Future Perspectives of Globalization

Globalization despite being seen as occurring â€Å"out there†, away from the daily lives and activities of women, the global economic and political effects have been evidenced in the struggles and lives of women and other members of the community the world over. Advertising We will write a custom essay sample on Future Perspectives of Globalization specifically for you for only $16.05 $11/page Learn More Unfortunately, the problems have not been visibly detected due to the perspective of multinational corporations, transnational and international political organizations. As such problems faced across races, religions, sexualities, ethnicities, classes and political arenas Fundamentally, Non-Governmental Organizations (NGOs) aimed at attending to groups with inadequate resources, political influence or diverse membership. However, according to Sonia Alvarez’s concept of â€Å"Latin American feminist NGO boom,† a number of feminist NG Os change from advocates to professionals attending to the needs of neoliberal states. As a result feminist activists and scholarly accounts have been concerned of the problems during institutionalization and professionalization of feminist practice. During the 1970s battered women’s shelters and rape crisis centers that were developed and expanded now indicate the success of feminist political activism the. However, the current women’s shelters and rape centers are sites for organized public advocacy, crisis intervention and community education targeting battered women, the elderly, abused survivors, rape victims and children, while availing supportive services and supportive services. Although institutionalization of activism against women violence in the shelters and crisis centers has raised the dust against the continued vibrancy of the feminist antiviolence movement, Clare Weber contrastingly elaborates the importance of transnational feminist networks for publ icizing the limits of national and local organizing against violence on women. The meeting by Nicaraguan women with the U.S. antiviolence activists established the organizing strategies that streamlined on the limits of the U.S. approach to ending violence against women. However, it was evident for local activists to connect their organizing with the transnational movements, there is need to understand the institutional and network links among women participants in different areas. Although structural adjusted programs (SAPs) and other neoliberal policies had become a key challenge, women forged back with transnational solidarity networks such as unions, NGOs and movements of local women working in EPZs and middle-class activists from the country and transnational NGOs and movements. Advertising Looking for essay on gender studies? Let's see if we can help you! Get your first paper with 15% OFF Learn More Additionally, increase in NGO-ization of women’s movement s with reduced critique while increasing role participation as experts and implementers of government and donor’s programs. As a matter of fact, while some NGOs acted as fronts of government, others referred to as â€Å"hybrid NGOs† maintained links with while working within and outside the system. In addition to mobilizing for resources for empowerment of women, the NGOs also acted as critiques of government policies and actions. The engagement of the activists is also maintained over time when meetings between international network representatives and local members are frequently held. Education on certain aspects that have not yet been implemented in the local arena, also helps motivate the women in the newly developed states and Asian, along Latin American countries. Once in a while, the local representatives should be funded to visit their international counterparts, in an effort to convince them of the realities that prevail in the relatively advanced nations. A s a result, their leadership positions in the home countries will be strengthened as they will be viewed as the enlightened participants; thus easing their tasks of convincing the misinformed citizens. In addition to activist networks, empowering of women has been made possible by enacting laws that cater for gender balance in the business sector. While most employers have to adhere to a balance in the workforce, the business opportunities have also been customized so as to allow for women to commence and operate any type of business previously dominated by their male counterpart. However, the challenge for single mothers or wives who are left to cater for the family single-handedly is associated with world increases in prices of food. Because the mother’s should first ensure the children are well fed before they can consume their meals, instances of malnutrition were reported. As a result, women groups in Zimbabwe, India and other countries pushed for the growth of the publ ic distribution system to provide subsidized food for the rural and urban poor. Other women groups affiliated with the World Food Program also ensured that children and women got the minimum food for sustenance. Another example of a network is the Central American Network of Women in Solidarity with Women Workers in the Maquilas, which was formed in 1996 formed by member women organizations on the northern boarder. The network during its first meeting decided to establish different regional networks of women’s organizations meant to work on issues affecting the maquilas. Advertising We will write a custom essay sample on Future Perspectives of Globalization specifically for you for only $16.05 $11/page Learn More The first meeting that was held in El Salvador under the funding of a Canadian Nongovernmental organization (NGO) was autonomously represented by women groups from El Salvador, Nicaragua and Guatemala; eventually being joined by two othe r Guatemalan groups and Honduras. With meeting of the Network taking place every six months, and each country’s role rotated each time, the happenings of the meeting would evenly contribute towards the member countries’ prosperity. Additionally, with visitors openly invited for these meetings as the events of the Network are discussed, the maquila workers are bound to benefit eventually. The Network was considerate of women contending that union movements exclude them from the decision-making position; especially the expected maquila women workers whose agendas are the bases of founding the movements, networks and groups. However, despite the negative labels on unions, certain Network participants share active and friendly relationships with particular unions, but the tense relations with labor movements are openly known. Therefore, the Network alternatively represents the union because it outlines the social and labor reality of the affected women. Once the rights f ro women had been secured, their position within the workplace was next. Unlike in the recently developed countries, the unequal status of women worldwide and the deteriorating status of women in the colonial countries in Asia and Africa along with Latin American countries was noticeable despite having adopted the path to development through the liberal modernization model. At this point, the efforts of the UN were shifted from legal rights to economic and social empowerment of women. In addition to the challenge that women were economically and socially challenged, their roles and positions within the workplace projected another facet for their discrimination. In order to ensure that the position of women within organizations was guaranteed, there was need to quickly strengthen the woman; hence empowering her socially and economically within the society. Therefore, the establishment of the United Nations Development for Women (UNIFEM), upon its formalization in 1984, was aimed at funding women projects around the world. However, both UNIFEM and INSTRAW upon implementation were limited by resources committed to them. Women in response to neoliberal policies, economic restructuring and international trade agreements, have organized through networks, transnational organizations and traditional vehicles for instance the International Ladies Garment Workers Union. Advertising Looking for essay on gender studies? Let's see if we can help you! Get your first paper with 15% OFF Learn More Additionally, cross-border organizations have been attained through global restructuring on national women organizations. In Central America, for example, Jennifer Bickham Mendez’s chapter challenges the work of economic structuring and neoliberal policies and politics in improving the living conditions of women workers in Maquila. Specifically, information on the women’s conditions of work, categories of products, rate of work that they are expected to deliver, their relationships with the supervisors/managers, and for which transnational corporations they work for. Once the information is collected, it is channeled through the network of NGOs and transmitted to the groups working in the North for them to understand and communicate to the public concerning the conditions. Similarly, Marina Karides’s chapter looks at transnational activism and organizing efforts of domestic workers. Through, Trinidad’s National Union of Domestic Employees (NUDE) women ca sual workers have had their rights protected through the global rhetoric and international agreements requiring governments to be accountable at home. In an effort to push governments that did not address the women’s grievances, the activists contacted government ministries concerning their international commitment stressing on the importance of the link between local and international injustices. Eventually, their efforts through the public shaming were able to get their interests addressed although to date not all the issues have been addressed. This essay on Future Perspectives of Globalization was written and submitted by user Amiyah Berger to help you with your own studies. You are free to use it for research and reference purposes in order to write your own paper; however, you must cite it accordingly. You can donate your paper here.

Server-Side Scripting in PHP

Server-Side Scripting in PHP Server-side scripting as it relates to web pages usually refers to PHP code that is executed on the web server before the data is passed to the users browser. In the case of PHP, all PHP code is executed server-side and no PHP code ever reaches the user. After the PHP code is executed, the information it outputs is embedded in the HTML, which is sent to the viewers web browser. One way to see this in action is to open one of your PHP pages in a web browser and then choose the View Source option. You see the HTML, but no PHP code. The result of the PHP code is there because it is embedded in the HTML on the server before the web page is delivered to the browser. Example PHP Code and Result While the server-side PHP file may contain all the code above, the source code and your browser only display the following information: My cat Spot and my dog Clif like to play together. Server-Side Scripting vs. Client-Side Scripting PHP isnt the only code that involves server-side scripting, and server-side scripting isnt limited to websites. Other server-side programming languages are Python, Ruby, C#, C, and Java. There are many instances of server-side scripting, which provides a customized experience for users. In comparison, client-side scripting operates with embedded scripts- JavaScript is the most familiar- that are sent from the web server to a users computer. All the client-side script processing takes place in a web browser on the end users computer. Some users disable client-side scripting due to security concerns.

U.S. History Essay Example | Topics and Well Written Essays - 750 words

U.S. History - Essay Example In the period after the French and Indian war victories, Britain commanded a lot of respect from many countries. This status was to last for a short while since the influence of Britain to its colonies started to wane afterward due to the heavy debt accumulated over the war. The parliament decided to enact the 1765 stamp act, which required the colonies to pay additional tax on British goods. Resistance and boycott of British goods met this move. The events of April 8, 1775, refer to the ride that Paul Revere went to in order to deliver a message to the people of Boston. This happened just within 10 days after a premature ride to Concord. The objective of the rides was to warn the inhabitants the possibility of an impending war. The legend, however, is in the fact that he covered 13 miles within two hours and gathered the Lexington militia. The fundamental principles of the United States government include self-governance, separation of powers and inherent rights. The self-governance principle is important in that it helps people choose their own president. The idea of separation of powers is in the constitution is to ensure that no specific body controls all the powers; instead, the three branches of the government have checks and balances against each other.The first foreign policy failure of John Adam’s administration was the endeavor to gain Texas from Mexico.The other issue he encountered with his foreign policy attempts was to increase the volume of trade with the West Indies.

Head Start Agency Research Paper Example | Topics and Well Written Essays - 2000 words

Head Start Agency - Research Paper Example The agency operates in accordance with the description of services stipulated in the Head Start Performance Standards and also the Head Starts Act of 2007 (Diane, 2007). The agency is funded the government through the United States Department of Health and Human Services (HHS). Head Start Agency started in May 1965. The idea of its formation was initiated by President Lyndon Johnson while working as a teacher in in the hardscrabble of West Texas where he witnessed immense poverty and developed an ideology that education was the only powerful tool for eradicating poverty (Sawhill &  Haskins, 2003). His idea turned into reality during the â€Å"heady, idealistic days of the Great Society’s war on poverty† (Palmaffy, 2011). The war on poverty was spearheaded by the Community Action Programs (CAPs) with an intention of rallying the poor for their own sake. Following the wrangles in CAP the local officials became uneasy to apply for the CAPs grants (Sawhill &  Haskins, 2003). However, due to a budget surplus and administrative pressure that required the officials either to use or lose the grants there was an emerging need of getting another way of helping the poor community (Butler et al., 2004). Sargent Shriver, the director of the Office of Economic Opportunity (OEO), went looking for viable political anti-poverty project that led to the establishment of Head Start program (Diane, 2007). The program received great support and funding in 1970s and 80s following the establishment that children had higher gain in IQ during their early years, and that diminished with age (Sawhill &  Haskins, 2003). That led to increased support for the program to ensure its success. The formation of Head Start agency was based on policy for eradicating poverty following the passage of Economic Opportunity Act of 1964. The formation of Head Start agency was based on believe that providing quality education to the children from a poor

Argue that Austen's novel is a reflection of its revolutionary age Essay

Argue that Austen's novel is a reflection of its revolutionary age - Essay Example Sandwiched between her older sister Elizabeth who stands in for her mother in her widowed father’s esteem and affection and her younger sister Mary who has made and advantageous and fruitful marriage to a young man due to inherit his own landed estate, Anne’s curious social position allows her a possibility of social mobility that echoes the social shifts taking place across Europe. As a woman, Anne’s social position would be inherently precarious, dependent on her father first and then on the man she married. The undefined nature of an unmarried woman’s social standing gave young women a certain social mobility that was universally acknowledged. A young woman could marry her way into improved social standing – as Austen’s two Miss Bennets do with their marriages to Mr. Bingley and Mr. Darcy in Pride and Prejudice – or, as Lady Russell warns Anne Elliot in Persuasion, a bad marriage could plunge a poor young woman â€Å"into a state o f most wearing, anxious, youth-killing dependance.† (1158) As a member of the early-nineteenth century aristocracy, Anne is a member of a landed gentry that makes dubious claims about the inherent nobility of birth. For every prudent, thoughtful aristocrat like Emma’s Mr. Knightley, there is an equal an opposite aristocrat in the style of Anne’s father. Sir Walter takes inordinate pride in his ownership of Kellynch Hall and his storied family tree, but he himself has frittered away his family fortune to the point that he must lease his ancestral home in order to maintain his lifestyle. Tellingly, Sir Walter’s lessee is no landed gentleman or wealthy second son of a gentleman but a professional man, an admiral in the British navy, who can afford the rent and upkeep of the estate. Perhaps most interestingly, as a rational person, Anne is willing to be persuaded, as the novel’s title suggests. Though she has a healthy appreciation for tradition, Anne a ppreciates – and responds to – plain good

The High Voltage Electricity Transmission Network Engineering Essay

The High Voltage Electricity Transmission Network Engineering Essay It is well known to many people that high voltage electricity transmission network represents the backbone of the whole regional power supply scheme in the country. The main purpose of this research is analyzing the most frequent common failures in the HV transmission lines and understanding the actual reasons behind these failures in the transmission network of a private electrical company in the Sultanate of Oman named OETC Oman Electricity Transmission Company. The business of that company is providing, developing and governing the Electrical Transmission System in the Sultanate of Oman. The data presented and information provided hereafter shall be considered extremely confidential and hence the assignment information is intended only for the use of this assignment and shall not be distributed to any other party without permission from the original source. In the start, the assignment firstly provides a brief explanation about the company and its role of electricity distribution. Then, it further analyzes different types of equipment failures that are encountered with HV network operation and reported by a local company. It sums up on general findings, results, conclusion and the recommendation regarding future maintenance. Electricity supply Oman Electricity Transmission Company OETC operates, organizes and maintains the majority HV transmission system in which electrical power is transmitted through 220kV and 132kV transmission lines to load centers in Muscat Governorate and the regions of Dakhliyah, Batinah, Dhahirah and Sharqiyah. It dispatches power from all Centrally Dispatched Generation Stations owned by the following companies: (1). 1. Ghubrah Power Desalination Station 2. Rusail Power Station 3. Wadi Jizzi Power Station 4. Manah Power Station 5. Al Kamil Power Station 6. Barka Power Desalination Station 7. Sohar Power Station The power transmitted by the company is delivered to the following distribution companies, which are licensed to distribute and supply power in a range lower than 132kV voltage (i.e. 66kV, 33kV,11kV and 0.415kV): 1. Muscat Electricity Distribution Company (MEDC) for Muscat area 2. Mazoon Electricity Company (MZEC) for South Batinah, Dakhliyah and Sharqiyah regions 3. Majan Electricity Company (MJEC) for North Batinah and Dhahirah regions Fundamentals of Power Generation and Transmission After the electricity leaves a power generation (1), the voltage is increased at a step-up grid substation (2). Subsequently, the energy travels along a transmission line to the area where the power is needed (3). Once there, the voltage is decreased, or stepped-down, at another primary substation (4), and a distribution power line (5) carries the electricity until it reaches a home or business (8). (1) Fig -1 Electrical Power System (1) Overhead Lines The main components of the HV high voltage power transmission are; the overhead towers, conductors, insulators, lightning arrestors, CVT CT and cable sealing ends. It has been well recognized since the starting of electric power generation that overhead transmission lines (OHL) have represented the most important component for the electric power transmission and distribution. The over head transmission line generally dedicated for high voltage range, while the buried type (underground cables) are commonly used in lower voltage range for the distribution purpose. However, in Oman, both systems are used in various applications depending on the cost, development conditions and topography constraints. OETC has planned, designed and erected overhead power lines for various voltage levels in many parts of the sultanate of Oman. Line voltage Selection According to IEC 60038 there are standard voltage ranges used for the electric power transmission and distribution. The following are the main voltage levels For 3-phase AC power supply: -Low voltage range from 220v up to 1 kV AC Medium voltage range from 1 kV to 36 kV AC High voltage range from 52 kV to 765 kV AC) and higher Generally the Low-voltage transmission and distribution networks serve households and other small business consumers. Networks on the medium-voltage level usually supply larger buildings and settlements, industrial plants and other large consumers; the power supply capacity is typically less than 10 MVA per circuit. The high voltage ranges up to 145 kV are usually used for sub-transmission of the electric power regionally, and also feed the medium-voltage electric network. This level is frequently selected to support the medium-voltage level even when electric power is lower than 10 MVA. Moreover, some of high-voltage transmission lines are also used to transmit the electric power from medium size power plants, like hydro power plants on water streams, channel or rivers, and provide electric power for large-scale units, such as considerable power plants or steel factories. The bandwidth of electrical transported power corresponds to the broad range of utilization, but it rarely exceeds 100 MVA per circuit, while the surge impedance load is 35 MVA (approximately). In most European countries, the high voltage lines of 245 kV were greatly used in interconnection of power supply systems and this before the 420 kV level was brought to this purpose. Nowadays, the usage of 245 kV lines is decreased to some extent due to the availability of the 420 kV transmission network. The 420 kV level represents the highest operation voltage used for AC transmission in Central Europe. It typically interconnects the power supply systems and transmits the energy over long distances. Some 420 kV lines connect the national grids of the individual European countries enabling interconnected network operation (UCTE = Union for the Co-ordination of Transmission of Electricity) throughout Europe. Large power plants such as nuclear stations feed directly into the 420 kV network. The thermal capacity of the 420 kV circuits may reach 2,000 MVA, with a surge impedance load of approximately 600 MVA and a transmission capacity up to 1,200 MVA.[SIEMENS Power Engineering Guide 2 009]11 Selection of conductors and earth wires Electric conductors are the main important part in the overhead power line network and they must be selected carefully for the electric transmission lines because this will ensure economical and reliable transmission and contribute directly to the total line costs. Therefore, to achieve better economic solution, aluminum and its alloys have been used as conducting materials for power lines due to the favorable price, the low weight and the necessity of certain minimum cross-sections. On the other side, aluminum is a very corrosive metal. But when a dense oxide layer is formed it can stop further corrosion. Therefore, up to a certain level, aluminum conductors are well-suited for areas in which corrosion is an issue, such as humid climate in areas located near coastal zone. Generally, there are a number of different designs in use for aluminum conductors. As an advantage, All-aluminum conductors (AAC) have the highest conductivity for a given cross-section; however, they possess relat ively low mechanical strength, which limits their installation to short spans and low tensile forces. To increase the mechanical strength, aluminum wires are made of mixing with other alloys like aluminum-magnesium-silicon alloys. In this way, the strength can be increased approximately twice that of pure aluminum. But practically, all-aluminum and aluminum alloy conductors have exhibited some susceptibility to vibrations. To solve this problem, compound conductors with a steel core, so-called aluminum conductor, steel-reinforced (ACSR), can avoid this disadvantage. The ratio between aluminum and steel ranges from 4.3:1 to 11:1. An aluminum-to-steel ratio of 6.0 or 7.7 provides an economical solution. Conductors with a ratio of 4.3 should be used for lines installed in regions with heavy wind and ice loads. Conductors with a ratio higher than 7.7 provide higher conductivity. But because of lower conductor strength, the sags are bigger, which requires higher towers. Experience has shown that ACSR conductors, just like aluminum and aluminum alloy conductors, provide the most economical solution and offer a life span greater than 40 years. Conductors are selected according to electrical, thermal, mechanical and economic aspects. The electric resistance as a result of the conducting material and its cross-section is the most important feature affecting the voltage drop and the energy losses along the line and, therefore, the transmission costs. The cross-section has to be selected so that the permissible temperatures will not be exceeded during normal operation as well as under short-circuit condition. With increasing cross-section, the line costs increase, while the costs for losses decrease. Depending on the length of the line and the power to be transmitted, a cross-section can be determined that results in the lowest transmission costs. The heat balance of ohmic losses and solar radiation against convection and radiation determines the conductor temperature. A current density of 0.5 to 1.0 A/mm2 based on the aluminum cross-section has proven to be an economical solution in most cases. [SIEMENS Power Engineering Guide 2009] (9) The table below shows the characteristics of AC overhead lines (data refer to a one circuit of a double-circuit line) Table -1 characteristic of AC overhead lines (9) High-voltage results in correspondingly high-voltage gradients at the conductors surface, and in corona-related effects such as visible discharges, radio interference, audible noise and energy losses. When selecting the conductors, the AC voltage gradient has to be limited to values between 15 and 17 kV/cm. Since the sound of the audible noise of DC lines is mainly caused at the positive pole and this sound differs from those of AC lines, the subjective feeling differs as well. Therefore, the maximum surface voltage gradient of DC lines is higher than the gradient for AC lines. A maximum value of 25 kV/cm is recommended. The line voltage and the conductor diameter are one of the main factors that infl uence the surface voltage gradient. In order to keep this gradient below the limit value, the conductor can be divided into subconductors. This results in an equivalent conductor diameter that is bigger than the diameter of a single conductor with the same cross-section. This aspect is important for lines with voltages of 245 kV and above. Therefore, so-called bundle conductors are mainly adopted for extra-high-voltage lines. Table 2.5-2 shows typical conductor configurations for AC lines. From a mechanical point of view, the conductors have to be designed for everyday conditions and for maximum loa ds exerted on the conductor by wind and ice. As a rough figure, an everyday stress of approximately 20 % of the conductor rated tensile stress can be adopted, resulting in a limited risk of conductor damage. The maximum working tensile stress should be limited to approximately 40 % of the rated tensile stress. Earth wires, also called shield wire or earth wire, can protect a line against direct lightning strikes and improve system behavior in the event of short-circuits; therefore, lines with single-phase voltages of 110 kV and above are usually equipped with earth wires. Earth wires made of ACSR conductors with a sufficiently high aluminum cross-section satisfy both requirements. Since the beginning of the 1990s, more and more earth wires for extra-high-voltage overhead power lines have been executed as optical earth wires (OPGW). This type of earth wire combines the functions just described for the typical earth wire with the additional facility for large data transfer capacity vi a optical fi bers that are integrated into the OPGW. Such data transfer is essential for the communication between two converter stations within an HVDC interconnection or for remote controlling of power stations. The OPGW in such a case becomes the major communication link within the interconnection. OPGW are mainly designed in one or more layers of aluminum alloy and/or aluminum-clad steel wires. One-layer designs are used in areas with low keraunic levels (small amount of possible lightning strikes per year) and small short-circuit levels. [SIEMENS Power Engineering Guide 2009](9) Selection of insulators Usually, insulators in the overhead line are subject to electrical and mechanical stresses, because they have to isolate the conductors form potential to earth and must provide physical supports. Therefore, Insulators must be capable of withstanding these stresses under all conditions encountered in a transmission line. Normally, the electrical stresses result from: The steady-state operating power-frequency voltage (highest operation voltage of the system) Temporary over voltages occurred at specific power frequency Switching and lightning over voltages Chapter -2 Introduction Electrical insulators are very critical and important component in the electric power systems such as distribution transmission lines. Previously, the electrical insulators which is made of ceramic and glass materials. But in 1963, a polymeric insulator were developed and its improvements in design and manufacturing in the modern years have made it attractive to utilities. polymeric insulator consists of a fibreglass core rod covered by weather-sheds or skirts of polymer such as silicone rubber, equipped with metal end fittings. It is also called composite insulators, which means made of at least two insulating parts a core and housing equipped with end fittings. Polymeric insulators have many advantages over the ceramic and glass insulators such as good performance in contaminated environment, light weight, easy handling, maintenance free, and considerably low cost etc. Because of these properties it is gaining popularity worldwide and replacing the conventional ceramic and glass insulators in many countries. Therefore, our research shall focus the light on the silicon rubber insulator and the main advantages can be achieved by using such type of electrical insulators. The following is a comparison showing the different factors between ceramic and composite insulators. FACTORS CERAMIC COMPOSITE Resistance to flashovers in Polluted atmosphere. Low High Resistance to puncture Puncturable (Class: B insulators) Not puncturable Resistance to Cracking and Erosion in Polluted atmosphere. Low High Contamination Pollution Highly affected Performance not affected Hydrophobicity Non hydrophobic. Unique Hydrophobicity character. Self cleaning property Due to Glaze and inclination of sheds. Due to Hydrophobicity recovery characteristic. Maintenance Needs maintenance like cleaning, washing, greasing. No maintenance is required Weight More 10% to 35% of Ceramic Insulator Resistance to breakage and Vandalism Breakable in Vandalism prone areas Unbreakable Artificial Pollution Test Mandatory Not applicable Power Arc Test Mandatory Not mandatory Table -1 comparison different factors between ceramic and composite insulators (10). Insulator types There are various insulator designs used in different applications, depending on the requirements and the application with certain insulator types: Cap-and-pin insulators (fig.2) are made of porcelain or pre-stressed glass. The individual units are connected by fittings of malleable cast iron or forged iron. The insulating bodies are not puncture-proof, which is the reason for a relatively high number of insulator failures. In Central Europe, long-rod insulators made from aluminous porcelain (fig.3) are most frequently adopted. These insulators are puncture-proof. Failures under operation are extremely rare. Long-rod insulators show superior behavior, especially in polluted areas. Because porcelain is a brittle material, porcelain long-rod insulators should be protected from bending loads by suitable fittings. Composite insulators are the third major type of insulator for overhead power line applications (fig.4). This insulator type provides superior performance and reliability, particularly because of improvements over the last 20 years, and has been in service for more than 30 years. Fig -2 Cap and pin (disc insulator) (9) Fig -3 Long-rod insulator with clevis cap (9) Fig -4 Glass fibre reinforced composite insulator with ball and socket fittings (Lapp insulator) (9) The composite insulator is made of a glass fiber reinforced epoxy rod. The glass fibers applied are ECR glass fibers that are resistant to brittle fracture (ECR = electrical grade corrosion resistant glass fibers). In order to avoid brittle fracture, the glass fiber rod must additionally be sealed very carefully and durably against moisture. This is done by application of silicone rubber. Nowadays, high temperature vulcanized (HTV) silicone is used. The silicone rubber has two functions within this insulator type: Sealing the glass fiber rod Molding into insulator sheds to establish the required insulation Metal fittings are compressed onto the glass fiber rod at both ends of the insulator, either with a ball socket or clevis connection fitting. Since the 1980s, compression fittings have been the prevailing type. The sealing of the area between fitting and silicone housing protecting the rod is most important, and is nowadays done with special silicone elastomer, which offers after vulcanization the characteristic of a sticky solid, similar to a fluid of high viscosity. Advantages of the composite long-rod insulator are: Light weight, less volume and less damages Shorter string length compared to cap-and-pin and porcelain long-rod insulator strings Up to 765 kV AC and 600 kV DC, only one unit of insulator (practical length is only limited by the ability of the production line) is required High mechanical strength Vandalism resistance High performance in polluted areas, based on the hydrophobicity (water repellency) of the silicone rubber Advantages of hydrophobicity are: Silicone rubber offers outstanding hydrophobicity over the long term; most other polymeric housing material will loose this property over time Silicone rubber is able to recover its hydrophobicity after a temporary loss of it The silicone rubber insulator is able to make pollution layers on its surface water-repellent, too (hydrophobicity transfer) Low surface conductivity, even with a polluted surface and very low leakage currents, even under wetted conditions. Insulator string sets Suspension insulator sets carry the conductor weight, including additional loads such as ice and wind, and are arranged more or less vertically. There are I-shaped (fig.5a) and V-shaped sets in use. Tension insulator sets (fig.5b, fig.5c) terminate the conductors and are arranged in the direction of the conductors. They are loaded by the conductor tensile force and have to be rated accordingly. Multiple single, double, triple or more sets handle the mechanical loadings and the design requirements. Fig -5a; I-shaped suspension insulator set for 245 kV (11) T Fig -5b&c; Double tension insulator set for 245 kV (Elevation, Top Plan, bottom) (9) The general electrical layout of insulation is ruled by the voltages to be withstood and the pollution to which the insulation is subjected. The standards IEC 60071-1 and IEC 60071-2 as well as the technical report IEC 60815, which provides four pollution classes, give guidance for the design of the insulation. Because IEC 60815 is applicable to AC lines, it should be noted that the creepage distances recommended are based on the phase-to-phase AC voltage (UL-L). When transferring these creepage distances recommended by IEC 60815 to a DC line, it should be noted that the DC voltage is a pole-to-earth value (UL-E). Therefore, these creepage distances have to be multiplied by the factor à ¢Ã‹â€ Ã… ¡3. Furthermore, it should be noted that the AC voltage value refers to a mean value, while the DC voltage is comparable to a peak value, which requires a further multiplication with factor à ¢Ã‹â€ Ã… ¡2. Insulators under DC voltage operation are subjected to more unfavorable conditions tha n they are under AC, due to a higher collection of surface contamination caused by the constant unidirectional electric field. Therefore, a DC pollution factor has to be applied. Table shown with figure 5a shows specific creepage distances for different insulator materials under AC and DC application, and is based on industry experience published by power supply companies in South Africa and China. The results shown were confirmed by an experienced insulator manufacturer in Germany. The correction factors shown are valid for porcelain insulators only. When taking composite insulators into consideration, an additional reduction factor of 0.75 can be applied. The values for a DC system must be seen as a guideline only, that must be verified on a case-by-case basis for new HVDC projects. To handle switching and lightning overvoltages, the insulator sets have to be designed with respect to insulation coordination according to IEC 60071-1 and IEC 60071-2. These design aspects determine the gap between the earthed fi ttings and the live part. However, for HVDC application, switching impulse levels are of minor important because circuit-breaker operations from AC lines do not occur on DC back-to-back lines. Such lines are controlled via their valve control systems. In order to coordinate the insulation in a proper way, it is recommended to apply and use the same SIL and BIL as is used for the equivalent AC insulation (determined by the arcing distance). [SIEMENS Power Engineering Guide 2009](9) Selection and design of supports Together with the line voltage, the number of circuits (AC) or poles (DC) and type of conductors, the configuration of the circuits poles determines the design of overhead power lines. Additionally, lightning protection by earth wires, the terrain and the available space at the tower sites have to be considered. In densely populated areas like Central Europe, the width of right-of-way and the space for the tower sites are limited. In the case of extra-high-voltages, the conductor configuration affects the electrical characteristics, the electrical and magnetic field and the transmission capacity of the line. Very often there are contradicting requirements, such as a tower height as low as possible and a narrow right-of-way, which can only be met by compromises. The minimum clearance of the conductors depends on the voltage and the conductor sag. In ice-prone areas, conductors should not be arranged vertically, in order to avoid conductor clashing after ice shedding. For low-voltage and medium-voltage lines, horizontal conductor configurations prevail; these configurations feature line post insulators as well as suspension insulators. Poles made of wood, concrete or steel are preferred. Fig.6 shows some typical line configurations. Earth wires are omitted at this voltage level. For high-voltage and extra-high-voltage power lines, a large variety of configurations are available that depend on the number of circuits (AC) or poles (DC) and on local conditions. Due to the very limited right-of-way, more or less all high voltage AC lines in Central Europe comprise at least two circuits. Fig.7 shows a series of typical tower configurations. Arrangement e is called the Danube configuration and is often adopted. It represents a fair compromise with respect to width of right-of-way, tower height and line costs. For AC lines comprising more than two circuits, there are many possibilities for configuring the supports. In the case of circuits with differing voltages, those circuits with the lower voltage should be arranged in the lowermost position (fig7g). DC lines are mechanically designed according to the normal practice for typical AC lines. The differences from AC Line layout are the: Conductor configuration Electric field requirements Insulation design For DC lines, two basic outlines (monopole and bipole), with variations should be considered. Fig.7i-l show examples for HVDC line configurations that are valid for all voltage levels. The arrangements of insulators depend on the application of a support within the line. Suspension towers support the conductors in straight-line sections and at small angles. This tower type offers the lowest costs; special attention should therefore be paid to using this tower type as often as possible. Angle towers have to carry the conductor tensile forces at angle points of the line. The tension insulator sets permanently transfer high forces from the conductors to the supports. Finally, dead-end towers are used at the terminations of a transmission line. They carry the total conductor tensile forces on the line side (even under unbalanced load condition, e.g., when conductors of one tower side are broken) and a reduced tension into the substations (slack span). Fig.6 Configuration of Medium voltage supports Various loading conditions specified in the respective national and international standards have to be met when designing towers. The climatic conditions, the earthquake requirements and other local environmental factors are the next determining factors for the tower design. When designing the support, a number of conditions have to be considered. High wind and ice loads cause the maximum forces to act on suspension towers. In ice-prone areas, unbalanced conductor tensile forces can result in torsional loading. Additionally, special loading conditions are adopted for the purpose of failure containment, that is, to limit the extent of damage. Finally, provisions have to be made for construction and maintenance. Depending on voltage level and the acting forces of the overhead line, differing designs and materials are adopted. Poles made of wood, concrete or steel are very often used for low voltage and medium-voltage lines. Towers with lattice steel design, however, prevail at voltage levels of 110 kV and above (fig.7). Guyed lattice steel structures are used in some parts of the world for high-voltage AC and DC lines. Such design requires a relatively fl at topography and a secure environment where there is no threat from vandalism and theft. Guyed lattice steel structures offer a substantial amount of cost savings with respect to tower weight and foundation quantities. However, a wider right-of-way has to be considered. Foundations for the supports Usually, overhead power line supports are installed on concrete foundations. The foundations have to sustain the overall weight of the tower and should be designed in accordance with the local or international standard applicable for the particular projct. Fig. 7;(a-h) Tower configurations for AC high-voltage lines. (i-l) Tower configurations for DC high-voltage lines The selection of foundation types and the design is decided by the: Total weight resulting from tower Location and Soil conditions Accessibility to the line route Availability of machinery Constraints of the particular country and the site Concrete blocks or concrete piers are in use for poles that exert bending moments on the foundation. For towers with four legs, a foundation is provided for each individual leg. Pad and chimney and concrete block foundations require good bearing soil conditions without groundwater. Driven or augured piles and piers are adopted for low-bearing soil, for sites with bearing soil at a greater depth and for high groundwater level. In case of groundwater, the soil conditions must permit pile driving. Concrete slabs can be used for good bearing soil, when subsoil and groundwater level prohibit pad and chimney foundations as well as piles. Fig. 8; Foundations for four-legged towers Route selection and tower spotting Selection of route and planning represent increasingly difficult tasks, because the right-of-way for transmission lines is limited and many aspects and interests have to be considered. Route selection and approval depend on the statutory conditions and procedures prevailing in the country of the project. Route selection nowadays involves preliminary desktop studies with a variety of route alternatives, environmental impact studies, community communication hearings and acceptance approval from the local authorities. [SIEMENS Power Engineering Guide 2009](9) Literature Survey The books and journals referred are detailed in references. The methodology has been decided after studying different literatures. The societal loss calculation have been taken from the paper Power Chain Managementà ¢Ã¢â‚¬Å¾Ã‚ ¢ Audit Service Focus Professional Engineering Services/ www.powerchainmanagement.com. The effective of electrical systems is critical to the success of businesses and facilities. The electrical problems facing businesses today can often seem overwhelming, especially knowing that key elements of electrical systems are susceptible to failure. It can be costly and difficult to design a system that predicts failure and minimizes risks of dangerous hazards such as arc flash and from the graph which shows how does it cost in the time of losing the power supply. Fig -2 cost raven (2) To approximate cost of transmission losses. The loss calculations are based on an peak load current for a line.(7) EC (Energy Cost) = 3 x R x I 2 x 8760 x LF x AIC x LIF, and DC (Demand Cost) = 3 x R x I 2 x IDC x LIF Where EC = energy cost, $ / yr DC = demand cost, $ / yr R = conductor resistance (ohms/phase/mile) X line length (miles) I = peak load current on the line (amperes) 8760 = hours / year LF = loss factor (average loss / peak loss) AIC = average incremental energy cost for the year ($ / kWh) LIF = loss increase factor (1 + PU system losses reflecting increase) IDC = incremental demand cost ($ / kW-yr) Diffident maintenance strategies considered are : Run to failure condition based monitoring on line monitoring Hot line maintenance The cost relationship between materials based solely on purchase prices, the life cycle economics at all the factors and gives consideration to the time value of money based on a present value analysis. The approach of using present value, life cycle costs is often considered the fairest means of comparison because it considers and properly weighs all the material variables. This life cycle cost study gives consideration to the following:(6) Environmental conditions Material costs and availability Construction costs Projected service life Inspection costs / Inspection frequency Maintenance costs / Maintenance frequency For the purpose of present value calculations, a 4% inflation rate and a 10% discount rate are assumed. The equation used for computing the present value (PV) of a single expend

Theraputic Hypothermia Essay -- Health Medicine Medical Essays Researc

Theraputic Hypothermia Hypothermia, defined as a core body temperature less than 95  °F(35 °C) occurs when heat loss exceeds the body’s heat production. (Ruffolo p.47) Thermal stability in humans depends on the body’s ability to adapt to changes in internal and external temperatures. Heat is transferred throughout tissues and fat, and is released at a rate directly related to the temperature of the environment through radiation, conduction, convection, and evaporation.   Ã‚  Ã‚  Ã‚  Ã‚     Ã‚  Ã‚  Ã‚  Ã‚  Hypothermia is typically seen as a bad thing; however, various studies have been proving it to be very useful. Traumatic brain injury initiates several metabolic processes that can exacerbate the injury. There is evidence that hypothermia may limit some of these deleterious metabolic responses. In a randomized controlled trial researchers compared the effect of moderate hypothermia and normhypothermia in 82 patients with severe closed head injuries (score of 3 to 7 on the Glasgow Coma Scale) The patients assigned to hypothermia were cooled to 33 degrees C an average of 10 hours after injury, kept at 32 degrees to 33 degrees C for 24 hours, and then re-warmed. A specialist in physical medicine and rehabilitation who was unaware of the treatment assignments evaluated the patients 3, 6, and 12 months later with the use of the Glasgow Outcome Scale. The demographic characteristics, causes, and severity of injury were similar in the hypothermia group and the normothermia groups. At 12 months 62% of the patients in the hypothermia group and 38% in the normothermia had good outcomes (moderate, mild, or no disabilities). The researchers concluded that â€Å"Treatment with moderate hypothermia for 24hours in patients with severe traumatic brain injury and coma scores of 5 to 7 hastened neurological recovery and may have improved the outcome. (Marion et all)   Ã‚  Ã‚  Ã‚  Ã‚     Ã‚  Ã‚  Ã‚  Ã‚  Two studies done (one in Australia and the other in Europe) showed the therapeutic value in survivors cardiac arrest. In the Australian study, which involved 77 patients who remained comatose after the restoration of spontaneous circulation, 49% of those treated with hypothermia were discharged home or into a rehabilitation facility compared to the 26% of those not treated with hypothermia. There were no significant differe... ...tion fluids, preparation solution, or baths can contribute to heat loss. Ruffolo Evaporation is the transfer of heat to the air from moist skin or mucous membranes. It occurs through wet skin, open body cavities and the respiratory tract. References (Works Cited) Ruffolo, Daria. www.rnweb.com. Vol. 65 No. 2. February 2002 Marion, DW et all. â€Å"Treatment of traumatic brain injury with moderate hypothermia†, University of Pittsburgh Medical Center. Safar, Peter & Patrick Kochanek. â€Å"Therapeutic Hypothermia After Cardiac Arrest†. New England Journal of Medicine, February 21, 2002 p.612-613 Holzer, Michael. â€Å"Mild Therapeutic Hypothermia To Improve The Neurologic Outcome After Cardiac Arrest.† New England Journal of Medicine, February 21, 2002 p.549 Clifton, Guy et all. â€Å"Lack of Effect of Induction of Hypothermia After Acute Brain Injury† New England Journal of Medicine. February 22, 2002. p.556 Rose, Victoria. â€Å"Children Recover Faster Than Adults From Accidental Or Therapeutic Hypothermia†. www.docguide.com. July 23, 2001 Unknown Author, â€Å"Reducing Brain Temperature May Benefit At-Risk Newborns† http://www.pslgroup.com/dg/4E73E.htm, December 17, 1997