservation. Conservation of natural resources is the major focus of Conservation Biology the scientific study of the nature and status of earths biodiversity with the aim of protecting species, their habitats, and ecosystem from excessive rates of extinc tion. To date, some 1.7 million known species exist but the great majority of species alive today, possibly as much as 90 per cent, are not known (Gunter, 2004). IUCN (1980) defined conservation as the management of human use of the biosphere so that it yields benefits to present generations while maintaining its potential to meet the needs of future generations. The scope of IUCNs theory of conservation is further expounded by the objectives of living resource conservation, and that is (1) to maintain essential ecological processes (2) to preserve genetic diversity and (3) to ensure the sustainable utilization of species and ecosystems. The key aim of biological conservation is to maintain the diversity of living organisms, their habitats and the inter sexual intercourseships between organisms and their environment (Spellerberg Hardes, 1992). Furthermore, as claimed by Siipi (2004), biological conservation can be carried out in various shipway but generally, it revolves around t he standard methods of ecosystem preservation, ecosystem restoration, and ecosystem engineering.There are several(prenominal) studies conducted on assessing attitudes towards environmental issues. Major themes of study commonly focused on the attitudes of the people towards environmental conservation (Badola, 1998 Fiallo Jacobson, 1995 Newmark et al, 1993 Infield, 1988 Walpole Goodwin, 2001). Other studies send offed their solicitude on the attitudes towards wildlife conservation (Morgan Gramann, 1989 Kellert, 1994 Sekhar Udaya, 2003 Gadd, 2005).Attitudinal surveys were also conducted to students pertaining to environmental awareness, knowledge and attitudes. Chan (1996) and Tikka et al (2000) reported that female students showed more positive environmental attitudes than male students. However, Arcury et al.(1986) showed that males are more aware and sensitive to environmental issues than females. While Thang Kumarasamy (2006) and Caro et al. (2003) reported that gender had limited or no bearing on students perceptions of the environment. foregoing researchers like Deng et al (2006) and Larijani and Yeshodhara (2008) also found out that environmental attitudes differ among race, cultures and societies. Academic major is said to be a contributing factor also which affects environmental attitudes (Karanth et al., 2008 Ozden, 2008) and as well as the type of conservation knowledge imparted to students strongly influenced their commitment towards conservation initiatives (Barraza and Walford, 2002). Results of different studies also showed different manners for several factors like school type, age, income, and residence (Korhonen Lappalainen, 2004 Tuncer et al., 2005).What are ENGOs?Definition of an NGOThere have been a lot of labels that apply for NGOs such as, peoples organization, peoples movement, trade union, cooperative, community organization, coalition, network, federation, fusion and united front. These names are still current but are now capt ured by a new catch-all category civil society organizations (CSOs). The concept of civil society is complex, vague and elusive, however, as it is difficult to deploy a single definition to cover a range of organisations broad enough to include the church, tribal structures, major world-wide agencies, single issue campaign groups, semi-independent general sector agencies, business fora, and small local/national NGOs, while still retaining operational(a) usefulness (Haley Clayton, 2003). . Moreover, civil society is sometimes referred to as the third sector, indicating its distinct status from the public and buck private sectors (McArthur, 2008). Thus, CSOs refer to different types of non-corporate private voluntary institutions promoting a variety of public causes.NGO is only one form of CSO, though often the two are taken to mean the same thing. However, it can be argued that all NGOs can be regarded as civil society organizations though not all civil society organizations are NGOs. NGOs take different forms and fly the coop different habits in different continents, with the NGO sector being most developed in Latin America and parts of Asia. The roots of NGOs are different according to the geographical and historical context. As disk operating systemd by Schiavo-Campo Sundaram (2001), NGOs are not-for-profit organizations and can be recognized as such if they are privately set up and sufficiently autonomous in its activity, that is independent of direct governmental control. Secondly, an NGO should cl advance(prenominal) define its voluntary character. Thirdly, it cannot be considered a political fellowship with an aim of attaining political power. And lastly, an NGO should support development which demonstrates its public kindle character. Furthermore, the non-governmental aspect of NGO, as stated by White (1994), places it conventionally outside the state in civil society, i.e. intermediate associational realm between state and family populated by organizations which are separate from the state, enjoy autonomy in relation to the state and are formed voluntarily by genus Phalluss of society to protect or extend their interests or values.Although there is contestation of the definition of an NGO, it is widely pass judgment that these are organizations which pursue activities to relieve the suffering, promote interests of the poor, protect the environment, provide basic social services, and undertake community development (Cleary, 1997). While Turner and Hulme (1997) stated that NGOs are generally registered organizations, community groups, professional associations, trade unions, cooperate charity organizations whose aim is to improve the well being of their members and of those areas in which they exists. The World posit, on the other hand, sees NGOs as private organizations that pursue activities to relieve suffering, promote the interests of the poor, protect the environment, provide basic social services, and/or underta ke community development.The concept of NGO came into use in 1945 following the establishment of the United Nations Organizations which recognized the need to give a consultative role to organizations which were not classified as neither government nor member states (Willett, 2002). There are certain features which differentiate NGOs from government agencies, even when they are performing similar roles. NGOs have the capacity to experiment and learn from experience, linking processes to outcomes and are also able to enlist the energies and commitment of intended beneficiaries. Fowler (1988) has identified two key distinctive characteristics of NGOs. Firstly, the relationship of the NGO with intended beneficiaries is based upon principles of voluntarism rather than those of control which is distinctive of government. This means that intended beneficiaries are involved in program design and management. Secondly, it is argued that NGOs have a task oriented approach that permits them to achieve becharm organisational development, which encourages change and diversity rather than control and uniformity, which may hamper progress.Environmental NGOs (ENGOs)One of the stakeholders involved in biological conservation is the so-called Environmental NGOs (ENGOS). These interest groups hope to save the worlds biological resources from rapid extinctions and aspire to awaken a sleeping public to the tragic loss of biological resources that is unfolding today. ENGOs exist at local, national and international levels (e.g. Friends of the Earth, WorldWide Fund for Nature, Greenpeace, etc.). Many ENGOs operate under the explicit purpose of preserving endangered species and ecosystems, and thus make biological conservation the join principle under which they operate. Others focus more broadly on sustainable development and within this framework, they also contribute to biological conservation. As stated by Trzyna (2008), not all conservation organizations have kept their tradit ional focus but they have become part of the broader environmental movement. There is an increasing number of organizations that started either as conservation or conventional environmental groups but now define themselves as part of the new movement for sustainability. Most of the largest NGOs operative on biological conservation are either based in the United States (e.g. Conservation International, The Nature Conservancy) or Europe (World Conservation Monitoring Center, Birdlife International).In the opinion of Astbury (1998), an ENGO has a mission statement and/or set of guiding principles emphasizing environmental concerns, e.g. biological conservation. They play an increasingly prominent and important role in representing environmental interest. Environmental NGOs are distinct from environmental movements in a way that there is a ceremonious organization exists in ENGOs. For example, the historied Chipko movement in India, involving village people who hugged trees when logge rs arrived to cut trees down, was not an NGO because although there were leaders and followers, there was no formal organization (Potter Taylor, 1996).These organizations are not really new but have been existing over the years. For instance, the Royal Society for the bulwark of Birds was founded in 1886 the Sierra club in 1892 the Audubon Society for Protection of Birds in 1886 the Wildlife conservation Society (as the New York Zoological Society) in 1895 and fauna and flora International (as the Society for the preservation of the Fauna of the Empire) in 1903. Some of the largest organizations were founded more recently, but with a specific focus on international conservation, including the World Wide fund for Nature (founded as, with some of its constituent organizations still operating as, the world Wildlife Fund) in 1961, and Conservation International in 1987 (Cobb et al., 2007).ENGOs may have existed for a century or more but it is only in recent decades, and curiously sin ce the success of NGOs in shaping the 1992 United Nations Conference on Environment and Development (UNCED) or the Earth Summit in Rio de Janeiro, that their numbers have multiplied. fighting(a) civil society organizations officially recognized by the United Nations (UN) in this particular international conference were grouped into major groups such as women, children and youth, original peoples and communities, NGOs, Workers and Trade, Scientific and Technological Community, Business and Industry and farmers.ENGOs are one of the key actors in shaping the creation of Agenda 21 and the Conventions on Biodiversity which saw a heightening of global consciousness about the needs of biodiversity conservation. These are international agreements signed by majority of the countries to guide the world in its actions for development and the environment in the 21st century. Over 20,000 participants of 9,000 organizations in 171 countries were present, and over 1,000 meetings were held betwee n NGO representatives in a forum parallel to official intergovernmental discussions (Fisher 1993). Thus, this event culminated the increasing attention paid to biological conservation by NGOs.Since then(prenominal), ENGOs expanded their conservation efforts on the ground, especially in tropical countries. For instance, the international conservation programmes of the Wildlife Conservation Society (WCS) have grown from just over $3 million in the late 1980s, to nearly $50 million in 2005, nearly half of WCSs overall operating budget (MacDonald Service, 2007). Although the WCS has programmes in North America, all but $5 million of these pecuniary resource are sent overseas in developing countries. The Nature Conservancy (TNC), founded in 1951 primarily focus on USA conservation issues, is probably the largest conservation organization in the world, with one million members, and an annual budget of over $800 million (The Nature conservancy, 2004). Conservation International (CI), wi th a focus on biodiversity hotspots and tropical wilderness areas, was founded in 1987 and has grown to an organization with an annual budget of over $ nose candy million.Roles ENGOs PlayENGOs involved in biological conservation are highly diverse, including local, national, regional, and international groups with various missions dedicated to environmental protection, sustainable development, poverty alleviation, animal welfare, and other issues.A key area in which ENGOs have made an imprint is in assisting the global community to establish global priorities. Such approaches included from those that look at representation of species and habitat types, those that focus on species diversity and levels of threats, those that focus on areas of higher or lower human impact as a surrogate for scaling threat and those that focus on levels of endemism and evolutionary uniqueness in a particular taxon (Cobb et al., 2007).ENGOs importance lies as well in their expertise (Esty, 1998 Charnovit z, 1996). They conduct scientific research and disseminate the results to policy-makers and public (Mohd Ahmad, 2005 Jasanoff 1997 Madon 1999). The degree to which NGOs pursue expert knowledge for complex scientific predicaments makes them critical international players. They translate this knowledge into action. As added by Hempel (1988), international environmental NGOs are usually better prepared than governments to implement studies of environmental protection. NGOs often have much better analytical and technical skills and capacity to respond more quickly than government officials. NGOs can also mobilize and influence individuals or group of individuals to hollo a problem through awareness campaigns and outreach (Bauer, 2006 Gunter, 2004) and express that issue interest to government agencies. ENGOs raise awareness through media stunts. Through TV, radio, newspapers, and magazines, ENGOS bring this environmental poke fun into peoples everyday lives and enable people to act b ear witness (Wapner, 1995). Additionally, ENGOS stimulate public pressure aimed at changing governmental policy or straightaway lobbying state officials. They facilitate in defining an issue area, convince policymakers and publics that the problems thus defined are soluble, prescribe solutions, and monitor their implementation (Keck and Sikkink 1998).ENGOs also aid in empowering local communities to increase capacity and capability in carrying out biological conservation projects they organize and conduct seminars, environmental education programmes and expeditions to natural and target private actors in their campaigning efforts (Raustiala, 1997 Themudo, 2000 Chitra, 2003 Jepson, 2005).Indeed, ENGOs have been major contributors to biological conservation by providing funds and expertise, building public support, promoting action, and advocating conservation interests. As argued Gunter (2004), ENGOs are the most appropriate medium for protecting biological resources because of thei r unique ability to see both(prenominal) small and big and their unique positions above and below the state. NGOs operate at both the micro and macro levels, working on the ground in local villages as well as participating in international negotiations. Moreover, Gunter argued that states are paradoxically both too big and too small when it comes to resolving transnational threats like loss of biodiversity or climate change.ENGOs generally obtain most of their funds from national governments, government agencies, bilateral and eight-sided banks, large foundations, transnational corporations, and international foreign aid agencies like UNDP, UNEP and the Global environmental facility (GEF) (Dowie, 2009 Bebbington Riddell, 1995). The GEF which is a multilateral funding mechanism prepared to reduce the burden from Southern countries for environmental protection has become a pilot program to a permanent financial mechanism in 1994 and is supporting the growth of ENGOS. GEF is under the stewardship of the World Bank and the United Nations. The World Bank manages a significant portion of GEF biodiversity funding and also makes additional grants and loans in the biodiversity and protected area domains.ENGOS engage in various activities meant to influence public support. Smith and Connelly (1999) identify ten (10) types of ENGO activity informal, discreet lobbying formal lobbying collecting and sending letters or petitions from the public producing scientific research and reports taking legal action organizing demonstrations and marches staging media stunts promoting consumer boycotts engaging in non-violent direct action and, engaging in violent direct action. To this list, one might also add giving campaign contributions or endorsements to environmentally-friendly candidates (Grossman and Helpman, 1994, 1999). This activity mostly instanter political support and can change the weight given to ENGOS in the political calculus (Binder, S and E. Neumayer, 2005)On t he other hand, Gunter (2004) summarized the common strategies used by ENGOs. The two main categories of different approaches are mainstream strategies which include lobbying, litigation, scientific/technical research, property acquisition/maintenance, and monitoring and participatory strategies like grassroots networking and community education. actually few studies are conducted on how people perceive ENGO as one of the crucial players in biological conservation. Researchers like Hyseni (2008), Wong (2003) and Ivy et al. (1998) assessed the attitudes of local people and students towards these organizations but the main focus of their studies were not directed to the roles of ENGOS in general. As Jasanoff (1997) contends, the systematic assessment of the role that ENGOS play in environmental decision making ashes noticeably absent in the studies to date.Philippine ENGOsTeehankee (1993) reported that environmental NGOs in the Philippines emerged in the late 1970s and early 1980s. Du ring the martial legality in the early 1970s, social movements appeared provoked by the dictatorship. Militant organizations pressured for political structural and ideological changes. Social movements and other civil society groups started to register as legal entities to be formally recognized by government. This was to avoid being tagged as illegal rabble rousers. In 1986, the EDSA I or the People Power novelty replaced the totalitarian martial law by the democratic force of the people. Accordingly, two streams from which present-day environmental NGOs originated were identified. The first stream is composed of nature lovers such as conservationist societies and hobby groups which alter expanded their concerns to socio-political issues related to environment and government policies. The other stream is said to consist of field-based activist groups concerned with human right issues of tribal communities and poor settlers being displaced by environmentally-destructive projects o f the martial law regime. The Philippine Federation for Environmental Concerns (PFEC) was established and this commemorated the first effort at coordination and networking among environmental NGOs. two more national federations emerged since then the Philippine Environmental Action Network (PEAN) and the Lingkod Tao Kalikasan (LTK). Numerous groups mushroomed then like Haribon Foundation, World Ecologists, Green Forum, and Earth Savers. Aside from the diversification of environmental NGO activities into community resource endeavours, the post-Marcos period was also characterized by the decision of prominent development NGOs, like the Philippine Rural Reconstruction front end (PRRM), to integrate environmental concerns into their strategic programs (Magno, 1999).. Environmental NGOs were very few before the 1960s. There were sporadic efforts at conservation. Up to about 1970, influenced by the spirit of the time, most development NGOs didnt consider the environment as part of the development framework. Environmental concerns were isolated from social development. Carrying capacity of the environment was not given importance due to the abundance of what nature can provide then. Environmentalists, on the other hand dedicated their work on protection and conservation of genus and species for its authenticity and aesthetic value with no qualms about poverty and human development. Most of the conservationists then came from philanthropists and rich individualsPhilippine ENGOs have done and still do fund raising, modelling and implementing operable methods and strategies in the protection and conservation of the environment toward sustainable development. They play multiple roles in influencing policy reform and formulation. The most common role would be that of a lobbyist, using social pressure and the media. Furthermore, many NGOs also play the role of community organizers, educators/trainors, researchers, media practitioners, negotiators, advocates, and catal ysts.Taiwan ENGOsTaiwans environmental awareness was not awakened until the 1970s and then was limited to small group of people, mainly from the intellectual class. Not until the late 1980s did the general publics concern over the environmental issues bloom. During this time, environmental problems had reached crisis proportions. The countrys economic miracle was achieved at the cost of environmental deterioration. Reported serious pollution incidents like the one caused by Du Pont in 1986 and the Lee Chang rong Chemical factory in 1982 drew public attention (McBeath Leng, 2006). These events showed that local residents finally had gained environmental consciousness due to unbearable pollution and environmental damage. At this stage, environmental protests led by opposition politicians reflected NIMBYism (not in my backyard)- complaints about local environmental pollution.As reported by Hsiao (1999), there are three streams of environmental movements in Taiwan. These are the anti-p ollution, nature conservation, and anti-nuclear movements. In the nature conservation movement, people become more concerned with destruction of Taiwans natural resources. Hence, ENGOs emerged and perceived as key actors in this particular campaign.After the lifting of martial law and as democratization programs were launched in the late 1980s, the environmental movement also gained momentum and developed a national instead of a local focus. During this period, ENGOs amass social capital and public trust in Taiwanese society. ENGOs helped to create a plural society through the enlargement of channels of social connection and communication. ENGOs were said to be champions and advocates of Taiwans democratization at early stage, and laid a foundation for democratic consolidation after the md-1990s. The general public gradually intentional to think beyond local instances of environmental abuse and paid greater attention to ensuring balance in national policy among economic developme nt, environmental protection, and social justice. Nation-wide ENGOs emerged then from the early to mid-1990s. Hsiao (1999) estimated that there are over 232 environmental NGOs in Taiwan. Most recognizable groups are The Society of Wildlife and Nature, Bird Society, Taiwan Greenpeace Association, Ecological Conservation Alliance, Life Conservationist Association, Homemakers Union and Foundation, Green Consumers Foundation, Wetlands Taiwan and The Nature Conservation Union. International environmental organizations are not regular participants in domestic environmental protection. Taiwans diplomatic isolation constrains its participation in major international organizations, and international lending institutions such as the World bank and Asian development Bank are not actively involved in its environmental policies. However, occasionally, ENGOs have built close relationships with major international NGOs. In the past, domestic ENGOs exposed cases of trafficking in illegal wildlife a nd ecological degradation to the international mass media and invited international NGOs to monitor Taiwans mitigation record.McBeath and Leng (2006) outlined the common roles that ENGOS play in Taiwan and these are organizing grassroots demonstrations, promoting public policy making, setting the agenda of public issues, educating the public on environmental issues, monitoring government policies and publicising environmental issues.

A review of Bioactivation and Tissue Toxicity

A review of Bioactivation and Tissue ToxicityKong Wei En (BP0711031415)Raymond Koh Chee How (BP0711031287)Jennie Lee Sheah Lin (BP0711031372)Prashanthini A/P Janardanan (BP0711031156)Hong Wei Siong (BP0711031194)Shalini A/P Shanmugavelu (BP0711031145)IntroductionXenobiotics are foreign chemicals in the body 1. The human body has adapted processes collectively termed as biotrans geological take shapeation to excrete these xenobiotics 1,2. Biotransformation generally occurs sequentially in ii anatomys 1,2. Phase I reactions add juvenile functional groups to the elicit compound while phase II reactions conjugate these new functional groups with polar groups 1,2. The end-result of biotransformation is rock-bottom lipid solubility, thus increasing renal excretion 1,2. The liver is the chief site for biotransformation, 1,2. Enzymes such as cytochrome P450 and peroxidase enzymes are responsible for biotransformation 3,4. Occasionally, bioactivation occurs, in which the inert parent co mpound is modified into toxic metabolites 1,3,4. The toxic metabolites are either electrophiles or shrive radicals, which interact with body wanders, subsequently causing toxicity 3,5.ElectrophilesElectrophiles are species lacking(p) in electron pair generated through Phase 1 metabolism by CYP450 5. They are short-lived (with the possible exception of some acyl glucuronides) and not usually detectable in circulation 5. Electrophiles can be generated from carbon, nitrogen or sulphur containing compounds 4. The most frequently metabolised structural alerts are aromatic systems with electron-donating substituents and some membered heterocyclic 6.Electrophiles character toxicity through the formation of irreversible covalent bond to nucleophilic tissue components which includes macromolecules (proteins, nucleic acids and lipids) or low molecular weight mobile phoneular constituents 4. covalent binding generates potent and long lasting toxic effects because the covalently modifie d enzyme/receptor is permanently inactivated 4. The covalent binding to deoxyribonucleic acid leads to mutation, tissue necrosis, carcinogenicity and tumour formation 4. Mutations arise when the electrophiles escape the repair mechanisms of the cell, may be fixed and passed to the progeny 4. If the electrophiles bind to protein, they will disturb the physiological homeostasis, leading to cell death 7. Examples of electrophiles include epoxide, hydroxylamines and aldehydes 4,5.Free radicalsFree radicals (species containing an odd number of electrons) may be cations, anions or neutral radicals 8. Free radicals are generally formed via NADPH CYP450 reductase or other flavin containing reductases 8. They will toxicity by per oxidization of cellular components. An important class of renounce radicals is organic free radicals such as hydrogen peroxide and superoxide anion 8. The potential toxicity of free radicals is far greater than electrophiles 8.Free radicals are able to construct chemical modifications and damage to proteins, lipids, carbohydrates and nucleotides 9. If the thermolabile free radical is formed close to DNA past it may produce a change in the building resulting in a mutation or cytotoxicity 9. Protein and non-protein thiol groups are readily oxidized by many free radicals and may lead to profound changes in enzyme activity 9. Another major pathway of metabolic disturbances is depending on covalent binding with cell components such as protein, lipid and nucleic acid to from a stable covalently bound adduct that may grossly distort structure and function 9. Reactive free radical may also damage cells through membrane damage 9. Examples of free radicals include hydrogen peroxide, hydroxyl radical and peroxynitrite 10.Examples of drugs undergoing bioactivation and causing subsequent tissue toxicityTable 1 Several drugs, with their corresponding toxic metabolic pathways and the subsequent adverse effects. medicineMetabolic pathwayAdverse effect schloramphenicolChloramphenicol is first oxidised by CYP monooxygenase into its dichloromethyl moiety 11. Hydrochloric acid is then eliminated to produce a excited metabolite that interacts with the -amino acid of a lysine residue in CYP monooxygenase 11. The enzymatic reaction is eventually retards over time, leading to adverse effects 11.Apalstic anemia 12Bone marrow toxicity 12AcetaminophenThe reactive metabolite is called N-acetyl-p-benzoquinone imine (NAPQI) 11.Metabolic pathway 1 Acetaminophen undergoes N-oxidation to become N-hydroxyacetaminophen, which then undergoes dehydration to form NAPQI 11. This pathway is probably uncommon as N-hydroxyacetaminophen is not a chief intermediate in the oxidation of acetaminophen 11.Metabolic pathway 2 NAPQI undergoes a Michael-type addition with either glutathione or protein thiol groups 11.Hepatotoxicity 11,12.Tienilic acidTienilic acid is oxidised by CYP2C9 to either thiophene sulfoxide or thiophene epoxide 11. These electrophilic re active intermediates alkylate CYP2C9, permanently binding themselves to the enzyme 11. The enzyme is subsequently inactivated 11. The body then produces anti-LKM2 autoantibodies against the native CYP2C9 enzyme and the modified CYP2C9 enzyme 11.Immunoallergic hepatitis 11HalothaneMatabolic pathway 1 In hypoxic states, halothane undergoes reduction to produce the 1-chloro-2,2,2-trifluoroethyl free radical 11. This free radical performs a radical attack, leading to the necrosis of hepatocytes 11. The radical may also react with the Fe2+ in the CYP enzyme to form an iron -alkyl complex 11. This complex then causes the necrosis of the hepatocytes 11.Metabolic pathway 2 Halothane undergoes oxidation to produce trifluoroacetyl chloride 11. Liver proteins are then trifluoroacetylated on their -NH2-lysyl residue 11. This newly formed neoantigen evokes an immune repartee towards the liver 11.Severe hepatitis 11Valproic acidValproic acid is metabolised by CYP2C9 into 2-propyl-4-pentenoic aci d, also termed as 4VPA 11. This metabolite can then undergo two pathways 11.Metabolic pathway 1 CYP enzymes metabolise 4VPA into a reactive metabolite, which then proceeds to alkylate the prosthetic heme of the CYP enzymes 11. Hence, the enzymes are inhibited 11.Metabolic pathway 2 The 4VPA metabolite undergoes -oxidation to generate the Coenzyme A ester of 3-oxo-2-propyl-4-pentenoic acid 11. This new metabolite alkylates the terminal enzyme of -oxidation (3-ketoacyl-CoA thiolase) by a nucleophilic attack at the olefinic terminus 11.Hepatotoxicity 11TroglitazoneMetabolic pathway 1 The thiazolidinedione ring undergoes oxidative cleavage to produce a reactive sulfoxide intermediate, which spontaneously opens its ring 11.Metabolic pathway 2 The phenolic hydroxyl group of troglitazone undergoes a one-electron oxidation catalysed by CYP3A to produce an unstable hemiacetal, which spontaneously opens to form a quinine metabolite 11. The quinine metabolite then undergoes the metabolic path way described earlier (metabolic pathway 1) 11.Metabolic pathway 3 The unstable hemiacetal produced in metabolic pathway 2 may undego hydrogen abstraction, resulting in the production of an o-quinone methide derivative 11.Hepatic failureDeath (due to hepatic failure) 11.Part 2 Applications of Bioactivation and Tissue Toxicity in Abacavir and LidocaineAbacavirAbacavir (first principle) is an anti-HIV drug classified as a nucleoside/nucleotide reverse transcriptase inhibitor (NRTI) 13. ABC possesses a significant role in the turnment of HIV patients 13. First, ABC is subjected to phase I oxidation to produce ABC-carboxylate, followed by phase II glucuronidation to generate the inactive glucuronide metabolite 13. Both the glucuronide and carboxylate metabolites are chiefly eliminated in the urine 13.ABC undergoes bioactivation to form reactive aldehyde metabolites 13. ABC metabolism to ABC-carboxylate involves a two-step oxidation via an aldehyde intermediate (unconjugated ABC-aldehyd e) which rapidly tautomerizes to the more stable conjugated ABC-aldehyde 13. This reactive metabolite is capable of reacting with proteins to produce covalent adducts, which results in the occurrence of adverse effects 13.The most prevalent acute ABC-induced adverse effects are the potentially life-threatening hypersensitivity reactions (HSR) that occur deep down the first 6 weeks of treatment 13. ABC also possesses the potential to induce cardiotoxicity, which raised further concerns about the prolonged administration of this drug 13.LidocaineLidocaine has been extensively apply in the treatment of ventricular arrhythmias 14. It is also usually administered intravenously to treat and prevent cardiac arrhythmias after acute myocardial infarction 14. Its chemical structure is an amide with an aromatic group 15. Lidocaine is chiefly metabolized by the microsomal enzyme system in the liver 15.The major biotransformation pathways are oxidation and hydroxylation 14. Lidocaine undergoes oxidative N-deethylation to form the toxic mono-ethylglycinexylidide, which is then hydrolysed to 2,6-xylidine 14,15. Finally, 2,6-xylidine is modified to 4-hydroxy-2,6-xylidine, which is excreted in urine 14. Lidocaine also undergoes hydroxylation of the aromatic nitrogen to form N-hydroxylidocaine and the toxic N-hydroxymonoethylglycinexylidide 14.The active and toxic metabolites known as mono-ethylglycinexylidide and N-hydroxymonoethylglycinexylidide primarily cause uneasy and cardiac toxicity 14,15. Early signs of CNS intoxication include shivering, muscular twitching and tremors of the facial muscles 15. As toxicity is low, it is safely and extensively used to treat arrhythmias 15.ConclusionTo eliminate xenobiotics from our body, processes collectively termed as biotransformation occurs in two phases. However, toxic metabolites (electrophiles or free radicals) may be produced in processes called bioactivation, which interact with body tissues and cause tissue toxicity. The bi oactivation and subsequent adverse effects of abacavir and lidocaine has been discussed in detail.References1 Rang H, Dale M, Ritter J. Rang Dales pharmacology. 7th Edition. Edinburgh Churchill Livingstone 2011.2 Dekant W. The role of biotransformation and bioactivation in toxicity. Springer. 2009 57-86.3 Walsh J, Miwa G. Bioactivation of drugs risk and drug design. Annual review of pharmacology and toxicology. 2011 51 145-67.4 Brahmankar DM, Jaiswal SB. Biopharmaceutics and Pharmacokinetics A Treatise. 2nd Edition. Vallabh Publications Prakashan 2012.5 Boyer T, Manns M, Sanyal A, Zakim D. Zakim and Boyers hepatology. Philadelphia, PA Saunders/Elsevier 2012.6 Walsh J, Miwa G. Bioactivation of drugs risk and drug design. Annual review of pharmacology and toxicology. 2011 51 145-67.7 Ioannides C, Lewis DFV. Cytochromes P450 in the Bioactivation of Chemicals,Current Topics in Medicinal Chemistry. 2004 41767-88.8 Leon Shargel , Andrew Yu, Suzanna Wu-Pong. Applied Biopharmaceutics Pha rmacokinetics. 6th ed. regular army McGraw Hill 2012.9 Trevor F. Slater. Free-radical mechanisms in tissue injury. Biochem J. 1984 Aug 15222(1)1-15.10 V. Lobo, A. Patil, A. Phatak, N. Chandra. Free radicals and functional foods impact on human health. Pharmacogn Rev. 2010 Dec 4(8) 118-2611 Wermuth CG, editor. The Practice of Medicinal Chemistry. 3rd edition. UK and USA Elsevier Ltd. 2008.12 Nassar AF, Hollenberg PF, Scatina J, editors. Drug Metabolism Handbook Concepts and Applications. New Jersey and Canada John Wiley Sons, Inc. 2009.13 Griloa NM, Charneirab C, Pereiraa SA, et al. Bioactivation to an aldehyde metabolite-Possible role in the onset of toxicity induced by the anti-HIV drug abacavir. Toxicology Letters. 2014 224 416-23.14 Collinsworth KA, Kalman SM, Harrison DC. The Clinical Pharmacology of Lidocaine as an Antiarrhythmic Drug. Circulation. 1974501217-30.15 Johansen . Comparison of Articaine and Lidocaine used as Dental Local Anesthetics. Faculty of Dentistry, Unive rsity of Oslo 2004. 25 p.

The Corrosion Of Metals Engineering Essay

The Corrosion Of Metals Engineering EssayEach year, billions of dollars are spent on repairing and preventing the damage of admixture parts caused by eroding, the electrochemical substance deterioration of admixtures. The majority of met bothic materials in a practical context are primarily exposed to corrosion in both atmospheric and sedimentary env crusadements. Metallic corrosion has become a global problem which has negatively affected the industrialised society hence why it has been studied in much(prenominal) comprehension since the beginning of the industrial revolution in the late eighteenth century. Corrosion also affects the average daily life both directly, as it affects the usually used service possessions and indirectly, as producers and suppliers of goods and services incur corrosion costs, which they pass on to consumers. (ASM International, 2012). The effects of corrosion are distinctively recognized on simple machine parts, charcoal grills and alloy tools al l of which will father a depleted efficiency once corroded. This corrosion may result in contamination which thus poses health risks. For example, the pollution due to escaping product from corroded equipment or due to a corrosion product itself. As a result of these consequences, corrosion legal profession has been studied in great depth. Corrosion of various metals may be prevented by applying a coating of paint, lacquer, grease of a less active metal to keep out air and moisture. These coatings will continue to suppress the effects of coating so long as they stay intact. Examples of metals that are heavily saved in the industrial world are put right and aluminium. Vast quantities of the ores or each metal are mined and carry through and throughed each year utilize large scale chemical reactions to produce metals of the purity required for their end use. For this report, the chemistry involved in the corrosion of both weightlift and aluminium will be researched as well as t he methods employed to prevent their corrosion. Justification as to why corrosion happens will be explained with reference to physical and chemical properties, electrochemistry, equilibrium, rates of reaction, enthalpy and solubility at every point where it is appropriate.Before explaining why corrosion happens, it is important to define corrosion in terms of electrochemical processes. An electrochemical reaction is defined as a chemical reaction involving the transfer of electrons through redox. Corrosion is a broad and complex subject that elicit be examined in three different categories electrochemical corrosion, galvanic corrosion and electrolytic corrosion. In all forms of corrosion, three components must be present an anode, a cathode, a metallic path for electrons to flow through, and an electrolyte for the ions to flow through. Both the anode and the cathode must be in contact with the electrolyte to allow the ions to flow. As well as this, fictitious character O and hydr ogen must also be available, either directly or as a result of chemical action and the resultant dissociation of water supply into its deuce constituents.In this report, electrochemical will be investigated in terms of its offhand nature and self-sustainability. Firstly, spontaneity is dependent on the sign of kick energy. Gibbs free energy coffin nail be defined by the following equation where is the enthalpy, is sulphur and is the temperature in kelvins. When is negative, the reaction will occur spontaneously (Zhang, H. 2012). For this to occur the entropy must increase and the enthalpy must decrease. This can be proven as a system of spontaneity aims towards disorder which directly coincides with entropy. Also, the change in enthalpy must be negative as thermal energy will be released from the energy stored within chemical bonds in a spontaneous system.Further to a greater extent than, in this electrochemical procedure, the negative electrode is the cathode and the positive electrode is the anode. Note that metals are used as they are good conductors of electric automobile current due to the specific bean bonding which then allows the electrons to be delocalized and move relatively freely. When these two electrodes are connected by a wire, free electrons flow through the wire from the anode to the cathode forming an electric current. Both the anode and cathode are submerged in separate substances respective to the elements of both electrodes from which the positive ions are attracted to the anode and the negative electrons are attracted to the cathode. The anode atoms are being oxidised as they are losing electrons and forming positive ions which then dissolves into solution. This results in a loss of overall quantity of zinc metal. In practical terms, this could be considered the pitting of the corrosion process which can be defined as a form of extremely localized corrosion that leads to the creation of small holes in the metal (ASM International, 1 987). Electrons formed at the anode travel to the cathode where they combine with the positive ions in solution to turn into the respective metal. Therefore the cathodic ions in solution are being reduced as they are gaining electrons. This production of extra cathode metal can be compared with rust which is a reddish- or yellowish-brown flaky coating of iron oxide that is formed on a metal by redox reactions.With just this in mind, the electric current would flow for only a limited time as the anode would have a build-up of positive ions being formed. While at the cathode increased amounts of electrons are being pumped into it. The result is an excessive positive charge that builds up at the anode that attracts electrons (negative) and prevents them woful away. While at the cathode the negative build up repels the electrons. As a consequence of this build-up of charge, no electron flow occurs and the cell eventually fails (Dynamic Science, 2012). Note that a solution cannot have a full charge and only a partial charge. To negate this issue, a common salt bridge is used which contains ions that complete the racing enlistment by moving freely from the bridge to the half cells. The substance that is placed into the salt bridge is usually an inert electrolyte whose ions are neither involved in either electrochemical change nor do they react chemically with the electrolytes in the two half-cells (IIT, 2012). As well as completing the circuit, it ensures that the charge between the two half cells remains electrically neutral. It does this by passing negative ions into the anodic half-cell where in that location shall be an accumulation of extra positive ions due to oxidation resulting in a slightly positive charge. Similarly, an accumulation of negative ions will exist in the cathodic half-cell due to the deposition of positive ions by reduction. Electrical neutralization is once once more achieved by the salt bridge providing positive ions to the cathodic su bstance. Thus, the salt bridge maintains electrical neutrality.IRON CORROSIONOnly a fewer metals, such(prenominal) as copper, gold and platinum occur naturally in their elemental forms. Most metals occur in nature as oxides in ores, combine with some unusable metal like clay or silica. Ores must be processed to get the pure metals out of them, and at that place are near as many different processes for this purpose as there are metals. The process, as well as the elements present, greatly influences the properties of the metal. An important characteristic of metals is the extremely authoritative effect that very small amounts of new(prenominal) elements can have upon their properties. The huge difference in properties resulting from a small amount of carbon allowed with iron to come upon steel is an example of this. Taking into consideration the amount of iron that is used globally, the effect of corrosion on iron alone requires millions of dollars each year. The problem with iron as well as many early(a) metals is that the oxide formed by oxidation does not firmly adhere to the surface of the metal and flakes off good causing pitting (KKC, 2012). Extensive pitting eventually causes geomorphological weakness and disintegration of the metal. The iron oxide acts as a sacrificial anode which is a stronger reducing divisor than iron that is oxides instead of the protected metal. Therefore it can be said that it acts as the anode. Since the oxide does not firmly adhere, it does little to protect the iron metal. As mentioned, iron in contact with moisture and air (oxygen) is corroded by a redox reaction. The anode reaction can be expressed as an oxidation of iron atomsBoth water and oxygen are required for the next sequence of reactions. The iron ions are further oxidized to form ferric ions (iron ) ions. This can be written asThese electrons are then conducted through the metal and are used to reduce atmospheric oxygen to hydroxide at another theatrical role of the iron. Therefore the cathodic reaction isConsidering that iron atoms dissolve at the anodic sides to form pits and ions which break up toward the cathodic sites ions are formed at cathodic sites filter toward the anodic sites. Iron (II) hydroxide forms in a random location between the cathode and the anode which is then oxidised by atmospheric oxygen to iron (III) hydroxide. This can be expressed byFrom here, the iron (III) hydroxide is then gradually converted to rust otherwise known as hydrated iron (III) oxide Where generally equals 3.The formation of rust does not have a designated position as it can occur at random away from the actual pitting or corrosion of iron. A possible explanation of this is that the electrons produced in the initial oxidation of iron be electrically conducted through the metal and the iron ions can diffuse through the water layer to another position on the metal surface which is available to the atmospheric oxygen (KKC, 2012). Also, points of stress, such as where the piece of metal has been shaped, are more active than unstressed regions and thus act as anodic sites. The electric current between the anodic and cathodic sites is completed by ion migration thus, the presence of electrolytes increases the rate of corrosion by hastening this mitigation. Therefore it is evident that the corrosion of iron can be directly related to a galvanising cell and can both be defined as electrochemical cells due to their spontaneous nature.ALUMINIUM CORROSIONSimilar to Iron, aluminium is also supersensitized to electrochemical corrosion when exposed to moister. Aluminium, both in its pure state and allow, is truly a remarkable metal as it is light, tough, strong and readily worked by all common processes. Unlike iron however, It has excellent resistant to corrosion in the marine environment, and it requires little maintenance. The fundamental reactions of the corrosion of aluminium in aqueous intermediate have been the subject of many studies. In simplified terms, the oxidation of aluminium in water proceeds according to the equation (ELSIVIER, 2012)This specific reaction is match by a simultaneous reduction reaction, similar to iron, in ions available in the solution which then consumes the oxidised electrons. In an aqueous solution such as fresh water, seawater or moisture, thermodynamic considerations can be used to represent only two possible reduction reactions that can occur. The other occurring reaction is the reduction of oxygen dissolve in the moistureQuite similar to the corrosion of iron, the aluminium atoms dissolve at the anodic sites to once again form pits and which diffuse toward the cathodic sites while ions are formed at the cathodic sites and diffuse toward the anodic sites. Therefore Where generally equals 3.Although aluminium is still susceptible to corrosion, the metal itself is very resistive. Aluminium alloys generally have excellent resistance to atmospheric corrosion require no pro tective coatings or maintenance beyond cleaning, which aids greatly in preventing unsightly pitting where dirt or salt accumulate. When aluminium is exposed to oxygen, it forms an oxide surface film that protects it from corrosive attack. The oxide acts as a sacrificial anode which is a stronger reducing agent than aluminium. It is then oxidised instead of the protected aluminium metal, serving as the anode. For the most part, damage due to atmospheric corrosion is pretty much limited to fairly slightly pitting of the surface with no significant loss of material or strength. Duration of impression is an important consideration in aluminium allows, the rate of corrosion decreases with time to a low steady rate regardless of the type of allow or the specific environment. Thus corrosion of both aluminium and iron can both be defined as electrochemical processes which are similar in nature but have different fortress potentials.PROTECTION METHODSCorrosion avoidance begins in the desig n process. Although corrosion concerns may ultimately reduce structural integrity, they should be a consideration to decrease money loss. Good maintenance practices are another way of avoiding corrosion, such as rinsing away salt water or avoid standing water. Corrosion protection systems, for the most part, are designed to reign corrosion, not necessarily eliminate it. The primary purpose is to reduce the rate of corrosion by having the smallest possible current. Current is defined as the flow of charge, or electrons, per time through a conductor hence. Since corrosion is the movement of electrons through redox, it can be quantified using this equation which represents the corrosion reaction per time or the corrosion rate. To do this, two efficient protection methods are available cathodic protection systems and coatings.All cathodic protection schemes operate on the basis of the voltaic corrosion process, so like voltaic corrosion cathodic protection systems require an anode, a cathode, an electrical connection and an electrolyte. Cathodic protection will not reduce the corrosion rate if any of these four things are missing. The basis of this protection method depends on the difference in corrosion potentials between the two metals immersed in the same electrolyte. This causes electrons to flow from the metal with the uplifteder activity and negative potential (anode) to the metal with less activity and negative potential (cathode). This flow of electrons continues until the two metals are at the same potential, that is, there is equilibrium between the voltages. Electrode potential is a measure of the tendency for a material to be reduced e.g. accepts electrons. Also, activity is a measure of how easily a metal will give up electrons. Thus, the more active a metal is, the more negative the electrode potential. This principle, directly relates to the two types of cathodic protection systems sacrificial anode systems called passive protection and impresse d current systems also known as active protection.Sacrificial anode systems are simple, require little but regular maintenance, and have low installation costs. We intentionally add a metal to the circuit to supply the electrons to the cathode. When metals are in a voltaic couple, the difference in there negative potentials causes the anodic metal to corrode and release metallic ions into the electrolyte. The more negativity in the corrosion potential means it will be a stronger reducing agent and will more readily give away electrons thus corroding first. Since the more negative metal in the closed circuit corrodes first, we can control corrosion by simply adding to the circuit a metal that possess two necessary characteristics a corrosion potential more negative than the metal that is being protected, it is expendable which is not essential to the operation of any particular system. Therefore when a metal possessing these characteristics is made the anode, corrosion is controlled .The impressed-current type of cathodic protection system depends on an external source of direct current. Alternating current cannot be used since the protected metal would likewise be alternating, between anodic and cathodic. Basically, the anode is immersed in the electrolyte is connected to one side of a DC power supply and the metal to be protected is connected to the other side. The voltaic current flow is detected and measure against a reference electrode. If unfavourable, current flow is adjusted automatically by the power supply control system to compensate. Due to the high currents involved in many seawater systems, it is not uncommon to use impressed current systems in marine situations. affect current systems use anodes (ICCP anode) of a type that are not easily dissolved into metallic ions, but rather sustain an alternative reaction, oxidization of the dissolved chloride ions (Deepwater, 2012).Advantages of this cathodic protection are that they can develop so much high er voltages than sacrificial anode systems, so they can either push current through lower conductivity electrolytes or through longer distances. Disadvantages include the possibility of over protecting certain metals. This can cause hydrogen embrittlement in high strength steels. In aluminium specifically, accelerated corrosion can occur of the very structure that is being protected. Therefore it is evident that this form of cathodic protection, although more complex, poses some reliable advantages as well as some detrimental disadvantages.

Kate Chopins The Story of an Hour :: Kate Chopin The Story of an Hour

Kate Chopins The Story of an HourKate Chopin was a Victorian writer whose writing manifests her lifetime experiences. She was not happy with the principles of the time, because women had fewer rights, and they were not considered equal to men. Afraid of segregation from society, people lived in a hypocritical world full of lies moreover, Kate Chopin was not afraid of segregation, and used her writing as a weapon against oppression of the soul. Marriage was an oppressor to Chopin, she had been a victim of this institution. Being a victim of marriage, Chopins Story of an Hour, is an expression of her believe that, marriage is an institution that oppresses, represses, and is a denotation of discontent among human beings.Mrs. Mallard jazzd her husband.She wept at onceThis was her first response to the news of his death. She would not had grieved over someone she did not love. Even in the heat of her passion she thinks about her lost love.She knew that she would weep again when she saw the kind, tender hands folded in death the face that had never looked safe with love upon her, fixed and gray and dead.Her love may not have been the greatest love of all time, but it was still love.Marriage was not kind to Mrs. Mallard, her life was dull and not worth living, her face showed the years of repression. If she did love this man, why was marriage so harmful to her? Marriage was a prison for herThere would be no powerful will bending her in that blind persistence with which men and women believe they have a right to impose a hidden will upon a fellow creature.Marriage oppressed her, she needed freedom, freedom to grow and do what she wanted to do, and marriage took that away from here. Chopin didnt believe that one mortal should take away anothers freedom.

Medieval Castles Essay -- essays research papers fc

gallant Castles and their InteriorAlthough it is thought that medieval times were barbaric they too enjoyed many comforts we still do straightaway. There is much more to the castle then its size or the stone arches inside which are still used in many homes today. Castles today are still flocked to by millions of people every year. Sometimes you even see copies of castles right here in the U.S.A plainly they are not sort of the same. Although they were originally built to protect the King, Castles became more and more popular among other nobles as well. Each family castle had their own special design and touch but most castles of medieval times had a lot of the same basic elements in their interior.Within the shell keep and behind the slap-up walls of these castles there was ever so one basic element the great hall. It was often on the ground floor but sometimes it was raised to the second floor for extra security. The great hall was a large one-room structure with a lofty ceili ng(Giess 58). This was where all the people of the castles slept (excluding the lord and the Lady). There was of course a great queen-size curtain put up so the ladies would be separate from the men. It wasnt until the finish up of the hundred when separate rooms were invented. The great hall was usually rigid in the very center of the castle and walls built out of stone surrounded the whole room. The entrance was in a sidewall near the lower end of the hall. An outside staircase would be built if the hall were on the second floor. The family would usually absorb its feasts in this room (Gies 60). For even more security they would have guards stand outside the great hall on all sides of the room so guests would feel safe when they were feasting (Nardo 57). Early halls were aisled uniform a church, with rows of woody posts or stone pillars supporting the timber roof. Windows were equipped with wooden shutters secured by an iron bar but they were rarely glazed. It wasnt until th e13th century a queen regnant or a great baron might have white or greenish glass in the windows. Then later in the14th century that glazed windows were in every castle (Gies59). In the castle, the first floor or ground floor (it was sometimes called) was the actual earth itself. ... ...d. All that clay now are ruins that dot the countryside every where throughout England.Even though the castle has disappeared it has not been completely forgotten. Today many decorators and homeowners borrow and try to liven up the barbaric look. A lot of people find in quite romantic. People are reminded of royalty and all the important people during this period like King Arthur and Robin Hood. In conclusion, the Medieval Castles interior decoration began to have importance and much of its innovations are still used today. work CITEDNardo, Don. The Medieval Castle. California Lucent Books, 1997.Singman, Jeffery L. Medieval Europe. Connecticut Greenwood Press, 1999.Gies, Frances, et. al. Life in a Medieval Castle. New York Thomas Crowell Company, 1974.Interior Design. World Book Encyclopedia. 1995. ed.Medieval Castles. 12 Dec 2001. http//www.castles-of-britain.com