Moral Dilemmas

4 November 2012 HUM 115 Catherine Reynolds: Moral Dilemmas The five of the moral dilemmas I chose were the following: The Partiality of Friendship; A Poisonous Cup of Coffee; A Callous Passerby; The Fat Man and the Impending Doom; and A Father’s Agonizing Choice. Out of these 4 dilemmas I have chosen the dilemma that is titled: A Callous Passerby. The reason why I chose this particular one is because I got a story that relates to this story. When it comes to saving a person life and not caring how the situation may go while doing but you know you can succeed in doing is a great deed.This certain dilemma would go under an altruistic moral theory because in the reading it states this moral is under the golden rule that I always taught: â€Å"Do unto others as you have them do unto you. † And this is basically saying do the right thing at all times and don’t let minor things do give you a set-back on the situation. My experience with this type of moral was to see a lady in a burning house trying to find her kids and grandkid and get them out the burning house. I was on my way to a movie and I was dressed too. I had new clothes, shoes, and just left the hair dresser early that morning.When I saw the house it looked like it just started burning. No fire trucks, polices, or ambulances were on the highway to come to the seen. The lady was outside and screaming for help. Good thing I had took the back way to my destination or else I would not have seen this incident. As the lady screamed â€Å"call for help, my kids are in there! † I knew right then she didn’t have a phone or couldn’t get to it. So I called for help and they said they were coming. So as I asked the lady how long has this been going on and she said about 30 minutes. As she was telling me what happened I heard some kids hollering and crying.I asked her how many were in the house and she said 4. Two of her grandchildren and her other two were her kids by adoption. When it came to me getting them out, I burned up my pants and shirt and also damaged my hair. But I think of the situation as a blessing because those kids would’ve of been burnt if I would not of save them. I was just thinking I am going to be late for the movie I have no more clothes to change into and my hair smells awful. However, I had to look at like this, I saved a life that wouldn’t have been here another day. The movies are always playing movies.My general conclusions about my moral compass are what I was taught growing up from childhood. When it came to me helping people when I knew I could I would go for it. My mother and father always said â€Å"think about what you do, and don’t do anything that you’ll regret later and always remember this â€Å"treat others how you wanted to be treated; and do unto others as you would have them do unto you. † Those words meant a lot to me growing up and the reason why is because I followed through t hose words in life and it got me feeling good about life because I know have done right.

A Doll’s House

A Doll's House, by Henrik Ibsen, portrays the lives of people who are dreadfully bound in their social settings. Nora is considered the typical example of feminine standards during this period. In the play, she is considered powerless and bounds herself to patriarchal expectations, which signifies women's social role as wife and mother. The plot format, characters, and theme play a vital role in contributing to the social hierarchy of this play. A Doll's House is written in three acts; instead, of the traditional five-act plays. The plot construction of this play is characterized by exposition, complication, and resolution. For example, in act one exposition takes place when Nora's character is exposed. She is determined to take care of her family; however, is also extremely conceded and completely dependent upon her husband, Torvald despite the way he treats her. The main events take place one after another with complication along with rising action occur in act two; the last act involves the steps to resolution as soon as the catastrophe takes place. â€Å"Listen, Torvald. I have heard that when a wife deserts her husband's house, as I am doing now, he is legally freed from all obligations towards her. In any case, I set you free from all your obligations.†(act III, 79) In Act III, Nora, finally, has the courage to leave her husband which leads to the resolution taking place.During this play, the audience is exposed to a variety of characters which result in the story being told from different perspectives. Nora is the protagonist of the play, and as the play goes on the audience views a mature in her. Torvald sees Nora as easily controlled like a pet or child. However, as the play goes on Nora emerges as a fully independent woman who abandoned her marriage and the burden of motherhood. Torvald is seen as unsympathetic and stiff throughout the play; as well as avoiding interaction with his children. Dr. Rank is introduced to the audience and is seen as corrupt when he expresses his desire for Nora. At the beginning of the play, Nora borrowed money from Krogstad without her husband's knowledge. Krogstad is the ultimate description of corrupt, he saw a chance to save his job at the bank when it becomes jeopardized by blackmailing Nora. All the characters described play a role in contributing to the social hierarchy of the play. A Doll’s House INST 2608-02 A Doll’s House response paper The two main characters in A Doll’s House that I am going to focus on are Torvald and Nora. They are a married couple living in a middle class home with three children and maids. Torvald has secured a position with a bank, after the New Year he will â€Å"get a big salary and earn pots and pots of money. † (Page 8) Nora has kept a large secret from Torvald regarding money borrowed to take a trip to Italy so Torvald could recuperate in a warm climate from an illness. The story centers on Nora trying to keep the secret from Torvald.Krogstad loaned the money to Nora and she forged the signature of her father as the co-signer on the contract. The plot thickens when Krogstad shows up at Nora’s house to blackmail her. Torvald refers to Nora as a little bird and talks to her like she is a lovely little doll. â€Å"What do we call little birds that like to fritter money? † (Page 9) Nora plays right along with all t he references to a lovely bird that needs her husband to approve everything she does. I was annoyed with their relationship because of the way he treated her and because she allowed it to happen.Nora is a strong, smart and independent woman, who allows her husband to dominate. She acted this was because society expected this of woman. She did not think for herself in fear of the men becoming angry. When Torvald discovers Nora’s secret and realizes he may be ruined by the blackmail of Krogstad, he turns on her. â€Å"I’ve really had my eyes opened, in all these years. You who were my pride and joy, a hypocrite! A liar! Worse! A criminal! † (Page 58) Nora realizes Torvald would not sacrifice his integrity for her. She proclaims that thousands of women sacrifice their integrity for men and she could not live with a stranger any longer.I was elated she made the decision to leave and stand up for what she believes. Nothing Torvald said would change her mind. She real ized her father had treated her like a doll and now her husband was doing the same thing. Nora walked away from everything in order to gain her independence and find out what she believed to be the truth. This took a very strong woman, because women were to be at home and raise the children. They were to look pretty and do as they were told. They were not to think or give opinions. Nora sacrificed everything to be free.

Current Network Characteristics and Components Essay

In reviewing the Kudler Intranet site it can be determined that all three Kudler offices are connected via a dedicated T3 line, set up as a bus topology. Each location is built around a 100base T, fast Ethernet environment. La Jolla serves as the home office location and the location for the main company server. The main server is an IBM blade server system C3000 with a UNIX operating system. As the main company server it runs all the corporate procurement and logistic software (SAP, ERP) and is responsible for all the print/file services, network services, company e-mail, storage control, and the internal and external web. Server backup is provided by a 10GB network-attached storage system. The retail stores are connected to the network via a point of sale server and point of sale terminals. Communications in and out of La Jolla is ported through two Cisco routers with firewalls. The La Jolla location currently has 19 VoIP phones and 19 employees. As previously stated, both the Del Mar and Encinitas locations are built around a 100base T network. Both locations have a local server which is also an IBM blade server system C3000 with a UNIX operating system. Both servers run the same services at the main company server with the exception of the corporate procurement and logistic software. Retail locations also run the same point of sales terminals. Each location currently has six employees and six VoIP phones. There are a total on 30 computers connected to the company network. Current Network Topology Each location is built on a bus topology. Each location employs 100 base T Ethernet with all stations connected via twisted pair cable. All the nodes (computers, servers, printers) are connected to the bus cable with interface connectors. Several problems come to mind with this type of network topology. Dependency on central cable in this topology has its disadvantages. If the main cable (bus) encounters some problem, whole network breaks down. A limited number of stations can be added to the network, these severely impacts future capacity growth. Performance degrades as additional computers are added or on heavy traffic periods. Data speeds can be severely impacted by an increase is users or if users are accessing the network at the same time. Also of concern with this type of topology is the possibility of higher maintenance costs and troubleshooting difficulty. Security is very low on this type of network architecture. Standards Several standards will be applicable to a project of this scope; these standards will depend upon the level of the OSI model that is being addressed. Frame relay will be used at the WAN level. IEEE 802.11 wireless LAN standards will be applicable with Wi-Fi certified devices. Voice over IP (VoIP) uses IP protocols and the International Telecommunication Unions ITU-T standard (H.323). References Reference Anonymous (2007) Kudler Fine Foods. Retrieved February 6, 2013, from https://ecampus.phoenix.edu/secure/aapd/CIST/VOP/Business/Kudler2/internet/index.asp Reference Anonymous (2007) Kudler Fine Foods Intranet. Retrieved February 9, 2013, from https://ecampus.phoenix.edu/secure/aapd/CIST/VOP/Business/Kudler2/intranet/index.asp

Case Study 1 Essay Example | Topics and Well Written Essays - 750 words - 3

Case Study 1 - Essay Example The National Cash Registered Country Club (NCRCC) started to benefit thousands of employees who became the core members leading to their development. The club later started offering some two golf courses. Award winning and the championship hosting on the PGA tour are some of the courses offered by the National Cash Register Country Club (NCRCC). The only limitation was that the club was not attracting some new members more especially the young families (Sanchez & Lazaro, 2010). The study is mainly focusing on membership study which is done as part of larger organization creativity to ensure adequate evaluation to different strategic directions that the club may wish to increase its membership. I feel to allow all group age to the club without eliminating some. As in this case, majority are always youths so they need to be given chance to participate in all events of the club. The NCRCC: Teeing Up a New Strategic Direction golf club situated in U.S is observed as the optional extra life styles. However, the McMahon Group came to specialize in the provision of research and strategic consulting to the golf club and providing full services to golf (Floyd &Hebert, 2010). Frank Vain, who was the president of McMahon Group, suggested that with the existence of NCR faced an added wrinkle since it was corporately held. The first impression of McMahon visit where they collected information’s on membership and operations together with the club specialists to discuss the trends of the industry with strategic planning committees (Petar, 2010). The board of National Cash Registered Country Club (NCRCC) hired president McMahon to help the employee with the direction and assistance of the NCRCC development board. Vain estimated historically that the NCRCC has about seven percent diffusion rate in the midst of the employees which was trending smaller which made some reinforcement to the NCRCC membership. However, the NCRCC needed to become

Issues about pedagogic design Essay Example | Topics and Well Written Essays - 500 words

Issues about pedagogic design - Essay Example Therefore, teacher is assumed to be the organizer rather than the main source of knowledge. After browsing Allwright and Hank (2009) â€Å"Method and the Learner†, I realized that my teaching style is similar to the teaching approach, design and procedure of socio-psychological approach to community language learning (CLL). CLL encourages the students to interact with one another to help them develop their ability to use a second language. Instead of leaving the leaving the learning and teaching process to the students, the second language teacher can also act as the teacher whereas the students are treated as learners. By showing the proper way of using a second language, teachers will be able to make the students apprehend the proper pronunciation of a word aside from making them learn the basic construction of grammar. My teaching style is closely related to Richards and Rodgers (2001) communicative language teaching in the sense that this approach and method in language te aching is focused on increasing the students’ communicative abilities. Increasing the students’ knowledge on second language is totally different from making them able to speak the language in public.

Management of Change Essay Example | Topics and Well Written Essays - 1500 words

Management of Change - Essay Example Since 1937, the company has grown significantly and brought changes in how food is packaged even before the consumers ever thought of those changes (Leonhardt, 2012). However, with time, many things have dented the image of the corporation and undermined the reputation the owners have worked hard to build. Areas of Change The company needs change in three identifiable and key areas of its operations in order to salvage its reputation and rejuvenate to a brand that is adored by many when it comes to having a meal. First is the area of food processing. The company needs to move more towards healthy foods and abandon its niche of dominant junk food. The company has been associated with food products that are â€Å"unhealthy† to the consumer at the time where health issues such as obesity and heart diseases are emerging to be great challenges to the world population. The second area that needs change is the lead time of supply. There should be change in the procedure of sourcing f or supply so that the time taken to deliver and, therefore, make it readily available is reduced. The third issue is that of the billing system in terms of its efficiency to eliminate complaints on overcharge in credit cards and how they respond to such concerns. These three issues are among other concerns in the organization that need to be subjected to change so that the organization remains a giant in the industry. Need for Change For every organization, the need for change is a constant requirement rather than a rare once in a year thing. An organization in the highly competitive and sensitive industry, such as Mc Donald, therefore, needs to embrace change through effective change management structures. Companies that engage themselves in all efforts of creating change have benefited a lot financially and in terms of growth. They are likely to be more competitive and even more adapted to external changes in the corporate world (Beer and Nohria, 2000). This, in essence, points th e need for the organization to initiate change in the areas mentioned above. This can also be clearly illustrated through the various models of change management. Models of Change Management The two models of change likely to help in going around the change barrier include that of the change curve and Lewin's Change Management Model. The change curve explains the different stages that an organization goes through before an effected change is fully accepted. It helps in making the change implementation to be expedited, thereby increasing its likelihood of success. The change curve proposes that change is approached through people because when they adapt to change fast, the organization also changes rapidly (Mind Tools, 2012). Lewin’s Change Management Model proposes a three pronged process that involves unfreezing, changing and refreezing. The first stage involves anchoring change acceptance through creating an enabling environment. The second change subsequently involves intr oduction of the change and finally synchronizing the changes in the organization’s structures in the final phase (Mind Tools, 2012). These models show the ease at which various organizations including the one on focus can learn to integrate change in its operations in a more effective and timely manner. They are a good reminder of the need for chan

What is the Enlightenment project and how did it impact upon Christian Essay

What is the Enlightenment project and how did it impact upon Christian Theology - Essay Example Creative and critical thinking is an essential tool in analysis of theology, since all its aspects are related to the basic human understanding the origin of all creation and nature given the universal belief of a superior being. It is in this perspective that the philosophy of the holy trinity resulted in a deep examination of the biblical information and the church in general. Two different factions of Christians have come up, one group believes in the trinity that has God the father, the Son and the Holy Spirit. This group is referred to as the Trinitarian group (Leupp 2008). The other group which believed that God is one distinct being has come to be referred to as the Non Trinitarian group. A heated debate has always ensued when the existence of the two groups is discussed or debated. The Trinitarian group can never visualize God as a single distinct person. Olson argues that a non-Trinitarian creator God would need a world as his counterpart because personhood is a mystery of r elationship.The statement further says that man is equal with God and his Godhead and with humankind in his manhood. The existence of the two groups is actually the origin of Christian theology. As Christians realized that different groups had different beliefs, the early scholars dug deeper into the Bible history and in particular the different propositions it had. This started out as reflections on the implications and what the Christianity faith means. This insight started out as early as in during the era that the New Testament was written. Different episodes that Jesus taught on the Christian living guided the early church on the way they could live their lives in a way that their faith and convictions supported. Similar any other area of study, Christian theology has evolved from early introduction to Christian theology over the years, patristic theology, medieval Christian theology, western theology and ultimately into the modern Christian theology. It is in the context of mo dern theology, that the enlightenment project first emerged. The enlightenment project has dominated philosophy in the recent three hundred years promising a conception of rationality independent of historical and social context and independent of any specific understanding of man’s nature or purpose (Costa 2005).The enlightenment indicated tremendous changes which were known as the Copernican Shifts. These changes signified complete shifts in how the Christians viewed the world. These changes brought sharp differences between various scholars and Christian theology experts. People abandoned their earlier ways in the wake of the new beliefs. An aspect of the Christian living that changed is the revolution in thinking. This revolution brought about some significant shifts: A shift in authority. Before the enlightenment, two traditional sources of authority existed; the classics and the bibl

Life of slaves in the Caribbean Essay Example | Topics and Well Written Essays - 750 words

Life of slaves in the Caribbean - Essay Example According to Shepherd (25), slavery, colonialism effects and several cultures diversely represent Caribbean. Slavery as an establishment was based on the platform of submission and dominance. The occurrence of slavery is experienced in a developed society’s notably the United States. When the Europeans arrived in the Caribbean Islands, constant change was effected. Introduction of the plantation system and inhabitants loss amounted to repercussions in the islands. The systems of plantation consisted of a powerful class, lower class, and a wealthy class. This is because the plantation systems and labor were required for prosperity. Slavery was a solution to the labor force for the capitalist class. According to Engerman & Barbara (43) Slavery played a fundamental function in the economy of the island hence sugar became the chief economic ingredient. During slavery, the economy of the Caribbean islands expanded leading to increased families disposable income from farming activit ies. Triangle trade was caused by demand in slaves who were required to cultivate crops such as sugarcane. European ships stopped in the African oceans to trade in metals, liquor, weapons, and ammunitions that were taken from captives in during raids and wars; furthermore, sugar and salt were exchangeable for slaves. Approximately fifteen million slaves were transported through the Oceans later settling into the Caribbean Islands. Conditions in the ship were not favorable. A lot of concentration was on the healthiest and young people because of their worth in America. History of slavery Slavery in the Caribbean islands dates from the time when population was required to manufacture sugar being the main trade. The white servants had earlier come before the African slaves. Although the white servants did not come in huge numbers, they were rewarded after contracts. During this period, workers who came from Barbados were kidnapped. Women acted as house cleaners while men operated as se rvants to the slave owners. Most Jamaicans and Irish girls went to work in the island. Rules were set for slaves as a tool for control purposes in the agricultural fields. The owners of plantations allowed slaves to undergo marriage and baptism. Effects of slavery in the Caribbean Human suffering increased because the harsh living conditions. Slaves were kept in dirty rooms and had nothing to eat and drink. Many people suffered from increased violence. Several slaves captured died along the journey. During this period, people were kidnapped in their fortified houses. Before Europeans got involved in exporting slaves, the African continent was made of smaller tribes, which warred during conflicts hence animosity between factions. The groups involved in war switched from the old habits of fighting with the coming of the Europeans. Most people lost their lives in the process of working in the European firms. According to Kiple (89), the harsh weather conditions made the Africans sick h ence causing death. In the plantation fields, Africans were often subject to attacks and were eaten by wild animals. African women were subjects of rape and this caused psychologically depression. Poverty affected Africans because of lack opportunity for enrichment through working for the Europeans. Slavery created an opportunity for underdevelopment because no African could attain formal education. The Europeans regarded Africans as monkeys. Frustrations became a benchmark in the Caribbean Island. People resorted to drugs, which could console during the working periods. Slavery created enmity between the Europeans and Africans because the Africans were recipients of improper treatment. Decrease in population was evident because most Africans died in the process of working for the Europeans in their bushes. If one did not work as per required by the bosses, punishment was the recipe. The end of slavery According to Kiple (67), after all the suffering of the Africans in the Caribbean and Western

Monetary policy responses by central banks during the early part of Essay

Monetary policy responses by central banks during the early part of the past decade aggravated the recent financial crisis - Essay Example The sub-prime mortgage market in particular was the target of these speculative flows which also made their way into the securities and equities markets as well. It can be said that the monetary policy of the Fed in the early years of the last decade encouraged excessive speculation in the United States economy (Mishkin, 2011, 23). However, to assign blame to the monetary policy of the Fed alone would be to exaggerate its role in the present global financial crisis as the issues of regulation and supervision of â€Å"exotic† financial products was one of the contributing factors as well. However, there is a consensual view which is increasingly being shared by many that at the heart of the reasons for the global imbalances lies the fact that the Fed kept interest rates â€Å"too low for too long† (Taylor,2008,14). This line of thought holds that by keeping the interest rates too low, the Fed encouraged the â€Å"real rate of return† in the US T-Bills or Treasurie s to increase leading to the rest of the world financing the yawning and steadily increasing current account deficit of the US. Further, the fact that these countries (led by Japan and China) were exporting huge amounts of goods and services gave them an incentive to â€Å"recycle† their dollar surpluses back into the US economy. Hence, it can be said that though the monetary policy of the Fed was aimed primarily at a domestic audience, due to the integrated and interconnected nature of the global economy indirectly contributed to the ongoing global financial crisis (BOE, 2010). It should be noted that the overly loose global monetary policy may have contributed to the weakening of the anchor on which â€Å"price stability† rested leading to excessive risk taking and by unleashing a global wave of euphoria contributed to the speculative tendencies in the financial sector. And this was a global phenomenon as well as central banks all over the world took their cue from t he Fed and pursued similar policies which had a cascading effect on the global economy in so far as the lethal combination of excessive liquidity and a lax regulatory structure combined to produce the global financial crises with which the world is even now struggling to cope with (Federal Reserve, 2010). References Blanchard, Dell’Ariccia, and Mauro, OB, G & P, 2010. Rethinking Macroeconomic Policy. IMF, Feb 2010, 1-18. ECB. (2010, April 9), â€Å"Could Monetary Policy have helped prevent the financial crisis?† Available from: http://www.ecb.int/press/key/date/2010/html/sp100409.en.html Mishkin, F, 2011. Monetary Policy Strategy: Lessons from the Crisis. National Bureau of Economic Research, Jan 2011, 1-65. Monetary Policy (2010), (Federal Reserve), Available: http://www.federalreserve.gov/monetarypolicy/default.htm (Accessed: 2011, Mar 14). News Releases (2011), (Federal Reserve), Available: http://www.federalreserve.gov/newsevents/default.htm (Accessed: 2011, Mar 14 ). News Releases (2011), (Bank of England), Available: http://www.bankofengland.co.uk/publications/news/2008/index.htm (Accessed: 2011, Mar 14). Taylor, JBT, 2008. The Financial Crisis and the Policy Responses: An Empirical Analysis of What Went Wrong. Stanford

Medical Marijuana Essay Example for Free

Medical Marijuana Essay â€Å"Marijuana is the finest anti-nausea medication known to science, and our leaders have lied about this consistently. [Arresting people for] medical marijuana is the most hideous example of government interference in the private lives of individuals. It’s an outrage within an outrage within an outrage†. Peter McWilliams Author and Advocate for Medical Marijuana Medical Marijuana has found its place once again as the medical plant that is recognized for its healing potential and properties. How the Government has suppressed its positive potential and healing powers for over 25 years. With the help from many patients, loved ones, research departments and advocate groups to get the Government’s attention to see and understand that the terminally ill and the sick should not be treated as common criminals. They are only trying to find some peace and serenity in their last days. The struggle and fight that has been going on for the last 25 years against the Government. The people were finally heard, with the legalization of Medical Marijuana. The Government wants to regulate everything for their own best interest, the positive effect of decriminalizing marijuana for the terminally ill and the positive economic benefits for our community. Cannabis Sativa, Marijuana, Weed, Herb, Mary Jane these are just a few names that this little 5 leaf plant goes by. How could this life saving and healing plant get such a bad reputation? When clearly it has nothing but positive powers, people all over the world have been using marijuana for thousands of years. Cannabis has been around since the Garden of Eden, it is even mentioned in the Bible. Yes in the Bible, in Exodus (30:22-23) â€Å"Holy anointing oil, as described in the original Hebrew version of the  recipe in Exodus (30:22-23), contained over six pounds of kaneh-bosem, a substance identified by respected etymologists, linguists, anthropologists, botanists and other researchers as cannabis, extracted into about six quarts of olive oil, along with a variety of other fragrant herbs. The ancient anointed ones were literally drenched in this potent mixture† (Bennett, 2010). â€Å"Marijuana proponents suggest that the recipe for the anointing oil passed from God to Mos es included Cannabis, or kaneh-bosem in Hebrew. They point to versions calling for fragrant cane, which they say was mistakenly changed to the plant calamus in the King James Version of the Bible† (Kari, 2011). Cannabis was good enough for God and Moses, then how come it is not good enough for us now? The United States Government wants to be in control and regulate everything we do as a United State Citizens. Marijuana was once considered a pharmaceutical medication used for a wide verity of reasons. In fact cannabis has a deep rooted history in what is now known as the United States of America. â€Å"Christopher Columbus brought Cannabis Sativa to America in 1492† (420 Milestone History Marijuana, (n.d.), 2010). â€Å"From 1000 to 1500, the use of marijuana spread further. In 1619, a law passed in Jamestown Virginia Colony, which required farmers to grow hemp. The French and British grew hemp in Colonies of Port Royal, Virginia, and Plymouth. Marijuana also became a major trade item between Central and South Asia during this time† (420 Milestone History Marijuana, (n.d.), 2010). The United States also had Presidents’ who grew cannabis. Yes Presidents’, â€Å"in Mount Vernon, George Washington grew hemp as his primary crop in 1797. Also Thomas Jefferson grew hemp as a secondary crop at Monticello. In 1840, medicines with a cannabis base were available in U.S. pharmacies. Hashish was available in Persian pharmacies† (420 Milestone History Marijuana, (n.d.), 2010). Therefore when did it become a crime to cultivate, possess, consume, and dispense marijuana? â€Å"In 1906, the Pure Food and Drug Act was passed in the U.S. and the Food and Drug Administration was formed. This was the first time drugs had any government oversight† (420 Milestone History Marijuana, (n.d.), 2010). â€Å"In 1930, The Federal Government gave control of illegal drugs to the Treasury Department, they created the Federal Bureau of Narcotics. Harry Anslinger a prohibitionist became the first commissioner  in 1930, he held that position until 1962. Anslinger declared war on drugs and effectively shaped America’s view’s and thought’s about marijuana† (420 Milestone History Marijuana, (n.d.), 2010). â€Å"October 2, 1937, Anslinger got Congress to enact the â€Å"Marihuana Tax Act†, which is to imposed registration and reporting requirements and a tax on the growers, sellers, and buyers of marijuana† (Eddy, 2010 p.2). In Eddy’s report he also writes that â€Å"Dr. William C. Woodward, legislative counsel of the American Medical Association (AMA), opposed the measure. In oral testimony before the House Ways and Means Committee, he stated that â€Å"there are evidently potentialities in the drug that should not be shut off by adverse legislation. The medical profession and pharmacologists should be left to develop the use of this drug as they see fit. Two Months later, in a letter to the Senate Finance Committee, he again argued against the act: â€Å"That there is no evidence, however, that the medicinal use of these drugs [cannabis and its preparations and derivatives] has caused or is causing cannabis addiction. As remedial agents they are used to an inconsiderable extent, and the obvious purpose and effect of this bill isto impose so many restrictions on their medicinal use as to prevent such use altogether. Since the medicinal use of cannabis has not caused and is not causing addiction, the prevention of the use of the drug for medicinal purposes can accomplish no good end whatsoever. How far it may serve to deprive the public of the benefits of a drug that on further research may prove to be of substantial value, it is important to foresee†. â€Å"Despite the AMA’s opposition, the â€Å"Marihuana Tax Act† was approved, causing all medicinal products containing marijuana to be withdrawn from the market and leading to marijuana’s removal† (Eddy, 2010 p.2). October 2, 1937, â€Å"On the very day the â€Å"Marihuana Tax Stamp Act† was passed; the FBI and Denver police raided the Lexington Hotel and arrested two people: Samuel R. Caldwell and Moses Baca. Three days later, Caldwell, a 58 year old unemployed laborer, became the first person in the U.S. to be convicted of selling of marijuana without a tax stamp. He was sentence to four years oof hard labor in Leavenworth Penitentiary. Presiding Judge J  Foster Symes, had previously stated that he considered Marijuana to be the worst of all narcotics and vowed to impose harsh sentences for violations of the â€Å"Marihuana Tax Act†. Caldwell was also fined $1,000 for the two marijuana cigarettes that were found in his possession. Baca, who was his customer, was found guilty of possession of Marijuana and was sentenced to 18 months in prison. Both men served their full sentences. Caldwell died a year after his release† (420 Milestone History Marijuana, (n.d.), 2010). This is why that â€Å"we the people† stood up, banded together, and formed  Organizations. People became spokespersons, advocates, â€Å"a voice for the cause†. Take for example, Peter McWilliams. He is the man I quoted in the beginning. â€Å"Peter was a self-help author, who advocated for the legalization of marijuana. He wrote over 40 books including â€Å"How to survive the loss of love†, â€Å"Ain’t nobody’s business if I do†. Along with poetry and how to use microcomputers. In 1996, he was diagnosed with AIDS and non- Hodgkin’s lymphoma. Like so many patients suffering from cancer or AIDS, he had extreme difficulty on keeping down the drugs that controlled his illnesses. He began to smoke marijuana to control the drug-induced nausea. It saved his life† (US: The Life and Death of Peter McWilliams, 2002). â€Å"NORML, the National Organization for the Reform of Marijuana Laws, was founded in 1970, as a nonprofit public-interest advocacy group whose mission is to end marijuana Prohibition† (Historical Timeline Medical Marijuana, (n.d.), 2011). â€Å"In 1971, President Nixon declared war on drugs. In 1972,The bipartisan Shafer Commission [National Commission on Marijuana and Drug Abuse], appointed by President Nixon at the direction of Congress [and chaired by former Pennsylvania Governor Raymond Shafer], considered laws regarding marijuana and determined that personal use of marijuana should be decriminalized. Nixon rejected the recommendation, but over the  course of the 1970s, eleven states decriminalized marijuana and most others reduced their penalties (Busted: Americas War on Marijuana., 2010). Possession of marihuana for personal use would no longer be an offense, but marihuana possessed in public would remain contraband subject to summary seizure and forfeiture. Casual distribution of small amounts of marihuana for no remuneration, or insignificant remuneration not involving profit would no longer be an offense (Busted: Americas War on Marijuana., 2010). 1973,â€Å"The Bureau of Narcotics and Dangerous Drugs (BNND) and the Office of Drug Abuse Law Enforcement (ODALE) are merged to form the US Drug Enforcement Agency (DEA)† (420 Milestone History Marijuana, (n.d.), 2010). In November, 1976, a Washington, DC man [Robert Randall] afflicted by glaucoma employed the little-used Common Law Doctrine of Necessity to defend himself against criminal charges of marijuana cultivation† (US v. Randall). â€Å"On November 24, 1976, federal Judge James Washington ruled Randalls use of Marijuana constituted a medical necessity, Judge Washington dismissed criminal charges against Randall. Concurrent with this judicial determination, federal agencies responding to a May, 1976 petition filed by Randall, began providing this patient with licit, FDA-approved access to government supplies of medical marijuana. Randall was the first American to receive marijuana for the treatment of a medical disorder† (National Institute on Drug Abuse [NIDA] 1998).  1978, â€Å"New Mexico passed the first state law recognizing the medical value of marijuana  [Controlled Substances Therapeutic Research Act]. Over the next few years, more than 30 states  passed similar legislation. (Scott, 1994). Voters in California [pass] a state medical  marijuana initiative in 1996. Known as Proposition 215(45 KB), it permits  patients and their primary caregivers, with a physicians recommendation, to pos sess and cultivate marijuana for the treatment of AIDS, cancer, muscular spasticity, migraines, and several other disorders; it also protects them from punishment if they recommend marijuana to their patients (Joy, PhD. Mack, 2011) The New England Journal of Medicine publishes an editorial written by Jerome P. Kassirer, MD, titled Federal Foolishness and Marijuana. The article states: Federal authorities should rescind their prohibition of the medicinal use of marijuana for seriously ill patients and allow physicians to decide which patients to treat. The government should change marijuanas status from that of a Schedule I drug (considered to be potentially addictive and with no current medical use) to that of a Schedule II drug (potentially addictive but with some accepted medical use) and regulate it accordingly† (Kassier, 1997). In January 2004, California passed SB 420, which states the guidelines for growing marijuana. Yes this bill also went through the court system. In May 2008, second district court of appeals ruling in Kelley case that the possession limits set by SB 420 violate the California Constitution because the voters approved Prop 215 can only be amended by the voters. With Prop 215 you can legally be in possession of marijuana and with SB 420 you can legally grow. This has drastically reduce crime in our cities and form a more productive society through its positive uses. In 2013, medical marijuana is a thriving and growing business for all those involved from the growers, to the â€Å"caregivers clubs† with their green cross symbols above their doors (yes like the Red Cross, but green) making it possible for the medical community, and the consumer to know they have found the right place. As of this date there is a total of 18 states and DC now known as Medical Marijuana States. With 11 more states pending legalization to legalize medical marijuana. Now legal for others to seek and receive this healing and lifesaving plant. Since the Government has allowed each state to listen to its people, and as it stands today marijuana is legal and available for all those who have a recommendation card. Now it is not a crime for the terminally ill and sick to gain access to the medication that they so greatly need to function on day-to-day bases. You might wonder, â€Å"How do I know so much or even care  about marijuana being legal†? I am also a member, because I have a recommendation card. I have had mine for about a year now. My doctor prescribed it for me when I told him I was depressed (over the death of my baby boy Marshall) and I did not want to take any manufactured manmade pill and have to worry about the side effects. Medical marijuana has done the trick for me, I take as need by my doctors’ direction. I have to say, that it has saved me. Also The Government, State and City get to collect the taxes and the dispensaries make their money and the clients get their much need lifesaving medication. Crime is down and people are employed, and the Government gets to have their say, but in the end â€Å"We the People† were finally heard, and this little plant is finally back where it belongs. To quote one of my favorite comedians: ~It’s not a war on drugs, it’s a war on personal freedom it’s what it is ok, Keep that in mind at all times. Thank you†~ ~ Bill Hicks~ References Bennett, C. (2010). Historical Timeline Medical Marijuana. Retrieved from http://medicalmarijuana.procon.org/view.resource.php?resourceid=000143 Eddy, M. (2010). Medical Marijuana: Review and Analysis of Federal and State Policies.. Retrieved from Federation of American Scientist/Congressional Research and State Service Reports: http://www.fas.org/sgp/crs/misc/RL33211.pdf Hicks, B. (1996). Lateralus (Album). Retrieved from Tool (Group) Joy, PhD., J., Mack, A. (2011). Marijuana as Medicine Beyond Controversy, 200. Retrieved from http://www.brainz.org/420-milestone-history-marijuana Kari, S. (2011). Historical Timeline Medical Marijuana. Retrieved from http://medicalmarijuana.procon.org/view.resource.php?resourceid=000143 Kassier, J. P. (1997). Federal Foolishness and Marijuana. Retrieved from http://www.brainz.org/420-milestone-history-marijuana McWilliams, P. (1996). Quotes by Peter McWilliams: Finest Quotes. Retrieved from http://www.finestquotes.com/author_quotes_authors-Peter+McWilliams-page-0.html Scott, E. (1994). Marional: The Little Synthetic That Couldn’t. Retrieved from http://www.druglibrary.org/significate-legal-cases.htlm 420 Milestone History Marijuana, (n.d.). (2010). Retrieved from http://www.braniz.org/420-milestone-history-marijuana Busted: â€Å"America’s War on Marijuana. (2010). Retrieved from http://www.pbs.org Historical Timeline Medical Marijuana, (n.d.). (2011). Retrieved from http://www.medicalmarijuana.procon.org/view.resource.php?resourceid=000143 National Institute on Drug Abuse [NIDA]. (1998). Retrieved from Provision of Marijuana and Other Compound for Scientific Research Recommendations of the National Institute on Drug Abuse National Advisory Council, NIDA website US: The Life and Death of Peter McWilliams. (2002). Retrieved from http://www.mapinc.org/drugnews/v00/n948/a03.html

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