Pompeii Essay Example | Topics and Well Written Essays - 3000 words

Pompeii - Essay Example The Greeks defeated the Etruscans in both 524 and 474 BCE and probably proceeded to take control of Pompeii (qtd. from Pompeii before the Romans involvement, 2005).As evidence, the hill near the mouth of the Sarno River or Sarnus River was used as a safe port by Greek and Phoenician sailors (Wikipedia, 2005). This theory is supported by the architecture and art in Pompeii that was influenced by the Greeks, such as the temple to Apollo mentioned earlier. Around 420 BCE the Samnites came to occupy the city of Pompeii (Leppman, 1968). The Samnites seem to have imposed their language, customs, and civic organizations upon Pompeii (qtd. from Pompeii before the Romans involvement, 2005). Rome entered onto the Pompeiian scene following the end of the Second Samnite War (290 BCE). The Romans landed their fleet at the mouth of the Sarno and sacked neighboring Salerno (Leppman, 1968). For almost two hundred years, however, the Roman rule of Pompeii was more a "matter of form than substance" (Leppman, 1968). Pompeii was under Rome's control, however, its inhabitants were practically independent (qtd. from Roman involvement in Pompeii, 2005). Although Pompeii was practically independent, its future was tangled with that of Rome. The Roman success in war over Carthage in the Second Punic War (218-201) and Romes victorious marches into Greece, Asia Minor, and Syria paved the way for an abundant economic enterprise for the Pompeiians (qtd. from Roman involvement in Pompeii, 2005). A colony of Roman veterans was planted in Rome as a punishment for Pompeiis role in the Social War (Carrington, 1994). Scholars have pointed out, however, that the Pompeiians ended up profiting in the whole ordeal, since Pompeii was quick to take advantage of the Roman destruction of neighboring Stabiae. This conflict did, however, mark the end of Pompeii's virtual independence, as Rome became much more active in Pompeii. This shift in power is borne out by the fact that ten years after the Social War, Rome renamed Pompeii Colonia Cornelia Venena Pompeianorum (qtd. from Roman involvement in Pompeii, 2005). Physical description The city of Pompeii has an irregular shape because it was formed by a prehistoric lava flow. Excavations indicate that the southwestern part of the town is the oldest, but scholars do not agree on the stages by which the walls were expanded or on who the builders were. The walls are 2 miles (3 km) in circumference, and they enclose an area of about 163 acres (66 hectares). Seven city gates have been excavated (Description of the remains, 2005).

Lexus Rx Essay Example for Free

Lexus Rx Essay In 2008, Toyota was ranked the world’s number one in motor vehicle production volume with more plants opening in Canada, USA and Mexico. Due to the worldwide recession, Toyota sales dropped tremendously, thereafter. Beginning in early 2010 Toyota’s sales, and stock price dropped again due to accelerator and brake problems with a number of their cars. People were afraid to drive and purchase the 2010 Prius as the brake problems occurred mainly in this line of car. Toyota was no longer ranked number one in motor vehicle production due to the problems the company faced in 2010. Currently in 2011, Toyota is concerned about how well the Lexus RX 330/350 has done in the North American market? Due to this matter, the operation management team has produced a report that concerns the Toyota Motor Company’s North American Lexus production decision made a few years ago and the production of Toyota’s strategy for North America. This report includes a critical assessment of the Toyota Production System (TPS), which will be used to demonstrate the basic understanding of the TPS and describe the TPS as a total entity. This report also includes a grid analysis which will be used to help make the North American plant location decision for the Lexus RX 330 Line by listing the key factors as either exogenous or endogenous, stating any relevant assumptions or constraints, and assigning two scores to each factor: one for production of the Lexus RX 330 at the Toyota Motor Manufacturing of Canada (TMMC), and one for production at a Toyota factory in the USA. Lastly, this report will recommend an appropriate production capacity to be built at TMMC, and it will assess Toyota’s current regional production strategy in North America. The operation management team will do a thorough assessment of Toyota production in North America. This report will mention the purposes and advantages of the TPS. It will show the profit earned from the Lexus RX 330 line over the five years period from 2003 – 2007, and how well it is currently doing in 2011. This report will evaluate the current distribution of Toyota production in North America and suggest why Toyota has chosen to produce its cars for the North American market in the current manner.

Investigation of Subgrade Reaction Coefficient in Sandy Soil

Investigation of Subgrade Reaction Coefficient in Sandy Soil Numerical investigation of subgrade reaction coefficient in sandy soils Adel Asakereh1, Hassan Jamali2*, Masoud mossafa1 1 Civil Department, University of Hormozgan, Bandar Abbas, Iran 2Young Researchers and Elite Club, Sabzevar Branch, Islamic Azad University, Sabzevar, Abstract The soil-foundation interaction is one of the most important issues in geotechnical engineering relating to soil behavior against side loading. Winklers model is the first and simplest method for considering the soil-foundation interaction. Because to determine the coefficient of the subgrade reaction of the soil before designing structure is vitally important, so, experimental, analytical and numerical methods have been proposed. This research chose a ground characteristic that is in Bandar Abbas (Iran). Purpose is to compare the proposed experimental formulae for determining the coefficient of the subgrade reaction with its corresponding values resulting from the behavioral models. Finite element analysis was performed by Plaxis software and important parameters were proposed by the engineers. Results show increasing footing diameter leads to a decrease in the coefficient of the subgrade reaction due to increasing load area which results in increasing settlement. It is found that i ncreasing each of the strength parameters of the soil can be expected to have an effect on increasing the subgrade reaction, although this increase depends on footing diameter. Also in sand soils, the soil cohesion effects on the increase of the subgrade reaction coefficient more than the internal friction angle. Keywords: Elasticity coefficient, Mat foundation, Subgrade reaction coefficient, Bandar Abbas City, Finite element analysis Introduction The application of mat foundations has a long history. This type of foundation has shown a very good performance in transferring construction forces to the ground. Currently in most cases, engineers use a constant value for the subgrade reaction coefficient to analyze the mat flexible foundations. This constant is obtained from geotechnical experiments such as plate loading. Many researchers have studied soil subsidence and the subgrade reaction coefficient using plate loading test [1-9]. Nomenclatures B Diameter of footing (m) Minimum marginal dimension of footing(m) c Cohesion (kPa) d Plate thickness (m) Df Embedment depth of foundation(m) Soil elasticity modulus (kPa) EI Flexural rigidity of footing (kN.m2) EA Axial rigidity of footing (kN.m2) Height of ith layer (m) If , Is, Id Dimensionless coefficients ks Subgrade Reaction Coefficient (kN/m3) m Constant coefficients P Vertical pressure (kPa) Greek Symbols v Poisson ratio Vertical Displacement (m) Angle of friction (Degree) Unit weight (kN/m3) Dry unit weight (kN/m3) The application of a uniform reaction coefficient over all of the foundation means neglecting the conditions of a continuum for the soil and the effects of cut in the soil layers. One of the fundamental issues in designing and calculating the foundations is the problem of soil-foundation interaction. It is very important to study soil behavior against the external loads. Soil behavior depends on many factors such as moisture content, density, particle-forming mineral types, grain size, grain shape, grading curve, current state of the stress, stress history, pore pressure, saturation point, permeability rate, time, and temperature. In order to study the soil-foundation interaction, many researchers have tried to investigate soil behavior against the imposed loadings to find a model for it. The material model is a mathematical relation for describing the stress-strain behaviour of a small element of the environment. As previously mentioned, soil behavior depends on many factors it is extremely difficult to provide a model including the effects of all factors. Thus in solving the problems of soil-foundation interaction, some properties of the soil are usually excluded to provide a simpler model with fewer parameters. Since the soil at a macroscopic scale is considered as a continuum, the simplest possible state we consider the soil as a linear, homogenous and consistent elastic semi-space. In such a case, the soil will have two parameters Poisson coefficient and the elastic modulus. The first and simplest model for investigating the soil and foundation interaction is a model offered by Winkler in 1867 [10]. In this model, the deformation of any point of the soil ground is related to the point stress value and the effect of the stresses and the changes in other points are neglected. In this model, soil is replaced with a set of independent springs with a specific stiffness coefficient. Thus, only one single parameter is considered for the soil, that is, the subgrade reaction coefficient represented by ks. One of the most prominent properties of this model is its discontinuous behavior [9]. The subgrade modulus is not a fundamental soil property and its magnitude depends on many factors including the shape of the foundation, the stiffness of the foundation slab, the shape of the loading on the foundation, the depth of the loaded area below the ground surface, and the time. As such, it is not constant for a given type of soil, making the estimation of a single general value for design a challenging task [11]. Consequently, researchers have suggested several ways to determine this parameter and several formulae have been offered for determining ks. Many researchers have worked on the calculation of subgrade reaction coefficient. Ismail [12] studied the applications of the artificial neural networks (ANN) and the simple-multiple regression analysis to predict the deformation modulus and the coefficient of the subgrade reaction of the compacted soils from the compaction parameters (such as maximum dry density (MDD) optimum moisture content (OMC), field dry density (FDD), and field moisture content (FMC)). Ding [13] compared four typical methods for determining the coefficient of the subgrade reaction including the test method, Lis method, MIDAS method, and finite element method. He showed that the test method is the one preferred by the designers, that the tangential coefficient should be in a range of one to two-third of the normal coefficient. The internal force of subway structures can be obtained by the test method and modified by a correction factor that is 1.05. Barmenkova et al. [14] carried out calculations of plates on a n elastic basis with variable and constant coefficients of subgrade reaction. In this paper, the calculation of plates bending was carried out by the finite element method. The results were compared for different models of plates on an elastic basis. For a two-layer plate on an elastic basis, which had heterogeneity in the plan, the results of calculation took into account the increase of the height of the upper structure. Kobayashi et al. [15] calculated the subgrade reaction coefficient for a foundation soil in an open pier using an extended Kalman filter (EKF) based on measurements taken during in situ horizontal loading tests on a pile. The numerical results would provide useful information for the future design of open piers and their foundations. Liao [16] reviewed the limitations of various simple and complex methods available for estimating the coefficient of subgrade reaction k, and developed a new method using the results of the plane strain finite element analyses of a loaded beam or slab resting on the surface of a homogeneous elastic soil layer. Although many studies have been carried out on determining the subgrade reaction coefficient, the dependence on many parameters leads to further parametric studies. Experimental and theoretical formulas for determining ks are based on available data from limited sites with some assumptions, so it is possible for them not to have sufficient precision in all areas. Therefore, determining the subgrade reaction coefficient in specific areas such as Bandar Abbas city and assessment of the effective parameters on subgrade reaction coefficient is vital. Besides, the Increasing in footing width, increases effective depth. Therefore, determination of ks in footing with more width is more complex especially in layered soil, because ks obtained from plate load test is different from ks under real loading of structure. Thus investigation of the footing width and the strength parameters of the soil on ks is needed. Performing plate load tests with large diameters is expensive and difficult, thus the present study uses finite element software of Plaxis to investigate the effect of the aforementioned parameters. Parametric studies on subgrade reaction coefficient of sand soil in Bandar Abbas city are few, so this paper uses geotechnical data of a site in Bandar Abbas city (Iran) to determine subgrade reaction coefficient by using of theoretical, experimental relations and numerical methods. Besides, the effects of the strength parameters (c,) and B on subgrade reaction coefficient are investigated too. This study is carried out by using and verifying numerical methods and ensuring the accuracy of the software. Numerical analysis has been done by finite element method using Plaxis software [17]. Analytical methods of subgrades reaction coefficient In order to obtain ks, one can generally apply plate loading, consolidation, triaxial, and CBR tests and experimental and theoretic relations provided by researchers [18]. Among them, plate loading testing and the experimental method are considered the most common methods. In this paper, experimental and theoretic methods are considered. There are several relations including Vesic [19], Biot [20], and Bowles [6] as well as relations resulting from elastic theory from elasticity theory to determine subgrade reaction coefficient. Biot [20] solved the problem of an infinite beam on a linear elastic subgrade and provided Eq. (1) for subgrade reaction coefficient. (1) Vesic [19] developed Biots work [20] and suggested Eq. (2) for the relation between ks and elastic characteristic of soil: (2) He also showed the difference between Winkler method and continuum does not exceed 10 percent. Bowles [6] showed the numerical value of in ordinary condition may be approximated by 1, and in most cases subgrade reaction coefficient is obtained by Eq. (3): (3) Using elasticity theory is another way to approximate ks. By reformulating the elastic subsidence in rectangular foundation, we obtain the following [21]: (4) These values are determined based on tables in the elastic subsidence section of basic soil mechanic references. m is the coefficient which is equal to 1, 2 and 4 for corner, edge, and center, respectively. ks is calculated in corners assuming m = 1 from Eq. (4) and it is multiplied by 0.5 to obtain k edges or by 0.25 to obtain ks centers. According to the above discussion, it can be seen that there are several formulae to determine soil subgrade reaction coefficient. General and geotechnical properties of the soil The site of the residential- mercantile building is located to the west part of Bandar Abbas city in Iran (Fig. 1) with seven floors over the ground floor (parking lot). The depth of the foundation settlement is equal to the height of the foundation as 1 meter and no groundwater grade was observed until the end of the excavation depth. In order to identify the underground layers, five boreholes were excavated (three 15-meter boreholes and two 20-meter boreholes) using a rotary drilling machine. During soil boring, some samples were extracted for laboratory experiments. After completion of the field operation, the extracted samples were tested for grading, Atterberg limits, moisture content of the natural soil, and direct shear test. The studies on the layers of the site soil show the soil type in the foundation subgrade is mainly silty sand (SM) from the ground level down to the depth of 8 meters, and the soil type is bad-grained sand (SP) from the depth of 8 meters downwards. Fig. 1. Location of Bandar Abbas city. Considering the field and laboratory experiments in order to determine the scale of soil subsidence and the bearing capacity of the site soil, the required parameters were selected from the five excavated boreholes as shown in Table 1. The data of the samplings is available down to 20 meters deep. The soil type was given down to the depth of the foundation effect (around 30m). Moreover, the soil weight at the 20 to 30 m depth (layer 11) has considered as being constant. Table 1. Soil properties of the site No. of Layers Dep. (m) Soil Type SPT (Ncor.) à Ã¢â‚¬ ° (%) c (kPa) à Ã¢â‚¬   (ËÅ ¡) ÃŽÂ ³ (kN/m3) ÃŽÂ ³d(kN/m3) 1 0-2 SM 21 4.1 0 29 17 16.3 2 2-4 SM 17 16.6 0 29.1 18.6 16.23 3 4-6 SM 24 14.9 0 28.8 18.6 16.18 4 6-8 SM 33 15.2 0 30.4 18.9 16.4 5 8-10 SP 38 23.7 0 32.4 20.1 16.24 6 10-12 SP 39 18.1 0 31.2 19.4 16.42 7 12-14 SP 47 24.2 0 31.2 20.6 16.58 8 14-16 SP 50 19.8 0 30 20 16.69 9 16-18 SP 50 19.2 0 32 20 16.77 10 18-20 SP 50 18.8 0 32 20 16.83 11 20-30 SP 50 18.8 0 32 20 16.83 Equations (5) and (6) were used to determine the elasticity modulus of the soil [6]: (5) For unsaturated sands, and (6) For saturated sands. Thus, the elasticity modulus for each of the soil layers is calculated based on the above formulae and the results are shown in Table 2. Table 2. Elasticity modulus of the soil layers No. of Layers SPT (Ncor.) Es (kPa)-dry 1 21 18000 2 17 16000 3 24 19500 4 33 24000 5 38 26500 6 39 27000 7 47 31000 8 50 32500 9 50 32500 10 50 32500 11 50 32500 Numerical analysis procedure First, the results of Brian Anderson et al. [22] were analyzed with Plaxis to verify the software. Brian Anderson et al. [22] performed in situ testing and numerical investigation for predicting settlement of shallow foundations. Accordingly, a 1.8 m diameter concrete footing was statically load tested. Prior to construction, in situ standard penetration test (SPT), cone penetration testing (CPT), dilatometer (DMT), and pressuremeter (PMT) and laboratory tests were performed to determine engineering properties of the soil. A reinforced circular 1.8 m diameter 0.6 m thick concrete footing was constructed using a corrugated pipe coupler as a form. To overcome a thin hard layer surface crust, the footing was embedded 0.6 m into the ground. The groundwater table was at 1.7 m from the ground surface, as illustrated in Fig. 2. Static load was 222 kPa. Due to the symmetry, half of footing with the width of 0.5 B is modeled asymmetrically. Avoiding boundary effects, a 6.5ÃÆ'-5 m model was s elected. The model depth was taken as 6.5 m, that is approximately equal to 4B=6.8 m and the width of the model was taken as 5 m, that is approximately equal to 3B [23] . Results proved that the displacement did not reach the boundaries in the analysis. To investigate the mesh dependency, a number of trial analyses were conducted through the verification study. The model included 1971 nodes and 235 elements. The boundary lines were defined as the limited deformation in horizontal direction and free deformation in vertical direction, and limited deformations both in horizontal and vertical directions at the lower boundary as showed in Fig. 3. Trial analyses proved that with specified dimension and meshing, errors would be negligible. In order to do the modeling with finite element method, the 15-node triangular element was used according to Fig. 4. Table 3 presents the input parameters used for the FEM analyses. Figure 5 presents applied stress-settlement diagram obtained from Plaxis in this study and reference to a point located under plate. There was a negligible difference between two diagrams, so Plaxis was suitable for analysis. Fig. 2. Geometry and mesh of the verification model.  Ã‚  Ã‚   Fig. 3. Soil-footing profile of verification model [22]. Fig. 4. 15-node triangular element. Table 3. Soil properties used in verification according to [22]. Bottom(m) (kN/m3) (deg) E(Mpa) c(kPa) 1.64 18.9 31.4 14.5 0 2.5 17.3 30.1 12.5 0 3.17 15.7 28.6 10.50 0 6.5 14.2 27.1 8.5 0 Fig. 5. Applied stress-settlement diagram. After software verification, the model was developed for determining the subgrade reaction coefficient of Bandar Abbas city and parametric study. In the created model (which included 2011 nodes and 256 elements), the loading was uniform and, a rigid foundation was considered in all phases of analysis. Model depth should be greater than 4B and model width greater than 3B for different diameters. Since it was intended to study the effect of foundation diameter on determining the value of subgrade reaction coefficient, an asymmetric model was used in the software for soil modeling. The relevant parameters of the general properties (wet and dry specific weight) and the relevant parameters of the soil resistance (c,) for all soil layers were derived from Table 1. Considering the results of the experiments and researches and the reliability of the developed numerical model with the results, and considering the soil type of the site (sand soil), Mohr-Coulomb behavioral model for the soil wa s used in this research. Since in Mohr-Coulomb behavioral model the stress-strain relation is fulfilled directly by the soil elasticity coefficient, thus in entering the data of the soil elasticity coefficient as one of the input parameters, the data of Table 2 were used. The values of the dilation angle in all layers were assumed to be 0. Considering the properties of the building in this project and the scale of the imposed loading (dead and live load), the value of the imposed pressure on the soil was assumed to be 120 kN/m2 where the plate element (with the concrete foundation properties) was used to transfer this load to the modeled soil. Among the most important properties of the element, it could be referred to its flexural hardness (EI) and its axis hardness (EA). These two parameters can be used to obtain the plate thickness that is the representative of the foundation thickness in this case. Considering the constant thickness of the foundation by 1 meter in this research, different values would be obtained for EI and EA in different models according to the Eqs. (7) and (8) [24]. Since the modeling was done with asymmetric method, thus half of the diameter of the real foundation was modeled, and the modeling was done in direction of x-axis, three times more than the foundations diameter (3B), and in the direction of y-axis equal to the number of the layers mentioned in Table 1. Moreover, Table 4 shows the parameters needed for determining the plate input parameters into Plaxis software. d=  ½ deq (7) (8) Fig. 6. Geometry of the model. Table 4. Plate parameters EI (kNm2/m) EA (kN/m) E (kPa) Df(m) Var. Var. 2.5ÃÆ'-107 1 Results and discussion Seven models were developed for different values of foundation diameter (8, 10, 12, 14, 16, 18, and 20 m). Then, they were analyzed by finite element method using Plaxis. Because of axis plain strain in Plaxis, foundation is considered as a strip with B/2 of diameter and 1 m, orthogonal to the plane as shown in Fig. 6. Amount of vertical displacement in center and below of the foundation (sections are in center and 1 meter below the above subgrade of soil model) is obtained according to the load determined by the construction analysis (120 kN/m2). The soil subgrade reaction coefficient is calculated by Eq. (9) for any values of foundation diameter [25]: (9)

The Dangers of Tattoos Essay -- Body Art

Tattoos are becoming a popular phenomenon that is seen everywhere. Today’s youth are getting permanent tattoos to be cool and trendy, but are not considering the long-term effects. Teenagers should be aware of all that body modification may include, it is not just a pretty picture. Adolescences must consider the dangers and conscientious result of attaining diseases, being underage, and having a permanent mark on their body.   Ã‚  Ã‚  Ã‚  Ã‚  The unsanitary conditions of getting a tattoo tend to go unnoticed by teenagers. The increase popularity in body art has also caused an increase in the incidences of Hepatitis, especially Hepatitis C. Hepatitis C is spread by contact with human blood. Since, the government regulation has not enforced hygiene requirements for tattoo parlors, disease such as Hepatitis C thrive in these environments. Another disease that can be acquired is HIV. The government does not force tattoo parlors to use new needles or to sanitize the old ones. Also, tattoos can get easily infected and leave a scar if not properly taken care of. Sometimes, people die from ink poisoning if too much ink gets into the blood stream. I haven’t even touched on how painful it is to get a tattoo and how painful it will be to obtain a disease. Young adults do not consider the dangers of a tattoo until it is too late.   Ã‚  Ã‚  Ã‚  Ã‚  Another problem with getting a tattoo is being underage. Teenagers have to convince their parents that a tattoo isn’t a foolish decision and they really want ...

Mankind is nah island Essay

The dynamic concept, belonging, is highly influenced by social marginalisation as individuals develop a sense of displacement amongst the dominant culture. Vangenderon’s, ‘Mankind Is No Island’, utilises film techniques, mise-en-scene and literary devices to explore the intangible concept of belonging. A sense of affiliation is established through the absence of belonging amongst the subjects of homelessness in two iconic cities, New York and Sydney. Representation All representation is subjective and incomplete. It allows us to understand an issue from a range of perspectives. The consideration of a variety of perspectives is necessary to developing a genuine understanding of an issue. Language is used to articulate, our particular perspective on an issue. The productive tension between the texts we have studied demonstrate how conflicting perspectives allow audiences to fully understand the complexity of representations. Appreciating that no single perspective contains the ‘truth’ allows us to value the unique contribution of each perspective. When preparing drafts: – Start with an idea that allows for growth in multiple directions – Choose one of those paths & stick to it – Allow yourself to end an idea then start again with new direction. Drafting strategies – Rewrite sections of your story that seem to be wasted. – Have a list of multiple next ‘moves’ to choose from – When stuck do some research of the topic – Work on the structure of the story. Intro – Answer the question -> INDICATE 2 ISSUES – Elaborate stance – outline issues further. – Clarify stance if you have made an overall assessment i.e. the effectiveness of Australian legal system. – Link back to question, reiterate stance/direction Note: Maximum clarity Body 1* – Issue #1 Legal Response. Body 2 – Issue #1 Non-legal response. Body 3 – Issue #2 Legal Response. Body 4 – Issue #2 Non-legal response. Conclusion * Topic sentence: Introduce focus of paragraph [your point] Prove: – Elaborate, clarify – Discuss example – legislatiom, stas, cases, keywords, key terminolotiy, quotes, related to this topic – Evaluation – reiterate what this evidence proves – Link – > main argument.

The Need to Restructure Gender Identies essays

The Need to Restructure Gender Identies essays In her novel To the Lighthouse Virginia Woolf explores love as a construct of gender systems. Being good to someone, a simple, basic definition of love, has a destructive effect on both the giver and receiver of the love. These destructive tendencies of love are shaped by gender identities, which Woolf establishes early in the novel; Mr. Ramsay is fixed as hard and logical and Mrs. Ramsay as soft and emotional. In the novel Mr. and Mrs. Ramsays love is destructive, such that it is wearing each of them individually because of their strict gender identities. Woolf focuses on this damage their love does because of their gender identities, yet also provides a sound basis for promoting loves benefits, for although they are draining each other as individuals, their love produces a functional marriage and happy family. Also many of the summerhouse visitors reap benefits from their love. Woolf emphasizes the need for individuals to not restrict themselves to a single gender identity, b ut blend both male and female traits into their personalities. Although love cannot exist without some harmful consequences, love is more constructive for the individual this way. Mrs. Ramsays version of love, determined by her gender identity, is giving too much sympathy. Mr. Ramsay is worn by her love because by giving him comfort, she weakens his self-esteem or self-assurance. He relies on her for reassurance. As Bankes points out, It was astonishing that a man of his intellect . . . could depend so much as he did upon peoples praise (22-23). During the Last Supper, somebody poses a question, inquiring about the Waverley novels staying power (lasting ability). Because of Mr. Ramsays . . . temperament, which must have praise, which must have encouragement, naturally [he] began to be uneasy; to want someone to say, Oh, but your work will last (107). Even when the topic is not...

Power of Plutonium

Power of Plutonium Free Online Research Papers I believe that we should we begin to manufacture one of the most destructive and powerful elements on the planet again? Nuclear chemists and engineers say yes, but the public says no. The United States stopped making this element with the United Nations ban on manufacturing nuclear weapons. But, with the continuing problem with our thinning energy resources, some want us to begin using more nuclear energy and less energy from natural resources. This paper is going to discuss what plutonium is, the advantages and disadvantages of its use, and why we should think about restarting our production of this useful element. during World War two United States dropped two nuclear bombs, Fat Man and Little Boy on Japan ending the war, the public has had some type of understanding about the power of plutonium and its devastating properties, but that is all anyone heard. After WWII, Americans started to think about what the atomic bomb could do to the people of the United States. When the U.S. started to build more reactors and produce more of the substance but mostly for our nuclear weapons programs. But some times this reaction can get out of hand, this is called a melt down. this can produce harmful effects if it isnt controlled quickly enough. After such instances as the Hanford, Washington reactor meltdown and the accident in the U.S.S.R. at Chernobyl. The United States government banned nuclear testing and also ended the production of plutonium.(Ref. 5) Now we have a problem. We are in need of future sources of energy to power our nation. We are running out of coal and oil to run our power plants.(Ref. 7) We also need it to further our space exploration program. People need to understand the advantages to using plutonium and that the disadvantages are not as catastrophic as they seem. With the turn of the century on its way, the reemergence of plutonium production will need to be a reality for us to continue our way of life. In 1941, a scientist at the University of California, Berkeley, discovered something that would change our planet forever. Glenn T. Seaborg, is credited for the discovery of the element plutonium.(ref. 10) Plutonium, or Pu #94 on the periodic table, is one of the most unstable elements on the earth. Plutonium is made when Uranium 235, absorbs a neutron. Plutonium is a silver metal that has a very high density of 19.816 g/cm3.(ref. 10 ) It is rarely found in the earths crust but the majority of the substance has to be produced by man at the core of nuclear reactors. Plutonium can be found fifteen different forms, or isotopes and their mass number can range from 232-246.(ref. 13) Radionuclide batteries used in pacemakers use Pu-238, while Pu-239 is used in reactors and for Nuclear weapons.(ref. 13) This paper will focus on the isotopes Pu-238 and Pu-239. Plutonium can be very helpful to the United States. there are many reasons for its use. The three major advantages to using this element are for an energy source, power for nuclear propulsion in space exploration and thermo-electric generators in cardiac pacemakers. The first use for plutonium, nuclear power, is obviously the most beneficial use. Plutonium 239 can be used to power nuclear reactors. The average nuclear reactor cont ains about 325 kilograms of plutonium within its uranium fuel.(ref. 7) This complements the uranium fission process. With the continually decreasing supply of coal and oil to power our nation, we need a substitute to complement our energy needs and right now the best replacement is that of nuclear energy.(ref. 7) At the moment there are one hundred and ten nuclear power plants in the United States and they produce one-fifth of the nations electricity. Nuclear energy has been proven to be the cheapest, safest, cleanest and probably the most efficient source of energy.(ref. 7) Nuclear power plants do not use as much fuel as the plants burning coal and oil. One ton of uranium produces more energy than several million tons of coal and plutonium can produce much more energy than uranium.(ref. 12) Also the burning of coal and oil pollute our air and the last thing we need is more pollution to worsen the greenhouse effect. Nuclear power plants cannot contaminate the environment because they do not release any type of pollution.(ref. 2) Plutonium can also be recycled by using a enrichment process. This will produce even more energy. Coal and oil can not be recycled. What is left by their uses is what has been contaminating our atmosphere since the 1800s. You might ask how exactly is plutonium converted into an energy source? Well it is obviously quite complicated to explain. Basically, power comes from the fission process of an atom of the element and produces over ten million times the energy produced by an atom of carbon from coal. One kilogram of plutonium co nsumed for three years in a reactor can produce heat to give ten million kilowatt-hours of electricity. This amount is enough to power over one-thousand Australian households.(ref. 7) Presented with this information, it is only common sense that we should not depend upon fossil fuels to take us into the 21st century. It is obvious that our future lies in the hands of nuclear reactors and the use of plutonium. The second major use for plutonium is for space exploration with its ability to power nuclear propulsion. Nuclear electric propulsion is using energy from plutonium to power space vehicles.(ref. 3) One of the major goals of NASA space program is to, one day, get to Mars, and it looks like the only way it is going to happen in our current fiscal condition, is if we use plutonium, instead of chemical fuel, to power our explorations. Nuclear electric propulsion can be defined as using small plutonium based bricks, to power space vehicles for interplanetary trips. Nuclear electric systems provide very low thrust levels and use only very small amounts of fuel during the voyage.(ref. 3,4) Using electric propulsion also allows the use of less fuel making the spacecrafts launch weight much lower than it would be with chemical fuel.(ref. 3) The last beneficial use for plutonium is for cardiac pacemakers. The thermo-electric generator, which is powered by radionuclide batteries, that powers the pacemaker uses Pu-238. One of the obvious uses of plutonium, whether is an advantage or disadvantage, is for weaponry. It is an advantage if we need to use it against a foe, but it is disadvantageous is our foes use it against the United States. Now that we are at the hands of the Non-proliferation Treaty and the Test Ban Treaty, we no longer can make and/or test nuclear weapons. (Ref. 5) This should help end ideas about nuclear war and other disadvantages to having plutonium in other country’s supplies. Now that we have recognized three important uses for Plutonium and that the threat of nuclear war is no longer as feasible as before, we should recognize the disadvantages of this great energy source. They mostly have to do with excess waste and health effects from the use of nuclear energy. In 1986, a reactor located in Russia at the Chernobyl power plant had a meltdown and radiation escaped from the plant.(ref. 8) Several dozen died from this incident. Nuclear explosions produce radiation. When it comes within human contact, radiation hurts cells, which can sicken people. The cause of the Chernobyl meltdown was mostly because of human error. They tried to perform an experiment at a time when they shouldnt have, and many people paid for their incompetence. There are waste disposal problems that occur with the use of nuclear reactors. Waste also produces radiation, which can be lethal. Since waste ca n hurt and kill people who come in contact with the substance, it cannot be thrown away in a dumpster like other garbage. Waste has to be put in cooling pools or storage tanks at the site of the reactors. Another problem is that the reactors can last for a maximum of fifty years. Even though plutonium is chemically hazardous and produces harmful radiation, it isnt close to being the most toxic substance on the planet. Such substances as caffeine or radiation from smoke detectors, that have the same amount of mass as plutonium, can have a greater toxicity. (Ref. 2) There are basically three ways plutonium can hurt humans. The first is ingestion. Ingestion, though not totally safe, it is not as bad as we think. The fact is, plutonium passes through the stomach and intestines and cannot be absorbed and therefore, is released with other waste we produce.(ref. 1) The second route plutonium can take to be hazardous is through open wounds. This form of contact is very rare and basically cannot happen if the element is handled correctly with protective measures such as correct clothing and health monitor procedures.(ref. 1) The last, main threat to our society comes from inhalation. If inhale d, plutonium is exhaled on the next breath or gotten rid off through the spit flow from the throat and bronchial system and released as with ingestion. But if some could get trapped and put into the blood stream or lymph nodes.(ref. 1) This has the possibility to cause cancer in the future. This might sound frightening, but what we need to realize is that inhaling this type of substance is part of some of our daily lives. The problem of inhaling Pu-239 isnt much different than inhaling such radio nuclides like decaying particles from radon. Radon is a radioactive gas that can cause cancer. (Ref. 6) It comes from the decay of uranium in soil, rock and water. Inhaling this substance can damage your lungs and lead to cancer over a lifetime. The gas can affect everyone, no matter where you live, work or go to school. If you live in a brick house, you could be taking a serious risk if you dont get the radon level tested. A 1990 National Safety Council report showed that radon causes, on the average, approximately 14,000 deaths a year and can go as high as 30,000 deaths a year.(ref. 6) After learning about what radon gas can do to humans, shouldnt we be more concerned about what a naturally occurring substance can do rather than worrying about what plutonium, and its rare contamination might do. Also, how many American citizens will actually have a chance to come in contact with any plutonium isotope in their lifetime? As you can see, if we start to produce plutonium once again, we will benefit greatly from its use. We can use it to help power nuclear reactors, which can power our nation. It can also be recycled and used once again which is one thing fossil fuels cannot do. Nuclear electric propulsion and its use of plutonium will help power space exploration into the next century and maybe even get us to Mars. Pu-238 is also helpful in powering cardiac pacemakers, one of the great biomedical inventions of the1900s. With these constructive and productive uses, we sh ouldnt even debate on the fact that we need plutonium for the future. You may think that by producing plutonium, it will automatically go toward our nuclear weapons program. With non-proliferation and testing banned, this, obviously, is no longer an option. What about nuclear waste and radiation exposure? Well, unless an individual does not use safety precautions and other preventive measures when and if he handles the substance, he or she shouldnt expect anything less of radiation poisoning and contamination. If youre still concerned about exposure to nuclear radiation, youre in for a big surprise when you find out you cant avoid it. There is more of a chance you will die from radon gas than there is from plutonium.(ref. 6) After considering all these factors, whether they are advantages or disadvantages, it is obvious that the use of plutonium is, in fact, feasible and the disadvantages are highly unlikely to affect your health and well being. You probably should be more worried about dying in an automobile accident or a plane crash. Bibliography 1.) http://world-nuclear.org/reference/pdf/uoc-study.pdf 2.) laplace.ee.latrobe.edu.au:8080/~khstatements/perspectives -on-plutonium.html (A Perspective on the Dangers of Plutonium) 3.) letrs.nasa.gov/cgi-bin/LeTRS/browse.pl?1994/E-8242.html (Nuclear Electric Propulsion) 4.) spacelink.msfc.nasa.gov/NASA. Projeicles/Proposes.Sysytems/Nuclear.Propulsion ( NASA fact sheet, Dec. 1991) 5.) tqd.advanced.org/3471.nuclear_politics_body.html (Nuclear Politics) 6.) www.epa.gov/docs?RadonPubs/citquide.txt.html (Citizens Guide to Radon) 7.)www-formal.stanford.edu/jmc/progress/nuclear-faq.html (Questions about Nuclear Energy) 8.) www.ieer.org/ieer/fctsheet/fm_hlth.html (IEER: Fissile Materials Health Environmental Dangers) 9.) www.nucmet.com/CompOver.html (NMI Company Overview) 10.) www.teleport.com/~aaugiee/plu.htm (Background on Pu-238/239) 11.) www.uilondon.org/nfc.html (The Nuclear Fuel Cycle) 12.) www.uilondon.org/ci3_plu.html (Core Issues no.3, The Uranium Institute 1995) 13.) www.uic.com.au/nip18.htm (Plutonium) C/ENS Zack Beecher Bn Public Affairs Officer Capt. 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