The advantages and disadvantages of the country’s

Before the dawn of civilization, man has traveled far for places unknown to him. Initially the traveling was only done with a purpose of food and shelter, but as time passed by and as we became more and more developed, the need to go to a place without any motive, without any intention started eloping in our minds. This motive free traveling came under the name of â€Å"tourism†.New Zealand is a country that is famous for its breath taking views and is quiet a hotspot for tourists, who want to come to a place which has all in store for people of all ages and backgrounds. Slowly but surely, New Zealand has developed a place for itself in the world’s top destination places, and people from almost everywhere in the world flock to this country to experience its natural beauty and resources. The tourism in New Zealand is bringing in good inflow of foreign exchange to the country and is very helpful to the economy.Even though the main economy of the country is through agricul ture and industrial inputs, tourism has craved a niche in the country, so much that it is estimated that the country’s 10% population is working for the hospitality sector. Increase in tourism, is developing the place more and more, and there can be seen a substantial rise of hotels in the country. International franchises of hotels are keen in opening up more and more of their hotels in the country to suffice the tourist onslaught of the country. The major advantage of New Zealand’s tourism is to the country’s financial background itself, and the major advantages of it can be assessed by the following:‘Tourism is important for New Zealand’s future economic growth. It contributes $18.6 billion to the economy each year — 9% of New Zealand’s gross domestic product. It is also an important source of employment. One in every10 New Zealanders works in the tourism industry. Tourism is our largest export sector. International visitors contrib ute $8.3 billion to the economy each year, which accounts for 19.2% of export earnings. During 2006, 2.4 million international visitors arrived in New Zealand’Tourism no doubt is very advantageous for New Zealand, as apart from pumping in money, is reviving the pride and refurnishing small town of the country, as now they have become major tourist hotspots. Tourism also is making the government revamp places that include parks and museums, and in one way local heritage is being preserved and well maintained because of tourism.The major disadvantage that can be considered is because of this high amount of tourism is that the hotels that are coming up every year, are causing damage to the flora of the country. The country in order to suffice high expectations is experiencing rapid changes in climate due to global warming. Also the high expectations are taking its toll on the labor market, and the hospitality industry is currently facing labor shortage and skilled manpower short age at the moment.Migrating people from just for the sake of hospitality sector might sound beneficial, but then New Zealand which is currently out of migration woes, might start suffering too, like other western countries. Also to motivate high amount of tourism is to relax visa procedure for entering the country, which is the biggest disadvantage as it is open invitation for people trying to become illegal immigrants and even maybe to terrorism. The country has it advantages and disadvantages for hospitality, but one thing that is for sure is the country will always thrive on tourism.Reference:https://apps.fas.usda.gov/gainfiles/200503/146119096.pdf

Continuous Assessments Essay

Continuous Assessment is an on-going process of gathering and interpreting information about students’ learning that you use to make decisions about what to teach, how to teach and how well students have learned. Basic characteristics of Continuous Assessments include the following; * It is an on-going process * It comprises of a variety of assessment methods * It gives timely feedback * Its aligned with curriculum and * Its collaborative with students. Some differences between Continuous Assessments and Formal Assessments Continuous Assessments| Examinations| Ongoing in the classroom throughout the year| Usually at the end of a unit, semester, term, year or cycle| Many different tasks| One exam or few tests per subject| Carried out by the teacher| Can be administered by someone other than the teacher| May be developed by the teacher| May be written by persons other than the classroom teacher| Marked by the teacher| May be marked by persons other than the classroom teacher| Teachers use assessment results to improve teaching| Don’t help teacher to identify learner weakness| Are connected to the syllabus being taught| May not be always be connected to what is taught|. General Advantages of Continuous Assessment * Learners will be assessed using different and appropriate assessment methods and this will provide a more valid assessment of the learner’s performance. * Assessment will now take place in an authentic context i. e. the learner will be assessed in a realistic situation, which is integral to the learning process. * During assessment, there will be immediate feedback into the learning process, thus promoting the formative role of assessment. * Opportunities are provided that would be impossible in a once-off external examination. * A variety of skills can be assessed by internal assessment, which otherwise would not have been considered for assessment purposes. * Assessment is on-going and therefore learners are compelled to work consistently and this will contribute to re-instating the culture of teaching and learning. * The educator who works closely with the learner will now carry out judgment of the learner’s performance. Specific Advantages of Continuous Assessment to the Learners * Monitor student progress * Develop study behaviour * Identify misconceptions * Motivate improvement Have realistic expectations. Specific Advantages of Continuous Assessment to the Parents * Involve in monitoring child’s progress * Understand student’s strengths and weaknesses * Strengthen learning partnership with school Seek assistance for their child Specific Advantages of Continuous Assessment to the Teachers * Evaluate effectiveness of their lessons * Modify teaching strategies * Improve judgments about what students have learned for final grades Evaluate effectiveness of programs How is Continuous Assessment Used? Continuous Assessment is usually used for the following Formative purposes; * Diagnosis: identify skills that students can do. * Diagnosis: identify errors that a student is making * Help decide how to change the lesson / unit plans * Provide students with practice * Help decide where to begin teaching * Modify students’ behaviour Continuous Assessment is usually used for the following Summative purposes; * Grading and promotion * Assigning final grades * Selection of students for programs * Provide superiors with data * Give awards (formally or informally) for work well done / effort made * Student classification Some Concerns of Teachers * Continuous Assessments is time consuming and requires a great deal of preparation and record keeping * A few students do not do well on projects during the term, but do well on final examinations; the zero on projects brings down their final grade * Some students are de-motivated when they do not see the rate of progress they anticipate * Lack of trust that the assessment tasks, such as projects and home work assignments that are not done under good supervision are the students’ own work *. Students seem overwhelmed with so many school-based continuous assessments that count towards their final grades, if every subject gives a project or a term paper, that’s a lot of work * The marks from continuous assessment are inconsistent across teachers Some Examples of Alternative Assessments * unseen written examinations * Seen written examinations * portfolio development * essays * projects * strategic or business plans * fieldwork * literature searches * journal article analysis/critiquing * oral presentations * dissertations * book, article, multi-media material reviews * laboratory reports * case studies * group/team work * audio/video tape production.

In Whose Honor Essay

The film â€Å"In Whose Honor? American Indian Mascots in Sports† produced by Jay Rosentein introduces a topic that is new to many viewers. In the film, he explores through interviews and school controversies the misuse of Native American culture through school sports mascots. Most of the people who embrace school mascots, such as those used by teams named the Chiefs, Indians, Braves, and Warriors unknowingly promote a stereotype of Native American culture that serves to embarrass and further alienate the people from their heritage. The fight to stop these unfair stereotypes are undertaken by many activists and their heroic stories are chronicled throughout this documentary. Issues with the mass media and it’s effect on shaping perceptions of people as a powerful force are also explored and from a sociological perspective all of these harmful images and portrayals are investigated. The most significant sociological revelation in the film is the clash between majority and minority culture. On a smaller scale, the majority culture and the norms that come with this are not parallel to minority culture except in forms of entertainment. Most of the intersect that connects majority and minority culture of any type is such things as dining at â€Å"ethnic† restaurants, listening to â€Å"ethnic† music, and watching movies and television that depict minority life through the eyes of the majority culture. Sports has traditionally been seen as racially neutral as a form of entertainment, but this film however, shows that even this arena is ridden with racial stereotypes is one used the trained sociological â€Å"eye† so to speak on them. Simply, stereotypes of any kind are harmful and detract from the long and proud tradition that the stereotyped people hold. I understand how the idea of racism and stereotyping talked about in scope in class correlates with the topic and the issues in the film. Racism is a systematic, institutionalized way of oppressing people and Native Americans have been oppressed since English settlers came to The United States. Now Native Americans are largely out of sight, on reservations where there is little contact with the majority culture. Just because there is little contact, however, does not mean that the people do not want to be depicted and portrayed by the majority culture in an accurate way. In one hand it seems like the proud traditions in history of the Native Americans have largely been forgotten, but on the other hand stereotypical images of them do emerge in the media. Stereotyping is less universal and widespread than racism, but each are harmful in their own ways. While racism serves to oppress a group of people to submission, shame, and even genocide; stereotyping serves to take only a few traits and traditions of people and make this seem like these traits are all that there is to the group. The Native American people have their own music, values, language, and many other specific norms to their group. Additionally not all Native American tribes are similar in their language, rituals, and other ways of living. So to lump all these tribes and Native Americans together as a whole with stereotypes about them is not only unfair, but it undermines the entire history and present culture of this group. One of the most harmful aspects of the Native American stereotype is that the people are all inherently violent. Though some tribes were known for their tenacity in wars, not all tribes were active in violent warring with other tribes. The sports stereotype, then damages the culture by making all Native Americans of past and present seem like violent people and this is simply not the case. Most all sport teams do have mascots that are renowned for their strength and warring skill; such as the Vikings, the Raiders, the Buccaneers, and so on. The fact that many schools use Native American names for the stereotype that the names hold is interesting as is the fact that many schools, due to Native American activism have chosen not to use Mascots or names that are offensive or stereotypical. The school depicted in the documentary, however, did not see how harmful their actions were and this type of ignorance is fairly representative of majority culture. I must say, as a member of the majority culture, that I was unaware of the harm of such stereotypes and I am an avid fan of all sports, as well. Most of the mascots I saw growing up were â€Å"silly† and their purpose was simply to get fans motivated to cheer for the team. However, I do recall a coach who led the Braves in Little League Baseball and wore the Native American headdress and carried a tomahawk to games. I remember being embarrassed for him and his behavior, but now realize that it was the way that he depicted Native Americans that ultimately bothered me. This film was definitely an eye-opener and there was a message of hope in the social activism that was carried out in the name of justice for all Native Americans. As we have talked about all the social changes in class that have been initiated by activism, it is good to see that these types of actions are still carried out today as they are very necessary. In conclusion, â€Å"In Whose Honor? American Indian Mascots in Sports† is a very sociologically sound documentary that weaves in many in-class and textbook topics. The historical effects of racism against the American people and the currently carried out stereotypes of Native Americans in sports is an example of how cultures can be oppressed and misunderstood. This also shows how important activism is in bringing about needed social change in the media, sports, and all arenas of majority culture.

The Analysis of Immediate Souths Secession from the Union Essay

The Analysis of Immediate Souths Secession from the Union - Essay Example The essay "The Analysis of the Immediate South’s Secession from the Union" talks about the rationality of the South actions during the years preceding the Civil War. One cannot ignore the fact that if the South did not declare succession, Lincoln would not have to declare war in the south. James McPherson, an expert in this subject and author of The Battle Cry of Freedom: The Civil War Era insists, â€Å"In July 1861, the U.S. House of Representatives passed a resolution, by a nearly unanimous vote, that affirmed that the North was not waging the war to overthrow slavery but to preserve the Union.†. Clearly, the focal point of the war was to keep the unity of nation for the sake of peace and security. By March, during Lincoln’s inauguration speech, states such as South Carolina, Mississippi, Florida, Alabama, Georgia, Louisiana, and Texas had already declared to secede. From the South’s perspective, it is clear that that nation was interested in its own political and economic pursuits. Clearly, the soldiers understood that the North had little or no interest in South’s domestic affairs. Slavery was vital towards the success of South’s economy. The failure for the North to acknowledge the idea motivated the Southern soldiers to pursue their own version of the â€Å"American Dream.† The major political and economic interests between North and South continued to reflect the justification for separation for the Southern soldiers. Hence, Lincoln’s reaction to impose force to unite the nation escalated the tensions. between both sides. Hence, the advantages of the South declaring secession centered on their economy. Without constraining the burden of supporting the North with its financial burdens, the South enjoyed the dire success of enhancing and revitalizing its own economy. The justification for the secession revolv ed around the fact that the South had many grievances. Since the colonies also fought the revolutionary because they had a list of grievances, it only seemed fair that the South had the equal right to repeat history. The Republican tariffs that were imposed and the free homestead in the west were vital towards the southern states to rebel. The disadvantages of the South declaring secession was the fact that no country regarded the South as its own union. The South was economically strong, but ideologically weak. It clearly lacked the foundation of unity that it once enjoyed while being with the Union. In addition, it had a weak foundation of government and did not possess a strong leader as Lincoln himself. Without a leader to take in charge, the South had no channels to unite for a war. the South did not It had no power to engage any international relations or ask its neighboring allies to finance its war. Although one may think that the secession was a rapid move, the South did ac t in a rationale way. The south at this point was to break away and enjoy the bounties of being an independent nation. With its full economic and financial power, the South was even turning heads in the European front. The South at this point realized the scrutiny they were in and did not want to suffer any longer from North’

Lower Divison Capstone Essay Example | Topics and Well Written Essays - 1000 words

Lower Divison Capstone - Essay Example K., & Versace, G.2011). Company authorities knew that the market was already ruled by some of the most prominent and famous luxury watch manufacturers such as the Anne Klein Watches, Rolex and Di Molodo Watches. Therefore, the Company authorities were well aware of the fact that the Company will have to deliberately set a low price because it faces a high degree of competition posed by legendary luxury watch manufacturer’s, who have been in the business from decades. Therefore, in launching the Versace Luxury Watches, the Company had to employ the theory of Price Penetration in an effort to gain a footing in the market. So, initially the prices of Versace watches were deliberately set very low as compared to the prices of other luxury Brand watches. The idea behind the implementation of price penetration strategy was to introduce the consumers to the Versace Watches at a lower price which would inevitably encourage the consumers to buy them. Secondly, the other purpose of sett ing lower prices was to encourage the customers to develop the habit of using Versace watches, so that when the Company eventually raises the prices, their sales would not be affected substantially. (Hassan et al 1994). Thirdly, the company’s use of penetration pricing strategy ensured that it would gain a substantial slice of the market because the low price of their watches would definitely attract retailers to buy large quantities of their product. The results of the implementation of the pricing penetration theory were simple; the Versace Watches were an instant success and their first annual sales were several folds higher than the Company had initially expected. The success of pricing penetration theory lies in the fact that Versace is a huge Company with revenue of over â‚ ¬ 162.7 million, thus the Company was well adapted to cope with the high cost of the implementation of the theory. (Davis, D. K., & Versace, G.2011). However, if I had been the senior manager at t he time the Company launched the watches, I would have definitely employed the theory of Market Skimming. Through the implementation of this theory, I would have ensured that the product is sold at a high price at the time of its launching because initially the product is unique in the market and for a large number of consumers; Uniqueness matters more than the price. (Needham et al 1990). Over the last few years, the Versace business environment has changed dramatically, and globalization has proved to be the catalyst of the change. In an effort to cope with the expansion of its business, Versace has sought to employ the strategy of employee empowerment. The company is based in Italy but is now expanding their business worldwide and for this the adoption of employee empowerment culture plays a vital role. Due to the opening of boutiques and stores across the world, the Company now relies extensively on the capabilities of its employees. The Company has introduced a range of trainin g programs and other services which ensures that their employees are more reliable and capable of performing better than ever before. On the other hand, the Company ensures that its employees feel trusted and gives the right of decision making to them. Furthermore, through various employee benefitting policies, the employees are given self confidence in an effort to ensure that they remain motivated and perform their duties to their full capabilities. Therefore, in many ways the Versace fashion house lets its employees know that for them, their

Corporate brands building of SMEs in B 2 B environment in UK Dissertation

Corporate brands building of SMEs in B 2 B environment in UK - Dissertation Example One of the most valuable assets of a company is corporate branding. Consumers need to believe in brand and put their trust in it. Furthermore, the importance of corporate brands increases in corporate marketing and small industries. These industries rely on few investors and customers. Since the revenue is low compared to bigger MNCs (Multinational Corporations) they need to build their corporate brand in order to remain trustworthy and thrive in the market (Inskip, 2004). There are various factors which can be attributed towards the importance of corporate branding. Corporate branding provides an identity to the business; logo and slogans becomes the face of a business and a representation of the business’s image (Bernstein, 2003). Strategic corporate branding also means better customer relationship and increased trustworthiness. Apart from that, strong corporate brands also come across as polished, professional and successful entities. It sends signs of high value and qualit y. SMEs provide employment opportunities as well as drive competition and innovation in many sectors. Also known as micro enterprise, these SMEs are growing in a fast pace in United Kingdom. According to reports by Federation of Small Businesses (2012), the average number of businesses in UK has crossed 5 million markets and out of them around 99.9 percent are SMEs. SMEs have been employing more than 14 million people and the combined turnover for the year 2012 was 1500 billion Euros. From the above statistics it is clear that SMEs have been playing an important role in overall business environment in United Kingdom.Thus, they are the backbone of economy in United Kingdom. Thus, it is extremely important that the steady growth of the businesses is maintained. The influence of internal and external forces is much more pronounced in SMEs compared to bigger companies (Davies and Chun, 2002). These include customer markets, business infrastructure and company characteristics. However, i n case of small companies the influence of business managers is much more than bigger organizations. Similarly, the distribution of finances, external shareholder categories and investor management are different in small and bigger enterprises. Small enterprises work as a much closer environment. Thus, it can be said that the policies and marketing campaigns followed by bigger organization might not work for SMEs brand building (Berthon, Ewing and Napoli, 2008). Comparing with consumers, B2B companies have their own decision making process and purchasing habits. In terms of their purchasing decisions which are depended on facts and needs, the world of B2B products is seen as more complex.The reason why B2B companies prefer to corporate brands rather product brands and the dynamic environments (competitive advantages and product innovations) will be discussed. This makes an interesting and insightful topic for further research and development. Chapter 2: Outline of the Research Probl em The research deals with marketing and brand building of corporate SMEs in B2B

Chemical equations, enthalpy changes and chemical equilibrium, acid, Assignment

Chemical equations, enthalpy changes and chemical equilibrium, acid, base and pH, and chemical reactions, chirality, simple organic functional groups and their reactions - Assignment Example State which functional group(s) on Compound  B  could exhibit each of these interactions and describe the properties of each interaction. In your answer make it clear which complementary functional group would need to be present in the receptor for the interaction to occur. From the description and given function of Compound A., it is easy to tell which compound it is since only amino acids and sugars are natural chiral molecules produced in both animals and plants and beyond that, we can tell that the compound is indeed Amino acid since amino acids not sugars are used to treat Parkinson’s Disease. Ligand binding will mostly be either ionic or hydrogen bonds. However, at times, the intermolecular forces of the van der waals will be used to bind the copound to the target receptor. The carboxylic group will exhibit the hydrogen intermolecular bonds due to presence of the hydrogen molecule while the amino group will exhibit the ionic intermolecular bonds since they form the ions and could also use the van der waals at times. Draw the product of this reaction, name the new functional group produced, state the type of reaction that has occurred, name any other products of the reaction and briefly explain how you arrived at your answer. The presence of the double bond (C=C) in Compound  C  means that the molecule can exist in two different forms, identified by the prefix  cis  or  trans, depending upon the arrangement of the functional groups and hydrogen atoms around the double bond. Draw the two possible forms of Compound  C  showing the positions of the functional group and hydrogen atoms. Assign each the appropriate prefix that would distinguish one from the other and briefly explain what these prefixes indicate. Equal moles of nitric acid (HNO3) and formic acid (HCOOH) were each dissolved in equal volumes of water. State and explain which of the resulting solutions would have the higher pH.

Theology Essay Example | Topics and Well Written Essays - 1500 words - 2

Theology - Essay Example This paper intends to discuss why would an intelligent mind believe or not believe in the existence of God, and what my opinion about the nature and existence of God is. A 90 minute debate was held in Alys Stephens Center in Birmingham, Alabama, on October 03, 2007 between two Oxford University colleagues; an atheist and secular humanist, Professor Richard Dawkins, and a Christian apologist, Professor John Lennox. The topic of the debate was the existence of God based upon the atheistic views that Dawkins presented in his book, The God Delusion. In the debate, Dawkins explains his theses regarding the rejection of God’s existence saying that science is based on evidence-based grounds whereas faith is blind and is based merely on satisfactory beliefs and thus it drags humans to believe what is told in religion without the need of understanding and exploring. This makes us say that an intelligent mind believes that science does not support religion; rather, it supports rationalism or atheism. Marx conception of God’s existence is purely atheistic. He affirms that an intelligent mind must argue that the designer God, if there is one, must need another designer to design him. Freud does not believe in God and asserts that â€Å"the sooner one accepts that God does not exist, the better† (qtd. in McFaul 9) if one wants to step into mature adulthood. Christianity poses dangers to the existence of humans as all wars and destructions come as a result of the religious beliefs and difference in faiths. Dawkins explains an argument from his book, that is, faith is blind whereas science is evidence-based (92) in which he argues that faith is by no reasons strengthening its grounds in the 21st century when it has nothing to do with evidence. On the other hand, according to Dawkins, â€Å"science uses evidence to discover the truth about the universe† and scientific discoveries are based on research and

Comparison Essay Example | Topics and Well Written Essays - 1000 words - 4

Comparison - Essay Example At the end of the play, Nora’s secrets get reveled to Torvald and she discovered that despite of her eight years marriage with Torvald, she must find courage to leave him. â€Å"Trifles† written by Susen Glaspel is based on a true story. It revolves around investigation of the murder of a farmer John Wright. The prime suspect of the murder is John Wright’s wife, Mrs. Wright; who claims she was sleeping when someone strangled her husband. The investigation is carried out by the sheriff, his wife, the attorney and two neighbors Mr. and Mrs. Hale. In this play, it has been shown that men discourage women and their capabilities. The investigation carried out by the men is entirely based on forensic evidence where women critically analyzed the case accordingly. Therefore by comparison, we will be able to observe that both dramas discus about what it means to be a woman; how men are found to be holding power over women; role of two genders have always seen to evolve an d change especially in the case of women that they have always struggled for their rights. Also we shall see how women can take an action and stand up for themselves. However we shall also put light on the difference of both women’s character. In comparison of both dramas, gender identity has found to be the main aspect in which a evaluation can be made. In â€Å"Trifles†, it has been seen that the sheriff, the attorney and Mr. Hale ignore the point of view of Mrs. Wright and neglect the critical evidences of the dreary marriage life that Mr. and Mrs. Wright had. Basically the argument of this drama is ‘how woman worry over trifles’ and one can analyze that the play successfully depicts the qualities of women as they tend to worry over minor things. In the same way the play â€Å"A Doll’s House† depicts the characters of woman living a troublesome married life. Nora’s husband Torvald in

Placement Report Essay Example | Topics and Well Written Essays - 1500 words

Placement Report - Essay Example Marks and Spencer has successfully expanded its market and today it has more than 900 retail outlets all over the world. It is also listed in London Stock Exchange. The company however started facing problems relating to its marketing department. Main theme of Marks & Spencer was to provide high quality and innovative products along with exceptional services but the company has started to fail in achieving these objectives because of the wide expansion in their product portfolio. Due to the expansion in the portfolio the company has lost its main objective slightly and because of this reason, competitors are able to grab the opportunity. However, the quality of service has been one of the hallmarks that have helped the company to survive difficult times and make sure that the company is able to do well than its competitors. This report analyses my personal experience that I have gone through during my employment at Marks and Spencer. The report analyses and evaluates not only my expe rience, but the experience of the overall team with which I was working. The report also highlights the success reasons of the team and the success factors because of which the team was able to accomplish the project appropriately and successfully. The report also presents the scenario and case that Marks and Spencer was facing and how our team helped the company to solve the issue and make sure that the company flourishes. This report also reflects my personal skills that I have developed during the employment period. Moreover, the report also highlights how I have been able to use my marketing concepts and knowledge at the organization that helped Marks and Spencer to achieve its objectives. EVALUATING THE WORK OF THE TEAM Marks and Spencer is a big name in the retail industry of United Kingdom as well as in other European countries. However, the company has been facing different types of issues. Some of the major issues that Marks and Spencer has been facing include: Bad position ing Uncompetitive prices Unavailability of the product in some of the outlets of the company Lack of awareness of the product in the mind of consumers Not focusing on traditional marketing techniques and promotional tools Issues in the Customer services of the company I found the abovementioned issues that have negatively impact the company and its sales over the years. However I was working in the customer services department and therefore the main issues that I have identified in this department include: Proactive customer services Poor presentations Ensuring customer satisfaction level Offering more products to customers or increasing sales per customer As a customer sales representative, I along with my team mates was assigned different tasks to solve the abovementioned issues. Our team was given training in order to improve the customer relationship and build better relations with the customers. Moreover, our team also worked ourselves and formulated different strategies in ord er to improve the reputation of the retail outlet in which I was working. At Marks and Spencer, employees are given some kind of freedom on how to satisfy the customers however they are given a broad outline of how to go

Review article Example | Topics and Well Written Essays - 250 words - 11

Review - Article Example The paper aims at investigating whether Vitamin A -based chromophore is essential in photo reception by the ipRGS. In addition, the paper seeks to investigate the function of melanopsin in signaling the photo-pigments. In responding to these uncertainty, the paper studies a knock-out mouse line which lacks the RPE65 (rpe65–/–), which is a substantial protein that regenerates the 11–cis–retinal in the RPE. In essence, the paper succinctly covers the topic by ascertaining that there are other photo receptors within the mammalian retina other than the known rods and cones. The main concept behind this paper is to have a clear understanding of the diversity of the ipRGCs and their different functions in regulating behavior. The findings illustrate that Rpe65–/– ipRGCs were 20–40–fold and are not photosensitive whether at single cell or behavioral (PLR) levels. The photosensitivity detected is expressed by exogenous 9–cis–retinal, an 11–cis–retinal analog. In addition, there was no detection of Melanopsin in the retinal pigment epithelium or any results both in the rod and cone sensitivities. This is a factor that led to ablation of Melanopsin in both the ERG and single cell

International Trade and Finance Speech Essay Example for Free

International Trade and Finance Speech Essay One may try to understand what exactly a foreign exchange rate is. To help understand, let’s view a foreign exchange rate as exchanging one dollar at a department store for a product. If one were to go into a department store and purchase a pair of socks in a three pack for one dollar, or each for 33 cents, one would be able to relate that the dollar-to-socks exchange rate is three socks because one exchanged a single dollar for three pairs of socks. Similarly, the sock-to-dollar exchange rate would be one-third of a dollar, meaning 33 cents. This is because if one decides to sell a single pair of socks, one would get 33 cents in exchange. Moffatt) The same principle hold true for foreign currency. On May 9, 2013 the U. S. -to-Euro exchange rate was . 767 EUR, meaning that for one U. S. dollar, one could purchase . 767 Euros. In order to determine the amount that one could exchange one Euro to the dollar, one could use this simple formula: Euro-to-U. S. exchange rate = 1 / U. S. -to-Euro exchange rate. Euro-to-U. S. exchange rate = 1 / 3767 = 1. 303. This equation shows that one Euro would be exchange for 1. 303 U. S. dollars. (Moffatt) Now that what have an understanding of what a foreign exchange rate is, let discuss how these rates are determined. Using the two previously discussed currencies, each of their rate are determined in a foreign exchange market that is open to a very large range of various sellers and buyers. Each country incorporates mechanisms that will in turn aid in managing the value of their currency. These mechanisms help in determining the, either pegged and fixed, or free-floating. A peg system is when a country tries to keep their currency at a fixed exchange rate, as the Chinese have done between 1994 and 2005. Doing this sometime devalue or over-value their currencies, which can result in either a trade deficit or surplus. Free-floating is when the currency’s exchange rate is allowed to vary against currencies of other countries, allowing supply and demand in the market forces to determine its exchange rate; exchange rates for these currencies are determined around the works by banks and are quoted through the financial markets. (Mayer) International Trade The effects of international trade means lower prices for goods and services; competition for the domestic markets and less of a choice for employment for University of phoenix students after graduation. When the country invests more in international trade that local business and companies; the Gross domestic product may start to suffer and business may start to go out of business due to loss in business. International trade takes away from local farmers and business owner’s success. If the country is constantly making international trades, eventually the United States would no longer have a need for local farmers. The local farmers would have surplus that may spoil due to not being sold. This could cause the farmer to become bankrupt. International trades mean less cost for products and services for the consumer, (Investopedia, n. ). So in return that means less business for the local farmers and business owners as mentioned before. The effect of international trade effects University of Phoenix student mainly after graduation. If all of the jobs are being outsources or traded overseas; what opportunities does that leave the new potential employees? The students would not have a job of choice, depending on the degree they have pursued. It would be unfortunate for a student to complete a program and not be able to use their degree effectively due to their job of choice being outsourced overseas. International trade is not all that bad as it is made out to be. Without international trade, we would not be able to experience different types of foods from other countries that cannot be produced in our country, (Investopedia, n. d). Tariffs and Quotas International relations and trade can be affected by the choices governments choose to fallow. First, what are tariffs and quotes? Tariffs or sometimes known as custom duties also, they are a certain amount of tax value placed by governments on international trade goods and are typically on imported goods. Quotas are limits placed on the importers, which gives them a certain amount of time they may import their goods. Quotas generally favor the importer, because they tend to drive the cost of goods up, which in turn gains revenue for the importing companies. Tariffs do the opposite, they generally will bring revenue to the government, because they are a tax and the government will gain in revenue. Although tariffs and quotas bring revenue to the companies and the government, they can also have a negative affect if the tax is too high or if the quotas are so small. Price of the goods will sky rocket and problems in the international trading world will arise. One example, which according to Colander (2010) stated,â€Å" Probably the most infamous tariff in U. S. istory is the Smoot-Hawley Tariff of 1930, which raised tariffs on imported goods to an average of 60 percent. It was passed at the height of the Great Depression in the United States in the hope of protecting American jobs. It didn’t work. Other countries responded with similar tariffs. As a result of these trade wars, international trade plummeted from $60 billion in 1928 to $25 billion in 1938, unemployment worsened, and the international depression deepened. † (Colander, 2010, p. 458). Import of Goods If the U. S. restricted all goods coming in from China then the U. S. would lose a significant amount of comparative advantage with China. What this means is that goods manufactured in China, India and other Asian countries are creating demand for advertising, management, and distribution, and are therefore creating jobs and income in the United States† (Colander, 2010, p. 453). Currently the U. S. is now a debtor nation and China plus India are creating jobs and helping the U. S. economy. The U. S. could not afford to restrict China because this could cause problems internationally with the two countries and the U. S. economy would suffer from bad relations. Why cannot the U. S. just minimize the amount of imports coming in from all other countries? The U. S. annot minimize the amount of imports coming in from other countries because this would hurt the U. S. economy as a whole. Minimizing the amount of imports could also hurt the reputation of the U. S. on the international trade level and the U. S. could end up losing trading partners with other countries. The U. S. is consuming more imports then selling of exports so minimizing the amount of imports would also be very difficult. Again this could make the U. S. economy crash from the loss of imports. â€Å"International trade, and changing comparative advantages, will become more and more important for the United States in the coming decades† Colander, 2010, p. 470). Surplus A surplus of imports that is brought into the United States is when imports exceed exports, meaning that the demand for U. S. goods or services is in the negative. A negative export affects the economy’s income and output, the employment rate, prices of goods and services, and the rate of inflation. An example of a product with an import surplus, and the impact that it had on the U. S. businesses and consumers is the motor-vehicle manufacturing sector. â€Å"The motor-vehicle manufacturing sector is the second-largest employer among all U. S. anufacturing industries, and auto parts and tires contribute the most direct jobs (nearly two-thirds or more) to the motor-vehicle sector. † (Scott, 2012) Since the United States Government helped with the restructuring of General Motors, there has been a strong turnaround in U. S. auto sales, but this still does not stop the massive import and surplus of automotive parts available on the U. S. market. Chinese exports to the United States have increase by 900 percent in the last decade, thus affecting the employment rate of those that would be working in the United States auto-parts industry.

Terminator Wave Energy Devices

Terminator Wave Energy Devices 1.0 Executive Summary The offshore ocean wave energy resource, as a derivative form of solar energy, has considerable potential for making a significant contribution to the alternative usable energy supply.Wave power devices are generally categorized by the method used to capture the energy of the waves. They can also be categorized by location and power take-off system. The energy extraction methods or operating principles can be categorized into three main groups; (1) Oscillating water Column (OWC) (2) Overtopping Devices (OTD) (3) Wave Activated Bodies (WAB); Locations are shoreline, near shore and offshore. This report discusses about Terminator wave energy devices which extend perpendicular to the direction of wave travel and capture or reflect the power of the wave. These devices are typically onshore or near shore; however, floating versions have been designed for offshore applications. 2.0 Introduction Traditional sources of energy such as oil, gas, and coal are non-renewable. They also create pollution by releasing huge quantities of carbon dioxide and other pollutants into the atmosphere. In contrast, waves are a renewable source of energy that doesnt cause pollution. The energy from waves alone could supply the worlds electricity needs. The total power of waves breaking on the worlds coastlines is estimated at 2 to 3 million megawatts. In some locations, the wave energy density can average 65 megawatts per mile of coastline. The problem is how to harness wave energy efficiently and with minimal environmental, social, and economic impacts. Ocean waves are caused by the wind as it blows across the open expanse of water, the gravitational pull from the sun and moon, and changes in atmospheric pressure, earthquakes etc. Waves created by the wind are the most common waves and the waves relevant for most wave energy technology. Wave energy conversion takes advantage of the ocean waves caused primarily by the interaction of winds with the ocean surface. Wave energy is an irregular oscillating low-frequency energy source. They are a powerful source of energy, but are difficult to harness and convert into electricity in large quantities. The energy needs to be converted to a 60 or 50 Hertz frequency before it can be added to the electric utility grid. Part of the solar energy received by our planet is converted to wind energy through the differential heating of the earth. In turn part of the wind energy is transferred to the water surface, thereby forming waves. While the average solar energy depends on factors such as local climate and latitude, the amount of energy transferred to the waves and hence their resulting size depends on the wind speed, the duration of the winds and the duration over which it blows. The most energetic waves on earth happen to be between 30 degrees to 60 degrees latitude, in general the waves generated are stronger on the southern parts of the countries (John brook, ECOR). Wave power devices extract energy directly from the surface motion of ocean waves or from pressure fluctuations below the surface. Wave power varies considerably in different parts of the world, and wave energy cant be harnessed effectively everywhere. It has been estimated that if less than 0.1% of the renewable energy available within the oceans could be converted into electricity, it would satisfy the present world demand for energy more than five times over. A variety of technologies are available to capture the energy from waves. Wave technologies have been designed to be installed in near shore, offshore, and far offshore locations. Offshore systems are situated in deep water, typically of more than 40 meters (131 feet). Types of power take-off include: hydraulic ram, elastomeric hose pump, pump-to-shore, hydroelectric turbine, air turbine and linear electrical generator. Some of these designs incorporate parabolic reflectors as a means of increasing the wave energy at the point of capture. 3.0 Type of Wave Energy Converters Ocean waves represent a form of renewable energy created by wind currents passing over open water. Many devices are being developed for exploiting wave energy. The energy extraction methods or operating principles can be categorized into three main groups (Harris Robert E. et al.): Oscillating Water Columns (OWC) Waves cause the water column to rise and fall, which alternately compresses and depressurize an air column. The energy is extracted from the resulting oscillating air flow by using a Wells turbine Overtopping Devices (OTD) Ocean waves are elevated into a reservoir above the sea level, which store the water. The energy is extracted by using the difference in water level between the reservoir and the sea by using low head turbines Wave Activated Bodies (WAB) Waves activate the oscillatory motions of body parts of a device relative to each other, or of one body part relative to a fixed reference. Primarily heave, pitch and roll motions can be identified as oscillating motions whereby the energy is extracted from the relative motion of the bodies or from the motion of one body relative to its fixed reference by using typically hydraulic systems to compress oil, which is then used to drive a generator. The wave activated bodies (WABs) can be further categorized in sub-groups describing the energy extraction by the principle motion of the floating body (heave, pitch and roll). A variety of technologies have been proposed to capture the energy from waves based on above extraction methods; Some of the technologies that have been the target of recent developmental efforts and are appropriate for the offshore applications being considered are terminators, attenuators and point absorbers (U.S. Department of the Interior, May 2006). Figure 1: Schematic drawings of WEC devices for operating principles and principal locations(Harris Robert E. et al.) The many different types of wave energy converters (WECs) can be classified in to various ways depending on their horizontal size and orientation. If the size is very small compared to the typical wavelength the WEC is called a point absorber. In contrast if the size is comparable to or larger than the typical wavelength, the WEC is known as line absorber, this can also be referred to as terminator or attenuator. A WEC is called terminator or attenuator if it is aligned along or normal to the prevailing direction of the wave crest respectively (John brook, ECOR). The relationship between the three main classifications Principal Location Operating Principle Directional Characteristic: These classifications are shown in Figure 2, presenting the possible operating principles for the location and the directional characteristics. At the shoreline the only feasible operating principles are oscillating water columns and overtopping devices, which are terminators. Figure shows that at near shore and offshore, point absorber or attenuator devices can only be WABs, whilst for terminator devices all three categories of the operating principles are possible. OWCs and OTDs are ‘static’ energy converters of the terminator kind. As a result their mooring has to be stiff, restraining modes of motions but allowing for adjustment towards a parallel wave approach and for tidal ranges. The station keeping requirements for the mooring of wave activated bodies can be either static or dynamic. Figure 2: Possible operating principles for the principal location and directional characteristic 3.1 Attenuators Attenuators are long multi-segment floating structures oriented parallel to the direction of the wave travel. The differing heights of waves along the length of the device causes flexing where the segments connect, and this flexing is connected to hydraulic pumps or other converters (U.S. Department of the Interior, May 2006). 3.2 Point Absorbers Point absorbers have a small horizontal dimension compared with the vertical dimension and utilize the rise and fall of the wave height at a single point for WEC (Harris Robert E. et al.). It is relatively small compared to the wave length and is able to capture energy from a wave front greater than the physical dimension of the absorber (James, 2007). The efficiency of a terminator or attenuator device is linked to their principal axis being, according, parallel or orthogonal to the incoming wave crest. The point absorber does not have a principal wave direction and is able to capture energy from waves arriving from any direction. As a consequence the station keeping for the terminator and attenuator has to allow the unit to weathervane into the predominant wave direction, but this is not necessary for the point absorber (Harris Robert E. et al.). 3.3 Terminators A Terminator has its principal axis parallel to the incident wave crest and terminates the wave. These devices extend perpendicular to the direction of wave travel and capture or reflect the power of the wave. The reflected and transmitted waves determine the efficiency of the device (Harris Robert E. et al.). These devices are typically installed onshore or near shore; however, floating versions have been designed for offshore applications. (U.S. Department of the Interior, May 2006). There are mainly two types in Terminator WEC. 3.3.1 Oscillating Water Columns (OWC) The oscillating water column (OWC) is a form of terminator in which water enters through a subsurface opening into a chamber with air trapped above it. The wave action causes the captured water column to move up and down like a piston to force the air through an opening connected to a turbine (U.S. Department of the Interior May 2006). The device consists essentially of a floating or (more usually) bottom-fixed structure, whose upper part forms an air chamber and whose immersed part is open to the action of the sea. The reciprocating flow of air displaced by the inside free surface motion drives an air turbine mounted on the top of the structure. 3.3.1.1 Efficiency of Oscillating Water Column (OWC) The efficiency of oscillating water column (OWC) wave energy devices are particularly affected by flow oscillations basically for two reasons. (1) Because of intrinsically unsteady (reciprocating) flow of air displaced by the oscillating water free surface. (2) Because of increasing the air flow rate, above a limit depending on, and approximately proportional to, the rotational speed of the turbine, is known to give rise to a rapid drop in the aerodynamic efficiency and in the power output of the turbine. A method which has been proposed to partially circumvent this problem consists in controlling the pitch of the turbine rotor blades in order to prevent the instantaneous angle of incidence of the relative flow from exceeding the critical value above which severe stalling occurs at the rotor blades (see Gato and FalcaËÅ"o, 1991). Although considered technically feasible (Salter, 1993) this has never been implemented at full scale owing to mechanical difficulties. Alternately, the flow rate through the turbine can be prevented from becoming excessive by equipping the device with air valves. Two different schemes can be envisaged, in the first one, the valves are mounted between the chamber and the atmosphere in parallel with the turbine (by-pass or relief valves, on or near the roof of the air chamber structure) and are made to open (by active or passive control) in order to prevent the overpressure (or the under pressure) in the chamber to exceed a limit which is defined by the aerodynamic characteristics of the turbine at its instantaneous speed. In the second scheme a valve is mounted in series with the turbine in the duct connecting the chamber and the atmosphere. Excessive flow rate is prevented by partially closing the valve. In both schemes, the air flow through the turbine is controlled at the expense of energy dissipation at the valves. Theoretically the two methods, if properly implemented, are equivalent from the point of view of limiting the flow rate through the turbine. However, the resulting pressure changes in the chamber are different (reduction and increase in pressure oscillations in the first and second cases, respectively). Consequently the hydrodynamic process of energy extraction from the waves is differently modified by valve operation in the two control methods. The main purpose of this work is to analyse theoretically the performance of an OWC wave energy device when valves are used to limit the flow through the turbine. Both schemes are considered and compared: a valve (or a set of valves) mounted in parallel with the turbine (by-pass or relief valve) or a valve mounted in the turbine duct. The hydrodynamic analysis is done in the time domain for regular as well as for irregular waves. The spring-like effect due to the compressibility of the air is taken into account and is discussed in some detail. Realistic characteristics are assumed for the turbine. Numerical results are presented for simple two-dimensional chamber geometry for whose hydrodynamic coefficients analytical expressions are known as functions of wave frequency. 3.3.2 Overtopping Devices (OTD) Overtopping devices have reservoirs that are filled by impinging waves to levels above the average surrounding ocean. The released reservoir water is used to drive hydro turbines or other conversion devices. Overtopping devices have been designed and tested for both onshore and floating offshore applications. It gathers the energy by waves overtopping into a raised reservoir, and extracting this by draining the water through low head turbines. OTD consists of three main elements: Two wave reflectors. Attached to the central platform these act to focus the incoming waves. The main platform. This is a floating reservoir with a doubly curved ramp facing the incoming waves. The waves overtop the ramp which has a variable crest freeboard 1 to 4 m and underneath the platform open chambers operate as an air cushion maintaining the level of the reservoir. Hydro turbines. A set of low head turbines converts the hydraulic head in the reservoir (Tedd James et al., 2005) 3.3.2.1 Overtopping theory The theory for modeling overtopping devices varies greatly from the traditional linear systems approach used by most other WECs. A linear systems approach may be used with overtopping devices. This considers the water oscillating up and down the ramp as the excited body, and the crest of the ramp as a highly non-linear power take off system. However due to the non-linearities it is too computationally demanding to model usefully. Therefore a more physical approach is taken. Figure 4 shows the schematic of flows for the Wave Dragon. Depending on the current wave state (HS, Tp) and the crest freeboard Rc(height of the ramp crest above mean water level, MWL) of the device, water will overtop into the reservoir Qovertopping. The power gathered by the reservoir is a product of this overtopping flow, the crest freeboard and gravity. If the reservoir is over filled when a large volume is deposited in the basin there will be loss from it Qspill. To minimize this, the reservoir level h must be kept below its maximum level hR. The useful hydraulic power converted by the turbines is the product of turbine flow Qturbine, the head across them, water density and gravity (Tedd James et al., 2005). In coastal engineering the average flow Q is converted into non dimensional form by dividing by the breadth of the device b, gravity g and the significant wave height HS: In the case of the floating OTD it has been seen that there is a dependency on the wave period. The dominant physical explanation for this is the effect of energy passing beneath the draft of the structure. Figure 6 Layout of OTD 3.3.2.2 Wave Reflector Wings One of the most distinctive aspects of the Overtopping WEC is the long slender wings mounted to the front corners of the reservoir platform. These are designed to reflect the oncoming waves towards the ramp. A wider section of wave is available to be exploited with only a moderate increase in capital cost. The overtopping volume in a wave is very dependent on the wave height; therefore by providing only a moderate increase in height, much more energy can overtop the ramp. In order to choose the correct lengths, angles, and position of these wings extensive computer modelling is used. Secondary bonuses of the presence of the wave reflector wings include: better weather-vaning performance to face the waves, lower peak mooring forces, and improved horizontal stability of the main platform. As the aft and rear mooring attachment points are separated further, the yaw of the platform is more stable. Therefore the device will not turn away from the predominant wave direction, and will also realign itself faster as when the wave direction changes (Tedd James et al., 2005). Lastly the reflectors wings act as stabilisers to the device. As they float under their own buoyancy they counteract any list of the platform. This is important as the more horizontal the platform is kept the less water is spilt and so the more efficient the device operation. 3.3.2.3 Low Head Turbines and Power Train Turbine operating conditions in a WEC are quite different from the ones in a normal hydro power plant. In the OTD, the turbine head range is typically between 1.0 and 4.0 m, which is on the lower bounds of existing water turbine experience. While there are only slow and relatively small variations of flow and head in a river hydro power plant, the strong stochastic variations of the wave overtopping call for a radically different mode of operation in the OTD. The head, being a function of the significant wave height, is varying in a range as large as 1:4, and the discharge has to be regulated within time intervals as short as ten seconds in order to achieve a good efficiency of the energy exploitation (Tedd James et al., 2005). On an unmanned offshore device, the environmental conditions are much rougher, and routine maintenance work is much more difficult to perform. Special criteria for the choice and construction of water turbines for the WEC have to be followed; it is advisable to aim for constructional simplicity rather than maximum peak efficiency. Figure 6 shows the application ranges of the known turbine types in a graph of head H vs. rotational speed nq. The specific speed nq is a turbine parameter characterizing the relative speed of a turbine, thus giving an indication of the turbines power density. Evidently, all turbine types except the Pelton and the cross flow type are to be found in a relatively narrow band running diagonally across the graph. Transgressing the left or lower border means that the turbine will run too slowly, thus being unnecessarily large and expensive. The right or upper border is defined by technological limits, namely material strength and the danger of cavitations erosion. The Pelton and the cross-flow turbine do not quite follow these rules, as they have a runner which is running in air and is only partially loaded with a free jet of water. Thus, they have a lower specific speed and lower power density. Despite its simplicity and robustness, the cross flow turbine is not very suitable for OTD applications (Tedd James et al., 2005). Figure 7 Head range of the common turbine types, Voith and Ossberger 3.3.2.4 Performance in Storms Survivability is essential, and Overtopping devices are naturally adapted to perform well in storm situations, where the wave will pass over and under the device with no potential end-stop problems. 3.3.2.5 Wave Prediction Performance of almost all wave energy converters can be improved with prediction of the incoming waves. The cost to implement would be low as the control hardware is typically in place, only the measuring system and improved control techniques need to be developed. To explain the concept behind the device a simple example can be used. If a measurement of some wavelengths ahead of the wave energy converter shows large waves passing, then at a given time later this energy will be incident on the device. The control of the device can then be altered quickly to extract this larger energy, e.g. by increasing hydraulic resistance to an oscillator’s motion allowing more energy to be captured within the stroke length, or by draining the reservoir of an overtopping device to allow for a large overtopping volume(Tedd James et al., 2005). The challenges are threefold; to implement a system for measuring the waves approaching the ramp, to accurately transform this into usable input for the control systems, and to construct new control strategies to make the best use of this. The standard approach for performing such deterministic sea-state prediction involves discrete frequency domain techniques. This is computationally intensive, as the two Fourier transforms must be made to convert from the time domain to the frequency domain and return to the time domain. 3.4 Energy Capture and Practical Limits The power captured from waves by the primary mechanical conversion (before secondary conversion to electrical power) can be related to the energy in the incoming waves over a certain width. Theoretical values have been established in some cases. For a heaving axi-symmetric body the maximum capture width is the inverse of the wave number. The capture width is often compared to the front width of the device. This width ratio can be larger than one for a point absorber with small dimensions compared to the wavelength. Viscous effects reduce efficiency. For an OWC, Wang et al. (2002) found that the capture width ratio may reach a value of 3 and above at an optimum wave period. For Pelamis, Retlzler et al. (2001) found a capture width up to 2 in regular waves and around one in random seas (Specialist Committee V.4, 2006). A continuous or a semi discrete array of wave energy converters acting as an absorbing wall perpendicular to the wave direction is called a terminator and its capture width equals the width of the device and is not related to the length of the incident waves. As the wave conditions are stochastic, the tuning parameters of the energy converters are compromises between the optimum values at various sea conditions. The capture width must be established for each sea state. Fixed devices are subject to sea level variation according to tidal effects. This is critical for fixed oscillating water columns and fixed overtopping systems whose performances are dependent on the mean sea level. The intake of an OWC must be located at an optimised design level from the mean free surface. The height of an overtopping system is also optimised for sea states occurring at a given mean sea level. Therefore, sites with minimal tide are preferred. From this point of view floating devices are more suitable. The immersion of a floating device can also be tuned with respect to the actual sea state. For instance the Wave Dragon overtopping device is partially floating on air chambers and its draught can be modified (Specialist Committee V.4, 2006). The performance of the overtopping device is sensitive to the distribution of the overtopping rate. The more variable the overtopping flow into the reservoir, the larger the capacity of the reservoir and turbines must be to achieve the same performance. 4.0 Mooring Requirements The two major requirements for a WEC mooring are to withstand the environmental and other loadings involved in keeping the device on station, and to be sufficiently cost effective so that the overall economics of the device remain viable. The following list shows the requirements that need to be considered for WEC moorings systems (Harris Robert E. et al.): The primary purpose of the mooring system is to maintain the floating structure on station within specified tolerances under normal operating load and extreme storm load conditions. The excursion of the device must not permit tension loads in the electrical transmission cable(s) and should allow for suitable specified clearance distances between devices in multiple installations. The mooring system must be sufficiently compliant to the environmental loading to reduce the forces acting on anchors, mooring lines and the device itself to a minimum; unless the stiffness of the mooring itself is an active element in the wave energy conversion principle used. All components must have adequate strength, fatigue life and durability for the operational lifetime, and marine growth and corrosion need to be considered. A degree of redundancy is highly desirable for individual devices, and essential for schemes which link several devices together. The system as a whole should be capable of lasting for 30 years or more, with replacement of particular components at no less than 5 years. The mooring must be sufficient to accommodate the tidal range at the installation location. The mooring system should allow the removal of single devices without affecting the mooring of adjacent devices. Removal of mooring lines for inspection and maintenance must be possible. The mooring must be sufficiently stiff to allow berthing for inspection and maintenance purposes. Contact between mooring lines must be avoided. The mooring should not adversely affect the efficiency of the device, and if it is part of an active control system it must also be designed dynamically as part of the overall WEC system. Revenues from WECs, in comparison to the offshore industry, are smaller and their economics more strongly linked to the location, installation costs and down time periods. The mooring system has an important impact on the economics and it is necessary to provide, at low installation cost, a reliable system that has little downtime and long intervals between maintenance. The suitability of design approaches from the offshore industry for WECs are ranked in Appendix I (Harris Robert E. et al.). 5.0 Environmental Considerations Conversion of wave energy to electrical or other usable forms of energy is generally anticipated to have limited environmental impacts. However, as with any emerging technology, the nature and extent of environmental considerations remain uncertain. The impacts that would potentially occur are also very site specific, depending on physical and ecological factors that vary considerably for potential ocean sites. As large-scale prototypes and commercial facilities are developed, these factors can be expected to be more precisely defined (U.S. Department of the Interior, May 2006). The following environmental considerations require monitoring (U.S. Department of the Interior, May 2006). Visual appearance and noiseare device-specific, with considerable variability in visible freeboard height and noise generation above and below the water surface. Devices with OWCs and overtopping devices typically have the highest freeboard and are most visible. Offshore devices would require navigation hazard warning devices such as lights, sound signals, radar reflectors, and contrasting day marker painting. However, Coast Guard requirements only require that day markers be visible for 1 nautical mile (1.8 km), and thus offshore device markings would only be seen from shore on exceptionally clear days. The air being drawn in and expelled in OWC devices is likely to be the largest source of above-water noise. Some underwater noise would occur from devices with turbines, hydraulic pumps, and other moving parts. The frequency of the noise may also be a consideration in evaluating noise impacts. Reduction in wave height from wave energy converterscould be a consideration in some settings; however, the impact on wave characteristics would generally only be observed 1 to 2 km away from the WEC device in the direction of the wave travel. Thus there should not be a significant onshore impact if the devices were much more than this distance from the shore. None of the devices currently being developed would harvest a large portion of the wave energy, which would leave a relatively calm surface behind the devices. It is estimated that with current projections, a large wave energy facility with a maximum density of devices would cause the reduction in waves to be on the order of 10 to 15%, and this impact would rapidly dissipate within a few kilometers, but leave a slight lessening of waves in the overall vicinity. Little information is available on the impact on sediment transport or on biological communities from a reduction in wave height offshore. An isolated impact, such as reduced wave height for recreational surfers, could possibly result. Marine habitatcould be impacted positively or negatively depending on the nature of additional submerged surfaces, above-water platforms, and changes in the seafloor. Artificial above-water surfaces could provide habitat for seals and sea lions or nesting areas for birds. Underwater surfaces of WEC devices would provide substrates for various biological systems, which could be a positive or negative complement to existing natural habitats. With some WEC devices, it may be necessary to control the growth of marine organisms on some surfaces. Toxic releasesmay be of concern related to leaks or accidental spills of liquids used in systems with working hydraulic fluids. Any impacts could be minimized through the selection of nontoxic fluids and careful monitoring, with adequate spill response plans and secondary containment design features. Use of biocides to control growth of marine organisms may also be a source of toxic releases. Conflict with other sea space users, such as commercial shipping and fishing and recreational boating, can occur without the careful selection of sites for WEC devices. The impact can potentially be positive for recreational and commercial fisheries if the devices provide for additional biological habitats. Installation and Decommissioning: Disturbances from securing the devices to the ocean floor and installation of cables may have negative impacts on marine habitats. Potential decommissioning impacts are primarily related to disturbing marine habitats that have adapted to the presence of the wave energy structures. 6.0 Discussions A vast number of parameters influence (and interact with) the net power production from any WEC: Overtopping, determined by Free-board (adjustable in Wave Dragons) Actual wave height Physical dimension of the converter (ramps, reflectors etc. Outlet, determined by Size of reservoir Turbine design Turbine on/off strategy Mooring system, free or restricted orientation toward waves Size of the energy converter Wave climate Energy in wave front (kW/m) Distribution of wave heights Availability Theoretical availability; Reliability, maintainability, serviceab Terminator Wave Energy Devices Terminator Wave Energy Devices 1.0 Executive Summary The offshore ocean wave energy resource, as a derivative form of solar energy, has considerable potential for making a significant contribution to the alternative usable energy supply.Wave power devices are generally categorized by the method used to capture the energy of the waves. They can also be categorized by location and power take-off system. The energy extraction methods or operating principles can be categorized into three main groups; (1) Oscillating water Column (OWC) (2) Overtopping Devices (OTD) (3) Wave Activated Bodies (WAB); Locations are shoreline, near shore and offshore. This report discusses about Terminator wave energy devices which extend perpendicular to the direction of wave travel and capture or reflect the power of the wave. These devices are typically onshore or near shore; however, floating versions have been designed for offshore applications. 2.0 Introduction Traditional sources of energy such as oil, gas, and coal are non-renewable. They also create pollution by releasing huge quantities of carbon dioxide and other pollutants into the atmosphere. In contrast, waves are a renewable source of energy that doesnt cause pollution. The energy from waves alone could supply the worlds electricity needs. The total power of waves breaking on the worlds coastlines is estimated at 2 to 3 million megawatts. In some locations, the wave energy density can average 65 megawatts per mile of coastline. The problem is how to harness wave energy efficiently and with minimal environmental, social, and economic impacts. Ocean waves are caused by the wind as it blows across the open expanse of water, the gravitational pull from the sun and moon, and changes in atmospheric pressure, earthquakes etc. Waves created by the wind are the most common waves and the waves relevant for most wave energy technology. Wave energy conversion takes advantage of the ocean waves caused primarily by the interaction of winds with the ocean surface. Wave energy is an irregular oscillating low-frequency energy source. They are a powerful source of energy, but are difficult to harness and convert into electricity in large quantities. The energy needs to be converted to a 60 or 50 Hertz frequency before it can be added to the electric utility grid. Part of the solar energy received by our planet is converted to wind energy through the differential heating of the earth. In turn part of the wind energy is transferred to the water surface, thereby forming waves. While the average solar energy depends on factors such as local climate and latitude, the amount of energy transferred to the waves and hence their resulting size depends on the wind speed, the duration of the winds and the duration over which it blows. The most energetic waves on earth happen to be between 30 degrees to 60 degrees latitude, in general the waves generated are stronger on the southern parts of the countries (John brook, ECOR). Wave power devices extract energy directly from the surface motion of ocean waves or from pressure fluctuations below the surface. Wave power varies considerably in different parts of the world, and wave energy cant be harnessed effectively everywhere. It has been estimated that if less than 0.1% of the renewable energy available within the oceans could be converted into electricity, it would satisfy the present world demand for energy more than five times over. A variety of technologies are available to capture the energy from waves. Wave technologies have been designed to be installed in near shore, offshore, and far offshore locations. Offshore systems are situated in deep water, typically of more than 40 meters (131 feet). Types of power take-off include: hydraulic ram, elastomeric hose pump, pump-to-shore, hydroelectric turbine, air turbine and linear electrical generator. Some of these designs incorporate parabolic reflectors as a means of increasing the wave energy at the point of capture. 3.0 Type of Wave Energy Converters Ocean waves represent a form of renewable energy created by wind currents passing over open water. Many devices are being developed for exploiting wave energy. The energy extraction methods or operating principles can be categorized into three main groups (Harris Robert E. et al.): Oscillating Water Columns (OWC) Waves cause the water column to rise and fall, which alternately compresses and depressurize an air column. The energy is extracted from the resulting oscillating air flow by using a Wells turbine Overtopping Devices (OTD) Ocean waves are elevated into a reservoir above the sea level, which store the water. The energy is extracted by using the difference in water level between the reservoir and the sea by using low head turbines Wave Activated Bodies (WAB) Waves activate the oscillatory motions of body parts of a device relative to each other, or of one body part relative to a fixed reference. Primarily heave, pitch and roll motions can be identified as oscillating motions whereby the energy is extracted from the relative motion of the bodies or from the motion of one body relative to its fixed reference by using typically hydraulic systems to compress oil, which is then used to drive a generator. The wave activated bodies (WABs) can be further categorized in sub-groups describing the energy extraction by the principle motion of the floating body (heave, pitch and roll). A variety of technologies have been proposed to capture the energy from waves based on above extraction methods; Some of the technologies that have been the target of recent developmental efforts and are appropriate for the offshore applications being considered are terminators, attenuators and point absorbers (U.S. Department of the Interior, May 2006). Figure 1: Schematic drawings of WEC devices for operating principles and principal locations(Harris Robert E. et al.) The many different types of wave energy converters (WECs) can be classified in to various ways depending on their horizontal size and orientation. If the size is very small compared to the typical wavelength the WEC is called a point absorber. In contrast if the size is comparable to or larger than the typical wavelength, the WEC is known as line absorber, this can also be referred to as terminator or attenuator. A WEC is called terminator or attenuator if it is aligned along or normal to the prevailing direction of the wave crest respectively (John brook, ECOR). The relationship between the three main classifications Principal Location Operating Principle Directional Characteristic: These classifications are shown in Figure 2, presenting the possible operating principles for the location and the directional characteristics. At the shoreline the only feasible operating principles are oscillating water columns and overtopping devices, which are terminators. Figure shows that at near shore and offshore, point absorber or attenuator devices can only be WABs, whilst for terminator devices all three categories of the operating principles are possible. OWCs and OTDs are ‘static’ energy converters of the terminator kind. As a result their mooring has to be stiff, restraining modes of motions but allowing for adjustment towards a parallel wave approach and for tidal ranges. The station keeping requirements for the mooring of wave activated bodies can be either static or dynamic. Figure 2: Possible operating principles for the principal location and directional characteristic 3.1 Attenuators Attenuators are long multi-segment floating structures oriented parallel to the direction of the wave travel. The differing heights of waves along the length of the device causes flexing where the segments connect, and this flexing is connected to hydraulic pumps or other converters (U.S. Department of the Interior, May 2006). 3.2 Point Absorbers Point absorbers have a small horizontal dimension compared with the vertical dimension and utilize the rise and fall of the wave height at a single point for WEC (Harris Robert E. et al.). It is relatively small compared to the wave length and is able to capture energy from a wave front greater than the physical dimension of the absorber (James, 2007). The efficiency of a terminator or attenuator device is linked to their principal axis being, according, parallel or orthogonal to the incoming wave crest. The point absorber does not have a principal wave direction and is able to capture energy from waves arriving from any direction. As a consequence the station keeping for the terminator and attenuator has to allow the unit to weathervane into the predominant wave direction, but this is not necessary for the point absorber (Harris Robert E. et al.). 3.3 Terminators A Terminator has its principal axis parallel to the incident wave crest and terminates the wave. These devices extend perpendicular to the direction of wave travel and capture or reflect the power of the wave. The reflected and transmitted waves determine the efficiency of the device (Harris Robert E. et al.). These devices are typically installed onshore or near shore; however, floating versions have been designed for offshore applications. (U.S. Department of the Interior, May 2006). There are mainly two types in Terminator WEC. 3.3.1 Oscillating Water Columns (OWC) The oscillating water column (OWC) is a form of terminator in which water enters through a subsurface opening into a chamber with air trapped above it. The wave action causes the captured water column to move up and down like a piston to force the air through an opening connected to a turbine (U.S. Department of the Interior May 2006). The device consists essentially of a floating or (more usually) bottom-fixed structure, whose upper part forms an air chamber and whose immersed part is open to the action of the sea. The reciprocating flow of air displaced by the inside free surface motion drives an air turbine mounted on the top of the structure. 3.3.1.1 Efficiency of Oscillating Water Column (OWC) The efficiency of oscillating water column (OWC) wave energy devices are particularly affected by flow oscillations basically for two reasons. (1) Because of intrinsically unsteady (reciprocating) flow of air displaced by the oscillating water free surface. (2) Because of increasing the air flow rate, above a limit depending on, and approximately proportional to, the rotational speed of the turbine, is known to give rise to a rapid drop in the aerodynamic efficiency and in the power output of the turbine. A method which has been proposed to partially circumvent this problem consists in controlling the pitch of the turbine rotor blades in order to prevent the instantaneous angle of incidence of the relative flow from exceeding the critical value above which severe stalling occurs at the rotor blades (see Gato and FalcaËÅ"o, 1991). Although considered technically feasible (Salter, 1993) this has never been implemented at full scale owing to mechanical difficulties. Alternately, the flow rate through the turbine can be prevented from becoming excessive by equipping the device with air valves. Two different schemes can be envisaged, in the first one, the valves are mounted between the chamber and the atmosphere in parallel with the turbine (by-pass or relief valves, on or near the roof of the air chamber structure) and are made to open (by active or passive control) in order to prevent the overpressure (or the under pressure) in the chamber to exceed a limit which is defined by the aerodynamic characteristics of the turbine at its instantaneous speed. In the second scheme a valve is mounted in series with the turbine in the duct connecting the chamber and the atmosphere. Excessive flow rate is prevented by partially closing the valve. In both schemes, the air flow through the turbine is controlled at the expense of energy dissipation at the valves. Theoretically the two methods, if properly implemented, are equivalent from the point of view of limiting the flow rate through the turbine. However, the resulting pressure changes in the chamber are different (reduction and increase in pressure oscillations in the first and second cases, respectively). Consequently the hydrodynamic process of energy extraction from the waves is differently modified by valve operation in the two control methods. The main purpose of this work is to analyse theoretically the performance of an OWC wave energy device when valves are used to limit the flow through the turbine. Both schemes are considered and compared: a valve (or a set of valves) mounted in parallel with the turbine (by-pass or relief valve) or a valve mounted in the turbine duct. The hydrodynamic analysis is done in the time domain for regular as well as for irregular waves. The spring-like effect due to the compressibility of the air is taken into account and is discussed in some detail. Realistic characteristics are assumed for the turbine. Numerical results are presented for simple two-dimensional chamber geometry for whose hydrodynamic coefficients analytical expressions are known as functions of wave frequency. 3.3.2 Overtopping Devices (OTD) Overtopping devices have reservoirs that are filled by impinging waves to levels above the average surrounding ocean. The released reservoir water is used to drive hydro turbines or other conversion devices. Overtopping devices have been designed and tested for both onshore and floating offshore applications. It gathers the energy by waves overtopping into a raised reservoir, and extracting this by draining the water through low head turbines. OTD consists of three main elements: Two wave reflectors. Attached to the central platform these act to focus the incoming waves. The main platform. This is a floating reservoir with a doubly curved ramp facing the incoming waves. The waves overtop the ramp which has a variable crest freeboard 1 to 4 m and underneath the platform open chambers operate as an air cushion maintaining the level of the reservoir. Hydro turbines. A set of low head turbines converts the hydraulic head in the reservoir (Tedd James et al., 2005) 3.3.2.1 Overtopping theory The theory for modeling overtopping devices varies greatly from the traditional linear systems approach used by most other WECs. A linear systems approach may be used with overtopping devices. This considers the water oscillating up and down the ramp as the excited body, and the crest of the ramp as a highly non-linear power take off system. However due to the non-linearities it is too computationally demanding to model usefully. Therefore a more physical approach is taken. Figure 4 shows the schematic of flows for the Wave Dragon. Depending on the current wave state (HS, Tp) and the crest freeboard Rc(height of the ramp crest above mean water level, MWL) of the device, water will overtop into the reservoir Qovertopping. The power gathered by the reservoir is a product of this overtopping flow, the crest freeboard and gravity. If the reservoir is over filled when a large volume is deposited in the basin there will be loss from it Qspill. To minimize this, the reservoir level h must be kept below its maximum level hR. The useful hydraulic power converted by the turbines is the product of turbine flow Qturbine, the head across them, water density and gravity (Tedd James et al., 2005). In coastal engineering the average flow Q is converted into non dimensional form by dividing by the breadth of the device b, gravity g and the significant wave height HS: In the case of the floating OTD it has been seen that there is a dependency on the wave period. The dominant physical explanation for this is the effect of energy passing beneath the draft of the structure. Figure 6 Layout of OTD 3.3.2.2 Wave Reflector Wings One of the most distinctive aspects of the Overtopping WEC is the long slender wings mounted to the front corners of the reservoir platform. These are designed to reflect the oncoming waves towards the ramp. A wider section of wave is available to be exploited with only a moderate increase in capital cost. The overtopping volume in a wave is very dependent on the wave height; therefore by providing only a moderate increase in height, much more energy can overtop the ramp. In order to choose the correct lengths, angles, and position of these wings extensive computer modelling is used. Secondary bonuses of the presence of the wave reflector wings include: better weather-vaning performance to face the waves, lower peak mooring forces, and improved horizontal stability of the main platform. As the aft and rear mooring attachment points are separated further, the yaw of the platform is more stable. Therefore the device will not turn away from the predominant wave direction, and will also realign itself faster as when the wave direction changes (Tedd James et al., 2005). Lastly the reflectors wings act as stabilisers to the device. As they float under their own buoyancy they counteract any list of the platform. This is important as the more horizontal the platform is kept the less water is spilt and so the more efficient the device operation. 3.3.2.3 Low Head Turbines and Power Train Turbine operating conditions in a WEC are quite different from the ones in a normal hydro power plant. In the OTD, the turbine head range is typically between 1.0 and 4.0 m, which is on the lower bounds of existing water turbine experience. While there are only slow and relatively small variations of flow and head in a river hydro power plant, the strong stochastic variations of the wave overtopping call for a radically different mode of operation in the OTD. The head, being a function of the significant wave height, is varying in a range as large as 1:4, and the discharge has to be regulated within time intervals as short as ten seconds in order to achieve a good efficiency of the energy exploitation (Tedd James et al., 2005). On an unmanned offshore device, the environmental conditions are much rougher, and routine maintenance work is much more difficult to perform. Special criteria for the choice and construction of water turbines for the WEC have to be followed; it is advisable to aim for constructional simplicity rather than maximum peak efficiency. Figure 6 shows the application ranges of the known turbine types in a graph of head H vs. rotational speed nq. The specific speed nq is a turbine parameter characterizing the relative speed of a turbine, thus giving an indication of the turbines power density. Evidently, all turbine types except the Pelton and the cross flow type are to be found in a relatively narrow band running diagonally across the graph. Transgressing the left or lower border means that the turbine will run too slowly, thus being unnecessarily large and expensive. The right or upper border is defined by technological limits, namely material strength and the danger of cavitations erosion. The Pelton and the cross-flow turbine do not quite follow these rules, as they have a runner which is running in air and is only partially loaded with a free jet of water. Thus, they have a lower specific speed and lower power density. Despite its simplicity and robustness, the cross flow turbine is not very suitable for OTD applications (Tedd James et al., 2005). Figure 7 Head range of the common turbine types, Voith and Ossberger 3.3.2.4 Performance in Storms Survivability is essential, and Overtopping devices are naturally adapted to perform well in storm situations, where the wave will pass over and under the device with no potential end-stop problems. 3.3.2.5 Wave Prediction Performance of almost all wave energy converters can be improved with prediction of the incoming waves. The cost to implement would be low as the control hardware is typically in place, only the measuring system and improved control techniques need to be developed. To explain the concept behind the device a simple example can be used. If a measurement of some wavelengths ahead of the wave energy converter shows large waves passing, then at a given time later this energy will be incident on the device. The control of the device can then be altered quickly to extract this larger energy, e.g. by increasing hydraulic resistance to an oscillator’s motion allowing more energy to be captured within the stroke length, or by draining the reservoir of an overtopping device to allow for a large overtopping volume(Tedd James et al., 2005). The challenges are threefold; to implement a system for measuring the waves approaching the ramp, to accurately transform this into usable input for the control systems, and to construct new control strategies to make the best use of this. The standard approach for performing such deterministic sea-state prediction involves discrete frequency domain techniques. This is computationally intensive, as the two Fourier transforms must be made to convert from the time domain to the frequency domain and return to the time domain. 3.4 Energy Capture and Practical Limits The power captured from waves by the primary mechanical conversion (before secondary conversion to electrical power) can be related to the energy in the incoming waves over a certain width. Theoretical values have been established in some cases. For a heaving axi-symmetric body the maximum capture width is the inverse of the wave number. The capture width is often compared to the front width of the device. This width ratio can be larger than one for a point absorber with small dimensions compared to the wavelength. Viscous effects reduce efficiency. For an OWC, Wang et al. (2002) found that the capture width ratio may reach a value of 3 and above at an optimum wave period. For Pelamis, Retlzler et al. (2001) found a capture width up to 2 in regular waves and around one in random seas (Specialist Committee V.4, 2006). A continuous or a semi discrete array of wave energy converters acting as an absorbing wall perpendicular to the wave direction is called a terminator and its capture width equals the width of the device and is not related to the length of the incident waves. As the wave conditions are stochastic, the tuning parameters of the energy converters are compromises between the optimum values at various sea conditions. The capture width must be established for each sea state. Fixed devices are subject to sea level variation according to tidal effects. This is critical for fixed oscillating water columns and fixed overtopping systems whose performances are dependent on the mean sea level. The intake of an OWC must be located at an optimised design level from the mean free surface. The height of an overtopping system is also optimised for sea states occurring at a given mean sea level. Therefore, sites with minimal tide are preferred. From this point of view floating devices are more suitable. The immersion of a floating device can also be tuned with respect to the actual sea state. For instance the Wave Dragon overtopping device is partially floating on air chambers and its draught can be modified (Specialist Committee V.4, 2006). The performance of the overtopping device is sensitive to the distribution of the overtopping rate. The more variable the overtopping flow into the reservoir, the larger the capacity of the reservoir and turbines must be to achieve the same performance. 4.0 Mooring Requirements The two major requirements for a WEC mooring are to withstand the environmental and other loadings involved in keeping the device on station, and to be sufficiently cost effective so that the overall economics of the device remain viable. The following list shows the requirements that need to be considered for WEC moorings systems (Harris Robert E. et al.): The primary purpose of the mooring system is to maintain the floating structure on station within specified tolerances under normal operating load and extreme storm load conditions. The excursion of the device must not permit tension loads in the electrical transmission cable(s) and should allow for suitable specified clearance distances between devices in multiple installations. The mooring system must be sufficiently compliant to the environmental loading to reduce the forces acting on anchors, mooring lines and the device itself to a minimum; unless the stiffness of the mooring itself is an active element in the wave energy conversion principle used. All components must have adequate strength, fatigue life and durability for the operational lifetime, and marine growth and corrosion need to be considered. A degree of redundancy is highly desirable for individual devices, and essential for schemes which link several devices together. The system as a whole should be capable of lasting for 30 years or more, with replacement of particular components at no less than 5 years. The mooring must be sufficient to accommodate the tidal range at the installation location. The mooring system should allow the removal of single devices without affecting the mooring of adjacent devices. Removal of mooring lines for inspection and maintenance must be possible. The mooring must be sufficiently stiff to allow berthing for inspection and maintenance purposes. Contact between mooring lines must be avoided. The mooring should not adversely affect the efficiency of the device, and if it is part of an active control system it must also be designed dynamically as part of the overall WEC system. Revenues from WECs, in comparison to the offshore industry, are smaller and their economics more strongly linked to the location, installation costs and down time periods. The mooring system has an important impact on the economics and it is necessary to provide, at low installation cost, a reliable system that has little downtime and long intervals between maintenance. The suitability of design approaches from the offshore industry for WECs are ranked in Appendix I (Harris Robert E. et al.). 5.0 Environmental Considerations Conversion of wave energy to electrical or other usable forms of energy is generally anticipated to have limited environmental impacts. However, as with any emerging technology, the nature and extent of environmental considerations remain uncertain. The impacts that would potentially occur are also very site specific, depending on physical and ecological factors that vary considerably for potential ocean sites. As large-scale prototypes and commercial facilities are developed, these factors can be expected to be more precisely defined (U.S. Department of the Interior, May 2006). The following environmental considerations require monitoring (U.S. Department of the Interior, May 2006). Visual appearance and noiseare device-specific, with considerable variability in visible freeboard height and noise generation above and below the water surface. Devices with OWCs and overtopping devices typically have the highest freeboard and are most visible. Offshore devices would require navigation hazard warning devices such as lights, sound signals, radar reflectors, and contrasting day marker painting. However, Coast Guard requirements only require that day markers be visible for 1 nautical mile (1.8 km), and thus offshore device markings would only be seen from shore on exceptionally clear days. The air being drawn in and expelled in OWC devices is likely to be the largest source of above-water noise. Some underwater noise would occur from devices with turbines, hydraulic pumps, and other moving parts. The frequency of the noise may also be a consideration in evaluating noise impacts. Reduction in wave height from wave energy converterscould be a consideration in some settings; however, the impact on wave characteristics would generally only be observed 1 to 2 km away from the WEC device in the direction of the wave travel. Thus there should not be a significant onshore impact if the devices were much more than this distance from the shore. None of the devices currently being developed would harvest a large portion of the wave energy, which would leave a relatively calm surface behind the devices. It is estimated that with current projections, a large wave energy facility with a maximum density of devices would cause the reduction in waves to be on the order of 10 to 15%, and this impact would rapidly dissipate within a few kilometers, but leave a slight lessening of waves in the overall vicinity. Little information is available on the impact on sediment transport or on biological communities from a reduction in wave height offshore. An isolated impact, such as reduced wave height for recreational surfers, could possibly result. Marine habitatcould be impacted positively or negatively depending on the nature of additional submerged surfaces, above-water platforms, and changes in the seafloor. Artificial above-water surfaces could provide habitat for seals and sea lions or nesting areas for birds. Underwater surfaces of WEC devices would provide substrates for various biological systems, which could be a positive or negative complement to existing natural habitats. With some WEC devices, it may be necessary to control the growth of marine organisms on some surfaces. Toxic releasesmay be of concern related to leaks or accidental spills of liquids used in systems with working hydraulic fluids. Any impacts could be minimized through the selection of nontoxic fluids and careful monitoring, with adequate spill response plans and secondary containment design features. Use of biocides to control growth of marine organisms may also be a source of toxic releases. Conflict with other sea space users, such as commercial shipping and fishing and recreational boating, can occur without the careful selection of sites for WEC devices. The impact can potentially be positive for recreational and commercial fisheries if the devices provide for additional biological habitats. Installation and Decommissioning: Disturbances from securing the devices to the ocean floor and installation of cables may have negative impacts on marine habitats. Potential decommissioning impacts are primarily related to disturbing marine habitats that have adapted to the presence of the wave energy structures. 6.0 Discussions A vast number of parameters influence (and interact with) the net power production from any WEC: Overtopping, determined by Free-board (adjustable in Wave Dragons) Actual wave height Physical dimension of the converter (ramps, reflectors etc. Outlet, determined by Size of reservoir Turbine design Turbine on/off strategy Mooring system, free or restricted orientation toward waves Size of the energy converter Wave climate Energy in wave front (kW/m) Distribution of wave heights Availability Theoretical availability; Reliability, maintainability, serviceab