Chinese media Essay Example | Topics and Well Written Essays - 1500 words

Chinese media - Essay Example The same could be said of China, a country in which activism is viewed as illegal and an act against the values shared by the government. However, the presence and availability of media activism has increased the country’s ability to take part in activism. With a massive population, media activism in China has provided a platform for communication for many people gagged from taking part in conventional activism processes (Wallis 410). Specifically, people in China have been cited as one of the greatest consumers of media activism in a country where freedom is not viewed as a democratic right. Media activism in China may be defined from two contrasting perspectives. There is the government and society definition of media activism. For the Chinese government, media activism is only legal where the users use the available technologies in communication to cite the positive features of the government. For instance, media houses in China are licensed to provide information as specified by the government. This form of media activism does not allow for criticism of highlighting of the errors by the governing body. The definition also covers providing information on the acts of the government depicting change, control, superiority and just (Yang 54). The social definition of media activism in China is the completely opposite of the stated definition. The definition mainly focuses on highlighting the need of change. Considering that the conventional media in China has no power to provide voice to the citizens, other media sources are relied upon to voice the frustrations on the government. Media activism from the people is defined as act by which the society is provided with an opportunity to challenge the existing non-democratic rule of law. China is highly defined by a rule of law inconsiderate of the rights of people. Problems in the nation can only be headlined

Dependent clause Essay Example for Free

Dependent clause Essay TRANSLATION: The process of turning an original or source text into a text in another language. TRANSLATION TECHNIQUES Direct Translation Techniques are used when structural and conceptual elements of the source language can be transposed into the target language. Direct translation techniques include: * Borrowing * Calque * Literal Translation Borrowing Borrowing is the taking of words directly from one language into another without translation. For example software, funk. English also borrows numerous words from other languages; abbatoire, cafe, passe and resume from French; hamburger and kindergarden from German; bandana, musk and sugar from Sanskrit. Calque A calque or loan translation is a phrase borrowed from another language and translated literally word-for-word. Examples that have been absorbed into English include standpoint and beer garden from German Standpunkt and Biergarten; breakfast from French dejeuner. Literal Translation A word-for-word translation can be used in some languages and not others dependent on the sentence structure: El equipo esta trabajando para terminar el informe would translate into English as The team is working to finish the report. Sometimes it works and sometimes it does not. And one sentence can be translated literally across languages does not mean that all sentences can be translated literally. El equipo experimentado esta trabajando para terminar el informe translates into English as The experienced team is working to finish the report (experienced and team are reversed). Oblique Translation Techniques Oblique Translation Techniques are used when the structural or conceptual elements of the source language cannot be directly translated without altering meaning or upsetting the grammatical and stylistics elements of the target language. Oblique translation techniques include: * Transposition * Modulation * Reformulation or Equivalence * Adaptation * Compensation Transposition This is the process where parts of speech change their sequence when they are translated. It is in a sense a shift of word class. Grammatical structures are often different in different languages. Transposition is often used between English and Spanish because of the preferred position of the verb in the sentence: English often has the verb near the beginning of a sentence; Spanish can have it closer to the end. This requires that the translator knows that it is possible to replace a word category in the target language without altering the meaning of the source text, for example: English Hand knitted (noun + participle) becomes Spanish Tejido a mano (participle + adverbial phrase). Modulation Modulation consists of using a phrase that is different in the source and target languages to convey the same idea: Te lo dejo means literally I leave it to you but translates better as You can have it. It changes the semantics and shifts the point of view of the source language. Through modulation, the translator generates a change in the point of view of the message without altering meaning and without generating a sense of embarrassment in the reader of the target text. It is often used within the same language. The expressions es facil de entender (it is easy to understand) and no es complicado de entender (it is not complicated to understand) are examples of modulation. Reformulation or Equivalence Here you have to express something in a completely different way, for example when translating idioms or advertising slogans. The process is creative, but not always easy. Adaptation Adaptation occurs when something specific to one language culture is expressed in a totally different way that is familiar or appropriate to another language culture. It is a shift in cultural environment. Should pincho (a Spanish restaurant menu dish) be translated as kebab in English? It involves changing the cultural reference when a situation in the source culture does not exist in the target culture (for example France has Belgian jokes and England has Irish jokes). Compensation In general terms compensation can be used when something cannot be translated, and the meaning that is lost is expressed somewhere else in the translated text. Peter Fawcett defines it as: making good in one part of the text something that could not be translated in another. One example given by Fawcett is the problem of translating nuances of formality from languages that use forms such as Spanish informal tu and formal usted, French tu and vous, and German du and sie into English which only has you, and expresses degrees of formality in different ways. WORD: It is one of the units of speech or writing that native speakers of a language usually regard as the smallest isolable meaningful element of the language, although linguists would analyze these further into morphemes There are eight different kinds of words in the English language. Nouns| Pronouns| Adjectives| Verbs| Adverbs| | Prepositions| | | Conjunctions| | | Interjections| | | NOUNS and VERBS are the most common and most essential. Every English sentence MUST contain a NOUN and a VERB. NOUNS name: people, places, things, ideas. They are always singular or plural. They are always common or proper. They may show ownership. PRONOUNS replace nouns. They have person, number, and case. ADJECTIVES describe nouns. They answer three questions: Which one? What kind? How many? VERBS have three jobs: show action, act like an equals sign, or hang around a main verb to show tense. They also have person, number, and case. ADVERBS describe verbs. They answer four questions: When? Where? How? How Much? PREPOSITIONS tell anywhere a mouse can run. CONJUNCTIONS connect things. INTERJECTIONS jump into show emotion. Sentence: it is a sequence of words capable of standing alone to make an assertion, ask a question, or give a command, usually consisting of a subject and a predicate containing a finite verb. Kinds of sentences. Simple Sentence it is a sentence having no coordinate clauses or subordinate clauses. Complex Sentence it is a sentence composed of at least one main clause and one subordinate clause. Compound Sentence it is a sentence composed of at least two coordinate independent clauses. Phrase it is a group of words forming an immediate syntactic constituent of a clause. Clause it is an expression including a subject and predicate but not constituting a complete sentence. Pre-modifier is a word (or words), usually adjectives or adverbs, that comes before the word that it describes. Basic Modifiers * Adjectives * Adverbs * Prepositional Phrases More Modifiers * Degree Modifier * Presumptive Modifier * Summative Modifier Post-modifier is a word, phrase, or clause that functions as an adjective or adverb to limit or qualify the meaning of another word or word group. Adjective Order Adjectives can be used to describe lots of things, from physical size, age, shape, colour, material, to more abstract things like opinion, origin and purpose. We can use adjectives together to give a detailed description of something. Adjectives that express opinions usually come before all others, but it can sometimes depend on what exactly you want to emphasize. For instance: That nice, big, blue bag. (You like the bag. ) That big, nice, blue bag. (You like the colour. ) When adjectives are together there is a general rule for the position of each type adjective, these are: Position| 1st*| 2nd*| 3rd| 4th| 5th| 6th| 7th| 8th| | Opinion| Size| Age| Shape| Colour| Material| Origin| Purpose| | Nice| Small| Old| Square| Black| Plastic| British| Racing| | Ugly| Big| New| Circular| Blue| Cotton| American| Running|.

Criminals are a product of their environment

Criminals are a product of their environment This essay will concern criminals in regards to their ecology. Ecological criminology is the observing of criminality, crime and victimization in relation to the area of individuals and organizations and how it forms and affects them. In broad terms crime is seen to evolve in pathological conditions of certain communities and areas. This association between crime and certain parts of a city namely areas with pathological conditions has a long past. Theorists such as Fregier (1840), Mayhew(1862) and The Chicago School of Sociology have contributed substantially to the debate of crime and the environment. Through Clifford Shaw and Henry McKays (1942) book  [1]  and other sociologist work such as Park and Burgess(1925)  [2]  comes the zonal hypothesis. It was found that cities develop concentric zones of life and activity. This is called this the concentric zone model. The model consist of five zones in the following order , the center is the Central business district, the transition zone of mixed residential and commercial uses, low-class residential homes (inner suburbs), better quality middle-class homes (Outer Suburbs) and the commuters zone. Baldwin and Bottoms also point out that offences are gathered nearby the city center According to Chicago School each district in concentric zones yields on something of the traits and abilities of the occupants. Through this knowledge it became known evident that there was a large amount of pathological behavior such as juvenile delinquency and alcoholism in the zone of transition. It also seems that the zone of transition adapted its own social organization such as cheaper rents, an unsettled population, and a few settled institutions and also tended to house recent peers of immigrants which seemed to yield the same forms of behavior including crime. Before one looks at the explanations of why the zone of transition is a problematic zone there are some methodological problems one must look at. There may be a distinction between the offence and the offender rate e.g. one person may be the cause of majority of specific crimes in a certain area. The rationality of authorized figures in relation to area based data may be brought into question. In the explanation given to define the zone of transition by the Chicago school it was alleged that the zone accommodated people unfamiliar to each other, urban life and to America also their surroundings seemed fluid which is also termed social disorganization. Social disorganization was based on three flexible elements such as poverty (unlike Sutherland which will be discussed further on), as the poor societies do not possess satisfactory funds to handle the difficulties occurring. The increase of residential mobility and racial diversity causes deterioration of community control through the deficiency of mutual beliefs which is viewed as permitting illicit conduct to advance and be transferred from one generation to the next. Similar to the social disorganization thesis Schuerman and Kobrin (1986) alleged a three phase procedure which denotes the evolving of high offender rate areas. These where shifts in land which meant increase in renting, changes in population which signified a decrease in people and increase in quantity of dissimilar beings as well as Changes in socio-economic statues which means additional inexperienced beings and advanced quantity of jobless people. In contrast to the idea that area of residence takes on character and quality of inhabitance, it is also noted that the inhabitants of an area take on characteristics and value of the area. This means the societal life of a zone can stimulus illicit inspiration. The societal life of a zone may have long term impact on the individuals personality, social activities, though processes a daily routines. As opposed to ideas such as certain areas influence individuals and vice versa, the theory of differential association according to Shaw and McKay, may illustrate how delinquent activities are ethnically transferred from one person to another. Edwin Sutherland (1924 and 1939) it was claimed that illicit conduct is cultured in contact through other individuals predominantly in intimate personal settings. This kind of knowledge not merely instructs the person about the detailed practices of performing delinquency, but similarly guides their drives, motives, attitudes and definitions of the law (Jones 2006). Wherever an individual is exposed to excess definitions favorable to violation of the law over definitions unfavorable to violation of the law they are more probable to turn out to be a criminal. The probability is ascertained by discrepancies in regularity, concentration, significance and period of the relationship. An exemplification of this is as Orcutt (1987) states that students were more likely to smoke marijuana if one of their four closest friends did. Alike Social disorganization Wolfgang and Ferracuti (1967) state that subcultures of violence can often be found in poor zones, they also state that individuals from such backgrounds learn positive approaches towards vehemence though a process of differential learning, association or identification. Wolfgang and Ferracuti also claim that such a procedure might aid to dispel any outlooks of culpability that might perhaps arise as of inside such individuals. The fortes of Sutherlands theory lay in its capability to demonstrate delinquencies are not related to poverty. For instance Sutherland applied the concept to white-collar and professional crime, asserting that people turn into white collar criminals since they became engaged into a business culture that deemed unlawful practices as lawful Sutherland reasoned that numerous clusters of people in civilization varied in their views as to what caused suitable conduct and out of this multiplicity of opinions, culture conflict turns into the most definite proof of the social disorganization within society, and an underlying cause of differential association. For the purpose of criticism and analysis in regards to the ideas given by the Chicago school of sociology, the image of urban life assumed by the Chicago school is no longer the same. This is because it assumes an even, unchanging landscape. An Additional reproach of the Chicago school is that British capitals post Second World War did not look like the Chicago concentric ring pattern due to people fleeing away from the citys in fear. The theory is also insubstantial on individuals as it doesnt institute enough for decisions made by individuals such as highly emotive crimes such as crimes of passion e.g. serial killer which doesnt associate with no one to learn his modus operandi also known as method of operating. Theorist such as Tittle et al. (1986) claim that it is not the mocking of specific methods or the learning of illicit outlooks that is significant, but the learning of enthusiasms to participate in delinquency that create distinct relations. McCarthy (1996) revealed compelling proof of tutelage in techniques of delinquency between homeless youths Haynie (2002) establish that the quantity of criminal contacts in a persons network not individual had a strong optimistic outcome on that characters following criminality, but was also a stronger effect than the contacts total levels of criminality. Meaning and individual which has more criminal minded friends then an individual which only has one extreme criminal friend is more likely to be influenced. In light of everything mentioned what can be understood is that different theorist have different views and ideas on factors and elements which condition a person to act in a criminal way. Therefore some theorist claim people are the product of certain areas whereas others believe that the areas are the product of the people living in it, which effectively means there is a two way presses going on. On the other hand some theorist believe that poverty is the underlining cause of delinquency where as some theorist believe that poverty plays no role and that it is merely the individuals motivation which is fuelled by engaging with delinquent people in an close intimate setting.

Causes Of Joint Failures Engineering Essay

Causes Of Joint Failures Engineering Essay This report emphasizes methods for determining, minimizing, and uniformly distributing the stress for cable joints and HV bushings. The analysis is intended to reduce the failures caused by high stressed, to provide maintenance cost reductions, and to improve service reliability. Predicting the remaining life of a joint is a major challenge to electric utilities, one that has long had the attention of design and maintenance engineers who manage overhead transmission lines. The recent joint failures reported by a few utilities follow the trend caused by aging joints and conductors. These problems are expected to increase over time because of higher line loadings under the current deregulated environment. Since typical inspection techniques have many limitations, it is currently difficult to isolate the components early enough to reliably avoid failure. If two electrical conductors are joined to form a stationary electric contact, i.e. an electric joint, the joint resistance does not remain constant but will increase during operating time. This long-term behaviour of the joint resistance can be influenced by different aging mechanisms like corrosion processes, interdiffusion, electromigration, fretting and stress relaxation. Especially in bolted aluminum joints at high current load, i.e. at high joint temperatures stress relaxation may play an important role in joint aging. Creep deformation of the conductor material decreases the joint force. The area and the number of a-spots decrease and may cause an increase of the constriction resistance which may occur suddenly, if mechanical vibrations act on the joint. In order to describe the factor of influence of creep on the aging behaviour of high current bolted aluminum joints, the relationship between the decreasing joint force and the joint resistance and the development of the joint force have to be determined. The relationship between the decreasing joint force and the joint resistance can be evaluated on the basis of the surface profile of the rough joint surfaces [7]. In order to extrapolate the development of the joint force beyond the time of experiments and to reduce the number of experiments with numerous types of joints geometry the development of the joint force is calculated. The calculation is performed by means of the Finite Element Method (FEM) based on material parameters of the conductors and the physical fundamentals of creep [8]. Due to the structural characteristics of bushings and cable ends. the electric fields near the grounding flange are highly concentrated. and have a strong axial component, resulting in corona and gliding discharge. The traditional way of improving this condition is to apply semiconducting paint or band on the insulating surface by the flange. The electric field is evened by decreasing the surface resistance of the insulating surface. However, the effect is not very good due to the thinness of the applied material. In addition, the applied material will aging or peel off in time, decreasing its effect to zero. Failure Mechanisms Causes of Joint Failures Joint failures are expected to increase with the increase demand for heavier loading operations. Some of the key contributors to joint failures include: inadequate cleaning of the conductor, complete absence of conductor cleaning, absence of corrosion inhibitor, improperly inserted conductor, incomplete die closures, and high load fault currents contributing to aging with thermal stresses. Installation and Quality Assurance Issues One of the main reasons for joint failures is improper installation. Misalignment of steel sleeve, crimping with wrong dye, no grease present in splice, and improperly cleaned conductor can greatly accelerate the failure process. Other factors that influence failures are internal crevice corrosion, releasing of compression force by thermal cycling, creep due to line tension, and fatigue cracking on bent joints. Corrosion Problems Corrosion is a major factor in the deterioration process of splice/connectors. Figure below is anexample of a failed field joint. Characteristics of a Joint Failure The final failure mode of connectors is either mechanical or thermal. Sometimes the steel sleevehas been installed off-center, resulting in one end of the conductor being barely inserted. This can result in a mechanical failure. A thermal failure is the result of high resistance heating or individual strands failing with the same consequence. These situations can either melt components or cause the joint to lose its connection. Failures generally show evidence of both mechanical and thermal failure in combination. Temperature and Resistance Relationship The degradation of a joint can be observed by changes in its resistance and temperature. The interface resistance is a very small part of the total joint resistance until there are signs of damage. Because of this effect, no noticeable heating takes place until late in the failure cycle. High temperature values are usually the result of high resistance measurements in a component. Resistance is a function, to varying degrees, of temperature. As an abnormally high resistance component begins to heat up, resistance increases, resulting in an even faster rate of temperature increase. This physical property of electrical conductors can quickly make a bad situation worse! In addition, as the component heats it may reach the material melting point. Often a complete structural failure results and the line drops. More often, however, the melted metal re-solidifies; as this happens resistance decreases, and thus temperature, may be reduced. This is only a 2-3 temporary phenomenon, but if the inspection is conducted at this point in the failure cycle, the data will certainly be misleading! Eventually both resistance and heating will again increase, and the material will again melt. This melting and re-welding can take place many times before total failure occurs, especially when copper alloy components are involved. Design of High Voltage Cable Joints General For the stress control, basically the following methods are known: Geometrical, where the contour of conducting elements is controlling the electrical field at the end of a high voltage cable. Resistive, where the resistance of a semiconducting material is used to reduce the electrical stress in high field regions. Refractive, where material with a high permittivity is used for pushing away the field from high stress regions. The first method which refers to the geometry of the joint, is more of a mechanical way of reducing or controlling stress. If we have to cables and there is a joint connecting them, what ever the stress distribution may be, it is possible to control both the parameters that are stress concentration and stress distribution. For example, if we have a straight joint exactly alligned with the cable shape, whatever stress it shows, we can reduce or vary the stress distribution, and stress concentration can be decreased by applying changes to the joint shapes such chamfering the joint a bit, and also by varying its size to a possible extent. While the resistive and refractive method is successfully used for medium voltage applications up to 72.5kV maximum, the geometrical field control method is the standard method for high voltage and extra high voltage applications. Controlling the field by a well defined contour still offers the best quality from design and production point of view. To install a pre-moulded joint they are normally slipped-over the prepared cable on site by using grease and special push-on tools. Another technology, widely used in the medium voltage range, is the cold shrink technology. With this technique a pre-moulded joint body is pre-expanded on a support tube, which can be removed while being placed around the cable on site. It has the advantage that no push-on tools must be used. Electrical Design One basic function of every termination or joint is to control the electrical field at the endof a cable or between two cables. This means that the electrical field is controlled by the contour of conducting elements integrated into the joint body. During design stage FEM (Finite Element Method) calculation programs are an important tool as the latest versions of these programs offer a vast range of possibilities such as: Calculation of the electrical field in any direction of the joint body Optimization tools for calculating the optimum shape of stress control elements Solving of coupled fields, like thermo mechanical stresses Models for non-linear behavior of materials, like stresses in polymeric materials Simulation of slip-on procedures Choice of Material Nowadays the materials used for high voltage joints are silicone rubber and EPDM. The basic requirements for an elastomeric material are as follows: Sufficient mechanical properties in order being expandable in the required range. Capability to withstand the required temperature range. Availabilty of material with constant quality and constant purity. Low ageing with respect to electrical and mechanical properties. According the requirements given above silicone rubber is an ideal and preferred material for cable joints. Therefore it can be concluded that silicone rubber is an excellent material for the use in cable accessories as it can fully cope with the electrical, mechanical and thermal requirements given by nowadays polymeric cables. Ageing An important aspect, which we still have to consider is the ageing factor of insulating material and interface. The ageing can be described by the life time law as follows: EN * t = const. Where, E = Electrical field in the insulation t = Time, where the electric field is applied N = Lifetime coefficient Stress Analysis For the Stress Analysis we have used a Finite Element Analysis (FEA) software in order to find the electric field distribution. We have done this by MAXWELL SV software. A little bit about the software first and then we proceed towards our analysis. USING THE SOFTWARE We have used a student version of MAXWELL SV software depending on the availability, which allows us to analyze a problem on the basis of 2D geometry. The resistive solution for reducing stress is of great importance as well. If another piece of metal is being used to joint two pieces of cable, it could produce more stress on the joint due to its own resistive and other properties. So, if the two pieces of wire are making contact through a third material, normally the third material is to be used as a jacket that overlaps two wires as shown below. In the above arrangement two cables have direct contact with each other and third material is making parallel circuit with two cables and is supporting electrical current through a joint. In the arrangement that involves a joint in series, the third material is making a series circuit with two cables and adding extra resistance to the joint with will increase the stress on the joint. On the other hand if we talk about the refractive part the situation could be explained as , if a single piece of sleeve is taken and we plot the rise in temperature due to sleeve. Exposed part of the cable will have low temperature as compared with the portion under sleeve and it will create difference of resistance at both ends of wire under sleeve, due to this difference thermal stresses on the ends of the two cables being joint. To reduce the stress it is recommended that sleeve should be good conductor to heat and the temperature of exposed part will be as same as the part under the shielded portion. SIMULATION BASED ANALYSIS For our simulation we have considered two cables joined together, where the joint between them is assumed to be a perfect one, and hence we can treat it as one perfect conductor. Therefore, the conductor can be a single copper cable as demonstrated in the results below. In reality when the cables are to be joined, the ends of the two separate cables must be stripped of its insulation. For modeling purposes this has been represented by a gap in the insulation between the conductor and outer sheath. This gap will initially be left empty to see the distribution with no insulation. In attempt to distribute the stress uniformly the gap will then be filled with a variety of material. The layer of the insulation at the joint is generally a lot thicker than the rest of the cable, and the simulations below make uses of this. The conductor has been assigned as a source of 500KV, and the outer sheath at ground potential. The insulating material for the two cables is XLPE. The results presented below show stress distribution in various scenarios where the geometry has been unchanged, and different insulation materials have been tested. Due to different properties of different insulating materials the stress distributions also vary. The first result presents the field distribution, where the gap has been left empty, to examine the initial stress with no insulation at all. Figure 1: Cable joint with no insulation at the joint XLPE Cable Insulation Outer Sheath (0V) Gap HV Conductor (500KV) In this situation the stress in the gap at the joint and surrounding insulation in very high. This would eventually result in failure of the joint due to the extreme stresses. Now that the initial stress has been determined, it is necessary to find how to minimize and uniformly distribute the stress. As mentioned previously the gap is now filled with a layer of a variety of materials. The layer at the joint is thicker than the insulation of a normal cable as to attempt to minimize and create a more uniform distribution of stress. Below the distribution for a variety of materials used to insulate the joint is presented. Figure 2: Field distribution for Silicon Insulated cable joint Joint Insulation Figure 3: Field distribution for FR4-Epoxy insulated cable joint Figure 4: Field distribution for Polyimide-Quartz insulated cable joint Figure 5: Field distribution for Polyethylene insulated cable joint Figure 6: Field distribution for Teflon insulated cable joint Figure 7: Field distribution for Polystyrene insulated cable Figure 8: Field distribution for Porcelain insulated cable Notice that there are two effects of using the thick insulation at the cable joint, first the concentration of the stress is brought down, and secondly the stress is distributed more uniformly. These are both important in ensuring the insulation is efficiently used, and maximizes the life span of the insulation. Notice that in the case of all but Polyimide-Quartz insulation the concentration is minimized somewhat, though the main effect is the uniform distribution of stress. On the other hand Polyimide-Quartz insulation greatly decrease the stress concentration, though the distribution is undesirable as the majority of the stress is concentrated at the conductor surface which will result in uneven wear of the insulation. Thus the optimal insulation will have even distribution of stress, and somewhat minimize the stress concentration. It was determined that the silicon insulation is best suited for this purpose. The distribution of the stress across the joint and surrounding insulatio n is very uniform, and the concentration is somewhat minimized as well. This result is consistent with industry practices as in general a thick layer of silicon is used at the joint for insulation []. Conclusion Cable Joints The Electric Stress has been determined for the general structure of a high voltage cable using finite element analysis, and a method suggested to create a more uniform, and less concentrated distribution of stress. The results obtained agree with what is currently standard practice in the high voltage industry. FINITE ELEMENT ANALYSIS Background Finite Element Analysis (FEA) was first developed in 1943 by R. Courant, who utilized the Ritz method of numerical analysis and minimization of variational calculus to obtain approximate solutions to vibration systems. Shortly thereafter, a paper published in 1956 by M. J. Turner, R. W. Clough, H. C. Martin, and L. J. Topp established a broader definition of numerical analysis. The paper centered on the stiffness and deflection of complex structures. By the early 70s, FEA was limited to expensive mainframe computers generally owned by the aeronautics, automotive, defense, and nuclear industries. Since the rapid decline in the cost of computers and the phenomenal increase in computing power, FEA has been developed to an incredible precision. Present day super computers are now able to produce accurate results for all kinds of parameters. What is Finite Element Analysis? FEA consists of a computer model of a material or design that is stressed and analyzed for specific results. It is used in new product design, and existing product refinement. A company is able to verify a proposed design will be able to perform to the clients specifications prior to manufacturing or construction. Modifying an existing product or structure is utilized to qualify the product or structure for a new service condition. In case of structural failure, FEA may be used to help determine the design modifications to meet the new condition. There are generally two types of analysis that are used in industry: 2-D modeling, and 3-D modeling. While 2-D modeling conserves simplicity and allows the analysis to be run on a relatively normal computer, it tends to yield less accurate results. 3-D modeling, however, produces more accurate results while sacrificing the ability to run on all but the fastest computers effectively. How Does Finite Element Analysis Work? FEA uses a complex system of points called nodes which make a grid called a mesh . This mesh is programmed to contain the material and structural properties which define how the structure will react to certain loading conditions. Nodes are assigned at a certain density throughout the material depending on the anticipated stress levels of a particular area. Regions which will receive large amounts of stress usually have a higher node density than those which experience little or no stress. Points of interest may consist of: fracture point of previously tested material, fillets, corners, complex detail, and high stress areas. The mesh acts like a spider web in that from each node, there extends a mesh element to each of the adjacent nodes. This web of vectors is what carries the material properties to the object, creating many elements. Introduction Bushings In todays competitive market, there is a need for the bushing manufacturing industry to improve bushing efficiency and to reduce costs; because high-quality low-cost products and processes have become the key to survival in the global economy. The reliability of equipment and facilities used in a power system is an essential precondition of the energy transmission security. High voltage bushing breakdown is one of the major contributors to the transformer failures. Since the electrical design of the HV bushings is the most important part of their manufacturing process, finding an algorithm for the electrical design of bushings in an optimum way is very important. Bushing failure is one of the leading causes of transformer failures. The electrical design of capacitive grading bushings is one of the important parts of manufacturing of these kinds of bushings. Capacitive grading bushings contain embedded in their insulation core concentric conductive foils, which are isolated from each other. By adjusting the diameter and length of these cylinders, the electrical stress and voltage drop in the core and along its surface can be influenced by variation of the ratio of the partial capacitances between the conducting cylinders, [1]. The grading of ac-bushing is achieved from the capacitances that are formed between the grading foils and thus determined by the permittivity of the insulating material. HIGH VOLTAGE BUSHINGS Bushings provide a point of interface such that the electric current can pass to and from the apparatus. The current is at some potential above ground and must be electrically insulated from the tank walls which are at ground potential. It can be thought of like a bridge where the potential is the length of the bridge and the longer the bridge the more support it must have such that it will not come into contact with the ground. The current path is the number of lanes. If the number of lanes are reduced on part of the bridge under heavy traffic flow, a multi-car pile up will occur. The two key factors are: 1) Insulating System to prevent a failure mode of over voltage. 2) Conductor Path to prevent a failure mode of over current. Over voltage will cause a flash over in the insulation and over current will cause overheating in the conductor due to I^2 * R losses. Figure 9: Diagram of typical high voltage bushings General Types: High-voltage bushings for use on transformers and breakers are made in several principal types, as follows: Composite Bushing.- A bushing in which insulation consists of two or more coaxial layers of different insulating materials. Compound-Filled Bushing.-A bushing in which the space between the major insulation (or conductor where no major insulation is used) and the inside surface of a protective weather casing (usually porcelain) is filled with a compound having insulating properties. Condenser Bushing.- A bushing in which cylindrical conducting layers are arranged coaxially with the conductor within the insulating material. The length and diameter of the cylinders are designed to control the distribution of the electric field in and over the outer surface of the bushing. Condenser bushings may be one of several types: Resin-bonded paper insulation; Oil-impregnated paper insulation; or Other. Dry or Unfilled Type Bushing.- Consists of porcelain tube with no filler in the space between the shell and conductor. These are usually rated 25 kV and below. Oil-Filled Bushing. A bushing in which the space between the major insulation (or the conductor where no major insulation is used) and the inside surface of a protective weather casing (usually porcelain) is filled with insulating oil. Oil Immersed Bushing.- A bushing composed of a system of major insulations totally immersed in a bath of insulating oil. Oil-Impregnated Paper- Insulated Bushing.- A bushing in which the internal structure is made of cellulose material impregnated with oil. Resin-Bonded, Paper- Insulated Bushing.- A bushing in which the major insulation is provided by cellulose material bonded with resin. Solid (Ceramic) Bushing.- A bushing in which the major insulation Is provided by a ceramic or analogous material. Bushing Failures Operating records show that about 90 percent of all preventable bushing failures are caused by moisture entering the bushing through leaky gaskets or other openings. Close periodic inspection to find leaks and make repairs as needed will prevent most outages due to bushing failures. Such an external inspection requires little time and expense and will be well worth the effort. High-voltage bushings, if allowed to deteriorate, may explode with considerable violence and cause extensive damages to adjacent equipment. Flashovers may be caused by deposits of dirt on the bushings, particularly in areas where there are contaminants such as salts or conducting dusts in the air. These deposits should be removed by periodic cleaning. Figure 10: Picture of High Voltage Bushing that has failed due to penetration of moisture One of the failures can also be a dielectric failure occurring with the paper insulation punctured through from the center draw rod, at a location about one third of the way down from the top terminal, to the grounded capacitance tap. HOW DOES THE BUSHINGS WITHSTAND THE STRESSES? The bushings must contain many layers of capacitors to grade the voltage down evenly from the potential at the centre conductor to ground potential. These capacitors are made up of many layers of paper and foil and usually filled with an insulating fluid such as oil. These layers of insulation can be checked by measuring the power factor of the bushing when the parent apparatus is out of service [2]. While the parent apparatus is in service, an infrared camera can be used to check for low oil levels. The oil level relates to the insulation quality of the grading capacitors. Infrared method will only work when the parent apparatus produces heat because it relies on the thermal mass difference between the fluid and the void at the top of the bushing. Bushings in transformers are ideal examples due to the heat produced by losses in the windings and core. The capacitor core of high voltage bushing is widely used to decrease the electric stress and to avoid field centralization where the high voltage lead drill through the tank wall of transformer. The floating potentials of capacitor core can be calculated with several methods[6], that are, the minimized energy algorithm, the partial capacitance algorithm and the electric charge conservation algorithm[6]. Some times dummy dielectric constant method are also used to solve the failure problems. When the electric flux line leaves higher dielectric constant region to lower dielectric constant region, if the ratio of higher dielectric constant to lower dielectric constant is much larger than 1, then it is nearly vertical on the interface in low dielectric constant material. Stress Analysis For the simulation we have tried two arrangements. First, the high voltage conductor is insulated by one large thick layer of silicone from the porcelain outer layer, which is held in place by two metal flanges at ground potential. Secondly, a capacitive graded arrangement where the conductor is insulated by several layers of silicone of varying axial length separated by thin layers of foil (form a large capacitor), again with two flanges at ground potential holding the structure in place. A voltage of 132KV is supplied to the conductor. The results presented below show the stress distribution where to distribute the stress uniformly the geometry of the structure has been altered. It is expected that with the two arrangements the distribution of the stress will vary greatly. Figure 11: Distribution of stress for first arrangement on bushing Figure 12: Distribution of stress for capacitively graded bushing arrangement In the first arrangement the electric stress is concentrated around the surface of the conductor, and the metal flange. While the other regions are under considerably less stress. The result is consistent with known theory. This is inefficient use of the insulation, as the wear of the insulation is not even. It is thus necessary to find a more desirable arrangement. Figure 12 shows the result of a capactively graded arrangement. Not only is the stress distributed more uniformly throughout the insulation, ensuring maximum efficiency and long life span, though the concentration is also reduced. This is the optimal design for high voltage bushings and is currently used in many high voltage applications. Again the result found is consistent with theory, as capacitive grading is vastly used to distribute stress uniformly. Conclusion High Voltage Bushings The Electric Stress has been determined for two different bushing arrangements using finite element analysis. The capacitive grading arrangement was found to be the best at distributing , and minimizing the concentration of stress. The results obtained agree with theory, and are applied throughout the industry.

Fanons Three Stages Related To The Indigenous People Of Chiapas :: essays research papers

Fanon's Three Stages Related to the Indigenous People of Chiapas The passage Shadows of Tender Fury by Subcommander Marcos of the Zapatista Army explains that the people of Chiapas are currently facing a period of revolution. The Zapatista army (consisting of Chiapian campesinos) has risen to combat the intolerant system of oppression by the Mexican government and has attempted to create a better lifestyle for the campesinos of Chiapas. Frantz Fanon's three stages to national culture; assimilation, self discovery, and revolution, relate to the struggle of the campesinos of Chiapas. In the last 500 years, the indigenous people of Chiapas have faced all three of Fanan's stages during their struggle for the development of a national culture. Five-hundred years ago when the first Europeans came in contact with the Mayan Indians, the first stage of Fanon's theory, assimilation, began formalizing. Throughout history the colonizers of Mexico were more technologically advanced than the natives. The Europeans had guns, cannons and massive ships. Not only did these possessions enable them to have greater brute force, but it took the white man to the level of the gods in the eyes of the natives. The colonizers could easily take advantage of this reverence. Fanon states "The effect consciously sought by colonialism was to drive into the natives' heads the idea that if the settlers were to leave, they would at once fall back into barbarism, degradation, and bestiality."(Fanon 211) The colonizers, believing the natives were savages that needed enlightenment, forced European culture upon them. The Europeans believed that to assimilate the natives to European culture was to help them progress. Therefore, to return to the old ways would have been regressing. When the natives objected to the forced assimilation, the colonizers smothered the rebellious efforts with stronger, more lethal weapons. Fanon compares the colonizer to a mother who restrains her "perverse" child so that he will not commit suicide.(Fanon 211) The analogy implies that the colonized must be protected (by the colonizer) from self-destruction. In the minds of the European colonizers, this idea of protection justified forcing assimulation onto the natives. Although the native campesinos (the poor people of Chiapas) haven't fully assimulated, they have adopted particular aspects of European and present day Mexican culture. The campesinos have learned the Spanish language and joined the catholic religion. An example of Fanon's first phase is when the colonizer tries to calm the angry, poor and exploited colonized people by promising social reform.(Fanon 207) These reforms promise things such as employment, welfare and education. According to Fanon, the government rarely follows through with pledged social reform. They find it easier to simply

Essay --

Abortion is a major debate in society today and has been an impassioned topic for decades. At issue is whether or not abortion should be permissible. Generally I support the idea of abortion given specific circumstances. If a woman becomes pregnant due to rape, she has no moral obligation to carry the baby to full term. It is a gross expectation for society to think a woman should give birth to a baby conceived from rape and to take care of the child as her own. In this discussion I will argue that abortion is permissible if the mother was a victim of rape. Judith Thomson is a philosopher that supports abortion. Judith starts off with her debate stating that â€Å"a fetus is no more a human than an acorn is a tree†. When does an acorn become an oak (Thomson 37-56)? The answer is that no one truly knows, there is no direct moment when one thing becomes another, it is the same way as a fetus. When does a fetus become a baby? Thomson uses the â€Å"famous violinist† analogy. In this analogy you are kidnapped, when you wake up in the morning you learn that you are connected to a famous violist who needs your kidneys for nine months. It is stated the violinist is an innocent person with a right to life whereas separating yourself from the violinist would kill him/her (Thomson 37-56). I believe in this case it would be moral to unplug yourself from the violinist, even if it means his/hers death. You did not consent to supporting the violinist for nine months and therefore you do not have an obligation to do so. This scenario can be used to support the victim who has been raped. If you have been raped you did not consent to sex or make a conscience decision to accept the ramifications from forced actions of copulation. Furthermore y... ... unjust aggressor who has violated the woman's dignity. Rape is an act of force and violence, unlike the conjugal love in marriage whereby both spouses give freely of themselves in an act of love. The woman who was raped is not responsible for the action, and thereby has the right to prevent the pregnancy or even stop the pregnancy through abortion. However, I agree with any arguments that state killing is wrong. I do agree that killing is wrong from the time the fetus becomes a human being, up to any age of an adult. People should not be allowed to take the life of another person as this is a crime. I believe that abortion should stay legal for several reasons; because women should have the right to make decisions regarding their own body and especially if they are a rape victim, and because they have the autonomy to exercise that right regardless of state laws.

Banning Cigarettes Essay -- essays research papers fc

Each year, the U.S. government passes numerous laws to protect its citizens. Yet, one perfectly legal product manages to seize over 400,000 American lives annually (American Lung Association, "American"). Despite the efforts of the U.S. government to protect its citizens, the government continues to ignore the single most preventable cause of premature deaths. The vicious culprit attributed to these deaths is the common cigarette. Death, however, is not the only transgression cigarettes are responsible for. Cigarettes pose a clear threat to the public, to the economy, and to the planet. Without a doubt, the government should ban cigarettes on account of the fact that they are harmful to the economy, to the body, and to the environment. The government should ban cigarettes because they hurt the economy. Essentially, cigarettes rob the economy of wealth. One area where cigarette smoking is costly is health care. Smokers often seek medical care because of the negative effects cigarettes have on the human body. As a result, the government spends a large amount of money treating medical illnesses that are, many times, preventable. In fact, "[s]moking costs the United States approximately $97.2 billion each year in health-care costs and lost productivity" (American Lung Association, "American"). Also, citizens must fund health care costs through tax dollars. A wiser and more productive utilization of tax dollars would be funding for schools. Despite...