Disscision questions american history Essay Example | Topics and Well Written Essays - 750 words

Disscision questions american history - Essay Example A separate village, ten miles away, was established due to the large inflow of inhabitants in the town. The villagers were unhappy with the governance of the town and demanded independence from the town. The town authority, however, did not want to lose the fertile taxable province and resented their demand. There was revolt against the ministers appointed by the town from 1672-1688. During this time, three ministers presided over the affairs of the village. During the reign of the fourth minister, there was widespread revolt against the town’s involvement in the affairs of the village. The priests of various New England colonies began to accuse Salem of revolting against the will of God. In 1692, the first traits of witchcraft appeared against these socioeconomic uneasiness, affecting the children. The family of the minister was the first to be deceased. The difference between the town and village and their urge to gain independence were the prime factors in the spread of wit chcraft in the region. (Trask) The US economy would have crumbled if not for the efforts of visionaries like Alexander Hamilton and James Madison. Hamilton arrived in the scene of American politics in its nascent stage in 1787. The previous Article was put up for discussion in 1787 by the thirteen states. Hamilton, representing New York, proposed the election of Governors and senators, which were opposed by the other members. A separate constitution was proposed with the powers being vested on executive, judicial and legal branches. Most of the states did not sign on it. At this juncture, Hamilton with James Madison and John Jay wrote 85 essays known as â€Å"The Federalist†. The essays underlined the importance of the constitution and they played an important part in achieving the support from the states. Hamilton met again in the next convention and persuaded other states to sign on

PHL323 social and cutural theory Essay Example | Topics and Well Written Essays - 2000 words

PHL323 social and cutural theory - Essay Example One can infer from the writings of Benjamin, the idea of language from his point of view. Language was perceived as one of the forms of communication and the idea represented by that language was in no way identifiable with the language itself. To make it simpler, language was considered to be just a medium of communication. It was not a stand-alone system of knowledge as such, but rather a set of symbols that aid in representation of reality. A language was needed to possess inherent meaning. Language, then, became an entity, which existed only if it had a function, in his point of view. One arguable point here was the cases where there were possibilities that a language with grammar, syntax and vocabulary could exist without the function of a desire to communicate. Computer generated poetry and languages were the instances; the question arises whether they can be taken under Benjamin's definition of language without the function of communication or creativity. Computer languages ha d the requisite grammar, syntax and vocabulary and they were used as a set of instructions that were seemingly understood by the computer. Here, there is the case where a live, organic mind communicates with a non-organic entity. Further, the non-organic entity, besides being capable of understanding, was also able to generate the language understandable by an organic entity. Thus, the computer, which was just a box, was able to generate language to communicate. Computers can also communicate with each other, which had been made possible through the advancements in technology. This led to the case where two non-organic entities were able to communicate. In such cases, the meaning and the language were separable. There is also the instance where an organic entity is capable of generating a language without the purpose of communication. It is the uncommunicative language of a mentally ill person. Even though Benjamin clearly stated that language and what was described using a language were not identifiable, it also remained that he believed that language always should communicate something. If something was made, it should have a function and a meaning. If not, it really cannot exist. While considering the circumstance where one language did not make any sense to a person who does not know that language, the purpose of the language to communicate was lost. The language, even though possessed a grammar, syntax and vocabulary, did not mean anything to that person except being conceived as incoherent noise. Language in such cases negotiated with meaninglessness. Benjamin's idea of language extended to include inanimate objects such as lamps too. His idea of language of such objects was their linguistic being, but it was man who could name something other than him. In this context, man was the only entity that possessed the universal language. Thus, man's linguistic being was to name things. But, a language as such did not end with just naming. It was a tool that en abled creation and possession but it in itself was not so. Benjamin finally resorted to the theological ideas such as that of God being the true possessor and so on to arrive at the higher function of language. Many also conceived theology as a means of escape opted by Benjamin when he was not able to go beyond a certain limit about his conception of such mystical thoughts. In one of his works, "On Language as Such and the

Diversity in Sports Essay Example for Free

Diversity in Sports Essay Diversity in sports simply means equal opportunities for every athlete irregardless of gender, color, race, or origin. This is what the true spirit of competition should be all about. Sports should not only involve the white race, Americans, or men but also other races and sex(Jackson 2007). Rev. Jesse Jackson, Sr. , in his report to the House Committee on Energy and Commerce, said that in recent years, diversity in sports has become very evident. In the world of American football, the Indianapolis Colts, coached by an African-American, won a Super Bowl. In baseball, the Chicago White Sox, a multi-racial team managed by Ozzie Guillen, a Latino, and Ken Williams, an African-American, won the World Series in 2005. A year later, the New York Mets, who is managed by a Latino manager and an African-American general manager, almost duplicated the White Sox’ feat, losing only in Game 7 of the National League Championship. This goes to show that moves to diversify sports are moving forward(Jackson 2007). The National Basketball Association (NBA) has led the way in terms of sports diversity by opening its doors to other races. Long ago, the NBA was dominated by Americans or Canadians. Recently, however, one can see the teams drafting players from Europe and recently Asia. The Major League Baseball (MLB) and National Football League (NFL) are likewise starting to provide opportunities for other races which is why spectators would get to see the likes of Alfonso Soriano and Sammy Sossa hitting homeruns here and there(Jackson 2007). Diversity in Sports 4 The NBA: Taking the Lead In Diversity Leading the way as far as diversity in professional sports is the National Basketball Association (NBA). For more than twenty years, the NBA has become the leader in promoting equal opportunities to all races. Here are some NBA diversity facts and figures as reported by The Institute for Diversity in Ethics and Sports(Spears, 2007): 15% of team vice presidents in the NBA are held by colored people, which is the highest in all of professional sports. 79% of NBA players have colors. In 2007, the number of African-American players increased to 75% which is higher than the 73% recorded in 2006. Employment opportunities for colored people at the League offices were at 34 percent, which is 2% higher than the previous year. 39% of professional positions in the League Office are occupied by women. 12 teams in the NBA are handled by African-American coaches. The NBA’s total of 40% still tops all of professional sports. With 53 African-American head coaches, the NBA has more than doubled the number of colored head coaches in any other professional sports. Next in line is the MLB with 25 colored managers. 41% of assistant coaches in the NBA are colored which is the highest so far in the history of the league. Diversity in Sports 5 There are four African-American CEO/Presidents in the league and two other presidents of basketball operations. To date, they are the only people who have held such position in all of professional sports. In 2006, there were eight African-American general managers in the NBA, which tops other professional sports league. By the end of 2006-07, the NBA had 64 percent white referees, 32 percent African-American, 3 percent Latin Americans, and a single black referee in Violet Palmer. Diversity in College Sports While professional sports is heading towards diversity, such is not the case in college sports. According to a report by the University of Central Florida, diversity has not been progressing in collegiate leagues. Here are the facts(Belew, 2006): In Division I schools, only 25. 2% of head coaches are African-American which is higher by 2% than the previous year. In Division IA, out of a total of 119 football head coaches, only six are African-American and zero percent are women. In college basketball, only 4. 1% of head coaches come from the minority group with 2. 6% being Latin Americans. The enforcement of Title IX did not help the cause of women in college sports as not a single one of them is represented. Diversity in Sports 6 In sports involving women, most Division I, II, and III coaching jobs are occupied by 89. 6%, 90. 9%, and 92. 9%, respectively. In the men’s division, the breakdown was 90. 6%, 89. 5%, and 93. 4%, respectively, served as head coaches. Diversity in the Olympics The Olympic Games is one of the many sporting competitions that practices diversity in sports. Once every four years, athletes from various nations converge in one venue in order to have a shot at sports excellence(Guttmann, nd). There are two varieties of this international sporting event namely Winter and Summer Olympics. Contemporary Olympics started in Athens, Greece in 1896, a couple of years after Pierre de Coubertin proposed the holding of an Olympic Games to push for peace in the world. The inaugural Games only had about 300 athletes from less than 15 countries taking part in 43 events in nine disciplines. When the Olympics returned to Athens in 2004, the number of participants had ballooned to 10,000 athletes representing 202 nations vying in 28 various sports(Guttmann, nd). Women In The Olympics During the inaugural Olympics, there were no female athletes who took part in the Games. Four years later, however, golf and tennis allowed the participation of women. In 1912, swimming and diving became available for women athletes as well. Sixteen years later during the 1928 Games, gymnastics and track and field had female athletes likewise. Since then, the number of women competing in the Olympics have considerably increased. At present, fifty percent of all teams are comprised by women, with the exception of the Muslim countries, where female participation is minimal(Guttmann, nd). Diversity in Sports 7 The Paralympics Games In the true spirit of diversity in sports, disabled people can have an opportunity to experience competitive spirit and sports excellence with their own version of the Olympic Games. Introduced in 1960, in conjunction with the Olympic Games in Rome, the Paralympics, as it is called, highlights male and female athletes representing six various disability groups. The emphasis of the Paralympics Games is not on the disability but on individual achievements. Since then, the growth of the event has become steady. From the initial 400 athletes that took part in 1960, a total of 3806 athletes representing 136 nations took part during the 2004 Athens Paralympics Games. Beijing, China will be the cite of the next Paralympics Games(International Paralympics Committee, nd). Conclusion When it comes to sports, not a single nation can dominate all the events. While host nations of the Olympics choose the events where they have the advantage, chances are other nations will beat them in other fronts. This is what diversity in sports is all about. Fairness and equality in the light of competition. References Belew, B(2006 December 17). Diversity in College Sports – Coaching. The Biz of Knowledge. Retrieved July 14 2008 from http://www. thebizofknowledge. com/2006/12/diversity_in_college_sports_co_1. html Guttman, A(nd). Olympic Games. Microsoft Encarta Online Encyclopedia. Retrieved July 14 2008 from http://www. encarta. msn. com

The Main Critiques Of Liberal Democratic Model

The Main Critiques Of Liberal Democratic Model One of the most important political ideologies used in the modern era especially by the Western countries is liberal democracy. A liberal democratic state involves of the goals of both liberalism and democracy. This essay will talk about the critiques of liberal democracy explaining the four criteria of liberal democracy and why it works or does not work in the context to the case study countries. In a liberal democratic model, it is necessary to have some basic criteria on liberal democracy. The four criteria that will be explored in relation to the case study countries are multiple distinct political parties, separation of power into different branches of government, an idea of equality and lastly secularism. According to Gordon Smith political parties are, the summation of pluralist tradition. This means political parties are very important because of the role they play in society. Pluralists debate that there should be multiple contenders in opposing centres of power as the power should not rest in one group rather be divided and diffused (Schwarzmantel, 1994:51). Political parties represent the public interests. Likewise, multi- party system creates diversity and competition in turn parties makes efforts and try out to reach to a larger group of people making their policies relevant. It emphasises different groups of interests within the liberal democratic state which prevents any one group from dominating. As each human being have different perspective of looking at the world, similarly each party might have a different interpretation on a policy because of the different ideals and values. The main aim of political parties is to capture state power. This pluralist view applies to a co untry like Russia where they have multi-party system. It is practically accurate to argue that at the national level Russia has attained at least a semi-pluralistic political system, with number of national parties and the strong influence of business interests. On the other hand Elite theory rejects the pluralist theory that power can be diffused and can be divided and spread among different groups of society. Elite theory argues that the power rests in the hands of few, who are wealthy. They assert that the average person cannot be heard because the power is usually concentrated in a few at the top. Democratic elite theorists argued that the decrease in internal party democracy and meeting process did not matter much, so long as competition between parties still give voters the final power. Elite theory says that two-party or multi-party system is usually dominated by an elite. For example in a country like USA elite theory works more than the pluralist theory. United States has two parties unlike the other countries that have multi-party system. In a multi-party system, political parties usually have specialised agenda which in turn represents their interests like environment, labor or business. But in America with a more generalised syst em, the two parties have to please a wider range of people to be elected. Consequently, both parties act neither too liberal nor too conservative. Many people agree that United States has a two-party system but there have been few cases where third party candidate won an election. Third party candidates have to struggle to get elected. The last time when the country saw a third party presented elected was in 1860 when Abraham Lincoln became President. In the view of elite theory they agree with the two-party system in United States as campaigns costs a fortune in this country. In their view the wealth buys the political power by recruiting capable individuals to serve the interests of the ruling class, and by financing the campaigns of politicians and the operation of political parties'(Module guide).Political parties are important for keeping the check and balance of power through peaceful means and are thus important in a liberal democracy. Without having any form of competition t hen from an elitist, then there would be only one outcome and that is whatever the elite considers the best then that will be the decision. In a country to be liberal democratic state power should be divided among different groups so that state cannot rule the masses on their own and the power is distributed among different factions of government. Pluralism critique of the state suggests a solution to how democracies can be realised in large and complex societies and how to achieve popular power and at the same time limit the power of the state. Pluralism is strictly against the totalitarian government. A pluralist society is on in which the decisions are taken by associations of citizens, acting independently of state. They assume state as a neutral actor which helps control conflicts and negotiations among groups. As all groups do not have equal resources or influence as some of the other groups in society, state does not favour any of the group rather remain neutral. Pluralism prefers a federal system of government in which power is divided among executive, legislature and judiciary. So that there is checks and balanc es and no one can misuse the power. Madison advocated a simple logic stating that, grant independent power to the different branches of government, and each member of that branch will have a personal interest in maintaining that power and preventing the other branches from carrying out their repressive designs. It means if the power is distributed among different bodies in the government, no person will be able to impose his or her will. Pluralist theory can apply to a country like France where there is a federal system of government although the executive is body is slightly stronger than that of legislature. However all the power does not rest with the executive, power also lies within the two remaining branches of government, the legislative, and the judiciary. The second critique which describes the state is elite theory. In their view, the separation of power is unimportant within the state because in the end unified elite hold the power. They assert that the elites will always hold power in the society in different forms and their nature will directly determine the properties of society in which they live. The post- war elite theory critique C. Wright Mills argued that important decisions made in United States policy making were most of the times made by unelected power elite. For example, Unites States has a federal system of government in which power is evenly distributed among the 3 bodies of government , namely legislature, executive and judiciary but there certain cases where there are power elite makes the decisions. For instance the head of a big American business corporation or even the President or his appointed staff. On the contrary, Marxist theory argues that economy is the most important element in the society and that the s ociety should grow towards a classless structure with an equal distribution of power. Each citizen should be treated equally irrespective of gender, cast and religion to live in peace. Thus, idea of equality should be present in every country which makes it an important aspect of a liberal democratic country. Marxist Theory can best explain that why there is inequality among countries. Marxists states that unequal distribution of wealth is caused by exploitation in production as well as distribution of wealth. Capitalism and notion of private property creates class differences and unequal distribution of power. Private property maximises the gap between rich and poor. For instance if a person owns a property, he gets to exploit people who dont which leads to other people working for the person who owns the property and can provide them with money. This form of organisation develops two classes, the bourgeoisie or ruling class who control and profit from the system and the working class who are much more numerous. In Marxist view wealth should be equally distributed am ong people. Rejecting this theory of Marxism, elite critiques argue that economic or social class forces do not determine what happens in society rather elites do. Italian writer Vilfredo Pareto criticises Marxists for overlooking the control of elite. For example in a country like America and Nigeria there is a huge income gap between rich and poor due to capitalism. The wealth is concentrated in the hands of elites which gives an adverse effect on the welfare of citizens. Utter poverty for a large percentage of the people of Nigeria is because of the mismanagement of the economy and widespread corruption by political elites. Therefore both the theories can be applied in the countries like Nigeria and United States. All the liberal democratic countries should accept that citizens should not be prevented from practicing their religion and the state is no one to interfere with the religious decisions of citizens or their institutions. Marxist sees religion as a feature only of a class-divided society. The theory argues that whichever class controls the economic production also controls the production and distribution of ideas in society via institutions such as church, education system and the media. For example, France has declared herself as a secular country having divided church and state during the French Revolution. However, over 80% of her citizens claim to be Roman Catholics, on the other hand 10% claim to be Muslim (CIA).In spite of being a secular state France does not allow manifestation of religion in public sphere. In 2004, an anti-religious law passed through legislature that banned the wearing of headscarves, turban, skullcaps, or large crosses in the public schools as (Graham, 109) .Therefore looking at this example of France it can be said that the Marxist theory can describe secularism in France as the person who is ruling is passing all the laws which controls all the power in the government and can influence any law in his favour. Moreover this law in the end can lead to divisions in society. Similarly, Pluralism accepts all the religions in the society and rejects the notion that there can be a single belief in religion or culture. That is, pluralism is a simple recognition of the fact that there are many different faith groups active in the country. Pluralist theory works well in the liberal democratic countries as they demonstrate well about secularism. Pluralist theory works well in religious country like United States which is a multi-cultural society consisting of many religious groups such as Christians, Muslims, Hindus.

Firewall Effects on Network Performance | Evaluation

Firewall Effects on Network Performance | Evaluation In an age where our society relies so heavily on electronic communication, the need for information security is constantly increasing. Given the value and confidential nature of the information that exists on todays networks, CIOs are finding that an investment in security is extremely beneficial. Without security, a company can suffer from theft or alteration of data, legal ramifications, and other issues that all result in monetary losses. [The Best Damn Firewall Book Period] Corporations are realizing the need to create and enforce an information security policy. As a  result, IT professionals are constantly being challenged to secure their networks by installing firewalls that provide more secure [Cisco Security Specialists Guide to PIX Firewall]. Firewalls are essential components in improving network security. Most firewalls are deployed at the edge of the network to filter legitimate traffic, and can be deployed in the core of the network to further supplement and protect the capability of the network and the application running over the network to deliver required services to the end user. Firewalls have become increasingly complex, evolving from offering traditional firewall capabilities to protect networks, to offering application-aware processing of several Internet protocols. Brief literature review: Firewalls are the first front line defense mechanism against intruders ,a firewall system can operate at five of the seven layers of the OSI reference model. However, most firewall systems operate at only four layers: the data link, network, transport, and, possibly, application layers. Based on the simplicity or complexity of a firewall product or solution, the number of layers covered varies. For example, a standard IP access control list (ACL) on a Cisco router functions at OSI Layer 3, and an extended IP ACL functions at Layers 3 and 4. [cisco press cisco router firewall security] Firewalls work by inspecting different fields in headers of the packet, finding the matching rule and doing the action specified in the rule. Common firewalls (and rules) examine at least IP addresses, next protocol type (TCP or UDP) and in case of TCP or UDP their respective port numbers. That usually gives five different variables (source destination address, protocol, source destination port) to work with. [Optimizing firewall performance]. [Performance analysis of the Linux firewall in a host]. As example ,a firewall that operates at only Layers 3 or 4 can filter only on IP protocol information, IP addresses, and TCP or UDP port numbers; it cannot filter on application information such as user authentication or commands that a user enters. Therefore, the more layers a firewall can process information from, the more granular it can be in its filtering process. [cisco press cisco router firewall security] There are many considerations that organizations should include in their firewall selection and planning processes. Organizations need to determine which network areas need to be protected, and which types of firewall technologies will be most effective for the types of traffic that require protection. [ Guidelines on Firewalls and Firewall Policy]. In addition, Incorporating a firewall into a network structure is likely to increase processing and even create bottlenecks [Evaluation of Firewall Effects on Network Performance] ,whereas Each rule that a firewall has to analyze results in additional processing overhead. This means that the more rules a firewall has, the longer it will take for the firewall to determine whether or not the packet in question may pass through. [Firewalls Overview and Best Practices]. As result Firewalls are one key factor in network performance. If they cant process their rules fast enough then the whole network slows down. [ Optimizing firewall performance] Some studies shows that the firewall is sensitive to the number of rules, the type of filtering, and the transmission rate. The results of our first scenario demonstrate that for each type of filtering, latency increases linearly as the number of rules increase. [Performance analysis of the Linux firewall in a host] Scope and limitation of the study: There are some points may represent the scope and limitation of the study, including: This project focus on evaluating the effect of firewall performance using an OPNET Modeler network simulator and analyzing on different scenarios and to compare the performance impact when firewall applied. This project also focusing on effects of firewall filtering on network performance. In this study we are going to select special type of firewall application firewall The number of workstation is limited which wont exceed 200 nodes. The result will be collected is based on the simulation so may be this result will not be applicable in real hardware. Statement of the research problem: This research reports on the evaluation of using firewall in three different scenarios, which can show the impact of applying the application firewall on the performance of the network. Therefore, the research addresses the following research problem: How can we make trade-off between the security and performance? Essentially I argue that in order to investigate the feasibility of getting the trade-off of using the firewall, its necessary to compare the result when the firewall applied in different scenario, it might be depends on the policy or function nodes. Research questions: To address the research problem identified in the previous section, the following research questions have been designed: What are negative aspects of firewall? What are positive aspects of combined security and performance? What are the effects of firewall in the link utilization? What are the effects of firewall in the Real time application? Research objectives: The main objective of this research is to investigate the impact of firewall policy on the performance of the network. To identify negative aspects of firewall. To determine positive aspects of combined security and performance. To examine the effects of firewall in the link utilization. To identify the impact of firewall in real-time application. To compare the result from different scenario to estimate the effects of policy. Significance of the study: The growing Demand for using firewall by the internet users and companies to provide more protection for them and the influence of apply firewall policy in the network performance gave the impetus for this study. To verify that we propose here three different scenarios, CNTs as the one of the components of MMIC transmission lines to enhance the electrical performance. This material offer some remarkable characteristics for microelectronics applications and their large kinetic inductance (skin effect), long mean free paths, high current carrying capability and high thermal conductivity made them ideal candidates for RF/microwave applications as transmission lines. Research methodology: The research methodology work will go through four stages namely: theoretical stage, data analysis and design stage, lab stage, and evaluation stage. Theoretical stage: The objective of the theoretical stage is to constitute a theoretical frame to enable the success of the lab stage through that frame. Data analysis and design stage: In this stage, all related data obtained in the theoretical stage will be analyzed and then a selection process will be done in order to get the high quality CNT and the right design for CNT-based TLs to be able to accomplish the research questions through synthesis and characterization process. Lab stage: At this stage, firstly, the growth parameters will be optimized by using chemical vapor deposition growth method In order to produce large scale and well-aligned CNTs. Next, the characterization process will be done on the samples. SEM, FESEM, and HRTEM techniques will be used to study the morphology of the samples. XRD and EDEX techniques are used to study the samples crystallographic structures and composition elements in the samples respectively. For electrical characterization, I-V and resistivity measurements using four point probes will be applied for low frequency. Lastly, in the implementation process, the determined high quality CNT will be used to fabricate transmission lines, and then RF characterization will be done using VNA at different frequencies. Evaluation stage: The experimental results are analyzed to evaluate the effectiveness of the new variables in order to get the best CNT for the TLs. Current Stage: For device applications, the orientation of the CNT is particularly important. Therefore currently, the growth parameters are optimized by using chemical vapor deposition growth method and then, scanning electron microscopy (SEM) is used to study the morphology of the samples in order to get large scale and well-aligned CNTs. The fabrication of CNTs on P-type silicon substrates; size 1 cm by 1 cm were done using nickel (Ni) as catalyst. The first process is to remove any impurity and oxidization on the Si substrate surface. The substrate will go through stages of cleaning process, starting with acetone, methanol and then rinsed with deionized water to remove organic contaminants and particles. Then, the Si wafer was cleaned by hydrogen gas to remove natural oxide. Next, a thin Ni film was deposited on a substrate as catalyst using Electron-Beam evaporator and the substrate was placed on alumina boat before placed inside a double-heater TCVD. The first heater was set at 1000 °C to decompose methane, while the second was set at 800 to 1000 °C for pre-treatment of the catalytic film. As A. Awang Teh et. al. proposed [41] a precursor of ammonia and methanol solution at ratios of 5:8 was used to enhance the growth of CNT in methane ambient. The second heater was first switched in flowing Argon at 100 sccm. When the temperature of the second heater reached setting point and stayed stable, first heater was then switched on and methane gas was flown at flow rate of 10-50 sccm. The total growth time of the CNTs varied from 30 to 3 hours. Finally, methane gas was turned off and the furnaces were cooled down to room temperature in flowing Argon at 100 sccm to avoid carbon oxidation. After fabrication is completed, The CNT morphology was examined using SEM. Figures 1- 6 show the growth of CNTs on Si substrate using Ni with different thicknesses and subjected to methane ambient at 850 oC for 2 hours. One of the first things to note is that the catalyst thickness affects the diameter and density of the CNT. The catalyst film thicker, the larger diameter and more density CNT we can get. Also, it can be seen clearly this relationship from the SEM results shown in fig.11 to 14. Furthermore, from the SEM image shown in figure 4 the least nickel or carbon nanoparticles protrude from the nanotubes was observed. These conductive nanoparticles cause electrical shorts between interconnects for device fabrication. For this reason we can consider that the optimum nickel catalyst thickness in our case is 10 nm. A final point to note is that there is no CNT at all in figure 1. It means that the catalyst film thickness is very thin and after recombination the size of catalyst nanoparticles is too small to synthesis CNTs. Another key parameter to affect CNT growth is temperature gradient. As we can see from the SEM results shown in figures 7-20, by controlling the growth temperature we can increase the growth efficiency and purity. At reaction temperature 900 °C, the growth of clean CNTs was observed. However, no CNTs were formed when the growth temperature exceeded 900 °C. Instead, amorphous carbon was observed on the surface of the substrate. Besides catalyst and temperature gradient, carbon source flow rate also plays an important role in the CNT growth. It can be stand out from experimental results shown in figures 21 to 28 that a higher flow rate will increase the decomposition rate, and consequently the growth rate of CNT. However, when the flow rate of Ni was 10 sccm there is not enough reactant to react with the catalyst and just catalyst nanoparticles were observed. The gas flow rate affects not only CNT density but also nanotubes diameter. The higher gas flow rate, the larger diameter of nanotubes will grow. However, after a critical point, increasing the flow will change the carbon product from CNTs to carbon nano-fibers (CNFs), as it was observed from the result. The last growth parameter we have optimized is syntheses time. From experimental results shown in figures 29 to 32 we can find the relationship between the syntheses time and the length on nanotubes. Longer synthesis time with longer catalyst lifetime, longer CNT we can get. More optimization and characterizations must be done on the samples in order to get well-aligned and density MWCNT, before transmission line fabrication. Preview of the thesis: This thesis is organized into five chapters. Chapter One serves as an introduction to this study, providing the theoretical framework, research objectives and significance of the present study. It also offers a brief overview of the methodology that is employed. Definitions and delimitations that map out the boundaries for the present study are also outlined. Chapter Two provides the literature review for this study and serves to develop key issues related to the theoretical framework. The third chapter is on methodology. This study approaches the issues of fabrication, simulation and modulation. The fourth chapter reports the results of the content analysis and discusses the findings. The fifth chapter reviews the research questions and summarizes the thesis. This chapter also provides suggestions for future research. Network Security is one of the most important fields dealing with the Internet. The ability to access and transfer information in a few seconds allows the government, companies, educational institutions, and individuals to accelerate the decision process or simply be informed. However, information can be very valuable and there is a need for better and faster security systems to protect information and networks. Therefore, it is best to limit the number of rules to no more than 30-50. However, for best performance, less than 25 rules are recommended. Also, firewalls process their rule base from the top down. As soon as the firewall finds a rule that applies to a particular packet, the rule is applied and the packet is processed (either allowed to continue or dropped). It is recommended that the most important and most utilized rules should be at the top of the rule list. This prevents the firewall from having to process through a number of rarely used rules to finally get to rules that apply to the majority of the network traffic. Determining the correct order of rules for a particular implementation is an ongoing process. Initially, there is a significant amount of testing and trial-and-error involved in determining the correct order that the rules should be in. Also, the rule base should be reviewed periodically to see if the organizations requirements or network usage has changed that wou ld require the reordering of existing rules as well as adding or removing rules. Finally, one should make sure to keep the number of domain objects in the rule base to a minimum, and also make sure that these objects are kept towards the bottom of the rule base list. Firewalls Overview and Best Practices There are many aspects to firewall management. For example, choosing the type or types of firewalls to deploy and their positions within the network can significantly affect the security policies that the firewalls can enforce. Policy rules may need to be updated as the organizations requirements change, such as when new applications or hosts are implemented within the network. Firewall component performance also needs to be monitored to enable potential resource issues to be identified and addressed before components become overwhelmed. Logs and alerts should also be continuously monitored to identify threats-both successful and unsuccessful. Firewall rulesets and policies should be managed by a formal change management control process because of their potential to impact security and business operations, with ruleset reviews or tests performed periodically to ensure continued compliance with the organizations policies. Firewall software should be patched as vendors provide updates to address vulnerabilities. [ Guidelines on Firewalls and Firewall Policy] The firewall can become a bottleneck. All network traffic that passes between the Internet and the DMZ, the DMZ and the private network, and potentially, the Internet and the private network, must be inspected by the firewall. This can result in the firewall becoming a bottleneck and reducing the performance between the network and the Internet.

Quasars Essay -- Essays Papers

Quasars Since their discovery, the nature of quasars has been one of the most intriguing and baffling problems as evidenced by the following quotations: " the problem of understanding quasi-stellar objects†¦ is one of the most important and fascinating tasks in all physics" - G.Burbidge and Hoyle. "The quasar continues to rank both as one of the most baffling objects in the universe and one most capable of inspiring heated argument" - Morrison. "The redshift problem is one of the most critical problems in astronomy today" - G. Burbidge. "Quasars still remain the profoundest mystery in the heavens" - Hazard and Mitton. The conventional interpretation of the spectral lines observed in quasars is based on the redshift hypothesis. Three hypotheses have been advanced to account for the supposed redshifts: 1. Cosmological hypothesis; the redshifts are due to the expansion of the universe, 2. Gravitational hypothesis, 3 Local-Doppler hypothesis; in this hypothesis the redshifts are due to the Doppler effect, but the quasars are relatively nearby and have nothing to do with the expansion of the universe. Of these hypotheses, the first one is the most publicized one. One is led to attribute to quasars very many mysterious properties if one assumes the redshift hypothesis to be correct. A patient analysis of the data on quasars over the years has led to the conclusion that the real source of the trouble is in the assumption that the spectra of quasars have redshifts. In the early 1960's quasars were known as 'radio stars' because the method used to discover the first quasars was based on coincidences between a strong radio source and a point-like optical source. Since each radio source was associated with a star it was originally thought that quasars were objects within the galaxy hence the term 'radio stars'. Quasars or quasi-stellar radio source, from the method by which they where originally discovered: as stellar optical counterparts to small regions of strong radio emission. With increasing spatial resolution of radio telescopes the strong radio emission often seemed to come from a pair of lobes surrounding many of these faint star-like emission line objects. The initial method of selection was strong radio emission, and then later any object with blue or ultraviolet excess wa... ... between galaxies, either through direct collisions or near encounters, can be important in turning on a quasar, by dumping fuel onto a black hole. However some quasars look unperturbed, so there may be other, more subtle mechanisms for feeding the black hole. Some of the galaxies we observed don't appear to know they have a quasar in their core. 3. Quasars that are radio quiet are often in elliptical galaxies, not always in spiral galaxies, as previously believed. Advanced instruments planned for Hubble should also help pin down more details. The Near Infrared Camera and Multi-Object Spectrometer (NICMOS), to be installed in 1997, and the Advanced Camera, to be installed in 1999, will have coronagraphic devices which will block out the glare of a quasar, allowing astronomers to see closer into a galaxy's nucleus. By viewing galactic structures in infrared light , the NICMOS should be able to provide important new details about the host galaxies of quasars. The continued study of quasars and the information that it will provide us with may help us to develop a better understanding of space and how we fit in to this great puzzle.

Flying Tigers :: American America History

Flying Tigers Flying Tigers is the name of a mercenary group of American pilots that helped defend China and the Burma Road from the bombing of the Japanese during World War II. The name of their planes was Tomahawks, but the Chinese called them Fei Hu for the sharks teeth painted on their planes. Flying Tigers were known as the American Volunteer Group of the Chinese Air Force. The Flying Tigers did not see combat until December 1941 when the Japanese started bombing China. Jim Gordon, the leader of the Flying Tigers, was running short on pilots after the war had started so he began searching for new pilots. Blackie, one of the volunteers, wanted to be part of the Flying Tigers, but Jim didn't want Blackie. So his wife begged Jim to let Blackie into his group. One day during the Japanese bombing, Blackie's plane caught on fire. He jumped out attached to his parachute, but one of the Japanese planes saw him and shot him. Another volunteer, Woody, joined the Flying Tigers, he wanted to prove to Jim Gordon that he was an expert at flying planes. During the first attack, Jim wouldn't let Woody fly, but Woody flew anyway. When he was aiming for a soldier, he noticed that his plane didn't have bullets and was nearly killed. After that happened, Jim thought Woody would one day be a good pilot because he was brave enough to take on three Japanese planes all by himself with no bullets. When the day of December 7, 1941 hit, President Franklin Delano Roosevelt ann ounced on the radio that Pearl Harbor was bombed which was, "A Day of Infamy," and when Jim heard on the radio he was very disappointed. The next day he decided to bomb Japan to help defend his country by himself, but Woody pretended to be the pilot flying the plane because he wanted to help Jim. When they got to Japan, they were aiming for a train full of Japanese soldiers. They started firing at them and when their plane caught fire, Jim and Woody decided to jump out. Then, all of a sudden, Woody pushed Jim out of the plane and flew the plane directly into the train and sacrificed his life to help Jim and his country.