Currency Overlay Techniques and Perspectives Essay

Currency Overlay Techniques and Perspectives - Essay Example What are the advantages and disadvantages, or more specifically, the risks and rewards, of several common currency overlay schemes? In â€Å"Mean/Variance Analysis of Currency Overlays† by Philippe Jorion, three of the four most common strategies are discussed and analyzed. These are 1) joint, or unit, currency management, its goal to optimize or hedge the entirety of the underlying assets, be they stocks, bonds, or currencies themselves; 2) partial optimization over the currencies, given a pre-determined position in the core portfolio; and 3) a separate optimization over currencies. In unit or joint hedging, it is assumed that â€Å"the manager has expertise in many asset classes and can structure a portfolio to account for correlations between assets and currencies,† (Jorion, 1994). Partial optimization manages currencies â€Å"separately from the core portfolio, but the manager still controls total portfolio risk.† Employing the method of separate optimization means to manage the currencies â€Å"completely independently of the rest of the portfolio,† even going so far as to measure their performance against a separate benchmark or hire a separate currency overlay manager to deal with this part of the portfolio as opposed to the equity manager. In the unit hedging approach, the tools work together to maximize the performance in light of the unique composition of the portfolio. Clearly, if done properly, this is the optimal approach.

Google Inc. is an American multinational corporation Essay Example for Free

Google Inc. is an American multinational corporation Essay These include search, cloud computing, software, and online advertising technologies. Most of its profits are derived from AdWords. Google was founded by Larry Page and Sergey Brin while they were Ph.D. students at Stanford University. Together they own about 16 percent of its shares. They incorporated Google as a privately held company on September 4, 1998. An initial public offering followed on August 19, 2004. Its mission statement from the outset was to organize the worlds information and make it universally accessible and useful, and its unofficial slogan was Dont be evil. In 2006 Google moved to headquarters in Mountain View, California, nicknamed the Googleplex. Rapid growth since incorporation has triggered a chain of products, acquisitions and partnerships beyond Googles core search engine. It offers online productivity software including email, an office suite, and social networking . Desktop products include applications for web browsing, organizing and editing photos, and instant messaging. The company leads the development of the Android mobile operating system and the browser-only Chrome OS for a netbook known as a Chromebook. Google has moved increasingly into communications hardware: it partners with major electronics manufacturers in production of its high-end Nexus devices and acquired Motorola Mobility in May 2012. In 2012, a fiber-optic infrastructure was installed in Kansas City to facilitate a Google Fiber broadband service. The corporation has been estimated to run more than one million servers in data centers around the world and to process over one billion search requests and about 24 petabytes of user-generated data each day. In December 2012 Alexa listed google.com as the most visited website in the world. Numerous Google sites in other languages figure in the top one hundred, as do several other Google-owned sites such as YouTube and Blogger. Its market dominance has led to criticism over issues including copyright, censorship, and privacy. History Google began in January 1996 as a research project by Larry Page and Sergey Brin when they were both PhD students at Stanford University in Stanford, California. While conventional search engines ranked results by counting how many times the search terms appeared on the page, the two theorized about a  better system that analyzed the relationships between websites. They called this new technology PageRank; it determined a websites relevance by the number of pages, and the importance of those pages, that linked back to the original site. A small search engine called RankDex from IDD Information Services designed by Robin Li was, since 1996, already exploring a similar strategy for site-scoring and page ranking. The technology in RankDex would be patented and used later when Li founded Baidu in China. Page and Brin originally nicknamed their new search engine BackRub, because the system checked backlinks to estimate the importance of a site. Eventually, they changed the name to Google, originating from a misspelling of the word googol, the number one followed by one hundred zeros, which was picked to signify that the search engine was intended to provide large quantities of information. Originally, Google ran under Stanford Universitys website, with the domains google.stanford.edu and z.stanford.edu. The domain name for Google was registered on September 15, 1997, and the company was incorporated on September 4, 1998. It was based in a friends . In January 2013, Google announced it had earned $50 billion in annual revenue for the year of 2012. This marked the first time the company had reached this feat, topping their 2011 total of $38 billion. Financing and initial public offering The first funding for Google was an August 1998 contribution of from Andy Bechtolsheim, co-founder of Sun Microsystems, given before Google was incorporated. Early in 1999, while graduate students, Brin and Page decided that the search engine they had developed was taking up too much time and distracting their academic pursuits. They went to Excite CEO George Bell and offered to sell it to him for $1 million. He rejected the offer and later criticized Vinod Khosla, one of Excites venture capitalists, after he negotiated Brin and Page down to $750,000. On June 7, 1999, a $25 million round of funding was announced, with major investors including the venture capital firms Kleiner Perkins Caufield Byers and Sequoia Capital. The company offered 19,605,052 shares at a price of $85 per share. Shares were sold in an online auction format using a system built by Morgan Stanley and Credit Suisse, underwriters for the deal. The sale of $1.67 billion gave Google a market capitalization of more than $23 billion. The vast majority  of the 271 million shares remained under the control of Google, and many Google employees became instant paper millionaires. Yahoo!, a competitor of Google, also benefited because it owned 8.4 million shares of Google before the IPO took place. There were concerns that Googles IPO would lead to changes in company culture. Reasons ranged from shareholder pressure for employee benefit reductions to the fact that many company executives would become instant paper millionaires. As a reply to this concern, co-founders Sergey Brin and Larry Page promised in a report to potential investors that the IPO would not change the companys culture. In 2005, articles in The New York Times and other sources began suggesting that Google had lost its anti-corporate, no evil philosophy. In an effort to maintain the companys unique culture, Google designated a Chief Culture Officer, who also serves as the Director of Human Resources. The purpose of the Chief Culture Officer is to develop and maintain the culture and work on ways to keep true to the core values that the company was founded on: a flat organization with a collaborative environment. Google has also faced allegations of sexism and ageism from former employees. The stock performed well after the IPO, with shares hitting $700 for the first time on October 31, 2007, primarily because of strong sales and earnings in the online advertising market. The surge in stock price was fueled mainly by individual investors, as opposed to large institutional investors and mutual funds. The next year, against Page and Brins initial opposition toward an advertising-funded search engine, Google began selling advertisements associated with search keywords. When the company changed names to Overture Services, it sued Google over alleged infringements of the companys pay-per-click and bidding patents. Overture Services would later be bought by Yahoo! and renamed Yahoo! Search Marketing. The case was then settled out of court; Google agreed to issue shares of common stock to Yahoo! in exchange for a perpetual license. In 2001, Google received a patent for its PageRank mechanism. The patent was officially assigned to Stanford University and lists Lawrence Page as the inventor. In 2003, after outgrowing two other locations, the company leased an office complex from Silicon Graphics at 1600 Amphitheatre Parkway in Mountain View, California. The complex became known as the Googleplex, a play on the word googolplex, the number one followed by a googol zeroes. The Googleplex interiors were designed by Clive Wilkinson Architects. Three  years later, Google bought the property from SGI for $319 million. By that time, the name Google had found its way into everyday language, causing the verb google to be added to the Merriam-Webster Collegiate Dictionary and the Oxford English Dictionary, denoted as to use the Google search engine to obtain information on the Internet. 2013 onward Google announced the launch of a new company called Calico on September 19, 2013, which will be led by Apple chairman Arthur Levinson. In the official public statement, Page explained that the health and wellbeing company will focus on the challenge of ageing and associated diseases. As of September 2013, Google operates 70 offices in more than 40 countries. Google celebrated its 15-year anniversary on September 27, 2013, although it has used other dates for its official birthday. The reason for the choice of September 27 remains unclear, and a dispute with rival search engine Yahoo! Search in 2005 has been suggested as the cause. The Alliance for Affordable Internet was launched in October 2013 and Google is part of the coalition of public and private organisations that also includes Facebook, Intel and Microsoft. Led by Sir Tim Berners-Lee, the A4AI seeks to make Internet access more affordable so that access is broadened in the developing world, where only 31% of people are online. Google will help to decrease internet access prices so that they fall below the UN Broadband Commissions worldwide target of 5% of monthly income. The corporations consolidated revenue for the third quarter of 2013 is reported in mid-October 2013 as US$14.89 billion, a 12 percent increase compared to the previous quarter. Googles Internet business was responsible for US$10.8 billion of this total, with an increase in the number of users clicks on advertisements. Acquisitions and partnerships Since 2001, Google has acquired many companies, primarily small venture capital-funded firms. In 2004, Google acquired Keyhole, Inc. The start-up company developed a product called Earth Viewer that gave a three-dimensional view of the Earth. Google renamed the service to Google Earth in 2005. Google acquired Urchin Software in April 2005, using their Urchin on Demand product to create Google Analytics in 2006. In October 2006, Google announced that it had acquired the video-sharing site YouTube  for US$1.65 billion in Google stock, and the deal was finalized on November 13, 2006. Google does not provide detailed figures for YouTubes running costs, and YouTubes revenues in 2007 were noted as not material in a regulatory filing. In June 2008, a Forbes magazine article projected the 2008 YouTube revenue at US$200 million, noting progress in advertising sales. On April 13, 2007, Google reached an agreement to acquire DoubleClick for $3.1 billion, giving Google valuable relationships that DoubleClick had with Web publishers and advertising agencies. Later that same year, Google purchased GrandCentral for $50 million. The site would later be changed over to Google Voice. On August 5, 2009, Google bought out its first public company, purchasing video software maker On2 Technologies for $106.5 million. Google also acquired Aardvark, a social network search engine, for $50 million, and commented on its internal blog, were looking forward to collaborating to see where we can take it. In April 2010, Google announced it had acquired a hardware startup, Agnilux. In addition to the many companies Google has purchased, the company has partnered with other organizations for research, advertising, and other activities. In 2005, Google partnered with NASA Ames Research Center to build of offices. The offices would be used for research projects involving large-scale data management, nanotechnology, distributed computing, and the entrepreneurial space industry. Google entered into a partnership with Sun Microsystems in October 2005 to help share and distribute each others technologies. The company also partnered with AOL to enhance each others video search services. Googles 2005 partnerships also included financing the new .mobi top-level domain for mobile devices, along with other companies including Microsoft, Nokia, and Ericsson. Google would later launch AdSense for Mobile, taking advantage of the emerging mobile advertising market. Increasing its advertising reach even further, Google and Fox Interactive Media of News Corporation entered into a $900 million agreement to provide search and advertising on the then-popular social networking site MySpace. In 2007, Google began sponsoring NORAD Tracks Santa, displacing former sponsor AOL. NORAD Tracks Santa purports to follow Santa Claus progress on Christmas Eve, using Google Earth to track Santa in 3-D for the first time. Google-owned YouTube gave NORAD Tracks Santa its own channel. In 2008, Google developed a partnership with GeoEye to launch a satellite providing  Google with high-resolution imagery for Google Earth. The satellite was launched from Vandenberg Air Force Base on September 6, 2008. Google also announced in 2008 that it was hosting an archive of Life Magazines photographs. Some of the images in the archive were never published in the magazine. The photos were watermarked and originally had copyright notices posted on all photos, regardless of public domain status. In 2010, Google Energy made its first investment in a renewable energy project, putting $38.8 million into two wind farms in North Dakota. The company announced the two locations will generate 169.5 megawatts of power, enough to supply 55,000 homes. The farms, which were developed by NextEra Energy Resources, will reduce fossil fuel use in the region and return profits. NextEra Energy Resources sold Google a twenty-percent stake in the project to get funding for its development. In February 2010, the Federal Energy Regulatory Commission FERC granted Google an authorization to buy and sell energy at market rates. The order specifically states that Google Energy—a subsidiary of Google—holds the rights for the sale of energy, capacity, and ancillary services at market-based rates, but acknowledges that neither Google Energy nor its affiliates own or control any generation or transmission facilities. The corporation exercised this authorization in September 2013 when it announced that it will purchase all of the electricity produced by the not-yet-built 240-megawatt Happy Hereford wind farm. Also in 2010, Google purchased Global IP Solutions, a Norway-based company that provides web-based teleconferencing and other related services. This acquisition enabled Google to add telephone-style services to its list of products. On May 27, 2010, Google announced it had also closed the acquisition of the mobile ad network AdMob. This occurred days after the Federal Trade Commission closed its investigation into the purchase. Google acquired the company for an undisclosed amount. In July 2010, Google signed an agreement with an Iowa wind farm to buy 114 megawatts of energy for 20 years. On April 4, 2011, The Globe and Mail reported that Google bid $900 million for six thousand Nortel Networks patents. On August 15, 2011, Google made its largest-ever acquisition to-date when announced that it would acquire Motorola Mobility for $12.5 billion subject to approval from regulators in the United States and Europe. In a post on Googles blog, Google Chief Executive and co-founder Larry Page revealed that the acquisition was a  strategic move to strengthen Googles patent portfolio. The companys Android operating system has come under fire in an industry-wide patent battle, as Apple and Microsoft have sued Android device makers such as HTC, Samsung, and Motorola. The merger was completed on the May 22, 2012, after the approval of Peoples Republic of China. This purchase was made in part to help Google gain Motorolas considerable patent portfolio on mobile phones and wireless technologies to help protect it in its ongoing patent disputes with other companies, mainly Apple and Microsoft After the acquisition closed, Google began to restructure the Motorola business to fit Googles strategy. On August 13, 2012, Google announced plans to layoff 4000 Motorola Mobility employees. On December 10, 2012, Google sold the manufacturing operations of Motorola Mobility to Flextronics for $75 million. As a part of the agreement, Flextronics will manufacture undisclosed Android and other mobile devices. On December 19, 2012, Google sold the Motorola Home business division of Motorola Mobility to Arris Group for $2.35 billion in a cash-and-stock transaction. As a part of this deal, Google acquired a 15.7% stake in Arris Group valued at $300 million. On June 5, 2012, Google announced it acquired Quickoffice, a company widely known for their mobile productivity suite for both iOS and Android. Google plans to integrate Quickoffices technology into its own product suite. On February 6, 2013, Google announced it had acquired Channel Intelligence for $125 million. Channel Intelligence, a technology company that helps customers buy products online, is active globally in 31 different countries and works with over 850 retailers. Google will use this technology to enhance its e-commerce business. The official confirmation of Googles acquisition of the Israel-based startup Waze occurred in June 2013. Waze is promoted as a community-based traffic and navigation app. Following the acquisition of Waze, Google submitted a 10-Q filing with the Securities Exchange Commission that revealed that the corporation spent US$1.3 billion on acquisitions during the first half of 2013. The filing also revealed that the Waze acquisition cost Google US$966 million, instead of the US$1.1 billion figure that was initially presented in media sources. The 2012 acquisition of WIMM Labs, a company that previously made an Android-powered smartwatch, was confirmed in August 2013. As of August 31, 2013, Google has not publicly commented on the news concerning WIMM Labs. The acquisition of  Flutter, a creator of hand gesture recognition technology, was confirmed by the corporation in early October 2013. The reported price is US$40 million and Google spokesperson stated: Were really impressed by the Flutter teams ability to design new technology based on cutting-edge research. Flutters technology allows users to enact hand gestures to control navigation for apps such as iTunes, Windows Media Player, and Winamp. Google data centers As of 2011, Google Inc. owned and operated six data centers across the U.S., plus one in Finland and another in Belgium. On September 28, 2011, the company announced plans to build three data centers at a cost of more than $200 million in Asia and purchased the land for them. Google said they will be operational within two years. Products and services Advertising For the 2006 fiscal year, the company reported $10.492 billion in total advertising revenues and only $112 million in licensing and other revenues. In 2011, 96% of Googles revenue was derived from its advertising programs. Using technology from the company DoubleClick, Google can determine user interests and target advertisements so they are relevant to their context and the user that is viewing them. Google Analytics allows website owners to track where and how people use their website, for example by examining click rates for all the links on a page. Google advertisements can be placed on third-party websites in a two-part program. Googles AdWords allows advertisers to display their advertisements in the Google content network, through either a cost-per-click or cost-per-view scheme. The sister service, Google AdSense, allows website owners to display these advertisements on their website and earn money every time ads are clicked. One of the criticisms of this program is the possibility of click fraud, which occurs when a person or automated script clicks on advertisements without being interested in the product, causing the advertiser to pay money to Google unduly. Industry reports in 2006 claimed that approximately 14 to 20 percent of clicks were fraudulent or invalid. In February 2003, Google stopped showing the advertisements of Oceana, a non-profit organization protesting a major cruise ships sewage treatment practices. Google cited its editorialpolicy at the time, stating Google does not accept advertising if the ad or site advocates against other individuals, groups, or organizations. The policy was later changed. In June 2008, Google reached an advertising agreement with Yahoo!, which would have allowed Yahoo! to feature Google advertisements on its web pages. The alliance between the two companies was never completely realized because of antitrust concerns by the U.S. Department of Justice. As a result, Google pulled out of the deal in November 2008. In an attempt to advertise its own products, Google launched a website called Demo Slam, developed to demonstrate technology demos of Google Products. Search engine According to market research published by comScore in November 2009, Google Search is the dominant search engine in the United States market, with a market share of 65.6%. Google indexes billions of web pages, so that users can search for the information they desire through the use of keywords and operators. In 2003, The New York Times complained about Googles indexing, claiming that Googles caching of content on its site infringed its copyright for the content. In this case, the United States District Court of Nevada ruled in favor of Google in Field v. Google and Parker v. Google. The publication 2600: The Hacker Quarterly has compiled a list of words that the web giants new instant search feature will not search. Google Watch has criticized Googles PageRank algorithms, saying that they discriminate against new websites and favor established sites. The site has also alleged that there are connections between Google and the National Security Agency and the Central Intelligence Agency. Google also hosts Google Books. The company began scanning books and uploading limited previews, and full books where allowed, into its new book search engine. The Authors Guild, a group that represents 8,000 U.S. authors, filed a class action suit in a New York City federal court against Google in 2005 over this service. Google replied that it is in compliance with all existing and historical applications of copyright laws regarding books. Google eventually reached a revised settlement in 2009 to limit its scans to books from the U.S., the UK, Australia, and Canada. Furthermore, the Paris Civil Court ruled against Google in late 2009, asking it to remove the works of La Martinià ¨re from its database. In competition with Amazon.com, Google sells digital versions  of new books. On July 21, 2010, in response to Bing, Google updated its image search to display a streaming sequence of thumbnails that enlarge when pointed at. Though web searches still appear in a batch per page format, on July 23, 2010, dictionary definitions for certain English words began appearing above the linked results for web searches. The Hummingbird update to the Google search engine was announced in September 2013. The update was introduced over the month prior to the announcement and allows users ask the search engine a question in natural language rather than entering keywords into the search box. Productivity tools Gmail, a free webmail service provided by Google, was launched as an invitation-only beta program on April 1, 2004, The service was upgraded from beta status on July 7, 2009, at which time it had 146 million users monthly. The service was the first online email service with one gigabyte of storage. It was also the first to keep emails from the same conversation together in one thread, similar to an Internet forum. The service offers over 15 GB of free storage, shared with other Google Apps, with additional storage ranging from 20 GB to 16 TB available for per 1 GB per year. Gmail uses AJAX, a programming technique that allows web pages to be interactive without refreshing the browser. Steve Ballmer, Liz Figueroa, Mark Rasch, and the editors of Google Watch have criticised the privacy of Gmail, but Google claims that mail sent to or from Gmail is never read by a human being beyond the account holder and is only used to improve relevance of advertisements. In 2004, Google started opensource software project hosting, called Google Code, which allows developers to download incomplete programs at no charge. Google Docs, another part of Googles productivity suite, allows users to create, edit, and collaborate on documents in an online environment, similar to Microsoft Word. The service was originally called Writely, but was obtained by Google on March 9, 2006, and was released as an invitation-only preview. On June 6 after the acquisition, Google created an experimental spreadsheet editing program, which was combined with Google Docs on October 10. Enterprise products Google Search Appliance was launched in February 2002, targeted toward providing search technology for larger organizations. Google Apps allows  organizations to bring Googles web application offerings, such as Gmail and Google Docs, into their own domains. The service is available in several editions: a basic free edition, Google Apps for Business, Google Apps for Education, and Google Apps for Government. In the same year Google Apps was launched, Google acquired Postini and proceeded to integrate the companys security technologies into Google Apps under the name Google Postini Services. Other products Google Translate is a server-side machine translation service, which can translate between 35 different languages. The software uses corpus linguistics techniques, where the program learns from professionally translated documents, specifically UN and European Parliament proceedings. Google launched its Google News service in 2002, an automated service which summarizes news articles from various websites. In March 2005, Agence France Presse sued Google for copyright infringement in federal court in the District of Columbia, a case which Google settled for an undisclosed amount in a pact that included a license of the full text of AFP articles for use on Google News. In 2006, Google made a bid to offer free wireless broadband access throughout the city of San Francisco along with Internet service provider EarthLink. Large telecommunications companies such as Comcast and Verizon opposed the efforts, claiming it was unfair competition and that cities would be violating their commitments to offer local monopolies to these companies. In his testimony before Congress on network neutrality in 2006, Googles Chief Internet Evangelist Vint Cerf blamed the tactics on the fact that nearly half of all consumers lack choice in broadband providers. Google currently offers free wi-fi access in its hometown of Mountain View, California. In 2010, Google announced the Google Fiber project with plans to build an ultra-high-speed broadband network for 50,000 to 500,000 customers in one or more American cities. On March 30, 2011, Google announced that Kansas City, Kansas would be the first community where the new network would be deployed. In July 2012, Google completed the construction of a fiber-optic broadband internet network infrastructure in Kansas City, and after building an infrastructure, Google announced pricing for Google Fiber. The service will offer three options including a free broadband internet option, a 1Gbit/s internet option for $70 per month, and a version that  includes television service for $120 per month. The project, called Android, turned out not to be a phone but an operating system for mobile devices, which Google acquired and then released as an open source project under the Apache 2.0 license. Google provides a software development kit for developers so applications can be created to be run on Android-based phones. In September 2008, T-Mobile released the G1, the first Android-based phone. On January 5, 2010, Google released an Android phone under its own company name called the Nexus One. A report in July 2013 stated that Googles share of the global smartphone market, led by Samsung products, was 64% in March 2013. Other projects Google has worked on include a new collaborative communication service, a web browser, and a mobile operating system. The first of these was first announced on May 27, 2009. The company described Google Wave as a product that helps users communicate and collaborate on the web. The service is Googles email redesigned, with realtime editing, the ability to embed audio, video, and other media, and extensions that further enhance the communication experience. Google Wave was initially in a developers preview, where interested users had to be invited to test the service, but was released to the general public on May 19, 2010, at Googles I/O keynote. On September 1, 2008, Google pre-announced the upcoming availability of Google Chrome, an open source web browser, which was then released on September 2, 2008. On July 7, 2009, Google announced Google Chrome OS, an open source Linux-based operating system that includes only a web browser and is designed to log users into their Google account. Google Goggles is a mobile application available on Android and iOS used for image recognition and non-text-based search. In addition to scanning QR codes, the app can recognize historic landmarks, import business cards, and solve Sudoku puzzles. While Goggles could originally identify people as well, Google has limited that functionality as a privacy protection. In 2011, Google announced Google Wallet, a mobile application for wireless payments. In late June 2011, Google soft-launched a social networking service called Google+. On July 14, 2011, Google announced that Google+ had reached 10 million users just two weeks after it was launched in this limited trial phase. After four weeks in operation, it reached 25 million users. At a launch event on July 24, 2013 in San Francisco, U.S., a newer version of the Nexus 7 Google tablet device was released to the public, alongside the  Chromecast dongle that allows users to stream YouTube and Netflix videos via smartphones. In 2013 Google launched Google Shopping Express, a delivery service initially available only in San Francisco and Silicon Valley. Moto X  Speaking at the D11 conference in Palos Verdes, U.S. in late May 2013, Motorola CEO Dennis Woodside, a former Google employee, announced that a new mobile device will be built by his company, which is wholly owned by Google, at a 500,000 square-feet facility in Texas, U.S. formerly used by the Nokia company. The facility will employ 2,000 people by August 2013 and the new phone, named the Moto X, will be available to the public in October 2013. The Moto X features Google Now software, and an array of sensors and two microprocessors that will mean that users can â€Å"interact with in very different ways than you can with other devices,† in the words of Woodside. Media reports suggest that the phone will be able to activate functions preemptively based on an awareness of what the user is doing at any given moment. Corporate affairs and culture On Fortune magazines list of best companies to work for, Google ranked first in 2007, 2008 and 2012 and fourth in 2009 and 2010. Google was also nominated in 2010 to be the worlds most attractive employer to graduating students in the Universum Communications talent attraction index. Googles corporate philosophy includes principles such as you can make money without doing evil, you can be serious without a suit, and work should be challenging and the challenge should be fun. Employees After the companys IPO, founders Sergey Brin and Larry Page and CEO Eric Schmidt requested that their base salary be cut to $1. Subsequent offers by the company to increase their salaries have been turned down, primarily because their main compensation continues to come from owning stock in Google. Before 2004, Schmidt made $250,000 per year, and Page and Brin each received an annual salary of $150,000. In 2007 and early 2008, several top executives left Google. In October 2007, former chief financial officer of YouTube Gideon Yu joined Facebook along with Benjamin Ling, a high-ranking engineer. In March 2008, Sheryl Sandberg, then vice-president of global online sales and operations, began her position as chief operating officer  of Facebook. At the same time, Ash ElDifrawi, formerly head of brand advertising, left to become chief marketing officer of Netshops. On April 4, 2011, Larry Page became CEO and Eric Schmidt became Executive Chairman of Google. In July 2012, Googles first female employee, Marissa Mayer, left Google to become Yahoo!s CEO. As a motivation technique, Google uses a policy often called Innovation Time Off, where Google engineers are encouraged to spend 20% of their work time on projects that interest them. Some of Googles newer services, such as Gmail, Google News, Orkut, and AdSense originated from these independent endeavors. In a talk at Stanford University, Marissa Mayer, Googles Vice President of Search Products and User Experience until July 2012, showed that half of all new product launches at the time had originated from the Innovation Time Off. Googleplex  Googles headquarters in Mountain View, California, is referred to as the Googleplex, a play on words on the number googolplex and the headquarters itself being a complex of buildings. The lobby is decorated with a piano, lava lamps, old server clusters, and a projection of search queries on the wall. The hallways are full of exercise balls and bicycles. Each employee has access to the corporate recreation center. Recreational amenities are scattered throughout the campus and include a workout room with weights and rowing machines, locker rooms, washers and dryers, a massage room, assorted video games, table football, a baby grand piano, a billiard table, and ping pong. In addition to the recreation room, there are snack rooms stocked with various foods and drinks, with special emphasis placed on nutrition. Free food is available to employees 24/7, with paid vending machines prorated favoring nutritional value. In 2006, Google moved into of office space in New York City, at 111 Eighth Avenue in Manhattan. The office was specially designed and built for Google and houses its largest advertising sales team, which has been instrumental in securing large partnerships. As of February 2012, a significant engineering team is based in New York City, and has been responsible for more than 100 engineering projects, including Google Maps, Google Spreadsheets. As of September 2013, Googles East Coast office is located at 76 Ninth Ave, New York City, New York. In November 2006, Google opened offices on Carnegie Mellons campus in Pittsburgh, focusing on shopping-related advertisement coding and smartphone applications and  programs. By late 2006, Google also established a new headquarters for its AdWords division in Ann Arbor, Michigan. Other office locations in the U.S. include Ann Arbor, Michigan; Atlanta, Georgia; Austin, Texas; Boulder, Colorado; Cambridge, Massachusetts; New York City; San Francisco, California; Seattle, Washington; Reston, Virginia, and Washington, D.C. Furthermore, Google has several international offices. In October 2006, the company announced plans to install thousands of solar panels to provide up to 1.6 megawatts of electricity, enough to satisfy approximately 30% of the campus energy needs. The system will be the largest solar power system constructed on a U.S. corporate campus and one of the largest on any corporate site in the world. The idea of trimming lawns using goats originated from R. J. Widlar, an engineer who worked for National Semiconductor. Google has faced accusations in Harpers Magazine of being an energy glutton. The company was accused of employing its Dont be evil motto and its public energy-saving campaigns to cover up or make up for the massive amounts of energy its servers require. Easter eggs and April Fools Day jokes Google has a tradition of creating April Fools Day jokes. On April 1, 2000, Google MentalPlex allegedly featured the use of mental power to search the web. In 2007, Google announced a free Internet service called TiSP, or Toilet Internet Service Provider, where one obtained a connection by flushing one end of a fiber-optic cable down their toilet. Also in 2007, Googles Gmail page displayed an announcement for Gmail Paper, allowing users to have email messages printed and shipped to them. In 2008, Google announced Gmail Custom time where users could change the time that the email was sent. In 2010, Google changed its company name to Topeka in honor of Topeka, Kansas, whose mayor changed the citys name to Google for a short amount of time in an attempt to sway Googles decision in its new Google Fiber Project. In 2011, Google announced Gmail Motion, an interactive way of controlling Gmail and the computer with body movements via the users webcam. Googles services contain easter eggs, such as the Swedish Chefs Bork bork bork, Pig Latin, Hacker or leetspeak, Elmer Fudd, Pirate, and Klingon as language selections for its search engine. The search engine calculator provides the Answer to the Ultimate Question of Life, the  Universe, and Everything from Douglas Adams The Hitchhikers Guide to the Galaxy. When searching the word recursion, the spell-checkers result for the properly spelled word is exactly the same word, creating a recursive link. When searching for the word anagram, meaning a rearrangement of letters from one word to form other valid words, Googles suggestion feature displays Did you mean: nag a ram? In Google Maps, searching for directions between places separated by large bodies of water, such as Los Angeles and Tokyo, results in instructions to kayak across the Pacific Ocean. During FIFA World Cup 2010, search queries including World Cup and FIFA caused the Goooogle page indicator at the bottom of every result page to read Gooooal! instead. Philanthropy In 2004, Google formed the not-for-profit philanthropic Google.org, with a start-up fund of $1 billion. The mission of the organization is to create awareness about climate change, global public health, and global poverty. One of its first projects was to develop a viable plug-in hybrid electric vehicle that can attain 100 miles per gallon. Google hired Larry Brilliant as the programs executive director in 2004, and the current director is Megan Smith. In 2008 Google announced its project 10100 which accepted ideas for how to help the community and then allowed Google users to vote on their favorites. After two years of silence, during which many wondered what had happened to the program, Google revealed the winners of the project, giving a total of ten million dollars to various ideas ranging from non-profit organizations that promote education to a website that intends to make all legal documents public and online. In 2011, Google donated 1 million euros to International Mathematical Olympiad to support the next five annual International Mathematical Olympiads . On July 2012, Google launched a Legalize Love campaign in support of gay rights. Tax avoidance   Google uses various tax avoidance strategies. Out of the five largest American technology companies it pays the lowest taxes to the countries of origin of its revenues. The company accomplishes this partly by licensing technology through subsidiaries in Ireland, Bermuda, the Bahamas, and the Netherlands. This has reportedly sparked a French investigation into Googles transfer pricing practices. Following criticism of the amount of  corporate taxes that Google paid in the United Kingdom, Chairman Eric Schmidt said, Its called capitalism. We are proudly capitalistic. During the same December 2012 interview Schmidt confirmed that the company had no intention of paying more to the UK exchequer. In 2013, Schmidt responded to questions about taxes paid in the UK by pointing to the advertising fees Google charged UK companies as a source of economic growth. Google Vice president Matt Brittin testified to the Public Accounts Committee of the UK house of commons that his UK sales team made no sales and hence owed no sales taxes to the UK. Environment Since 2007, Google has aimed for carbon neutrality in regard to its operations. In June 2013, the Washington Post reported that Google had donated US$50,000 to the Competitive Enterprise Institute, a libertarian think tank. In July 2013, it was reported that Google had hosted a fundraising event for Oklahoma Senator Jim Inhofe, who has called climate change a hoax. See also Comparison of web search engines Criticism of Google Dont Be Evil Google Google Balloon Internet Google Catalogs Google China Google Chrome Experiments Google logo Google platform Google Ventures – venture capital fund Google X Google+ Googlebot – web crawler Googlization List of Google domains List of mergers and acquisitions by Google Ungoogleable References External links not add links at the Internet Archive at Hoovers Bibliography: Wikipedia

The Israeli and Palestinian Gaza Conflict Essay -- International Conf

Broad international consensus regarding the political and legal controversies of the Israeli and Palestinian Gaza conflict has been minimal at best. At its worst it has fueled the controversies created by the United Nations Fact Finding Mission, through which, both sides maintain their positions and justification for their actions. In ordered to obtain an opinion on this issue one must examine the factual historical background of the Gaza Conflict. By identifying the major legal and political discrepancies, observing the perspectives of those who defend Israeli actions, and those who have a strong critique against those actions we can grasp the complexity of this issue and make an assessment of actions on both sides. In 2005 Israel withdrew forces from the Gaza Strip but did so with conditions toward Palestinian authorities. It must put an end to terror tactics in and around Israeli territory. This seemed a promising step toward Palestinian and Israeli peace until 2006 when the political group Hamas took power and declared that it would not recognize the existence of Israel. It rejected the Oslo Accords and Arab Peace Initiative and separated itself from negotiating with Israel. Since coming to power Hamas had openly advocated for attacks against Israel. In 2007 Hamas’s influence spread to the Gaza Strip, that same year Israel implemented a blockade that crippled Gaza’s economic activity which raised ethical and moral political questions in the international community. In early 2008, after many mortars and rockets were fired across the border into Israel, the air force and defense forces retaliate taking the lives of many Palestinian civilians and militants. Israeli defense officia ls viewed these attacks as Hamas breaking the P... ...onflict have been addressed legally, although they have not been respected by either side which hinders the legitimacy of international authority. A major problem that I have observed is the inability of the United Nations Security Council to ascribe certainty to all laws broken and provide punishment to both sides. This lack of legal authority will continue to plague the progress both politically and within the legal institutions being used to approach the situation. Resolution and absolution of the definitions and particulates of these major issues are necessary to achieve lasting peace in the region and eventual coexistence. Works Cited Alan Dershowitz â€Å"The Case Against the Goldstone Report† â€Å"The UN Gaza Report: A Substantive Critique† Ambassador Dore Gold Noura Erakat â€Å"It’s Not Wrong, It’s Illegal† â€Å"United Nations Fact Finding Mission† Richard Goldstone

Formal Letter in the Public services Essay

This is a formal letter used to send information out to external parties. This specific letter is used to engage students in an exciting opportunity and potential career option. Letters are used by all in the public services and this letter that I have has been given is used by someone in the armed forces as they need to tell the headteachers about an excellent challenge for their students. Letters like this are used to inform someone about a meeting that will be happing at a certain time and day and where it will be at. In the RAF this would be a normal form of communication that they would use to inform one another of important dates coming up, but in the normal day an e-mail would suffice. Firstly on this letter the name of the Sergeant sending it is highlighted in bold this is so it will get the reader’s attention straight away and the reader will want to continue to read it, it will also show who they need to respond to in order to get the day out for their students and then underneath it states that it is from the RAF so this is letting the person know where the letter has come from and who they are, and then underneath this there is other information about where the letter will be sent off to and who will be getting the letter, this information will let the person that is delivering it know where it has to go to as it has the street name and the post code. Secondly they have information about the person that it has been sent to they use lines to split it up so that they page looks better and the information will be easier to read, Tony splits it up because he does not want the reader to think that there will be lots of information to read through which often puts readers off reading it as they think it is going to be too much, and too much effort. This also would get the readers to view the letter as the reader will think it is important and will want to know the information that he has written in on the letter. Thirdly the information they have put in the other side of the split up box is about if the person would like to write back to them, so if they need more information or just want to ask them something about what they have written in the letter they can contact them on the provided details and use the reference so Tony knows immediately what they are talking about. This information is also given because they will need to reply to say that they would.

Electromechanical Energy Conversion

Introduction Chapter 3 Electromechanical Energy Conversion Topics to cover: 1. Introduction 3. Force and Torque 5. Friction 2. Electro-Motive Force (EMF) 4. Doubly-Excited Actuators 6. Mechanical Components Introduction (Cont. ) For energy conversion between electrical and mechanical forms, electromechanical devices are developed. In general, electromechanical energy conversion devices can be divided into three categories: – Transducers (for measurement and control), which transform signals of different forms. Examples are microphones, pickups, and speakers Force producing devices (linear motion devices), which produce forces mostly for linear motion drives, such as relays, solenoids (linear actuators), and electromagnets. – Continuous energy conversion equipment, which operate in rotating mode. A device would be known as a generator if it convert mechanical energy into electrical energy, or as a motor if it does the other way around (from electrical to mechanical). Lor entz Force & EMF Lorentz force is the force on a point charge due to electromagnetic fields. It is given by the following equation in terms of the electric and magnetic fieldsF ? q(E? v? B) The induced emf in a conductor of length l moving with a speed v in a uniform magnetic field of flux density B can be determined by a e ? ?v? B? ? dl ? b In a coil of N turns, the induced emf can be calculated by e ? ? Concept map of electromechanical system modeling d? dt where ? is the flux linkage of the coil and the minus sign indicates that the induced current opposes the variation of the field. It makes no difference whether the variation of the flux linkage is a result of the field variation or coil movement. EMF EMF – Example: EMF in a Linear Actuator – Example SolutionSketch L(x) and calculate the induced emf in the excitation coil for a linear actuator shown below. Assuming infinite permeability for the magnetic core and ignore the fringing effect, we can express the self inductance of the coil as L? x ? ? where Rg ? x? ? N2 ?o N 2 l ?d ? x? ? Rg ? x ? 2g L(x) L(0) 2g ?o ? d ? x? l O is the air gap reluctance. ? e? ? N 2l d? d ? Li ? di dL dx di ? ? L ? i =L? x ? ? i o v 2g dt dt dt dx dt dt EMF – A Single Conductor in a Uniform Field e ? ? I dc If i=Imsin? t , e? Force and Torque – Example Solution (Cont. ) If i=Idc , ?o N 2 l 2g ? Im ? Im ?o N 2l 2gFor a single conductor in a uniform magnetic field, we have v ? d ? x I m cos ? t ? vI m sin ? t ?o N l 2 2g ?o N 2 l 2g d Fm ? Il ? B ?o N 2 l In a rotating system, the torque about an axis can be calculated by 2g d ? x cos? t ? v sin ? t ? ? T? r ? Fm v ? ? ? ? d ? x ? ? ? ? d ? x ? 2 ? 2 ? v 2 cos t ? arctan? ? where r is the radius vector from the axis towards the conductor. B Fm l I X Force and Torque – A Singly Excited Actuator Consider a singly excited linear actuator. After a time interval dt, we notice that the plunger has moved for a distance dx under the action of the force F.The mechanical work done by the force acting on the plunger during this time interval is thus dWm ? Fdx Force and Torque – A Singly Excited Actuator The amount of electrical energy that has been transferred into the magnetic field and converted into the mechanical work during dt is dWe ? dWf ? dWm ; dWe ? eidt ? vidt? Ri2dt e ? d? dt ? v ? Ri Because dWf ? dW ? dW ? eidt ? Fdx ? id? ? Fdx e m we obtain From the total differential dW f ? ? , x ? ? ? W f , x ? i? Therefore, ? W f , x ? d? ? and ? W f , x ? ?x F dx ?W f ? ? , x ? ?x Force and Torque Force and Torque – A Singly Excited Actuator (Cont. ) A Singly Excited Actuator (Cont. ) From the knowledge of electromagnetics, the energy stored in a magnetic field can be expressed as ? Wf ? ? , x? ? ? i? ? , x? d? In the diagram below, it is shown that the magnetic energy is equivalent to the area above the magnetization or ? -i curve. Mathematically, if we define the area underneath the magnetization curve a s the coenergy (which does not exist physically), i. e. 0 For a magnetically linear (with a constant permeability or a straight line magnetization curve such that the inductance of the coil is independent of the excitation current) system, the above expression becomes 1 ? Wf ? ?, x? ? 2 L? x? and the force acting on the plunger is then F ?Wf ? ?, x? ?x 1 ? ? ? dL? x? 1 2 dL? x? ?i 2 ? L? x? ? dx 2 dx ? 2 we can obtain Wf ‘ ? i, x? ? i? ?Wf , x? ? Wf (? , x ) dW f ‘ ? i , x ? ? ? di ? id? ? dW f ? ? , x ? ? ? di ? Fdx Therefore, ? ?W f ‘ ? i , x ? ?i ? W f ‘ ? i , x ? ?i di ? and ?W f ‘ ? i , x ? ?x F? dx ? W f ‘ ? i , x ? ?x (? , i ) Wf ‘ ( i, x ) O i Force and Torque Force and Torque – A Singly Excited Actuator (Cont. ) – Example 1 Calculate the force acting on the plunger of a linear actuator as shown below. From the definition, the coenergy can be calculated by iWf ‘ ? i , x? ? ? ? ? i , x? di ? 0 Wf ‘ ? i, x? ? ? (? , i ) Wf (? , x ) For a magnetically linear system, the above expression becomes Rg 1 L? x? i 2 2 Ni Wf ‘ ( i, x ) Rg and the force acting on the plunger is then F? ?Wf ‘ ? i , x ? ?x 1 dL? x ? ? i2 dx 2 O i (c) Force and Torque Force and Torque – Singly Excited Rotating Actuator – Solution to Example 1 Assume infinite permeability for the actuator core. The self inductance of the excitation winding can be readily obtained as L? x? ? N 2 ? o N 2l? d ? x? ? 2Rg 2g Therefore, the force acting on the plunger is F? ? Rg Ni ?l 1 2 dL ? x ? 2 i ? ? o ? Ni ? 2 dx 4gThe minus sign of the force indicates that the direction of the force is to reduce the displacement so as to reduce the reluctance of the air gaps. Since this force is caused by the variation of magnetic reluctance of the magnetic circuit, it is known as the reluctance force. Rg The singly excited linear actuator becomes a singly excited rotating actuator if the linearly movable plunger is repla ced by a rotor. Through a derivation similar to that for a singly excited linear actuator, one can readily obtain that the torque acting on the rotor can be expressed as the negative partial derivative of the energy stored in the agnetic field against the angular displacement or as the positive partial derivative of the coenergy against the angular displacement. Force and Torque Solution b) Voltage induced – Example †¢ The magnetically-linear electro-mechanical circuit breaker as shown is singly-excited via a N-turn coil. Its magnetic reluctance varies with the angle ? as R ? Rm? ? R0 , where Rm and R0 are constant. †¢ Derive the torque developed by the field from the system co-energy. †¢ When the device is excited with a direct current i=I, the angular displacement increases quadratically as ? ?t ? ? 1 ? t 2 ? ?t ? ? 0 , 2 where ? ? and ? 0 are constant. Find the voltage induced in the coil . Singly Excited Rotating Actuator Total turns, N = N1 + N2 Frame relu ctance Rf ? rf 2 Gap reluctance Rg ? 2rg ? ? lf 2? 0 ? r wd 2lg ?0rd (2? ? ? ) , 2? ? 760 ? 1. 33 rad Rg(? ) Rcore ?g Rarmature Fm=Ni e(t ) ? ? N 2 IRm (? t ? ? ) [ R0 ? Rm 1 ? t 2 ? ?t ? ? 0 ]2 2 ? Singly Excited Rotating Actuator ? Singly Excited Rotating Actuator airgap length, lg = 0. 001 m airgap radius, r = 0. 0745 m airgap depth, d = 0. 0255 m frame length lf = 0. 496 m limb width w = 0. 024 m Singly Excited Rotating Actuator ? (? ) ? T? ? NI R f ? Rg (? ) lf Rf ? 2 ? ? r wd Magnetic flux at equilibrium : ? NI ?0 ? ? ? R (? ) ? R f ?g ? ? ?0 NI lf 2 ? 0 ? r wd ? lg ?0rd? ? , Rg ? 2l g ?W f? ? ? ? N2 ? ?, ? R (? ) ? R ? f? ?g dRg dRg 2l g sign(? ) , where ? d? d? ?0 rd (2? ? ? )2 1 2 ? L(? ) 1 2 ? I ?I 2 2 122 ?1 IN 2 ?Rg (? ) ? R f ? 2 2l Rr sign(? ) 1 ? ? I 2N 2 , where Rr ? g 2 2 ?0 rd 4 ?Rg (? ) ? R f ? (2? ? ? ) ?0 rd (2? ? ? ) Restoring Torque ?1, x ? 0 sign ( x ) ? ? 1, x ? 0 NI? 0d lf l ?g 2 ? r w r? Force and Torque Singly Excited Rotating Actuator – Sing ly Excited Rotating Actuator (Cont. ) Torque Nm Flux mWb Flux, Torque for 2-pole motorEnergy In g eneral, 1. 5 Coenergy dW f ? id? ? Td ? dW f ‘ ? ? di ? Td ? ? i W f ? ? , ? ? ? ? i ? ? , ? ?d ? W f ‘ ? i , ? ? ? ? ? ?i , ? ?di ?W f ? ? , ? ? i? ?W f ? ? , ? ? T ?W f ‘ ? i , ? ? ?i ?W f ‘ ? i , ? ? T? 0 1. 0 mWb, Nm 0. 5 0 If the permeability is a constant, W f , ? ? ? 0. 0 0 5 10 15 20 25 30 35 40 45 rotor angle 50 55 60 65 70 75 80 1 ? 2 2 L ? 1 ? ? ? dL ? 1 2 dL ? ?i 2 ? L ? ? d ? 2 d? ? ? W f ‘ ? i , ? ? ? 2 T? T? 12 i L ? 2 1 2 dL ? i 2 d? Force and Torque Force and Torque – Doubly Excited Rotating Actuator – Doubly Excited Rotating Actuator (Cont. If a second winding is placed on the rotor, the singly excited actuator becomes a doubly excited actuator. The general principle for force and torque calculation discussed here is equally applicable to multi-excited systems. The differential energy and coenergy functions can be derived as dW f ? dWe ? dWm where dWe ? e1i1dt ? e2 i2 dt , e1 ? d? 1 dt , e2 ? d ? 2 dt , and dWm ? Td ? Hence, dW f 1 , ? 2 , ? ? ? i1d ? 1 ? i2 d ? 2 ? Td ? ? and ? W f 1 , ? 2 , ? ? ? W f 1 , ? 2 , ? ? ? W f 1 , ? 2 , ? ? d ? 1 ? d ? 2 ? d? 1 2 ? ? dW f ‘ ? i1 , i 2 , ? ? ? d i1 ? 1 ? i 2 ? 2 ? W f ? 1 , ? 2 , ? ? ? ?1 di1 ? ?2 di 2 ? T d ? ? ? W f ‘ ? i1 , i 2 , ? ? Therefore, T ? i1 di1 ? ? W f ‘ ? i1 , i 2 , ? ? ?Wf 1 , ? 2 , ? ? ? i2 or di 2 ? T? ? W f ‘ ? i1 , i 2 , ? ? Force and Torque – Doubly Excited Rotating Actuator (Cont. ) – Example 3 ? ? L? 1 For magnetically linear systems, ? ? 1 ? ? L11 ? ? ? L ? 2? ? 21 L 1 2 ? ? i1 ? L 22 ? ?i2 ? ? ? i1 ? ? ? 11 ?i ? ? ? ? ? 2? ? 21 or ? 1 2 ? ? ? 1 ? ? 22 ? ? ? 2 ? ? The magnetic energy and coenergy can then be expressed as W f ? ?1 , ? 2 , ? ? ? Therefore, d? ? W f ‘ ? i1 , i2 , ? ? Force and Torque and 1 1 2 ? 1 1 ? 12 ? 2 2 ? 2 ? ? 1 2 ? 1 ? 2 2 2 W f ‘ ? i 1 , i 2 , ? 1 1 L 1 1 i 12 ? L i 2 ? L 1 2 i1i 2 2 2 22 2 ? W f ‘ ? i 1 , i 2 , ? ? 1 2 d L 1 1 ? 1 2 d L 2 2 ? d L 1 2 ? ? i1 ? i2 ? i1i 2 2 2 T ?W f 1 , ? 2 , ? ? ? A magnetically-linear doubly-fed electromechanical actuator has two windings and a mechanical output with spatial rotary displacement ?. The self and mutual inductances of the windings are respectively L11 ? ? 5 ? cos(2? ) mH, L22 ? ? 50 ? 10 cos(2? ) mH, and L12 ? ? L21 ? ? 100 cos? mH. Brushless doubly-fed machine The first winding is supplied with i1 = 1. A while the second winding draws i2 = 20 mA. Determine: a) The general electromagnetic torque of the actuator as a function of ? . b) The maximum torque that the actuator can develop. Solution to Example 3 (a) Solution to Example 3 (cont. ) The  energy  stored  at  the  doubly? fed  actuator  is, 1 1 2 2 W f ? L11i1 ? L12 i1i2 ? L22 i2 2 2 1 1 ?3 2 ?3 2 ? (5 ? cos 2? ) ? 10 i1 ? (0. 1cos? )i1i2 ? (50 ? 10 cos 2? ) ? 10 i2 2 2 The  ex pression  of  electromagnetic  torque  is  obtained  as  follows:   ? ?W f (i1 , i2 ,? ) T ? i1 ? 1. 5, i2 ? 0. 02 ? 2 2 1 ? (i1 L11 ) ? (i1i2 L12 ) 1 ? (i2 L22 ) ? ? ? 2 2 1 1 (1. 5) 2 ( ? 2 sin 2? ) ? 10 ? 3 ? (1. 5)(0. 02)(? 0. 1sin ? ) ? (0. 02) 2 ( ? 20 sin 2? ) ? 10 ? 3 2 2 ?3 ? ? ( 2. 25 sin 2? ? 3 sin ? ) ? 10 Why Magnetic Field? Ratio of Electric and Magnetic Energy Densities in the air gap we ? 0 ? 0 E 2 1 ? ? wm B2 3. 6 ? 10 5 †¢ Saturation Flux Density Bs = 2T in commonlyused magnetic materials †¢ Air breakdown voltage Ebd=1,000,000 V/m b) At  maximum  torque, dT ?0 d? Differentiating  T  from  part  (a), 4. 5 cos 2? ? 3 cos ? ? 0 ? 1. 5 cos 2? ? cos ? ? 0 or               1. 5( 2 cos 2 ? ? 1) ? cos? ? 0 Solving  for  ? by  the  quadratic  formula, ?  =  55. 94 °Ã‚  and  153. 25 °Ã‚  (extraneous)Substituting  the  value  of  ? into  the  torque  expression  yields, T(max) ? ?(2. 25 s in 2(55. 94) ? 3 sin(55. 94)) ? 10 ? 3 ? ?4. 57 ? 10 ? 3 Nm Electric Machines †¢ Electric motor converts electrical energy into mechanical motion. †¢ The reverse task, that of converting mechanical motion into electrical energy, is accomplished by a generator or dynamo. †¢ In many cases the two devices differ only in their application and minor construction details, and some applications use a single device to fill both roles. For example, traction motors used on locomotive often perform both tasks if the locomotive is equipped with ynamic brakes. Introduction Electric Motors Electric Machine Insulation Class DC Motors Universal (DC/AC) AC Motors †¢ Induction †¢ Synchronous Stepping Motors Brushless DC Motors Coreless DC Motors Linear Motors MEMS Nano Motors †¢ A critical factor in the reduced life of electrical equipment is heat. The type of insulation used in a motor depends on the operating temperature that the motor will experience. †¢ Average insulation life decreases rapidly with increases in motor internal operating temperatures. †¢ Electric motor converts electrical energy into mechanical motion: Lorentz force on any wire when it is onducting electricity while contained within a magnetic field †¢ Rotor: rotating part †¢ Stator: stationary part †¢ Armature: part of the motor across which the voltage is supplied MaglevMagnetic Levitation Three phase AC induction motors rated 1 Hp (750 W) and 25 W with small motors from CD player, toy and CD/DVD drive reader head traverse DC Generators / Dynamos AC Generators / Alternators As the first electrical generator capable of delivering power for industry, the dynamo uses electromagnetic principles to convert mechanical rotation into a pulsing direct electric current through the use of a commutator.Without a commutator, the dynamo is an example of an alternator, which is a synchronous singly-fed generator. With an electromechanical commutator, the dynamo is a classical direct current (DC) generator. The DC generator can operate at any speed within mechanical limits but always outputs a direct current waveform. Mechanical energy is used to rotate the coil (N turns, area A) at uniform angular velocity ? in the magnetic field B, it will produce a sinusoidal emf in the coil: Permanent Magnet DC Generators d? d ? ? ( NBA cos ? ) dt dt ? NBA? sin ? t e(t ) ? ? http://micro. magnet. fsu. edu/electromag/java/generator/dc. tml Automotive alternator Rotor emf and current are induced by rotating magnetic field http://micro. magnet. fsu. edu/electromag/java/generator/ac. html Mechanical Components Mechanical Components – Mass and Inertia The mechanical component which stores kinetic energy is a mass in a translational system, and a moment of inertia in a rotational system. – Mass and Inertia (Cont. ) The kinetic energy stored by a mass moving at a velocity v, or a moment of inertia rotating at an angular speed ?. can be calculated by ? x M T F J Wk ? 1 Mv2 2 d? d 2? T? J 2 ? J dt dt dv d 2x F? M ?M dt 2 dt 1 J? 2 2 (translational system) rotational system) Comparing with the relationships of voltage, current, and magnetic energy in an inductor: V? L By the Newton’s second law, we have Wk ? or di dt and WL ? 1 Li2 2 we may regard a mass or a moment of inertia as an inductor which stores magnetic energy, if we let J? L M? L or Mechanical Components Mechanical Components – Springs An ideal spring is a device with negligible mass and mechanical losses, whose deformation is a single-valued function of the applied force or torque. A linear ideal spring has deformation proportional to force or ? 1 torque. – Springs (Cont. ) For a given distortion of x and ? the potential energy stored in a spring is 1 1 W p ? ? Td ? ? K ? 2 W p ? ? Fdx ? Kx 2 T x1 F ? K ? x 1 ? x o ? ? Kx (linear spring) (torsional spring) Comparing with the relationships of electric charge, voltage and electric energy in a capacito r: Q V? C F 2 2 WC ? and 1 1 Q2 VQ ? 2 2C we may regard a spring as an electric capacitor which stores electric potential energy, if we let T ? K 1 ? ?o ? ? K ? K? 1 C Friction Friction Modelling Friction: force that opposes the relative motion or tendency of such motion of two surfaces in contact. Friction between the two objects converts kinetic energy into heat.Coefficient of friction (Frictional coefficient): dimensionless scalar value which describes the ratio of the force of friction between two bodies and the force pressing them together, needs not be less than 1 – under good conditions, a tire on concrete may have a coefficient of friction of 1. 7. Static friction (stiction) occurs when the two objects are not moving relative to each other: Rolling friction occuring when one object â€Å"rolls† on another (like a car's wheels on the ground), is stiction as the patch of the tire in contact with the ground, at any point while the tire spins, is stationary relati ve to the ground.Kinetic (or dynamic) friction occurs when two objects are moving relative to each other and rub together: – Sliding friction is when two objects are rubbing against each other. – Fluid friction is the friction between a solid object as it moves through a liquid or a gas. The drag of air on an airplane or of water on a swimmer are two examples of fluid friction. Lu-Gre Model (1995): ? 0 , ? 1 bristles’ stiffness and damping coefficient ?2 viscous friction FC , F S Coulomb and Stribeck friction ? F f ? ? 0 z ? ? 1z ? ? 2v ? z? v? v z g (v ) 2 1 g (v ) ? [ FC ? ( F S ? FC ) e ? v / v S ) ] ?0 Mechanical Components Mechanical Components – Damper The mechanical damper is analogous to electrical resistor in that it dissipates energy as heat. An ideal damper is a device that exhibits no mass or spring effect and exerts a force that is a function of the relative velocity between its two parts. A linear ideal damper has a force proportional to the relative velocity. In all cases a damper produces a force that opposes the relative motion of the two parts. Mechanical friction occurs in a variety of situations under many different physical conditions.Sometimes friction is unwanted but must be tolerated and accounted for analytically, as, for example, in bearings, sliding electrical contacts, and the aerodynamic drag on a moving body. In other cases friction is desired and is designed into equipment. Examples are vibration dampers and shock absorbers. d ? x2 ? x1 ? dt dx ?B dt F? B ? B? R d 2 ? ?1 ? dt d? ?B dt T? B – Damper (Cont. ) Mechanical Components Mechanical Components – Damper (Cont. ) The damping due to Coulomb friction, as shown by the characteristic, can be regarded as a nonlinear resistor, which can keep the voltage across it to be constant.The Coulomb friction force can be expressed as – Damper (Cont. ) There is another kind of damping caused by the drag of a viscous fluid in turbulent flow. 2 F ? ? Bs d x2 ? x1 dt F ? ?d Fn ? ? d Fn d ? x2 ? x1 ? dt ? ? ? Bs dx dt d ? x2 ? x1 ? dt ? 2 ? R ? B s dx dt dx dt ? dx dt or T ? ? Bs d 2 ? ?1 ? dt Comparing with V=RI, we may conclude that ?F R? d n dx dt ? ? ? Bs d? dt ? ? 2 2 ? R ? B s d ? dt MR Dampers as a semi-active device MR Damper New Models Non-symmetrical Model (2007) ? F ( x) ? c0 x ? ko ( x ? x0 ) ? ?z ? ? ? z ? (? ? ( ? ? ? sign( zx) z ) x n : hysteresis variable, ? , ? , ? , ? , n, c0 , k0 : model parameters Bouc-Wen Model: ? F ( x ) ? c0 x ? k o ( x ? x0 ) ? ? z ? ? ? ? z ? ? ? z | x || z | n ? 1 ? ? x | z | n ? ? x z: hysteresis variable , ? , ? , ? , ? , n , c 0 , k 0 : model parameters Static Hysteresis Model (2006) ? F ( x) ? cx ? kx ? ?z ? f 0 ? z ? tanh( ? x ? sign( x)) z : hysteresis variable, ? , ? , f 0 , c, k : model parameters Minimally-Parameterised Model (2007) ? F : G ( x ) ? D ( x ), F ( x) ? ? 1 ? F2 : G ( x ) ? D ( x ), b G ( x) ? a ? ? 1 ? exp ( cx ) ? D ( x ) ? rexp{? ( x / 2? ) 2 } ? 0 x ? 0, x