Logic exercise hypothesis testing Assignment Example | Topics and Well Written Essays - 250 words

Logic exercise hypothesis testing - Assignment Example Doug disregards Al’s statements as not true and argues that at least one of Charles’ statements is true, further he claims that he does not like to eat game. It is clear that, statements 2 and 3 made by Al are true; Bill’s third statement is the only true statement, and statements 1, 2 made by Charles are also true. Doug also makes two true statements, 2 and 3. Therefore, it can be said that, Bill is the poacher, based on the fact that a guilty party makes only one true statement (Poletiek, 2001), is the guilty one. The Butcher’s first statement that he was not there is entirely false, so is his second and third statements, as well. Given that the Butcher’s first statement is false and the Baker first statement claims to agree with it, it means that, his statement is not also true. The Candle stick maker makes at least two true statements, 1 and 2. The Cobbler’s third statement is not true since it contradicts his first statement. He says that he agree with the bakers third statement, which is in agreement with the Butcher’s second statement, which claims that the Cobbler did it. All of the Blacksmith’s statements are true; therefore, he is the only suspect that makes no false

Introduction about Drones and Seattle Police's Drones Essay

Introduction about Drones and Seattle Police's Drones - Essay Example The ones used for attacking enemy lines have recently been a part of war on terrorism where they are used to figure out enemies on the ground and then they are used to eliminate these enemies. The ones used for surveillance purposes have been used both domestically and internationally for security purposes. For example: recently the state of Seattle purchased two drones each costing a total of $41,000 (Clarridge, 2012). These drones are under the testing phase and are controlled by the police department of Seattle. These drones have been adopted by the police department for the purpose of surveillance and these drones have cameras along with infrared eye attached to it. There are various benefits of using drones, these include: they are in expensive, they save lives and they provide a competitive advantage to the side that is using them (Benjamin 18). Clarridge, Christine. "Police Department demonstrates new drone, to help allay concerns | Local News | The Seattle Times." The Seattle Times | News, sports, weather, events in the Northwest. N.p., 27 Apr. 2012. Web. 13 Mar. 2013.

Strategic Management Case Study Essay Example for Free

Strategic Management Case Study Essay Introduction.   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   Strategic management is one of the most challenging but important element that defines the success of both private and state owned organization. The fundamental issue of defining and clearly stipulating an organizations strategy is to enable the institution have a distinct sense of direction, vision and strategy that will enable the institution deliver efficient services and/or products to its clientele and add value to its customers, achieve sustained a market niche or market share, and thus position the company strategically in the market in order to gain and maintain competitive advantage over its rivals (Dobson, Starkey Richards, 2004).   Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚  Ã‚   In state owned enterprises or generally institution where the government is the major stakeholder, one of the biggest problems is balancing between social and commercial objectives in defining the mission statement and policies governing the general direction and brand name or the organization. TVNZ as an organization has had a relatively positive growth in the long run and is still one of the major broadcasting organizations in New Zealand. From the given case, analyzing TVNZ’s historical performance reveals several strength, opportunities weaknesses and threats that the organization is facing given its nature as a broadcaster, form of organization (I.e. public organization) and its line of operation market (Spicer, Powell Emanuel, 1997). This paper is an in depth evaluation into TVNZ a state owned New Zealand broadcasting institution using the strength weakness, opportunity and threat analysis, the paper will analyze the dilemma of managing the company as a revenue generating entity and a medium of furthering social objective for the government and further recommend policies that can be used in defining strategic management objective that can the company meet both objectives. Strength of the organization.   The company was able to invest in latest technology namely digital media making it more competitive and hence retaining its market share. A good example can be illustrated by the Alvan TV center which had the latest equipment that enabled the company to outsource its services to other production firms and diversify its operation to teleccomunications (Hanson et al, 2008). Another feature that made the organization grow is monopoly, the organization enjoyed a monopoly thus had ample time to set up a good base and acquire a large market share. Therefore, though the organization has not enjoyed monopoly from 1980, the company was able to retain and maintain 70% of the market share thus with good strategy it will be able to consistently work to improve and provide good services (Hanson et al, 2008). Weaknesses of the organization. Among the major weaknesses TVNZ has include the fact that it has to balance between social objective and commercial ones. Looking at the companies history, balancing between commercial oriented operation and pursuing social oriented objectives as stipulated by regulations (given the fact that it is a government owned institution) has led to different approaches that have even led to pursuance of different contradicting strategy which have proved to be counterproductive and detrimental to the organizations well being and growth. For example, in 2002 when the charter was introduced, some politician expected the company to adopt social objective but still remain profitable and self sustaining as a business entity. In most cases, social and commercial objectives normally contradict and hence it would be a very difficult and almost impossible for TVNZ to fully adopt social oriented programs and still remain at the same level or increase advertising revenue (Hanson et al, 2008). Reviewing the programs being aired to conform to values that are in tandem or will further the growth of social standards and the integrity of the country means that entertainment department will have to change its program line up to conform to acceptable cultural standards. This can consequently lead to a fall in ratings given that many viewers prefer to watch explicit entertaining channels rather than informative programs.   Therefore, the company will loose a lot of advertising revenue since ratings might significantly drop given the loss of market share to privately owned broadcasters who will continue airing what the majority of viewers want to watch (Hanson et al, 2008). Opportunities in the organization. The organization as a government institution has had various features that led to the organization growth and stability to become a giant internationally recognized broadcasting house. One of the opportunities that act as a driving force for the company is, being a state owned institution, it has abundant resources and relatively cheap source of funding that can be used to further its objectives and attain optimality. For example, the company has the capability of diversifying its market to capture the international market and this can help it strategically in that in the event of loosing a significant share of the local market, the company can still remain profitable from its international focus (Hanson et al, 2008). Threats.   The major threats facing TVNZ as an organization are political interference and government regulations that are imposed on the company given the fact that it is a chartered company. Over the past 35 years of its existence, there has been a major strategic shift of the company due to government regulation which brought about to be indecisiveness and lack a clear long term vision and hence compelled the institution to dilly dally between pursuing   social objectives and commercial objectives. According to Spicer, Powell Emanuel (1997), there has always been pressure from treasury to TVNZ a revenue generating entity while other politicians feel that commercial objectives are secondary to social objective. This has led to dilution of the company’s mission statement and vision which are core elements in charting the long term growth and sustainability of any organization whether private or public, profitable or not-for-profit. Entrance of other players in the market and fragmented clientele might lead to loss of revenue if the company keeps on changing its tactical strategy due to inconsistency which brings about unreliability. For example, according to Hanson et al (2008), each of the five CEO’s introduced a different strategy of management with diverse views for example Brent Harmont (1991 – 1995) in an attempt to make entry in the international market introduced a very complex organizational structure which was realigned by Chris Anderson (1995 – 1998) in attempt to reclaim the companies core business. Solutions. Strategic management involves analyzing the institution by looking at the nature of business with regards to the customers needs or defining the nature of your market and your competitive advantage, financial obligation and needs required to satisfy your clientele needs, other stake holder’s needs and external environment and the learning and growth of the company (Dobson, Starkey Richards, 2004). According to Beiman (2006), Establishing a clear, repeated, and ongoing strategy management process more than doubles the chances of becoming a winner†¦.. And helps companies establish clear strategies that, when used effectively, serve as a foundation for an effective strategy management process. Analyzing the threats and weaknesses facing TVNZ as an institution, it is obvious that the loss market share due to pursuance of social objective is imminent. Given that this is externally based and hence out of control of management in relation to strategic management and formulating of policies, management has to formulate strategies to mitigate and redefine their strategy in order to maintain or compensate the loss that can be instigated by the conditions stipulated by the charter (Sexty, 1983 Spicer, Powel Emanuel, 1997). Firstly, TVNZ has to redefine its objective and evaluate their strategies in terms of mission, vision and objectives spelled out by the charter. This entails looking at the customer needs and market niche as restricted by the set out conditions. The charter postulates that the broadcaster needs to promote New Zealand’s cultural value’s among other objectives, these introduces a new aspect thus TVNZ needs to focus on the clientele who fit this criteria. Therefore, instead of approaching it as a threat the company should focus on ways that will turn this into revenue generating by applying strength – opportunity techniques (QuickMBA, n.d. Beiman, 2006). After formulating the company’s policies, it is very important that management considers the change process. Given the volatility in the market, efficient change management entails formulating chronological implementation policies that will gradually introduce stakeholders to the changes that will take place, effective and consistent communication between the customers, management and other stakeholders and setting up a good feedback mechanism techniques that will ensure that both implementers (TVNZ), and the market understand and appreciate the change process (Schein, 2004). Thus management should continue to play the stewardship role by consistently briefing the employees, customers and other stakeholders to minimize resistance and possibly loss of revenue, effective communication vertically ensures that the employees understand the need for change and these leads to smooth and successful change in two ways. Firstly, employees will be motivated due to involvement and understanding of the change, secondly, they will act as agent in conveying the message to the external environment thus facilitate smooth and successful implementation (Schein, 2004). TVNZ as a charter company compared to other stations has the capability of acquiring funds hence one strategy would be to diverse the business and expand their market internationally. In addition, the business can capitalize on telecommunication given its resources hence increase revenue that will cushion potential loss of advertising revenue. The strength-opportunity approach can be illustrated by the examples below: Tourism sector can benefit from TVNZ if they adopt strategies to sell New Zealand’s heritage, rich culture and geographical wonders globally. Similarly, given the level of globalization in the business world, investors are always looking for new areas to invest their funds, therefore TVNZ can be used as a medium to sell the country as a good investment destination. This move will enable the company attract a new type of clientele worldwide in the business and tourism sector e.g. hotels, airlines, banks among others who can benefit from services offered by the station given its new approach and objectives.         REFERENCES: Beiman, I.   (2006). Chapter 6: Managing SOE’s for improved performance. Retrieved 24th June 2008 from http://www.adb.org/Documents/Books/Balanced-Scorecard/chap6.pdf Dobson, P., Starkey K Richards, J. (2004). Strategic management: Issues and cases. Blackwell Publishing Inc. Hanson, D. et al (2008). Strategic management: Competitiveness and Globalization. Asian pacific 3 Ed. South Melbourne. Thomson Publishing Inc. Spicer,B., Powell, M. Emanuel, D. (1997).   The remaking of television New Zealand 1984 – 1992. Auckland University Press. QuickMBA (n. d.). Strategic Management: SWOT analysis. Retrieved 24th June 2008 from http://www.quickmba.com/strategy/swot/ Schein, E. (2004) Organizational Culture and leadership. Jossey-Bass A Whiley imprint. Inc. Sexty, R. (1983). â€Å" Accountability dilemma in Canadian public enterprises: Social versus commercial responsiveness.†Ã‚   Annals of Public and Cooperative economics. Vol. 45 (1). Pp 19

Breastfeeding: Advantages and Disadvantages

Breastfeeding: Advantages and Disadvantages This essay is potentially vast in its scope as the advantages and disadvantages of breastfeeding can vary enormously depending on which authority one chooses to consult. (1) We shall therefore take an overview and present the generally accepted arguments in this area. There is a substantial evidence base for the benefits of breastfeeding for not only the infant, but also the mother, the families and society as a whole. (2). The benefits are not only nutritional, but cover other areas such as development, immunity, psychological well-being, overall health risks, social and environmental areas (3) Human milk is widely recommended as the food of choice for the otherwise healthy full-term newborn. Apart from providing the optimal nutrition it contains a number of cellular and humoral components such as phagocytes, immunocompetant cells, immunoglobulins and hormones and also plays a (as yet, not fully defined) role in promoting intestinal mucosal maturation. (4) Because of these (and other) considerations, the World Health Organisation recommends exclusive breastfeeding for at least the first six months of life. (5) There is widespread evidence that the trend towards universal breastfeeding is increasing (viz. 6) in most of the developed countries, Fewtrell gives a global figure of 2% per year. but studies show that this trend is not equal across all socio-economic and demographic groups. If we specifically consider the UK situation then we can show that the commencement of breastfeeding is equal in the working and non-working mothers groups, although if one considers the situation of how many mothers are still breastfeeding at six months post partum, the incidence in the working mothers group is less than half that in the non-working group. (7) What then is the evidence base for the benefits of breastfeeding? In addressing this question we shall confine our comments to those relevant to the developed world. If we consider the Kramer study, which compared the benefits of continued breastfeeding from 3 months to 6 months, the authors were able to demonstrate that the additional 3 months produced benefits in terms of greater weight gain, greater growth (length) together with a reduced incidence of gastrointestinal infection. (8) In absolute terms however, the benefits of breastfeeding over formula milks (or cows milk) is much greater. A huge number of potential childhood infections have been demonstrated to have a lower incidence in the breastfed child including bacterial meningitis, diarrhoea, respiratory tract infections, otitis media, urinary tract infections (9) as well as less common entities such as necrotising enetrocolitis (10). It is also significant that the all-cause mortality rates are 21% less in breast fed infants. We should note that this figure, although accurate, is misleading, as many high risk babies are not breast fed because of their intercurrent problems. (11) Apart from infections, many other health benefits can be demonstrated. There is a reduction in the incidence in sudden infant death syndrome under the age of 1 yr. (12). Diabetes (Type I and Type II) is less common amongst breastfed babies (in later life) as are the incidences of conditions such as lymphoma, leukaemia and Hodgkin’s disease. (13). Breastfeeding tends to be associated with a lower incidence of obesity, hypercholesterolaemia and asthma. (14) There is a slightly weaker evidence base to support the benefit of breastfeeding in terms of neurological development. Some authorities suggest that it can improve cognitive development. (15) and it may also reduce the perception of some painful stimuli. (16) In addition to benefits for the child, there are also a number of demonstrable benefits for the mother who breastfeeds. If suckling occurs at the time of birth, the resultant release of oxytocin reduces the incidence of post partum haemorrhage and increases the speed of uterine involution. (17). In the period after the birth, breastfeeding reduces both fertility and menstrual loss, it facilitates a return to pre-pregnancy weight, it reduces the risk of both ovarian and breast cancer (18) and may well reduce the incidence of osteoporotic fractured hips (19) In the opening segment of this essay we alluded to the benefits to the community as a whole. These can be defined in terms or reduced health costs to the community by virtue of the protective effects of breastfeeding. There are also less definable benefits in terms of reduced employee absenteeism. Some authorities have gone as far as to point to the environmental benefits of reduction in energy expenditure on production, distribution and disposal of formula feeds and their packaging. (20) Thus far we have considered the positive benefits of breastfeeding but in order to provide a balanced argument, we should also consider the disadvantages. The pre-term infant or severely underweight or ill baby has special needs and there are a number of reasons why they should not be breastfed. The pre-term infant has immature physiological systems and the kidneys may not be able to handle the osmotic gradients that are required to excrete the amount of fluid necessary to remove the amount of nutritional load required for adequate growth. This may result in respiratory problems and exacerbation of any pre-existing cardiac conditions (viz. patent ductus arteriosus). For this reason, most pre-term infant are electively parentrally fed and then weaned onto enteral feeding when their gastrointestinal tract and other physiological systems are mature enough to handle the fluid load. (21) If the mother is ill or has a potentially communicable illness such as HIV/AIDS or TB, then breastfeeding is contraindicated, as it is in conditions when certain drugs (both medicinal and recreational) are taken by the mother. (22). We should also record that the evidence for HIV/AIDS spread is not secure, as some studies have suggested that breastfeeding actually confers a degree of protection against HIV/AIDS for the child. This is still an area of considerable debate. (23) It is also clear from an examination of the literature on the subject, that there is a great deal of misinformation on the subject of breastfeeding in the popular press (and to a lesser extent in the medical press). Breastfeeding is not contraindicated in conditions such as Hepatitis B or C +ve. (24). Most febrile conditions are not a contraindication to breastfeeding as the maternal immune response will be passively given to the child in any event. Some authorities suggest that tobacco smoking is a contraindication to breastfeeding. If we remove considerations of general health from the consideration, there is no reason why tobacco smoke should be considered a bar to breastfeeding as such. (it clearly may be ill-advised however) (25). Some authorities suggest on theoretical grounds that breastfeeding should be suspended during the period of physiological jaundice of the newborn. A number of recent studies have shown that this is not necessary and may cause insurmountable difficulties in rehabilitation-establishing breastfeeding after the event. (26) In essence, within the scope of the exclusions referred to above, healthcare professionals should actively encourage and support mothers in their ability to breastfeed their offspring. In doing so, one should always consider the autonomy of the mother (27) and attempt to provide empowerment and education in order to facilitate the best result rather than compulsion or emotional blackmail. (28). This should help to ensure the maximum possible take up of breastfeeding from mothers who have been able to make a fully informed decision. If direct breastfeeding is not possible, then, generally speaking, expressed breast milk is the preferred substitute. In this essay we do not presume to have covered anything like an exhaustive presentation of the arguments, but there is no doubt, from an overview of the evidence base on the subject, that in the vast majority of cases, both mother and child will derive substantial benefits from being able to breast feed for at least the first six months of life. References (1) Duerbeck N B (1998) Breast-feeding: what you should know so you can talk to your patients. Comp Ther 1998 ; 24 : 310 318 (2) Kramer M S, Chalmers B, Hodnett E D, et al. (2001) Promotion of Breastfeeding Intervention Trial (PROBIT): a randomized trial in the Republic of Belarus. JAMA. 2001 ; 285 : 413 – 420 (3) Schanler R J. (2001) The use of human milk for premature infants. Pediatr Clin North Am. 2001 ; 48 : 207 – 219 (4) Margolis L H and J. B. Schwartz (2000) The Relationship Between the Timing of Maternal Postpartum Hospital Discharge and Breastfeeding. J Hum Lact, May 1, 2000 ; 16 (2) : 121 128. (5) Fewtrell M S , J. B Morgan, C. Duggan, G. Gunnlaugsson, P. L Hibberd, A. Lucas, and R. E Klein man (2007) Optimal duration of exclusive breastfeeding: what is the evidence to support current recommendations? Am. J. Clinical Nutrition, February 1, 2007 ; 85 (2) : 635S 638S. (6) Bonuck K A, K. Freeman, and M. Trombley (2006) Randomized controlled trial of a prenatal and postnatal lactation consultant intervention on infant health care use. Arch Pediatr Adolesc Med, September 1, 2006 ; 160 (9) : 953 960. (7) Kramer M S, Kakuma R. (2001) The Optimal Duration of Exclusive Breastfeeding. Geneva, Switzerland: World Health Organization ; 2001 (8) Kramer M S , Guo T, Platt R W et al. (2003) Infant growth and health outcomes associated with 3 compared with 6 mo of exclusive breastfeeding. American Journal of Clinical Nutrition, Vol. 78, No. 2, 291 295, August 2003 (9) Heinig M J. (2001) Host defense benefits of breastfeeding for the infant. Effect of breastfeeding duration and exclusivity. Pediatr Clin North Am. 2001 ; 48 : 105 –123 (10) Dewey K G, Heinig M J, Nommsen-Rivers L A. (1995) Differences in morbidity between breast-fed and formula-fed infants. J Pediatr. 1995 ;126 : 696 – 702 (11) Chen A, Rogan W J. (2004) Breastfeeding and the risk of postneonatal death in the United States. Pediatrics. 2004 ;113 (5) (12) Horne R S, Parslow P M, Ferens D, Watts A M, Adamson T M. (2004) Comparison of evoked arousability in breast and formula fed infants. Arch Dis Child. 2004 ; 89 (1) : 22 –25 (13) Davis M K. (1998) Review of the evidence for an association between infant feeding and childhood cancer. Int J Cancer Suppl. 1998 ; 11 : 29 – 33 (14) Toschke A M, Vignerova J, Lhotska L, Osancova K, Koletzko B, von Kries R. (2002) Overweight and obesity in 6- to 14-year old Czech children in 1991: protective effect of breast-feeding. J Pediatr. 2002 ; 141 : 764 – 769 (15) Horwood L J, Darlow B A, Mogridge N. (2001) Breast milk feeding and cognitive ability at 7–8 years. Arch Dis Child Fetal Neonatal Ed. 2001 ; 84 : F23 – F27 (16) Carbajal R, Veerapen S, Couderc S, Jugie M, Ville Y. (2003) Analgesic effect of breast feeding in term neonates: randomized controlled trial. BMJ. 2003 ; 326 : 13 (17) Labbok M H. (2001) Effects of breastfeeding on the mother. Pediatr Clin North Am. 2001 ; 48 : 143 – 158 (18) Rosenblatt K A, Thomas D B. (1993) Lactation and the risk of epithelial ovarian cancer. WHO Collaborative Study of Neoplasia and Steroid contraceptives. Int J Epidemiol. 1993 ; 22 : 192 – 197 (19) Paton L M, Alexander J L, Nowson C A, et al. (2003) Pregnancy and lactation have no long-term deleterious effect on measures of bone mineral in healthy women: a twin study. Am J Clin Nutr. 2003 ; 77 : 707 – 714 (20) Jarosz L A. (1993) Breast-feeding versus formula: cost comparison. Hawaii Med J. 1993 ; 52 : 14 – 18 (21) Denne, S. C., Karn, C. A., Ahlrichs, J. A., Dorotheo, A. R., Wang, J. Liechty, E. A. (1996) Proteolysis and phenylalanine hydroxylation in response to parenteral nutrition in extremely premature and normal newborns. J. Clin. Invest 97 : 746 -754 (22) Read J S; (2003) American Academy of Pediatrics, Committee on Pediatric AIDS. Human milk, breastfeeding, and transmission of human immunodeficiency virus type 1 in the United States. Pediatrics. 2003 ; 112 : 1196 – 1205 (23) Coutsoudis A, Rollins N. (2003) Breast-feeding and HIV transmission: the jury is still out. J Pediatr Gastroenterol Nutr. 2003 ; 36 : 434 – 442 (24) Pickering : (2003) American Academy of Pediatrics. Transmission of infectious agents via human milk. In: Pickering LK, ed. Red Book: 2003 Report of the Committee on Infectious Diseases. 26th ed. Elk Grove Village, IL: American Academy of Pediatrics; 2003 : 118 – 121 (25) American Academy of Pediatrics, (2001) Committee on Drugs. Transfer of drugs and other chemicals into human milk. Pediatrics. 2001 ; 108 : 776 – 789 (26) American Academy of Pediatrics, (2004) Subcommittee on Hyperbilirubinemia. Management of hyperbilirubinemia in the newborn infant 35 or more weeks of gestation. Pediatrics. 2004 ; 114 : 297 – 316 (27) Sines D (1995) Impaired autonomy: the challenge of caring. Journal of Clinical Nursing 4 (2) 109 -115. (28) Marinker M.(1997) From compliance to concordance: achieving shared goals in medicine taking. BMJ 1997 ; 314 : 747 – 8. ############################################################### 12.05.07 PDG Word count 2,183 Polycrystalline Ceramics: Sub Grain Structure Polycrystalline Ceramics: Sub Grain Structure Pure un-doped zirconia is a polymorph which has three allotropes namely: Monoclinic, Tetragonal and finally Cubic. These phases tend to transform into each other when exposed to certain temperature ranges and such transformation is important for the processing and mechanical properties of zirconia. The monoclinic phase of pure un-doped zirconia is stable at room temperature and remains so up to about 11700C, where it then transforms into tetragonal phase. It becomes stable tetragonal at this temperature and remains so up to 23700C, where it turns to cubic. The cubic phase occurs up to the melting temperature of 26800C. Monoclinic phase The monoclinic form also referred to as baddeleyite, is a thermodynamically stable phase at a temperature range between room temperature and approximately 9500C. It contains four ZrO2 molecules per unit cell and has a space group of P21/c. Figure 2.1 shows the lattice parameter of monoclinic form. Its structure is described as a distorted fluorite (CaF2 structure). It is difficult to define the crystal structure of monoclinic zirconia because of its complexity as well as the problem of making a monoclinic single crystal with the satisfactory qualities due to: micro-cracking, low purity, twinning and disproportionate solid solution formation. Tetragonal phase This is a high temperature phase (t) firstly discovered by a group of scientist during its transformation from the lower temperature monoclinic phase over a temperature of about 11500C. Figure 2.1 shows the lattice parameter of tetragonal form. The structure is similar to that of monoclinic polymorph in the sense that it is also distorted CaF2 structure. Hence, tetragonal zirconia (t-ZrO2) can be described using the face centred tetragonal Bravais lattice as oppose to the body centred tetragonal lattice, that contains a unit cell with volume twice the size of the primitive cell. (3) Figure 2.2b shows a simple schematic of a tetragonal unit cell. Its structure comprises of eight oxygen ions surrounding a zirconium ion, with half at a distance of 0.2455nm forming an elongated tetrahedron and the remaining four are at a distance of 0.2065 forming a flattened tetrahedron (the elongated and flattened tetrahedron are rotated 900 to each other). The transformation from tetragonal to monocli nic can start (Ts) and finish (Ts) over a range of temperatures. This reaction can be measured using the following experimental techniques: DTA, XRD and dilatometry. (3) Cubic phase Unlike the other structures, the cubic polymorph is quite easy to explain as it has a fluorite structure (CaF2). Figure 2.2c shows a simple schematic of a tetragonal unit cell. It has a lattice parameter of the order 0.508nm (this however depends on the temperature purity of zirconia that is partially stabilised zirconia at room temperature or pure zirconia at elevated temperature) and a crystal symmetry of Fm3m.   The martensitic transformation For a martensitic transformation to occur, a change in shape is required which must also produce a plane that does not change during transformation. This is so that it is common to the phase produced as well as the parent phase. The phase transformation in zirconia involves a change in volume of between 4 to 5%. The matrix inhibits the transformed particle of zirconia causing a partial shape change. However, the transformation creates a strain which is held in the monoclinic and its surrounding grains. As a result of this, researchers have come up with the idea that transformation stresses are relieved by deformation twinning. When this happens, most of the lattice strain is then restricted to the monoclinic/matrix interface. Micro-cracks can be formed at this matrix/monolithic interface or in the monoclinic particle if this lattice strain increases. The twinning found in monoclinic is caused by deformation twinning, as the researchers have observed using TEM that a section of the st rain related with the transformation happens as a result of a mechanism known as slip. (3) The phase transformation particularly from tetragonal to monoclinic is of great importance, as it attributes the zirconias excellent properties. [from fulltext.pdf] It was firstly discovered by Garvie et al that the transformation of metastable tetragonal phase to monoclinic phase acts as a toughnening mechanism to crack propagation resistance in zirconia. The transformation is quick and results in a 4 to 5 percent increase in volume which leads to formation of micro-cracks and eventually macro-cracks in the material. This process induces compressive stresses and thus toughens the materials. Gupta et al backed this theory up. Studies showed that the transformation mechanism is highly dependent on grain size and by doping the ceramic material with stabilisers. Examples of stabilisers are yttria (Y2O3), magnesia (MgO), calcia (CaO), etc. Y-TZP ceramics is in the family of these toughened materials. Tetragonal zirconia doped with Yttria (Y-TZP) has great strength of over 1000MPa and tou ghness weighing between 6 and 10 MPa.m1/2. This makes it an ideal contender in medical applications, particularly in hip joints. ZrO2 Y2O3 The phase diagram shown in figure 3 was firstly discovered by Scott (1975), this study was agreed and used by many more researchers. The tetragonal phase field is the main aspect of figure 3. It shows that up to about 2.5mol% of Yttria can be produced in solid solution in addition with the low eutectoid temperature leading to the formation of a fully tetragonal ceramic, this will happen as long as the grain is of an appropriate size. The theory of transformation toughening produced some excitement in the materials industry however this excitement came to a halt when Kobayashi et al discovered a flaw in Y-TZP ceramics. Y-TZPs undergoes low temperature degradation during ageing at temperatures ranging from 100 to 4000C, this is particularly enhanced when it is exposed to water or is in humid environments. This degradation is due to the formation of flaws such as micro-cracks and macro-cracks (mentioned earlier) at the surface which gradually goes into the bulk of the material. These flaws are due to the spontaneous transformation from tetragonal phase to monoclinic phase. Material scientists have documented literature regarding the degradation however there have been contradictory views as to the mechanism of this phenomenon. Figure 4 is a graphshowing the low temperature degradation of different types of TZPs. Figure 5 shows ageing temperature against surface monoclinic levels. Some of these researchers focused on the interaction between water (or water vapour) and YTZP, whilst others focused on ways to prevent this from happened. Sato et al came up with a theory where the hydroxyl group from water (H2O) reacts with zirconia from the bonds between zirconia and oxygen (that is Zr-O-Zr bonds) forming Zr-OH bonds at crack tips. This accelerates the rate at which the metastable tetragonal phase transforms to monoclinic at low temperatures. They came up with the conclusion that there is a strain which stabilizes the tetragonal phase, however under certain circumstances it is released and with the combination other pre existing flaws accelerates the transformation. The theory put forward by Yoshimura et al is similar to that of Sato et al in the sense that the Zr-OH bonds are also formed. However, the reaction process which leads to the same outcome is what differentiates the two theories. Their research showed a comparison of the transformed monoclinic phase to the untransformed tetragonal ZrO2. Hydroxyl (OH-) was in the monoclinic ZrO2 whereas there was no trace in the latter. Due to their findings, they came up with the theory that the degradation process occurred in stages: upon exposure to water, Zr-OH bonds are formed as a result of H2O being adsorbed on the YTZP surface. This creates a stress site which builds up as the OH- ions diffuse through the surface and lattice causing the formation of nucleation sites for the phase transformation. This occurs until the stress reaches crack level causing the transformation to occur at the surface leading to the formation of micro and macro cracks all the way through to the bulk. Lange et al [7] witnessed ÃŽÂ ±-Y(OH)3 crystallites of about 20 50 nm in size forming and came up with the idea that the hydroxide formed creates a monoclinic nuclei by removing Yttria from the grains of the tetragonal phase on the surface. As Yttria is being withdrawn, growth of the nuclei continues until a critical size where it will grow spontaneuously, leading to the transformation of tetragonal grains to monoclinic. Micro cracks and macro-cracks begin to occur as the transformed grain gets large enough. This process happens over and over again as the micro and macro-cracks act as a site for water molecules to penetrate into to the grains. This process occurs only if the grains are larger than the critical size. However, if they are smaller, the transformation will be influenced by the diffusion of Yttria on the surface. Other researchers such as Winnubst and Burggraf support this theory, as they found traces of Yttria on surface layer of the YTZP specimen. Their specimen was exposed to temperature of 1770C in a nitrogen environment for over 5hrs and using an auger electron microscope, they found a yttrium rich surface layer. The listed theories were based on YTZPs mechanism during degradation. Whalen et al identified that the reason for this degradation is the spontaneous transformation from tetragonal phase to monoclinic phase at the surface which then eventually spreads to the bulk. They came up with the idea of stabilising the tetragonal phase. This could be done by either of the following two methods: the chemical factor which is increasing the stabiliser content on the surface or the microstructural solution which is reducing the grain size at the surface. The latter was decided upon and this was done by the process of post sintering grinding followed by annealing treatment. 2.45mol% Y2O3/ZrO2 was the material involved in the research. Samples of the material were made using isostatic pressing at pressure of 275MPa and then sintered at a temperature of 15000C for a time period of 2hrs. A 2mm disk was formed of which its two sides had different surfaces treatments, One side being polished and the other being surface grounded. The phase compositions at surfaces were then examined using XRD. The XRD result indicated there was a significant difference in the phase composition of both sides. The ground side showed little transformation change whereas there was 50% increase in monoclinic phase after annealing. This provided evidence that the ground and annealed surface hindered the process of phase transformation from tetragonal to monoclinic at the surface. As a result of this, there were no micro-cracks formed at the surface and hence the expected mechanical properties were achieved. Talk and compare it to mine later (TEM as oppose to XRD, advantages of process) The aim of this project is to provide evidence (if any) of the occurrence of refined grains (recrystallization) in Y-TZP structures as a result of deformation. The ideology used to explain the concept of recrystallization in metals can be used to explain its occurrence in ceramics as this is a new phenomena in the ceramic industry. Grain refinement requires certain conditions in its exposure in polycrystalline ceramics and they are: plastically deforming the material (as a result of applying a stress) and followed by heat treatment. Deformation is basically a change in body shape which occurs as a result of an applied force. Materials may experience either elastic which is impermanent deformation that upon the release of an applied stress is recovered or plastic deformation which is permanent deformation that is non recoverable when a stress is applied. YTZPs recrystallization behaviour can be explained by its ability to plastically deform. The stress and strain behaviour of a material is used to determine the start and the degree of plastic deformation. Figure 6 shows an example of a typical stress and strain curve. Yield tensile strength is the point at which elastic deformation ends and the material begins to plastically deformation. Most polymers and metals undergo elastic followed by plastic deformation but this is not the case for ceramics. They undergo elastic deformation followed by fracture with little or no plastic deformation. YTZP has superplasticity properties and this nature can be used to explain refinement in its microstructure. Plastic deformation is governed by the movement of large numbers of dislocations. Hindering dislocation motion will increase a materials strength. Ceramics are inorganic materials held together by both ionic and covalent bonds. The bonding combination results in hindering the motion of dislocations, hence their high strength but brittle behaviour. Dislocation is an important factor in understanding plastic deformation and so certain elements need to be examined in order to understand the concept. Most materials comprise of an arrangement of atoms referred to as a crystal structure (these can either be single or polycrystalline that is having multiple crystals as the name suggests). This project will focus on polycrystalline zirconia, however understanding single crystals help in explaining the behaviour of polycrystalline materials. All crystal structures have flaws that distort the regular arrangement of the atoms. These flaws can either be point defect (that is they may have vacancies or interstitials), surface, line (dislocations) and volume defects. The activities and effects of all these flaws are interconnected thus the importance in the need to understand them. As the dislocations move, they tend to interact with one another however this interaction is a complex as an amount of dislocations (rephrased from pdf). The collective motion of dislocations leads to gross plastic deformation. http://composite.about.com/library/PR/2001/blmpi1.htm Dislocations can either be screw, edge or a hybrid of both. Edge dislocation: in this dislocation, the line of defect is parallel to the shear stress. The dislocation movement is similar to that of a caterpillar in the sense that the motion is in small amounts at a time. Figure 7shows a typical schematic of the motion of dislocations. A is the extra half plane of atoms. As shear stress is applied, the bond between the upper and lower part of B is broken. The extra atom plane of atom A bonds with the lower part of B converting the lower part to an extra half plane. This motion causes the top half to move with respect to the bottom half. Screw dislocation: this is similar to that of edge in the sense that it also occurs with shear stress however, the defect line is perpendicular to the shear stress as oppose to being parallel. Just like the edge dislocation only a minute fraction of bonds are broken at a given time. Although the motions are different, the overall plastic deformation for both dislocations is the same. The primary mechanism that causes plastic deformation in crystals is called slip. As dislocations move across the crystals, they shear the crystals along their planes of motion. Slip System The degree of ease of motion of dislocations is different with in all crystallographic directions and crystallographic planes of atoms. Normally dislocation motion occurs in a preferred plane and within that plane there are specific directions at also which it occurs. The combination of the plane and direction is referred to as a slip system. The plane at which this motion occurs is referred to as slip plane, and the direction is referred to as slip direction. The slip system depends on the crystal structure of the material. Slip will only occur when the value of applied the shear stress exceeds a certain critical value. The mechanism at which slip occurs is different in single crystals that of polycrystalline materials. Schmid defined the critical shear stress in single crystals as shown in figure 9: Deformation is much more complicated in polycrystalline materials as the crystallography orientations of numerous grains have to be taken into account. This orientation is random and therefore causes the direction of slip to vary from one grain to another. Its complexity extends further more to the grain boundaries which acts as barriers to dislocation motion. Twinning is another mechanism at which plastic deformation can occur. The idea of twinning in plastic deformation is to allow further slip to occur by producing changes in plane orientations. It occurs when a fraction of the crystals adopts an orientation that is correlated to the orientation of the rest of the untwined lattice in an exact proportioned way. Figure 10 shows an illustration of an un-deformed crystal with one undergoing slip and twinning. There is a clear difference between slip and twinning. The crystal orientation in a slip is the same above and below the slip plane whereas in twinning differs across the twin plane. More differences is illustrated in figure 11 Slip Twinning Where it occurs Widely spread planes Every plane of region is involved Occurrence On many multiple slip systems simultaneously On a particular plane for each crystal Time required Milli seconds Micro seconds Size (in terms of inter atomic distance) Multiples Fractions. ANNEALING PROCESS LEADING TO RECOVERY, RECRYSTALLIZATION AND GRAIN GROWTH Annealing is a high temperature process that causes changes in a materials structure, leading to alterations in its properties. When a material is plastically deformed, majority of the energy is dissipated as heat, but a minute fraction is stored in the material as strain energy which is associated with a range of lattice imperfections established as a result of deformation. The deformation process as well as a number of various factors (such as temperature and rate of deformation) determines the amount of energy stored in the material. A reduction in deformation and an increase in intensity of deformation cause a vast increase in the amount of retained energy. The release of stored energy There are two main techniques of releasing the energy retained by a material due to plastic deformation and they are an-isothermal annealing and isothermal annealing. Anisothermal annealing occurs when the material is continuously heated from a lower temperature to that of a higher one (the energy discharged is determined as a function of temperature) whereas, Isothermal annealing occurs when the temperature is constant. The materials microstructure will undergo either or maybe all of these three restoration processes: recovery, recrystallization and grain growth. The extent of plastic deformation can sometimes determine the mechanisms of recovery and recrystallization. These processes require heat treatment to cause rearrangement of grain boundaries and dislocations. Recovery It is the initial stage of annealing that takes place at the low temperature stage of annealing. As a material is plastically deformed, a minute portion of mechanical energy is stored which exists in crystals as stacking faults, point defects (such defects are interstitials and vacancies) and dislocations. When a material is plastically deformed, it is at a thermodynamically unstable state of higher energy. This is converted to lower energy states by the application of annealing leading to a change in microstructure. There are two process involved in recovery: slip annihilating and polygonization. Slip annihilation occurs when dislocations of opposite signs (that is in the case of edge dislocations, the fusion of the positive and the negative edge dislocation or in the case of screw in which the right hand screw merges with the left hand screw) merge together thereby cancelling each other out. Polygonization is the rearrangement of dislocation after annihilation recovery to a lower energy configuration. During recovery, this strain energy built up is relieved to some extent by dislocation motion, due to enhanced atomic diffusion at high temperatures. Recovery leads to physical properties like thermal and electrical conductivities being recovered to their pre worked states. [ggbk] Recrystallization After recovery, grains are not entirely strain free. That is the energy state of the grains is relatively high. New sets of strain free grains having near equal dimensions in all directions with low dislocation densities are formed. This process is known as recrystallization. This mechanism of producing new equaxed grains is driven by the difference in internal energy between the unstrained and strained material. The process of recrystallization can occur after or during deformation. The manner at which recrystallization occurs is of two kinds which vary with materials. Firstly a continuous manner, at which the microstructure gradually evolves into a recrystallized one or a discontinuous manner at which distinct new grains nucleate and grow Recrystallization after deformation is referred to as static whereas the latter is known as dynamic. The extent at which recrystallization occurs is dependent on two factors namely: time and recrystallization temperature. The temperature at which recrystallization is completed in an hour is referred to as recrystallization temperature. It is usually a third to half the materials melting temperature. The rate at which recovery process occurs is inversely proportional to time (that is it reduces with increasing time). Recrystallization has an entirely different kinetic. During the isothermal annealing, recrystallization starts very slowly then builds up gradually up to a certain point where it slows down. This can be shown in figure 13 In some cases it can be as high 0.7th the melting temperature. An illustration of the relationship between recrystallization temperature and percentage cold work is shown in figure 14. It is understood that as the percentage cold work increases, the recrystallization temperature decreases. Other factors affect the rate and occurrence of recrystallization. The annealing temperature is one of a few factors that have an effect on recrystallization. A materials recrystallization temperature reduces annealing time. The stress applied is another factor both recrystallization and temperature, an increase in stress applied means a lower temperature is required to activate the process. Also, the deformation on the material must be enough to allow nucleation and growth. A process known as grain growth occurs in a polycrystalline material after recrystallization provided the annealing temperature is maintained. The restoration mechanism does not require prior deformation or recrystallization and therefore will occur during annealing in their absence in a polycrystalline material. Grain boundary is the driving force for recovery. Stored energy produced as a result of a material being plastically deformed is released during the process of annealing causing a change in microstructure. This energy released is as a result of various mechanisms due to crystal defect interactions: A decrease in crystal defects due to their reactions with each other. Dislocations with opposite signs interacting causing their annihilation and dislocation loop shrinkage. Relocation of dislocations causing the formation of lower energy configurations such as grain boundaries with low angles. The formation of grain boundaries with high angles. These reactions occur during the restoration process of recovery. After this process, the following can occur: Dislocations as well as point defects being absorbed as a result of the migration of high angle grain boundaries. A decrease in the overall grain boundary area. These micro-structural changes occur during the restoration process of recrystallization and recovery. As a result of these micro-structural modifications, an ideal definition of recrystallization is derived: Along with the micro-structural changes, the properties of the specimen also change correspondingly. Thus, deformation and annealing are important processing methods for producing desired properties of the material by controlling its microstructures. Recrystallization mechanism The start of recrystallization is referred to as nucleation and occurs when dislocations are rearranged so as to form low dislocation density sections that have a high angle grain boundary with great mobility and thus is capable of quick movement over the strained region or recovered matrix. Recrystallization has a low driving force and high grain boundary energies; as a result of these characteristics, thermal variations cannot explain regions surrounded by high angle grain boundaries that are free from defects upon annealing. Therefore, the formation of recrystallized grains does not occur during annealing but previously exists in the deformed state. Three methods can be used to describe nucleation and they are: Movement of high angle boundaries that already exist before annealing: this happens when pre existing grain boundaries move into grains that are highly strained as illustrated in figure 16 this process requires a favourable energy balance between an increase in the overall grain boundary surface and a reduction in stored energy as a result of the removal defects triggered by the migration of the boundary. Movement of sub boundaries (that is low angle boundaries): this model is based on the theory of polygonization where stored energy is reduced during annealing as a result of rearrangement and removal of defects. It occurs when sub grain boundaries besiege regions containing low dislocation densities. Upon formation of sub grains, with the help of sub grain boundary movement, they are able to grow at the expense their neighbouring grains. Dislocations are absorbed by migrating sub boundaries and because of this, their mobility, orientation differences and energies are increased until their transformation into high angle boundaries, thus illustrating nucleation. Sub grains coalescence: this occurs when two neighbouring subgrains merge leading to their crystal lattices coinciding. It is regarded as a slow process but when compared to migration of sub grains is favoured for annealing at low temperatures. it is illustrated in figure 17. In this method, stored energy is reduced leading sub boundaries disappearing, sub grains growing and increase in orientation differences between coalescence groups and their neighbouring sub grains. These lead to the formation of high angle boundaries which move at high speeds and cause the process of recrystallization nucleation. It is vital to identify the fact that the total energy balance that takes the disappearance of sub boundaries into account with the increase and orientation difference is favourable (that is it leads to a reduction in total free energy). This mechanism is illustrated in figure 18. The occurrence of these three models is relatively diverse and they will therefore occur under different conditions. The basic requirement for the occurrence of the movement of pre existing grain boundaries that is the existence of differences in large strain between neighbouring grains is well accepted by researchers. However, there is conflict as to when the mechanisms sub grain boundaries migration and the coalescence of sub grains occur. Researchers believed the coalescence of sub grain boundaries are linked with large dispersion of sub grain angles distribution, relatively moderate strain, and reasonably low annealing temperatures. Whereas the mechanism of sub grain migration is linked with high annealing temperatures, strains that are relatively high and large dispersion in the distribution in sub grain size. Growth of recrystallized regions The basic mechanism causing recrystallization and grain growth is the migration of grain boundaries with high angles. However their driving force is what differentiates them from each other. The energy of the high angled grain boundaries is the main driving force for grain growth whether it being abnormal or normal growth. Whereas that for recrystallization is the energy stored during straining appeared as crystalline defects. In defect free regions that are encircled by boundaries with high angle, recrystallization progresses by enlargement of this nucleus over the non recrystallized medium. Grain growth and recrystallizations migrating high angle boundary curvature signal is another important factor that differentiates the two. http://asmcommunity.asminternational.org/portal/site/www/AsmStore/ProductDetails/?vgnextoid=a75a7dcbe4e18110VgnVCM100000701e010aRCRD ASM Handbook Volume 14A, Metalworking: Bulk Forming (ASM International) http://www.accuratus.com/zirc.html http://www.totaljoints.info/ceramic_for_total_hips.htm#2 http://www.azom.com/details.asp?ArticleID=940 http://books.google.co.uk/books?id=eUZw4SgqaPYCpg=PA126lpg=PA126dq=phase+transformation+mechanism+leading+to+microcracks+zirconiasource=blots=fCFhf-satfsig=WNiOjbUtX06mA_d1NkXIEEHcOsshl=enei=r568S9zCKJHFsgaxkd3lCQsa=Xoi=book_resultct=resultresnum=4ved=0CBYQ6AEwAzgK#v=onepageqf=false EXPERIMENTAL PROCEDURE Equipment Three samples of YTZP, 0ne made from 3mol Y2O3/ZrO2 powder and the other two made from the same powder but by two other manufacturers. Focused Ion Beam (FIB): is a technique used by material scientists in the analysis of a materials microstructure. the samples obtained can either be analysed directly using the FIB or transferred and viewed under a TEM or SEM. This process is similar to that of an SEM however ions (particularly gallium ions) rather than electrons. Figures 19a and b show how the FIB operates. The surface of the sample being tested is subjected to primary gallium ion beams. This spits a small part of the material, leading to the formation of either secondary ions (either positive or negative) or neutral atoms on the surface. Secondary electrons (e) are also produced from the gallium beam. This is collected as well as the signal from the split ions to form an image which is either analyzed using the FIB itself, SEM or TEM. http://www.fibics.com/fib/tutorials/introduction-focused-ion-beam-systems/4/ images is from here. GNU image manipulation program (GIMP): is an image editing software used to measure grain sizes. Vickers indentation: is used to form indentations which are viewed and studied under an optical microscope. A square imprint is formed from the Vickers indenter, where the two diagonal lengths are measured. In this project, the Vickers indentation is used to form plastic deformation. The surface defects such as scratches and unevenness need to be controlled, hence the reason for polishing. High temperature furnace: used for sintering and annealing. TEM Cold isostatic pressing Sample preparation Three mol% Y2O3/ZrO2 solid solution powder was used in this experiment. The powder was pressed into a disc at 200MPa, then sintered at 14500C for 2 hours. Two discs were produced, each pressed with loads 7.5 tons and 5 tons respectively. The load was reduced to 5 inorder to reduce the chance of lamination, as it occurred with the 7.5. Measurements and dimensions Sample 1: broken Sample 2 Weight 25.7711g 19.6836g Diameter 39.23 39.11 Height (thickness) 7.1 6.51 Dimensions after sintering<

My Miracle :: Personal Narrative Writing

My Miracle "Dad, I need to go to Hailey's to borrow a shirt for school tomorrow," I shouted from the back room. It had been a hard week for me. My cheerleading squad was preparing for a performance, and we had been practicing before and after school. While I waited for an answer from my dad, the game show, "Who Wants to be a Millionaire," sounded in the background. "Dad, I am going to run to Hailey's real quick," I repeated my shout. A reply came: "It's snowing pretty hard, wait for my show to end and I will take you. I am on my way to the store anyway." I looked out the window to see snow coming down pretty heavy. On any other day, I would have argued to leave right away, but for some reason I didn't argue. Ten or fifteen minutes later, however, I decided I really needed to go. I said, "Mom just take me, I have a lot of stuff to do tonight." My mom said she didn't want to drive on the bad roads. "Wait for your dad," she told me. So I waited. Finally, the show ended and we were on our way out the door. The roads were slippery and the snow was coming down hard. I looked out the windows of the car and in my mind, I heard my mom reminding me to slide the seat away from the dashboard. I chuckled to myself that a seventeen-year old would be too small to sit with an airbag, but I was. As I slid the seat back, my dad asked, "Cara is your seat belt on?" I fastened my seat belt and stared at the snow. It was a peaceful night; it felt quiet and serene. It felt good to have a few minutes of alone time with my dad. We were lost in conversation, and before I knew it we were in front of Hailey's house. I ran in and waved goodbye to my dad. I found the shirt I wanted, and played a game with Hailey and her sisters while we waited for my dad. We joked about my mismatching outfit that consisted of doctor scrubs, a football sweatshirt, and snow boots. While we were laughing, I noticed the headlights in the driveway and hurried out. I excitedly explained the game we had played to my dad as we drove away from Hailey's house.

Impact of Race in Othello Essay -- GCSE Coursework Shakespeare Othello

Impact of Race in Othello One of the major issues in Shakespeare's Othello is the impact of the race of the main character, Othello. His skin color is non-white, usually portrayed as African although some productions portray him as an Arabian. Othello is referred to by his name only seventeen times in the play. He is referred to as "The Moor" fifty-eight times. Webster's Revised Unabridged Dictionary (1913) states that a Moor is "Any individual of the swarthy races of Africa or Asia which have adopted the Mohammedan religion. In Spanish history the terms Moo, Saracens, and Arabs are synonymous." This indicates that Othello is constantly being degraded and set up as an evil person throughout the play. What this really means is that Othello is being judged by his skin color rather than the person under the skin. The view that whites and non-whites are equal is a relatively new concept in our society. In institutionalized racism, such as American slavery, those of a different color were often viewed as inferior. As Shakespeare wrote Othello, this idea was becoming quite prominent as England entered the African slave trade. One can look at the racial issues from the perspective of color, slavery, and society. There are many references in the play to indicate that Othello was dark colored. The first image we, as a reader, are given of Othello is that of a black ram having sexual relations with Desdemona (1.1.89-90). Later on in the play, there are many other references to Othello's color and race. Desdemona's father, Brabantio, is appalled to learn that his daughter is having a relationship with a "sooty bosom" (2.3.27). Emilia refers to Othello as a black devil (5.2.132). Othello even calls himself black (3.3.265). Iago also... ...hello is driven mad by the force of Iago's suggestions, indicating that he is merely a victim of another man's jealousy. Works Cited 1 Norman Sanders, ed. Othello. Cambridge: New York, 1995: 12. 2 C. W. Slights. "Slaves and Subjects in Othello," Shakespeare Quarterly v48 Winter 1997: 382. 3 C. W. Slights. 380. 4 Norman Sanders, ed. 10. 5 J. Adelman. "Iago's Alter Ego: Race as Projection in Othello," Shakespeare Quarterly v48 Summer 1997: 130. 6 C. W. Slights. 388. Works Consulted Bradley, A. C.. Shakespearean Tragedy. New York: Penguin, 1991. Di Yanni, Robert. â€Å"Character Revealed Through Dialogue.† Readings on The Tragedies. Ed. Clarice Swisher. San Diego: Greenhaven Press, 1996. Reprint from Literature. N. p.: Random House, 1986. Muir, Kenneth. Introduction. William Shakespeare: Othello. New York: Penguin Books, 1968.   

Francis Bacon and Plato Essay

The arguments presented by both Francis Bacon and Plato both call for different approaches in pursuing knowledge. In doing this, one must be accurately point out the important facets present in each argument and deduce what style is appropriate for an individual’s use. Looking at Francis Bacon’s arguments, it can be said that he is focused on the progression of ideas that will lead to the acquisition of knowledge. However, the ‘form’ that Bacon advocates differs to the original meaning proposed by Plato. He further advocates that the ‘form’ must be attained to gain knowledge. As long as man continues to strive for the form, knowledge will soon follow. On the other hand, Plato’s dialogue focuses on the way knowledge is achieved through the process of remembering the past. Socrates used this analysis in checking the validity of such argument. He makes a philosophical connection between knowledge and virtue. Thus, it has been contended that knowledge is virtue – creating the possibility of teaching. Seeing the two approaches in a nutshell, I believe that there must be a collaborative consensus between the two theories. It may be true that we must constantly strive for the form that Bacon advocates and at the same time use natural forces and mechanisms that can help achieve knowledge. However, Plato’s arguments can also shed some important light in the analysis of obtaining knowledge. But seeing that I must choose between the two, the argument presented by Francis Bacon I believe presents a more valid approach. I believe my answer is correct since believe that man continues to struggle for existence. Man continuous life depends on each one’s ability to grasp knowledge through mechanisms and processes that will help each one to survive. The different laws that govern us remain to be manifested and shown. The tendency of man to move forward and accept challenges should be the case. This is contrary to the view of Plato that one must look back to gain knowledge. In conceiving a central purpose in human life, there must be a conscious effort by an individual for continuous development to cope with the changing times. In my own perspective, I feel that the central purpose of living a life is continuous learning by acquiring knowledge and experiences that will benefit my individual growth as time passes. This event can only take place if the individual is continuously aware that he/she has the capability of shaping his/her personality. Looking at this, it can be argued that there are several characteristics of a well-lived, fulfilling life. In my own opinion, a well-lived fulfilling life must create opportunities for each individual to constantly struggle and be victorious. This is because for every success and failure in a struggle, certain inputs are obtained by an individual. These are experiences distinct only to individuals which foster the creation of knowledge. Another characteristic is that individuals must constantly strive for their betterment. We do not become stagnant and a waste in the society and community. Another characteristic of knowledge is that it can create a degree of completeness to an individual. By gaining knowledge, the questions that men aspire can be answered or attained. The pursuit of knowledge is attaining these purposes because of knowledge capability to raise and increase the quality of thinking by individuals. Continuity is thus necessary in creating the environment for knowledge for individuals. In addition, by gaining knowledge, we expand our purpose and existence. It may be known that during our conception, the only thing we cater is our own. But as we continually grow in age and maturity, the levels of understanding and knowledge extend not only in scope but also each one’s abilities. In the end, knowledge gives individuals the opportunity to explore more what life has to offer.