Drinking As A Social Problem In College Essay Example

Drinking As A Social Problem In College Essay Example Drinking As A Social Problem In College Paper Drinking As A Social Problem In College Paper Essay Topic: College The problem of drinking among the youth shows no sign of slowing down, according to the 2004 Substance Abuse and Mental Health Services Administration. More and more students are drinking after school and most of these are students under age 16. This paper states that alcohol drinking must not be lowered to 18 because primarily, it serves as a gateway to drugs, as alcohol has been linked to substance abuse. This is the reason there is wisdom in keeping the minimum drinking age at 21. In fact, lowering the minimum age to 18 years old during the late 1960’s and early 70’s by some states proves to be a mistake. During that period, the states saw a sudden rise in vehicular accidents involving youths. Consequently, when the minimum age was changed to 21 years in the 1980’s, teen vehicular deaths dropped by as much as 28 percent. Therefore, it is important to restrict access to alcohol to those who are over 21 years of age, along with strict implementation of existing laws. This will all the more prove that this regulation can save lives in a manner that is both effective and inexpensive. (National Institutes of Health News, 2004). Drinking alcohol should remain at age 21 and should not be lowered at all. One of the major culprits here is the presence of television commercials which have been designed to lure the youth to drink because of the status symbol that it creates. Often the image it creates is that of young people who figure in an accident or of people who have difficult hangovers the next day. Primary culprit in this problem is mass media. It is unfortunate that the alcohol industry uses all kinds of advertisements so that the young drink at a very young age. This is even made more enticing because of the peer pressure that young people undergo from their friends who drink. A sense of purpose and a strong determination will stop a person from following the habits of his friends. One reason why drinking alcohol must be restricted to adults who are 21 and above is the fact that there have been studies by the Substance Abuse and Mental Health Services Administration that say that adolescents who drink heavily can get the same long-term health risks of the adults who also drink heavily. Health wise, these young people develop a lot of diseases even if they are still young. These are illnesses such as pancreatitis, hemorrhagic stroke, cancer and some forms of cirrhosis of the liver. The statistics on health are alarming. Alcohol is able to destroy the central nervous system and shrinks the brain tissue causing it to be permanently damaged. Even animal studies demonstrate that young brains are vulnerable to the dangerous effects of alcohol, especially on learning and memory function (Substance Abuse and Mental Health Services Administration, 2004). The Task Force on Community Preventive Services says that the process of maintaining and implementing an age 21 minimum legal drinking age (MLDA) are based on the strong evidence of effectiveness which includes a median of 16% decrease in the motor vehicle accidents (Shults, 2001). It is important that people understand the excessive consumption of alcohol contributes to a staggering 4,600 deaths among those young people who are the underage youth who are persons less than the 21 years of age in the United States (CDC. Alcohol Related Disease Impact). Even the Task Force on Community Preventive Services says that the process of maintaining and implementing an age 21 minimum legal drinking age (MLDA) are based on the strong evidence of effectiveness which includes a median of 16% decrease in the motor vehicle accidents (Shults, 2001). The statistics of students drinking, particularly the young ones who do so before they are 21, can be a real cause of alarm. Today, the facts speak for it- the US seems to be one of the countries that have one of the highest drinking age limits. The current legal drinking age is set to 21 and this most welcome move for the advocates and conservative people. Whatever good thing that was presupposed by several authorities before regarding the drinking age, it seems that the ones who are being affected seem to think otherwise. The different binges convince authorities that students will just go and follow their own rules by buying alcoholic drinks disregarding the rule about it (Hanson). Researches reveal that six youths will die every day in non-driving alcohol-related causes, such as homicide, suicide, and drowning. These little horrors happen every day, every year. It would be tempting to shrug off drinking among students done secretly or within the school proximity as a rite of passage, but cold, hard statistics point out that it is not so. Students who experiment with alcohol are guaranteed to use it. In a study conducted by the National Center on Addiction and Substance Abuse at Columbia University in 2003, it was found out that high school seniors who tried alcohol-even those that tried once, about 91. 3 percent are still drinking by the 12th grade (Substance Abuse and Mental Health Services Administration, 2004). Disturbingly, of the high school students who have ever been drunk, 83. 3 percent or over two million youths are still getting drunk by the 12th grade and individuals who begin drinking before the age of 15 are four times more likely to become alcohol dependent than those who begin drinking at age 21. The same study makes it clear that teen drinking is the number one source of adult alcoholism. We may think that drinking is glamorous. Indeed the media bombard us with advertisements that portray it so. Often the image it creates is that the worst thing that can happen to us is a raging hangover. The stark and appalling reason for this is the alcohol industry uses advertisement that appeal to the youth, as most heavy and problem drinkers begin drinking before they reach age 21. This is aggravated by peer pressure as youths who have friends who drink, also take it at an earlier age. Nevertheless, high self-esteem, self-discipline, impulse control, and a sense of purpose enable youths to withstand peer pressure. Yes, these characteristic takes guts, but nevertheless, true character is made. There had been studies about the continuing effects of drinking alcohol and this was revealed by the National Center on Addiction and Substance Abuse at Columbia University in 2003. It was seen that high school seniors who tried alcohol-even those that tried once, were still drinking when they reached the 12th grade. This is an alarming 91. 3 percent. More than this, of the different high school students who have already started drinking even before they reached the age 18, are four time more likely to become alcohol dependent than those who begin drinking at age 21. This also emphasizes the point that teen drinking is the main cause of adult alcoholism. These young people already make a habit of drinking and this is continued as they grow old. Indeed, young people are drinking more. It is said that the average amount drunk by 11-15 year olds in 1990 was 0. 8 units per week rising to 1. 6 units in 1998. It is said that the average amount drunk by teenagers who are 11-15 year old in 1990 was 0. 8 units per week and was still increasing to 1. 6 units in 1990 (Alcohol Concern. Young People’s Drinking Factsheet 1). What is even alarming again is the fact that young people tend to select the stronger brands of beer, cider and lager. The end goal is to find the association of drinking with â€Å"here and now† cognitive problems in short-term and internally cued prospective memory as well as long-term memory problems, which are more related to storage and retrieval difficulties. A possible solution to this is to include increased alcohol excise taxes and also to limit alcohol outlet density, limiting the exposure of youth to alcohol marketing (Bonnie RJ, O’Connell ME, 2004). Indeed, the gut truth is that the use of alcohol is frightening. According to the Substance Abuse and Mental Health Services Administration, adolescents who drink heavily assume the same long-term health risks as adults who drink heavily. This means they are at increased risk of developing cirrhosis of the liver, pancreatitis, hemorrhagic stroke, and certain forms of cancer. Studies also show that alcohol depresses the central nervous system and shrinks the brain tissue, causing permanent damage. Furthermore, animal studies show that young brains are vulnerable to dangerous effects of alcohol, especially on learning and memory function. More in-depth studies are needed to verify if these or other factors are responsible for greater cognitive decline in smokers. The different laboratory studies are able to show confounding variables, although this can be a problem in cases where there is too much control, as the traditional processes involved in prospective memory will not be activated and one cannot be sure that the results obtained would have occurred in real life. References Alcohol Concern. Young People’s Drinking Factsheet 1. Accessed March10, 2009 at: http://72. 14. 235. 132/search? q=cache:kO5u04-P2DQJ:www. alcoholconcern. org. uk/files/20040706_145136_young%2520people%2520factsheet%2520-%2520updated%2520March%25202004. pdf+drinking+alcohol+by+young+peoplehl=tlct=clnkcd=1gl=ph Bonnie RJ, O’Connell ME, eds. Reducing underage drinking: A collective responsibility. Washington, DC: The National Academies Press; 2004. CDC. Alcohol Related Disease Impact (ARDI). Accessed March10, 2009 at: http://apps. nccd. cdc. gov/ardi/Homepage. aspx. Hanson, D. The Legal Drinking Age Science vs. Ideology. Accessed March10, 2009 at: http://www2. potsdam. edu/hansondj/YouthIssues/1046348726. html National Institutes of Health News (2004). Alcohol Abuse Increases, Dependence Declines Across Decade. Accessed March10, 2009 at: nih. gov/news/pr/jun2004/niaaa-10. htm National Center on Addiction and Substance Abuse at Columbia University. February 2002. Rev. ed. February 2003. Teen Tipplers: Americas Underage Drinking Epidemic. 155 pp. Retrieved March10, 2009 at: http://camy. org/research/underage2004/ Quick Stats. Age 21 Minimum Legal Drinking Age. Quick Stats. Age 21 Minimum Legal Drinking Age. Retrieved March10, 2009 at: cdc. gov/Alcohol/quickstats/mlda. htm Shults RA, Elder RW, Sleet DA, Nichols JL, Alao MO, Carande-Kulis VG, Zaza S, Sosin DM, Thompson RS. Task Force on Community Preventive Services. Reviews of evidence regarding interventions to reduce alcohol-impaired driving. Am J Prev Med 2001;21(4S):66–88. Substance Abuse and Mental Health Services Administration (2004). The National Survey on Drug Use and Health Report 2004. Accessed March10, 2009 at: oas. samhsa. gov/2k4/ageDependence/ageDependence. htm Substance Abuse and Mental Health Services Administration. â€Å"n. d. † Youth and Underage Drinking: An Overview. Department of Health and Human Services. Accessed March10, 2009 at: health. org/govpubs/RPO990/default. aspx

Internal Controls Essay Example | Topics and Well Written Essays - 250 words - 2

Internal Controls - Essay Example Significantly, the company has been marred will intolerable control environment. The management has failed to enhance effective communication leading to the adverse change in attitude among employees. In addition, the company has failed to identify inadequacies that pose a significant risk of loss and inaccuracies in the financial management department. According to the audit conducted in the year 2013 (Farewell, Byron 117), SONY Company has not been conducting regular assessment of its internal control system and hence the management may fail to detect a fault in good time. Furthermore, failure to conduct a regular assessment will make some of the control system obsolete leading to huge losses. An effective control system should focus on diligence and effective communication that is geared toward changing employee’s attitude towards the control system. (Susan 543) declares that the control system should be regularly examined and updated to reduce the risks emanating from obsolete technology. In this case, the control system should be several strands ahead of the technology used by fraudsters and dishonest employees. Risk reviewing and monitoring should be highly regarded. In this case, the management should constantly monitor the internal control system in order to identify areas that require advancement. This reduces the chances of incurring a material risk that would cause financial loss if it takes

Aids and hiv Essay Example | Topics and Well Written Essays - 1750 words

Aids and hiv - Essay Example HIV infection occurs by the person to person transfer of semen, blood vaginal discharge, pre-semen or breast milk. Major sources of disease transmission are unsafe sex, used needles, breast milk and transmission from mother to baby at birth (Weiss, 1993) (Douek et. al., 2009). Governments and pharmaceutical companies around the world are taking measures to fight against HIV infection. We will specifically emphasize on the role of government & pharmaceutical companies in African countries towards prevention and eradication of HIV/AIDS from masses. Heavy health budgets, quality of life and growth of economy are few of many factors that push governments around the world to invest and legislate to fight against spread of HIV infection. Corporate responsibility, social welfare and philanthropic programs are some of the incentives that drive pharmaceutical companies to push for comprehensive AIDS prevention agenda. Government & pharmaceutical companies use legislation, research grants, dru g control, awareness campaigns and enforcement strategies as tools to counter the spread of AIDS. Pharmaceutical companies and government agencies in developed world are very efficient at promoting the understanding of drug use that leads to HIV infection. Research is being done into how social behaviors promote drug-use that eventually helps in spreading AIDS due to bodily fluid transfer (Williams et. al., 2000). African countries on the other hand generally lack pro-active approach in terms of educating masses regarding the spread of HIV infection. While there are success stories in Africa that include â€Å"The Global Fund to Fight AIDS, TB and Malaria†, â€Å"The United States President’s Emergency Plan for AIDS Relief† (PEPFAR), Senegal and Uganda governmental initiatives to fight AIDS, there are also problems faced in countering the spread of AIDS. These problems include Prevalent corruption in governmental regulatory bodies Lack of political will in most of African leadership Social taboos and norms Lack of institutions and infrastructure Pharmaceutical companies trying to gain profits rather than penetration in African market With lesser amount of money and resources put into fight against AIDS due to factors stated above, a general lack of awareness prevails in most Africa nations. South African health minister, an ardent proponent of alternative medicine therapy for AIDS has been able to convince his followers into avoiding anti-retroviral drugs (an accepted primary source of AIDS treatment). Instead people lacking awareness regarding the treatment of the disease were lured to the false claims of using improved diet, or cheap generic vitamin pills as a simple and relatively inexpensive way to marginally delay the need to start HIV medication. A detailed study by Ben Goldacre, published in his book in 2009, reads out the following lines â€Å"†¦ Alternative therapists like to suggest that their treatments and ideas have not been sufficiently researched. †¦ research had indeed been done, with results that were far from promising.† (Goldacre, 2009, pp.187 – 188) Among the success stories, driven by governmental steps to eradicate the causes of HIV infection, the most noteworthy are the steps taken by Senegal and Uganda governments (UNAIDS, 1999). These include Problems regarding AIDS infection were recognized at promptly. Adequate funding was provided to fight HIV/AIDS. Difficult political decisions were taken to cater for

Evolution of Death Penalty in America Essay Example | Topics and Well Written Essays - 750 words

Evolution of Death Penalty in America - Essay Example This paper illustrates that in American death penalty history, the first execution was recorded in 1608, and the victim was Captain George Kendall in the Jamestown colony of Virginia. According to the Bureau of Justice Statistics, 3,859 persons were executed under civil jurisdiction in the United States from 1930 to 1967. During this period, nearly 54% black and 45% white were executed whereas the remaining one percent was members of other racial groups including American Indians, Chinese, and Japanese. In this period, the number of executions in the state of Georgia represented more than nine percent of the national total. As Melissa points out, the number of executions in other US cities including Texas, California, and New York were 297, 292, and 329 respectively between 1930 and 1967. In addition, the US Army executed 160 persons during the same period. In the 1960s, the fundamental legality of the death penalty was widely questioned throughout the United States. Much legal perso nnel suggested that the capital punishment was â€Å"cruel and unusual† and hence it was unconstitutional under the Eighth Amendment.   In the late 1960s, the Supreme Court restructured the way the capital punishment was administered. In 1971, the Court held that dealing with capital sentencing discretion was â€Å"beyond present human ability†; and later on the legality of the death penalty was again discussed before the Supreme Court in 1972 in landmark case Furman v. Georgia. (408 U.S. 238) (DPIC). The Court stated that since the jury had the power of complete sentencing discretion, it might result in arbitrary sentencing. On 29th June 1972, the Court held that existing death penalty statues were no longer valid and therefore, the Court voided 40 death penalty statutes, and suspended the death penalty practice in the US. The overall holding in Furman reflected that particular capital sentencing statues were only unconstitutional and it influenced the Court to rethink about the legal validity of death penalty. As a result, the Court allowed states to rewrite their death penalty statutes to abolish the issues cited in Furman. Although some stats eliminated all unguided jury discretion by mandating death penalty for those convicted capital crimes, the Supreme Court held that this practice was unconstitutional. Some other states provided sentencing guidelines for the judge, and this practice allowed the â€Å"introduction of aggravating and migrating factors in determining sentencing† (DPIC). The Supreme Court approved these guided discretion statues in 1976. The ten-year moratorium on death penalty was ended on 17th January 1977 with the execution of Gary Gilmore. Finally, the state of New York also enacted death penalty law in 1995.In response to the increasing objections against capital punish ment, the US Supreme Court has framed some strict regulations on death penalty. As Johnson (2001) points out, one of the recent developments in the state of Texas is that it passed a bill of banning the execution of mentally retarded persons. The recent death penalty cases add to the earliest Supreme Court cases addressing capital punishment. While analyzing US death penalty data, it is evident that the highest number of executions was occurred between the period 1999 and 2005. However, the recent data show that the number of executions have significantly declined during the last five years. In 2009, only 37 persons were executed and this figure represents the least number for the last decade (DPIC 2). The current Court practices show that it rarely sentences death penalty. The recent cases including Penry v. Johnson, Director, Texas Department of Criminal Justice, Institutional Division, Atkins v. Virginia, and Roper, Superintendent, Potosi Correctional Center v. Simmons are some o f the

Cassava Starch Essay Example for Free

Cassava Starch Essay Cassava (Manihot esculenta), also called manioc, tapioca or yuca, is one of the most important food crops in the humid tropics, being particularly suited to conditions of low nutrient availability and able to survive drought (Burrell, 2003). The plant grows to a height of 1 to 3 m and several roots may be found on each plant. Although cassava leaves are sometimes consumed, the major harvested organ is the tuber, which is actually a swollen root. The plant is propagated mostly from stem cuttings. A major limitation of cassava production is the rapid post harvest deterioration of its roots which usually prevents their storage in the fresh state for more than a few days (Okezie and Kosikowski, 1982). Cassava ranks very high among crops that convert the greatest amount of solar energy into soluble carbohydrates per unit of area. Among the starchy staples, cassava gives a carbohydrate production which is about 40% higher than rice and 25% more than maize, with the result that cassava is the cheapest source of calories for both human nutrition and animal feeding. A typical composition of the cassava root is moisture (70%), starch (24%), fiber (2%), protein (1%) and other substances including minerals (3%) Compared to other crops, cassava excels under suboptimal conditions, offering the possibility of using marginal land to increase total agricultural production (Cock, 1982). Plant breeders, agronomists and recently molecular biologists have made substantial improvements in cassava yields during the last two decades. While, genetic characterization and mapping has revealed some insights into the molecular nature of cassava (Tonukari et al. 1997; Fregene et al. 003) Plastics are synthetic substances produced by chemical reactions. Almost all plastics are made from petroleum, except a few experimental resins derived from corn and other organic substances. Plastic has many properties which has made it a raw material of choice for Manufactures of plastic Bags and packing materials. Cost of production, lightweight, strength, easy process of manufac ture, and availability are few of the properties. Man has simply not put the plastic to the right use/ or using it without taking proper care of other related norms of usage. The hazards plastics pose are numerous. The land gets littered by plastic bag garbage presenting an ugly and unhygienic seen. The Throw away culture results in these bags finding their way in to the city drainage system, the resulting blockage cases inconvenience, difficult in maintaining the drainage with increased cost, creates unhygienic environment resulting in health hazard and spreading of water borne diseases. This littering also reduces rate of rain water percolating, resulting in lowering of already low water levels in our cities. The soil fertility deteriorates as the plastic bags form parts of manure remain in the soil for years. People need alternative and effective components of plastic that is safe and biodegradable which will not harm and pollute the earth. Significance: This study is important to be able to help Mother Earth in reducing its pollutants and toxic or harmful wastes. Through this study, the researchers will be able to help other people, the animals and the environment. The researchers would like to stop plastic pollution and be part of the solution. Plastic bags and bottles, like all forms of plastic, create significant environmental and economic burdens. They consume growing amounts of energy and other natural resources, degrading the environment in numerous ways. In addition to using up fossil fuels and other resources, plastic products create litter, hurt marine life, and threaten the basis of life on earth. There is over 45 million tons of plastics per year and nearly every piece of plastic ever made still exists today because of its long-life properties. Biodegradable plastics could be an effective solution to all of these problems. Biodegradable plastics are a much better choice than non biodegradable plastics because they are friendlier to the earth and the environment. Biodegradable plastics break down faster, can be recycled easier and are non-toxic. With these characteristics of biodegradable plastics, we could help save lives and the environment as well and reduce the threat plastics give to marine life. Plastic, the wonder material that we use for everything, is perhaps the most harmful of this trash because it does not readily break down in nature but if it is biodegradable, these plastics break down faster so they have a much shorter effect on the earth, and they will degrade completely. Normal plastics are manufactured using oil, and this process is very harmful to the environment by polluting the air and environment, but this is not the case with green biodegradable plastics. Using biodegradable plastics will minimize the effects that these products have on the earth, and help eliminate their waste much faster. Review of Related Literature: In the past few decades, there has been a marked advance in the development of biodegradable plastics from renewable resources, especially for those derived from starch-based materials. The goal of this development is to obtain biodegradable plastics that perform as well as traditional plastics when in use and which completely biodegrade at disposal. Several starch-based plastics have been introduced into the market, and are used in some applications now. Starch foam is one of the major starch-based packaging materials. It is produced by extrusion or compression/explosion technology. This product has been developed as a replacement for polystyrene which is used to produce loose-fillers and other expanded items. Another type of starch-based plastics is produced by blending or mixing starch with synthetic polyester. For this type of biodegradable plastics, granular starch can be directly blended with polymer, or its granular structure can be destructurized before being incorporated into the polymer matrix. The type of starch and synthetic polymer as well as their relative proportions in the blends influence the properties of the resulting plastics. The last group of starch-based plastics is polyesters that are produced from starch. The major starch-derived polyesters in the market now are polylactic acid and polyhydroxyalkanoate. Experimental studies have demonstrated that cassava starch could be used for making various types of packaging products. As a major source of starch in tropical and subtropical regions, cassava is a promising raw material for the development of biodegradable plastics in these areas. Research has been done on HYPERLINK http://en. wikipedia. org/wiki/Biodegradable _blank o Biodegradablebiodegradable plastics that break down with exposure to sunlight (e. g. , HYPERLINK http://en. wikipedia. org/wiki/Ultra-violet_radiation _blank o Ultra-violet radiationultra-violet radiation), water or dampness, bacteria, enzymes, wind abrasion and some instances rodent pest or insect attack are also included as forms of HYPERLINK http://en. ikipedia. org/wiki/Biodegradation _blank o Biodegradationbiodegradation or HYPERLINK http://en. wikipedia. org/wiki/Environmental_degradation _blank o Environmental degradationenvironmental degradation. It is clear some of these modes of degradation will only work if the plastic is exposed at the surface, while other modes will only be effective if certain conditions exist in landfill or composting systems. HYPERLINK http://en. wikipedia. rg/wiki/Starch _blank o StarchStarch powder has been mixed with plastic as a filler to allow it to degrade more easily, but it still does not lead to complete breakdown of the plastic. Some researchers have actually HYPERLINK http://en. wikipedia. org/wiki/Genetic_engineering _blank o Genetic engineeringgenetically engineered bacteria that synthesize a completely biodegradable plastic, but this material, such as HYPERLINK http://en. wikipedia. org/wiki/Biopol _blank o BiopolBiopol, is expensive at present. The diversity and ubiquity of plastic products substantially testify to the versatility of the special class of engineering materials known as polymers. However, the non-biodegradability of these petrochemical-based materials has been a source of environmental concerns and hence, the driving force in the search for ‘green’ alternatives for which starch remains the frontliner. Starch is a natural biopolymer consisting predominantly of two polymer types of glucose namely amylose and amylopectin. The advantages of starch for plastic production include its renewability, good oxygen barrier in the dry state, abundance, low cost and biodegradability. The longstanding quest of developing starch-based biodegradable plastics has witnessed the use of different starches in many forms such as native granular starch, modified starch, plasticized starch and in blends with many synthetic polymers, both biodegradable and non-biodegradable, for the purpose of achieving cost effectiveness and biodegradation respectively. In this regard, starch has been used as fillers in starch-filled polymer blends, thermoplastic starch (TPS) (produced from the combination of starch, plasticizer and thermomechanical energy), in the production of foamed starch and biodegradable synthetic polymer like polylactic acid (PLA) with varying results. However, most starch-based composites exhibit poor material properties such as tensile strength, yield strength, stiffness and elongation at break, and also poor moisture stability. This therefore warranted scientific inquiries towards improving the properties of these promising starch-based biocomposites through starch modification, use of compatibilizers and reinforcements (both organic and inorganic), processing conditions, all in the hope of realizing renewable biodegradable substitutes for the conventional plastics. Definition of Terms Biodegradable able to decompose naturally: made of substances that will decay relatively quickly as a result of the action of bacteria and break down into elements such as carbon that are recycled naturally Starch – a white, granular or powdery, odorless, tasteless and complex carbohydrate found chiefly in seeds, fruits, tubers, roots and stem pith of plants, notably in corn, potatoes, wheat, and rice; an important foodstuff and used otherwise especially in adhesives and as fillers and stiffeners for paper and textiles. Plastics – the word plastic is derived from the words plasticus (Latin for â€Å"capable of molding†) and plastikos (Greek â€Å"to mold,† or â€Å"fit for molding†). Plastics are polymeric, moldable and synthetic materials which are derived from fossil fuels, such as oil, coal or natural gas. Plastics consist of organic (carbon-containing) long molecular chains that give them many of their unique properties. They can be made hard, flexible, strong, transparent, light and elastic. * Polymer – long-chain molecules that repeat their structures over and over * Polyethylene Bags the bags that you will see commonly used, such as plastic grocery bags, are made from petroleum byproducts, which is the root of most all of the environmental problems that they are the source of. Not only do they take substantially longer to break down or degrade, but as they do they release highly toxic chemicals. Resin – It is a hydrocarbon secretion of many HYPERLINK http://en. wikipedia. org/wiki/Plant o Plantplants, particularly coniferous trees. It is valued for its chemical constituents and uses, such as varnishes and HYPERLINK http://en. wikipedia. rg/wiki/Adhesive o Adhesiveadhesives, as an important source of raw materials for organic synthesis, or for incense and perfume. * Polymer Methyl Ethyl Ketone Peroxide (MEKP) The most popular type of hardener because of its economy and ease of use. * Polyester Resin Polyester resins are the most commonly used matrix in the marine and composite industry. These resins are styrene-based, flammable and cata lyzed when combined with Methyl Ethyl Ketone Peroxide(MEKP). Polyester resins are unsaturated resins formed by the reaction of dibasic organic acids and polyhydric alcohols. Premix Polyester Resin R10-60 – It is a fast gel premix polyester resin used for wood, kapiz, and other lamination with cellophane, â€Å"Lumirror† or â€Å"Mylar† films. It is also used to make decorative jewels and flowers from ceramic molds, to make small coatings from polyethylene amp; silicone rubber molds, and to cast on intrinsic molds such as steel or bass frames. * Plastic Resin Glue – Plastic resins are made by heating hydrocarbons in what is known as the cracking process. The goal here is to break down the larger molecules into ethylene, propylene, and other types of hydrocarbons. The amount of ethylene produced depends on the cracking temperature. Once the cracking process has been completed, the compounds are formed into chains that are known as polymers. Different polymers are combined to make plastic resins that have the characteristics needed for different applications Methodology: A. Materials 2 Cassava Tubers 180 ml of Premix Polyester Resin 300 ml of Polymer MEKP Hardener 100 grams Petroleum Jelly 3 old shirts Measuring cup Grater Plastic Spoon Knife 3 Plastic Containers Chopping board B. Procedure Gather the Cassava Tubers. Ground and squeeze it to extract the starch. Get hold of 240 grams of the starch and divide it into 3 equal parts: 80 grams in trial 1, trial 2 and trial 3. Place 60 ml of the plastic resin glue (Premix Polyester Resin) with 50 grams of flour catalyst for T1, 75 grams for T2 and 125 grams in T3. Mix and stir the components and pour it in the shirt with Petroleum Jelly and let it dry under the sun. To test its capacity to carry weight, use the plastic to carry objects. For its ability to hold water, put water inside the plastic. To test its tensile and bending properties, stretch the plastic as far as you can. Repeat steps 5-7 using T2 and T3.

Comparing Polymers: Metal and Ceramics

Comparing Polymers: Metal and Ceramics Ceramics are inorganic and nonmetallic materials formed from metallic and nonmetallic elements whose interatomic bonds are either ionic or mostly ionic. Many of the ceramics desirable properties are obtained usually by a high temperature heat treatment. Ceramics are made up of two or more elements. In a crystalline structure is more complex than that of metals. When the bonding is mostly ionic the crystal structure is made up of positively charged metallic ions, cations, negatively charged nonmetallic ions and anions. When the ions are bonded together the overall charge must be neutral. To have a stable system the anions in the structure that surround a cation must be in contact with that particular ion. There needs to be a ratio of the cation radius to the anion radius for the coordination and understanding of the structures geometry. If for example there is a lack of coordination, the cation would be incorrectly incased by the anions thus causing a collapse in its expected structur al stability. There are many different types of structures exist for ceramics. One crystal structure is the AX type where there are an equal number of cations and anions. Another crystal structure that exists for ceramics has a different number of cations and anions but still has a neutral charge because the ions have different magnitudes of charge is called an AmXp structure. An AmBnXp structure has more than one type of cation, represented by A and B but only one type of anion. This type of structure is also seen in close packing of ions in metals. Imperfections occur in the crystal structure of ceramics very similar to metal structural defects. Defects can occur in each of the two ions of the structure. At any time there can be cation, anion interstitials, cation or anion vacancies. Most defects or imperfections occur in pairs to maintain the electroneutrality. A Frenkel defect is a cation vacancy and cation interstitial pair. When a cation and anion vacancy pair occurs they are called a Schottky defect. Ceramics can also have impurities in the crystal structure like metals. Figure 12.21 gives a schematic diagram of the Frenkel and a Schotkey defects (pg 435). In many cases ceramics tend to be very brittle which can lead to catastrophic failure with very few signs of fatigue. This is due to the fact that ceramics absorb very little energy before they fracture. When ceramics are subjected to a tensile stress, they almost always fracture before any plastic deformation takes place. Fracture occurs because of the formation and propagation of cracks perpendicular to the applied load. Ceramics have a greater ability to resist compression than tension. The modulus of elasticity decreases with more pores in the ceramic material. When there are many pores in the material they act as stress concentrators which expose the material to weak portion. However, ceramics are very hard and are good for applications where abrasive or grinding action is needed. Most polymers are organic and are composed of hydrocarbons with interatomic forces that are represented as covalent bonds. Most polymers chains are quite long and very complex. These long molecules are made up of repeat units which are repeated along the chain. The smaller repeating unit is called a monomer. Polymers can be made up of a single repeat unit, called a homopolymer, or two or more different repeating units called copolymers. Polymers generally have a very large molecular weight. These molecular chains tend to have many kinking, bending, and coiling along with entanglement with neighboring chains may occur. This causes the outcome material to be very elastic. Polymer chains can have side groups which cause different configurations based on which side and with what regularity they bond. They can present a level of crystallinity similar to the packing of the molecular chains to create an ordered atomic array. This crystal structure can be much more complex than metallic crystal structures. Defects in polymers also differ from those found in metals and ceramics. Defects in polymers are linked to the chain ends because they are slightly different than the chain itself and emerge from the segments of the crystal. Polymers are very sensitive to strain rate, temperature, and chemical nature of the environment. Different polymers can exhibit different stress strain behavior depending on the complexity of the mole cular chain. Certain polymers display a level of is brittle where fracture occurs before elastic deformation which is very similar in the case of ceramics. Another type of polymers is very similar to metals where elastic deformation takes place first followed by yielding and plastic deformation. A third type is exhibited by elastomers which have totally elastic and recoverable deformation. Polymers generally have a lower modulus of elasticity and tensile strength then metals. Some Polymers can be stretched up to ten times longer than its original state where metals and ceramics cannot easily accomplish. Polymers exhibit viscoelasticity at temperatures between where elastic and liquid like behaviors are prevalent. Similar to metals and ceramics, polymers can experience creep. Creep is a time dependent factor due to deformation under stress or elevated temperature. In both ceramics and polymers, creep depends on time and temperature. Polymers may be ductile or brittle depending on tem perature, strain rate, specimen geometry, and way of loading which is very similar to the properties of metals. Polymers are brittle at low temperatures and have somewhat low impact strengths. Polymers can experience fatigue under a repetitive loading. They are generally softer than metals and ceramics and unlike metals and ceramics, polymer melting occur over a range of temperatures instead at a specific temperature. Metals are a material made up of metallic elements that are bonded metallically like common alloys. The electrons are not bound to any particular atom creating a matrix of ion cores surrounded by many electrons. They are very good conductors of heat and electricity where as ceramics and polymers are lacking. Polymers and metals are both ductile and are not that brittle though metals also exhibit a level of malleability. Ceramics are very brittle, they tend to fracture under a load which means they are lacking in ductility. Polymers are the softest material due to their complex structure, while ceramics are the hardest but are not very tough because they fracture before plastic deformation occurs. Polymers plastically deform very easily and have the smallest Youngs modulus. Ceramics have the highest value because of their brittleness and never reach the point of plastic deformation because they would fracture first. The values of Youngs modulus for metals fall between those for polyme rs and ceramics. These three materials have diverse structures and exhibit different levels of defects. Alloying, using the term in the broadest sense. Simply an alloy is a metal compound that consists of 2 or more metal or nonmetallic elements. These combinations of metallic and non metallic elements ultimately create new compounds that in result display superior structural properties as compared to the elements by themselves. The type of alloy mixtures is highly dependent on the desired mechanical property of the material. Alloying can be applied to metals, ceramics and polymers where in each specific properties are desired. One of the most desired properties of metal alloys is the hardenability. A material with a high level of hardness will resist deformation caused by surface indentation or abrasion while a material with a low hardness level will deform more easily under similar conditions. The main factor in a materials hardenability is its martensite (the rate which austenitized iron carbon alloys are formed when cooled) also content and is related to the amount of carbon in a material. With this application of alloying on metals, the material can exhibit greater strain and stress resistances as well as elasticity. These properties are favorable when dealing with construction and manufacturing processes. A ceramic alloy is basically a fusion of a ceramic with of 2 or more metals. As seen in metal alloys, ceramic alloys can consist of impurity atoms in a solid state. In ceramic alloys an interstitial and substitutional states are possible. In an interstitial type, the anion has to be bigger than the impurity of the ionic radius. The substitutional impurity applies where the impurity atom usually forms a cation in the ceramic material thus the host cation will be substituted. Figure 12.23 provides a great visual representation of interstitial and substitutional types in a ceramic alloy (pg 437). Significantly, to properly achieve a solid state of solubility for substituting impurity atoms, the charge and the ionic size must be as the same as the host ion. If they were different it there would need to be some other way for the electroneutrality to be maintained within the solid. An easy way to do this is to create a formation of lattice defects of vacancies or interstitial of both ion t ypes. Cobalt chromium is a perfect example of a ceramic alloy in which was designed to be used for coronary interventions thus because it does not degrade once placed in the human body. Polymer alloys consist of two or more different types of polymers in a sense blended together. There are a variety of additives that can be blended or mixed in with the polymer to create the desired effect for the material. Polymer additives that support the modification of its physical properties are fillers, plasticizers, stabilizers and of course flame retardants. Fillers are generally introduced to a polymer, when a greater comprehensive strength and thermal stability is desired. Creating these types of alloys are very beneficial because they are generally very easy to create and use in their desired form. Plasticizers help improve the flexibility and toughness of polymers by reducing the hardness and stiffness of the material. They are often introduced to polymers that are generally brittle at room temperature. These additives are especially useful because they generally lower the glass transition temperature thus allowing the polymer to have a extent of pliability. Due to the f act that certain polymers are not resilient to environmental conditions, stabilizers are introduced. They provide stability and integrity against deterioration against the mechanical properties. The two most common forms of environmental deterioration are UV exposure and oxidation. A major concern with many polymers is that they are highly flammable. Flame retardants are introduced to such polymers to reduce the combustibility of the material by interfering with its ability to combust through a gas phase or initiating a different combustion reaction that generates less heat. This process will reduce the temperature that would eventually cease the burning process. Kirill Shkolnik 105940393 ESG 332 R01 Exam #2 (Question #2) Describe with reference to phase diagrams and dislocation theory, how precipitation age hardening can be achieved in aluminum alloys. Generally aluminum is a metal with a low level of density compared to other metals. Due to this low level of density, it conducts electricity and heat better than copper. Aluminums just over 1200 degrees Fahrenheit which is comparably low to other metals. Due to these simple facts, it seems ideal to bond elements such as titanium, silicon, copper, zinc and other materials to magnify aluminums positive attributes. The process precipitation age hardening can amplify the alloying of aluminum. This process involves supersaturating a solid solution precipitating evenly dispersed particles on the aluminum. This will help stop the movement of dislocations within the metal structure. The basic concept of dislocation is the atomic misalignment of atoms in a linear plane. These atomic misalignments affect a whole series of atoms on a plane. The series of misalign atoms form a line called a dislocation line. There are two known types of dislocation called the screw and edge dislocation. Screw d islocation and edge dislocation are the primary types of dislocations but require a certain amount of each other to occur. By reducing the amount of dislocations can radically increase the strength in the metal. The process of alloying usually makes a pure material harder. The process of alloying is having one metal bond with impurity atoms from other materials to change its mechanical properties. An alloying process called solid solution alloying uses a solution to substitute bonds inside the metal. The limiting of dislocation movement is a major factor for alloying because it can be used to strengthen metals. Alloying metals with the precipitation hardening makes the strength of the new material stronger as the progress of the process is delayed. The reason for precipitation hardening is sought after is because of its abilities in making metals stronger. Aluminum alloys can have precipitation in a very specific way. Heat treatment occurs when one material is heated a supersaturated mixture at a specific phase and so two different phases can be present together. A precipitate forms in small pieces throughout the entire material. When the mixture is at its equilibrium, the forming process comes to an end. The small pieces of precipitate then diffuse together to form one large precipitate. This stage of the precipitate tends to weaken the materials fundamental structure. The small pieces of precipitate in the material make it harder for dislocations to move. When strength of the material diminishes due to the movement of the precipitate it is called overaging. There are two things need for heat treatments to be applied. Figure 11.21 provides a graphical representation the relationship between temperature and composition for aluminum and copper (pg 402). The copper phase represented at a shows a supersaturated solid solution in aluminum while the compound that between the two elements is symbolized as ?. Interestingly the point M represents the max solubility point at certain temperature and composition in the material. Point N represents the solubility limit of a and (a + ?) L symbolizes the temperature needed for the solution to become a liquid. If a major amount of solute is made available in the solution, we would have a precipitation hardened alloy. The limit of the solubility curve vastly decreases in concentration as the temperature decreases. There are two different ways precipitation can occur. One process is the use heat treatment where the solute can be dissolved to form a solid single phase solution. This method can be done by heating an alloy to a very high temperature. Figure 11.24 shows that the ? phase is blended into a phase (pg 404). Then the alloy is cooled where all that is left is a supersaturated a phase. Precipitation heat treatment the (a + ?) phase is heated to a specific temperature to allow the ? phase to precipitate. The alloy is cooled and the hardness of the alloy is determined by time. A logarithmic function a comparison with strength and time proves the dependence of temperature and strength. Kirill Shkolnik 105940393 ESG 332 R01 Exam #2 (Question #3) Describe what is meant by the term glass transition temperature and illustrate your answer from polymer and ceramic point of view. Typically a glass transition temperature is where a noncrystalline form of a polymer or a ceramic is cooled and transforms from a super cooled liquid into a glass. A ceramic or a glassy material is a noncrystalline material that becomes increasingly more viscous when it is cooled. Due to the fact that glassy materials are noncrystalline there is no definite temperature when the liquid will transform into a solid. Though, it is also important to note that in noncrystalline materials the specific volume is dependent on temperature and will decrease with the temperature. The glass transition temperature displays a reduction in the rate at which the specific volume decreases with temperature. When the temperature is below this value, the material is in a ceramic from and directly above this point the material is considered a supercooled liquid. The glass transition temperature occurs in both glassy and semicrystalline polymers, but not in crystalline materials. As certain molecular chain s in noncrystalline materials temperature drop due to lack of motion the glass temperature transition occurs. Basically glass transition is the time in which a steady transformation occurs from the liquid state to a slightly rubbery state and then to the final more rigid solid material. The glass transition temperature is the state in which the material goes from its rubbery to rigid state. This transition can take place in both directions. As a polymer for example is cooled to a rigid solid, it can be heated and undergo the same transition in reverse. As the material undergoes all of these changes its properties change from state to state. Some materials can experience greater change include the stiffness, heat capacity, and the coefficient of thermal expansion for the material during this transition. The glass transition temperature also acts as a limit boundary for applications of polymers and polymer matrix like components. If this temperature is beyond the material threshold, it will no longer fit the desired properties the task had called for and the application would be useless. The molecules that had been frozen in place below the will both rotate and translate at the temperatures above. Molecular characteristics have an impact on the chains stiffness and will in turn affect the glass transition temperature for the material. Some molecular characteristics that can cause the chains flexibility to be reduced and the glass transition temperature to increase that include bulky side groups on the molecular chain. Also these characteristics can affect polar atoms or groups of polar atoms on the side of the molecular chain, double bonds, and aromatic groups. The glass transition temperature will also increase as the molecular weight of the material increases. Branching also influences the of a material, many branches will decrease the chains mobility and increase, a lower density of branches will cause the to decrease as the molecular chains will have a freer range of motion. Crosslinks can occur in glassy polymers and can affect, they cause the reduction of motion and therefore increase. If there are too many crosslinks occur in the material, the molecular motion would be so limited that glass transition may not occur. It can be understood that many of the same molecular characteristics which affect the glass transition temperature also affect the melting transition temperature. The two are affected in such a similar manner that is usually somewhere between 0.5 to 0.8 times the melting transition temperature. Figure 15.19 demonstrates this mathematic relationship (pg 548). Both ceramic and polymers have a glass transition temperature. A glass can be referred to by several different names; such as vitreous solid, an amorphous solid or glassy solid. An amorphous solid has the mechanical properties of a solid, but does not have long range molecular order where they are in motion at a very slow rate that it be considered rigid for regular purposes. When glas sy materials have been supercooled below the glass transition temperature they will take on characteristics similar to those of a crystalline solid. This solid will become rigid with an increased hardness and will be more brittle. However, if a glassy material is heated to above its glass transition temperature it will become softer and many of the intermolecular bonds will break allowing the material to flow at an increasing fluid viscosity. A polymer below the glass transition temperature is more rigid, but as it enters its glass transition phase, the material becomes more rubbery as its viscosity increases. The polymer can enter its glass transition at a lower temperature when critical factors that usually affect the motion of the molecules in the material are not all present. When molecular weight of a polymer increases, the glass transition temperature will also increase. Many factors that increase the the rubber gasket would not do its job properly. Polymers can exhibit the following structures: amorphous, semi-crystalline and crystalline. Describe these structures and explain how the mechanical properties may be influenced by these structural forms for a polymer of the same chemical formula. Polymers can develop amorphous, semi-crystalline and crystalline structures of the same chemical formula. Polymers can exist as liquids, semi solids, or solids related to the crystal structures respectively. However each of these structures exhibit a variety of different mechanical properties. The crystallinity of a polymer depends on the intermolecular secondary bonding which will heavily influence the extent of any mechanical property of the polymer. The tensile strength, elastic modulus and compression strength of a crystalline structure will be stronger than a semicrystalline structure and significantly stronger than amorphous type structure. For a crystalline structure the molecular chains of the polymer are tightly packed together in an organized atomic group which take up space and will affect the polymers mechanical properties. These crystalline structures are heavily influenced by the glass transition temperature. Also the isomer and chemical formula lays out crucial factors that will be very important in the formation of the bulk material structure. From certain large bulky functional groups there becomes an impending hindrance that will inhibit the movement capability of a molecule. This process will increase the energy requirement for any phase change. The outcome of this process is a greater transition temperature. This new temperature transition will increase the chances for the formation of a crystalline structure. The reason for this is and time span before the material becomes a disorganized liquid and requires a longer time for the molecules to arrange themselves properly. When polymers have many branches the weaker the material will be, even though crystalline structures are stronger than less ordered materials. Figure 15.18 demonstrates the change in these structural states when specific volume and temperature are compared (pg 546). Pure polymers have a very small melting point ranges and bond strength. Doped polymers and polymer alloys will generally have wider melting point ranges. The process of branching will decre ase the strength of a polymer, which would continuously decrease the melting point temperature. Though, the act of branching on heavily dense branches will decrease molecule mobility. Also within this process the molecular weight is affected as well. Kirill Shkolnik 105940393 ESG 332 R01 Exam #2 (Question #4) How are T-T-T and C-C-T diagrams used to design heat treatment schedules for plain carbon steels. Time-Temperature-Transformation or T-T-T and continuous cooling transformation or C-C-T are used for heat treatment schedules for plain carbon steel. T-T-T are commonly known as an isothermal transformation diagrams can show the change of different phases at certain temperatures. C-C-T can be used to calculate percent transformation against the logarithm function through time. The use the isothermal transformation and continuous cooling transformation diagrams can be used to develop a heat treatment for plain carbon steels. These diagrams will support the understanding of carbon steels through phase diagrams. When a structure is heat treated, its cooling process helps retain its structure. This process can be analyzed through T-T-T. Figure 10.13 displays a graphical representation of temperature against time with a third dimension with the percent of the steel alloy transformed to pearlite (pg 326). The understanding of a rapid cooling alloy sully depends on the understanding and application of heat treatment. It is understood that isothermal transformations do not change in temperature but continuous cooling transformation diagrams do. C-C-T and T-T-T display the same dimensions but over a larger spectrum of time and temperature. Figure 10.28 shows different forms of steel alloys (pg 338). A material that has been cooled to a temperature slightly below it s eutectoid temperature, and isothermal transformation is maintained for an extended period of time, interestingly it cannot be depicted on T-T-T diagrams in spheroid forms.

Treasure Island :: Free Essays Online

Treasure Island Robert Louis Stevenson was born on November 13, 1850 in Edinburgh, Scotland. He was the only child of Thomas Stevenson and Margaret Isabella Balfour. Stevenson's father belonged to a family of engineers who were responsible for many of sea lighthouses built around the coast of Scotland. His mother, Margaret, came from a family of church ministers and lawyers. Due to his father's distinguished career, it was naturally believed that Stevenson would follow in his father's footsteps, just as other family members had accomplished through the generations. Surprisingly found, writing would be his natural calling. At age two, Stevenson caught what is known as the croup, which is an inflammatory disease of the larynx and trachea. As a young child, Stevenson was plagued with illnesses, just as his mother. It was originally believed that Stevenson might have inherited tuberculosis from his mother Margaret. It is somewhat ironic that the actual cause of his premature death was due to a cerebral hemorrhage just as his father apparently died due to thrombosis, or the clotting of his blood. Unfortunately, Stevenson’s health was continually questionable throughout his lifetime. In 1867, Stevenson entered Edinburgh University and initially began to work towards a Science degree. He later switched to Civil Engineering to appease his father and spent some time working in the field. His interest in writing began at an early age but his father hoped to convince Stevenson that it was a great hobby because his father had aspirations of him carrying on with the family tradition and become a civil engineer. Coincidentally, while Stevenson was vacationing on an island named Earraid, he met a stonemason, who at the time was working on a lighthouse, named John Silver. This name will eventually be used and well known in his famous novel, Treasure Island. The summer of 1881 proved to be a turning point in Stevenson's career. Shortly after his marriage to Fanny Osbourne, Stevenson would begin a novel, which would mark the beginning of his career. Due to inclement weather and Stevenson’s questionable health, the family spent an increased amount of time indoors. On one particular day, Stevenson and his stepson Lloyd drew and labeled a map, which would eventually be the inspiration for Treasure Island. The map triggered Stevenson's imagination and he began by writing a chapter a day, a total of nineteen, and read the chapters aloud nightly to his family for entertainment.