Four Stroke Engine - How it works

Four-stroke cycle used in gasoline engines. The right blue side is the intake and the left yellow side is the exhaust. The cylinder wall is a thin sleeve surrounded by cooling water.

Four Stroke Engine - Graphical Representation

Power output limit

The four-stroke cycle
1=TDC
2=BDC
 A: Intake 
 B: Compression 
 C: Power 
  D: Exhaust 

The maximum amount of power generated by an engine is determined by the maximum amount of air ingested. The amount of power generated by a piston engine is related to its size (cylinder volume), whether it is a two-stroke or four-stroke design, volumetric efficiency, losses, air-to-fuel ratio, the calorific value of the fuel, oxygen content of the air and speed (RPM). The speed is ultimately limited by material strength and lubrication. Valves, pistons and connecting rods suffer severe acceleration forces. At high engine speed, physical breakage and piston ring flutter can occur, resulting in power loss or even engine destruction. Piston ring flutter occurs when the rings oscillate vertically within the piston grooves they reside in. Ring flutter compromises the seal between the ring and the cylinder wall which results in a loss of cylinder pressure and power. If an engine spins too quickly, valve springs cannot act quickly enough to close the valves. This is commonly referred to as 'valve float', and it can result in piston to valve contact, severely damaging the engine. At high speeds the lubrication of piston cylinder wall interface tends to break down. This limits the piston speed for industrial engines to about 10 m/s.

[edit] Intake/exhaust port flow

The output power of an engine is dependent on the ability of intake (air–fuel mixture) and exhaust matter to move quickly through valve ports, typically located in the cylinder head. To increase an engine's output power, irregularities in the intake and exhaust paths, such as casting flaws, can be removed, and, with the aid of an air flow bench, the radii of valve port turns and valve seat configuration can be modified to reduce resistance. This process is called porting, and it can be done by hand or with a CNC machine.

[edit] Supercharging

One way to increase engine power is to force more air into the cylinder so that more power can be produced from each power stroke. This can be done using some type of air compression device known as a supercharger, which can be powered by the engine crankshaft.
Supercharging increases the power output limits of an internal combustion engine relative to its displacement. Most commonly, the supercharger is always running, but there have been designs that allow it to be cut out or run at varying speeds (relative to engine speed). Mechanically driven supercharging has the disadvantage that some of the output power is used to drive the supercharger, while power is wasted in the high pressure exhaust, as the air has been compressed twice and then gains more potential volume in the combustion but it is only expanded in one stage.

[edit] Turbocharging

A turbocharger is a supercharger that is driven by the engine's exhaust gases, by means of a turbine. It consists of a two piece, high-speed turbine assembly with one side that compresses the intake air, and the other side that is powered by the exhaust gas outflow.
When idling, and at low-to-moderate speeds, the turbine produces little power from the small exhaust volume, the turbocharger has little effect and the engine operates nearly in a naturally-aspirated manner. When much more power output is required, the engine speed and throttle opening are increased until the exhaust gases are sufficient to 'spin up' the turbocharger's turbine to start compressing much more air than normal into the intake manifold.
Turbocharging allows for more efficient engine operation because it is driven by exhaust pressure that would otherwise be (mostly) wasted, but there is a design limitation known as turbo lag. The increased engine power is not immediately available, due to the need to sharply increase engine RPM, to build up pressure and to spin up the turbo, before the turbo starts to do any useful air compression. The increased intake volume causes increased exhaust and spins the turbo faster, and so forth until steady high power operation is reached. Another difficulty is that the higher exhaust pressure causes the exhaust gas to transfer more of its heat to the mechanical parts of the engine.

[edit] Rod and piston-to-stroke ratio

The rod-to-stroke ratio is the ratio of the length of the connecting rod to the length of the piston stroke. A longer rod will reduce the sidewise pressure of the piston on the cylinder wall and the stress forces, hence increasing engine life. It also increases the cost and engine height and weight.
A "square engine" is an engine with a bore diameter equal to its stroke length. An engine where the bore diameter is larger than its stroke length is an oversquare engine, conversely, an engine with a bore diameter that is smaller than its stroke length is an undersquare engine.

[edit] Valvetrain

The valves are typically operated by a camshaft rotating at half the speed of the crankshaft. It has a series of cams along its length, each designed to open a valve during the appropriate part of an intake or exhaust stroke. A tappet between valve and cam is a contact surface on which the cam slides to open the valve. Many engines use one or more camshafts “above” a row (or each row) of cylinders, as in the illustration, in which each cam directly actuates a valve through a flat tappet. In other engine designs the camshaft is in the crankcase, in which case each cam contacts a push rod, which contacts a rocker arm which opens a valve. The overhead cam design typically allows higher engine speeds because it provides the most direct path between cam and valve.

[edit] Valve clearance

Valve clearance refers to the small gap between a valve lifter and a valve stem that ensures that the valve completely closes. On engines with mechanical valve adjustment excessive clearance will cause noise from the valve train. Typically the clearance has to be readjusted each 20,000 miles (32,000 km) with a feeler gauge.
Most modern production engines use hydraulic lifters to automatically compensate for valve train component wear. Dirty engine oil may cause lifter failure.

[edit] Energy balance

Otto engines are about 35% efficient – in other words, 35% of the energy generated by combustion is converted into useful rotational energy at the output shaft of the engine, while the remainder appears as waste heat.^{[citation needed]}By contrast, a six-stroke engine may convert more than 50% of the energy of combustion into useful rotational energy.
Modern engines are often intentionally built to be slightly less efficient than they could otherwise be. This is necessary for emission controls such as exhaust gas recirculation and catalytic converters that reduce smog and other atmospheric pollutants. Reductions in efficiency may be counteracted with an engine control unit using lean burn techniques.^[1]

Starting position, intake stroke, and compression stroke.

Ignition of fuel, power stroke, and exhaust stroke.

Justin Bieber -Baby Lyrics

Ohh wooaah (3x)
You know you love me,I know you care
Just shout whenever, And I'll be there
You want my love, You want my heart
And we will never ever ever be apart

Are we an item? Girl quit playing
Were just friends, What are you saying
Said theres another, Look right in my eyes

My first love broke my heart for the first time,
And I was like
Baby, baby, baby ohhh
Like baby, baby, baby noo
Like baby, baby, baby ohh
I thought youd always be mine mine

Baby, baby, baby ohh
Like baby, baby, baby noo
Like baby, baby, baby ohh
I thought youd always be mine,mine (oh oh)

For you, I would have done whatever
And I just can't believe, we ain't together
And I wanna play it cool, But I'm losin' you
I'll buy you anything, I'll buy you any ring
And im in pieces, Baby fix me
And just shake me til' you wake me from this bad dream

Im going down, down, down, dooown
And I just cant believe my first love would be around.

And I'm like
Baby, baby, baby ohh
Like baby, baby, baby noo
Like baby, baby, baby ohh
I thought youd always be mine, mine

Free Message Service -Way2sms.com

As of today, Way2SMS now serves 10 million people across the country. It’s a large number, Just 8 months ago we served less than half as many people, and thanks to you we’ve made great progress over the last year towards reaching every corner in the country. The rapid pace of  our growth is humbling and exciting for us, and it affirms that people everywhere are realizing the power of staying connected to others via Way2SMS.

So today as we celebrate our 10 millionth user,  we’re doing what we like doing most—building and launching new products for users. This week we’ll host a celebration at our headquarters, and we’ll release a handful of new things that will improve users experience on way2sms, including a couple that users  have requested a lot.

On this Occasion we would like to share several facts behind way2sms

• The site we all use every day is built by a relatively small group of the smartest engineers who are solving substantial problems and each making a huge impact for the 10 million users using way2sms.
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Quick facts about Justin Bieber.

Justin Bieber.

Justin Bieber full name is Justin Drew BieberHe was born March 1st, 1994 (16 years old).
His nicknames: J-Beebs, Justin, JB, Biebs, Bieber, Beebs
His mother name is Pattie
His father name is Jeremy Bieber
His dad plays guitar, and his mom sings.
His grandma was a great piano player.
His Dad remarried.
He is very protective for her lil sister.
He wants to buy a house for his mom when he has $1,000,000.
He is not into blink-blink.
He started dating when he was 13.
His first kiss was when he was 13.
His favorite TV show is smallville.
his favorite video game is nba 2k.
His favorite colors are blue and purple
His favorite food is spaghetti
He speaks fluent French
He is claustrophobic – fear of being in narrow or enclosed spaces, eg: closet, elevators
He perfers Macs over PCs
His favorite number is 6
His favorite music is R&B and Pop
His favorite artists; Usher, Michael Jackson, BoysIImen, Stevie Wonder.
His celebrity crush is Beyonce.
He likes vitamin water
His favorite drink is orange juice
He has a half sister named Jazmine & brother names jaxon
He is a lefty
He can play trumpet, guitar, piano, and drums
He likes captain crunch (with berries)
He can count to ten in German
He once asked out Rihanna and Alexa Chung (got rejected)
His two best friends are Ryan butler and Christian beadles
He once dated Caitlin Beadles (Christians Beadles sister)
His shoe size is 7 and a half
He likes sporty, active, nice, down to earth girls.
He likes sour patch kids
His most embarrassing moment is when he broke his foot on stage during a song (he stayed and finished the song, didn’t even miss a note! so proud ))
He grew up in Canada (Stratford Ontario)
He is signed by Usher. Justin Timberlake was reportedly in the running to sign Bieber.
His label is Island def jam.
He likes playing soccer.
His favorite slang word is “shawty”
He likes tacos
His favorite pie is apple
He likes to skateboard and is good at it
He loves Tim Hortons (very Canadian)
His best friends – Ryan butler & Chaz Somers
He likes blue eyes
He likes a good smile
His first CD came out in Novemeber 17th 2009
He got his first plaque at YTV’s The Next Star at Canadas wonderland
He would date anyone he falls in love with.
He is now pals with Taylor Swift
He plays four instruments; guitar, piano, drums and trumpet
He raised 150,000 lbs of food for food Bank, with the help of his fans.
He loves his fans!


Read more: Justin Bieber Facts | Justin Bieber Zone http://www.justinbieberzone.com/about-justin-quick-facts/#ixzz17qbRFGJ7

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Value Added Tax

A value added tax (VAT) is a form of consumption tax. It is a tax on the "value added" to a product or material, from an accounting view, at each stage of its manufacture or distribution. The "value added" to a product by a business is the sale price charged to its customer, minus the cost of materials and other taxable inputs. A VAT is like a sales tax in that ultimately only the end consumer is taxed. It differs from the sales tax in that, with the latter, the tax is collected and remitted to the government only once, at the point of purchase by the end consumer. With the VAT, collections, remittances to the government, and credits for taxes already paid occur each time a business in the supply chain purchases products from another business. The reason businesses end up paying no tax is that at the time they sell the product, they receive a credit for all the tax they have paid to suppliers.
Maurice Lauré, Joint Director of the French Tax Authority, the Direction générale des impôts, was first to introduce VAT on April 10, 1954, although German industrialist Dr. Wilhelm von Siemens proposed the concept in 1918. Initially directed at large businesses, it was extended over time to include all business sectors. In France, it is the most important source of state finance, accounting for nearly 50% of state revenues.^[1]
Personal end-consumers of products and services cannot recover VAT on purchases, but businesses are able to recover VAT (input tax) on the products and services that they buy in order to produce further goods or services that will be sold to yet another business in the supply chain or directly to a final consumer. In this way, the total tax levied at each stage in the economic chain of supply is a constant fraction of the value added by a business to its products, and most of the cost of collecting the tax is borne by business, rather than by the state. Value Added Taxes were introduced in part because they create stronger incentives to collect than a sales tax does. Both types of consumption tax create an incentive by end consumers to avoid or evade the tax. But the sales tax offers the buyer a mechanism to avoid or evade the tax--persuade the seller that he is not really an end consumer, and therefore the seller is not legally required to collect it. The burden of determining whether the buyer's motivation is to consume or re-sell is on the seller, but the seller has no direct economic incentive to the seller to collect it. The VAT approach gives sellers a direct financial stake in collecting the tax, and eliminates the problematic decision by the seller about whether the buyer is or is not an end consumer.

Justin Timberlake

Hip Hop Videos

http://www.youtube.com/watch?v=GWKDlF_oAXI
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http://www.metacafe.com/watch/2476486/best_hip_hop_dance_forever/
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http://www.videojug.com/film/how-to-dance-hip-hop-like-justin-timberlake
http://video.google.com/videoplay?docid=-2020029531334253002#

HIP-HOP: BEYOND BEATS AND RHYMES is a riveting documentary that examines representations of gender roles in hip-hop and rap music through the lens of filmmaker Byron Hurt, a former college quarterback turned activist. Conceived as a “loving critique” from a self-proclaimed “hip-hop head,” Hurt examines issues of masculinity, sexism, violence and homophobia in today’s hip-hop culture.

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Darwin's Theory of Evolution

Darwin's Theory of Evolution - The Premise
Darwin's Theory of Evolution is the widely held notion that all life is related and has descended from a common ancestor: the birds and the bananas, the fishes and the flowers -- all related. Darwin's general theory presumes the development of life from non-life and stresses a purely naturalistic (undirected) "descent with modification". That is, complex creatures evolve from more simplistic ancestors naturally over time. In a nutshell, as random genetic mutations occur within an organism's genetic code, the beneficial mutations are preserved because they aid survival -- a process known as "natural selection." These beneficial mutations are passed on to the next generation. Over time, beneficial mutations accumulate and the result is an entirely different organism (not just a variation of the original, but an entirely different creature).
Darwin's Theory of Evolution - Natural Selection
While Darwin's Theory of Evolution is a relatively young archetype, the evolutionary worldview itself is as old as antiquity. Ancient Greek philosophers such as Anaximander postulated the development of life from non-life and the evolutionary descent of man from animal. Charles Darwin simply brought something new to the old philosophy -- a plausible mechanism called "natural selection." Natural selection acts to preserve and accumulate minor advantageous genetic mutations. Suppose a member of a species developed a functional advantage (it grew wings and learned to fly). Its offspring would inherit that advantage and pass it on to their offspring. The inferior (disadvantaged) members of the same species would gradually die out, leaving only the superior (advantaged) members of the species. Natural selection is the preservation of a functional advantage that enables a species to compete better in the wild. Natural selection is the naturalistic equivalent to domestic breeding. Over the centuries, human breeders have produced dramatic changes in domestic animal populations by selecting individuals to breed. Breeders eliminate undesirable traits gradually over time. Similarly, natural selection eliminates inferior species gradually over time.
Darwin's Theory of Evolution - Slowly But Surely...
Darwin's Theory of Evolution is a slow gradual process. Darwin wrote, "…Natural selection acts only by taking advantage of slight successive variations; she can never take a great and sudden leap, but must advance by short and sure, though slow steps." [1] Thus, Darwin conceded that, "If it could be demonstrated that any complex organ existed, which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down." [2] Such a complex organ would be known as an "irreducibly complex system". An irreducibly complex system is one composed of multiple parts, all of which are necessary for the system to function. If even one part is missing, the entire system will fail to function. Every individual part is integral. [3] Thus, such a system could not have evolved slowly, piece by piece. The common mousetrap is an everyday non-biological example of irreducible complexity. It is composed of five basic parts: a catch (to hold the bait), a powerful spring, a thin rod called "the hammer," a holding bar to secure the hammer in place, and a platform to mount the trap. If any one of these parts is missing, the mechanism will not work. Each individual part is integral. The mousetrap is irreducibly complex. [4]
Darwin's Theory of Evolution - A Theory In Crisis
Darwin's Theory of Evolution is a theory in crisis in light of the tremendous advances we've made in molecular biology, biochemistry and genetics over the past fifty years. We now know that there are in fact tens of thousands of irreducibly complex systems on the cellular level. Specified complexity pervades the microscopic biological world. Molecular biologist Michael Denton wrote, "Although the tiniest bacterial cells are incredibly small, weighing less than 10^-12 grams, each is in effect a veritable micro-miniaturized factory containing thousands of exquisitely designed pieces of intricate molecular machinery, made up altogether of one hundred thousand million atoms, far more complicated than any machinery built by man and absolutely without parallel in the non-living world." [5]

And we don't need a microscope to observe irreducible complexity. The eye, the ear and the heart are all examples of irreducible complexity, though they were not recognized as such in Darwin's day. Nevertheless, Darwin confessed, "To suppose that the eye with all its inimitable contrivances for adjusting the focus to different distances, for admitting different amounts of light, and for the correction of spherical and chromatic aberration, could have been formed by natural selection, seems, I freely confess, absurd in the highest degree."

Mahathma Gandhi

BIOGRAPHY OF MAHATMA GANDHI : Mohandas Karamchand Gandhi was born on October 2, 1869 in Porbandar, India. He became one of the most respected spiritual and political leaders of the 1900's. GandhiJi helped free the Indian people from British rule through nonviolent resistance, and is honored by Indians as the father of the Indian Nation. The Indian people called Gandhiji  'Mahatma', meaning Great Soul. At the age of 13 Gandhi married Kasturba, a girl the same age. Their parents arranged the marriage. The Gandhis had four children. Gandhi studied law in London and returned to India in 1891 to practice. In 1893 he took on a one-year contract to do legal work in South Africa.

At the time the British controlled South Africa. When he attempted to claim his rights as a British subject he was abused, and soon saw that all Indians suffered similar treatment. Gandhi stayed in South Africa for 21 years working to secure rights for Indian people.
He developed a method of action based upon the principles of courage, nonviolence and truth called Satyagraha. He believed that the way people behave is more important than what they achieve. Satyagraha promoted nonviolence and civil disobedience as the most appropriate methods for obtaining political and social goals. In 1915 Gandhi returned to India. Within 15 years he became the leader of the Indian nationalist movement.
Using the principles of Satyagraha he led the campaign for Indian independence from Britain. Gandhi was arrested many times by the British for his activities in South Africa and India. He believed it was honorable to go to jail for a just cause. Altogether he spent seven years in prison for his political activities.
More than once Gandhi used fasting to impress upon others the need to be nonviolent. India was granted independence in 1947, and partitioned into India and Pakistan. Rioting between Hindus and Muslims followed. Gandhi had been an advocate for a united India where Hindus and Muslims lived together in peace.
On January 13, 1948, at the age of 78, he began a fast with the purpose of stopping the bloodshed. After 5 days the opposing leaders pledged to stop the fighting and Gandhi broke his fast. Twelve days later a Hindu fanatic, Nathuram Godse who opposed his program of tolerance for all creeds and religion assas

Martin Luther King

Biography

Martin Luther King, Jr., (January 15, 1929-April 4, 1968) was born Michael Luther King, Jr., but later had his name changed to Martin. His grandfather began the family's long tenure as pastors of the Ebenezer Baptist Church in Atlanta, serving from 1914 to 1931; his father has served from then until the present, and from 1960 until his death Martin Luther acted as co-pastor. Martin Luther attended segregated public schools in Georgia, graduating from high school at the age of fifteen; he received the B. A. degree in 1948 from Morehouse College, a distinguished Negro institution of Atlanta from which both his father and grandfather had graduated. After three years of theological study at Crozer Theological Seminary in Pennsylvania where he was elected president of a predominantly white senior class, he was awarded the B.D. in 1951. With a fellowship won at Crozer, he enrolled in graduate studies at Boston University, completing his residence for the doctorate in 1953 and receiving the degree in 1955. In Boston he met and married Coretta Scott, a young woman of uncommon intellectual and artistic attainments. Two sons and two daughters were born into the family.

In 1954, Martin Luther King became pastor of the Dexter Avenue Baptist Church in Montgomery, Alabama. Always a strong worker for civil rights for members of his race, King was, by this time, a member of the executive committee of the National Association for the Advancement of Colored People, the leading organization of its kind in the nation. He was ready, then, early in December, 1955, to accept the leadership of the first great Negro nonviolent demonstration of contemporary times in the United States, the bus boycott described by Gunnar Jahn in his presentation speech in honor of the laureate. The boycott lasted 382 days. On December 21, 1956, after the Supreme Court of the United States had declared unconstitutional the laws requiring segregation on buses, Negroes and whites rode the buses as equals. During these days of boycott, King was arrested, his home was bombed, he was subjected to personal abuse, but at the same time he emerged as a Negro leader of the first rank.

In 1957 he was elected president of the Southern Christian Leadership Conference, an organization formed to provide new leadership for the now burgeoning civil rights movement. The ideals for this organization he took from Christianity; its operational techniques from Gandhi. In the eleven-year period between 1957 and 1968, King traveled over six million miles and spoke over twenty-five hundred times, appearing wherever there was injustice, protest, and action; and meanwhile he wrote five books as well as numerous articles. In these years, he led a massive protest in Birmingham, Alabama, that caught the attention of the entire world, providing what he called a coalition of conscience. and inspiring his "Letter from a Birmingham Jail", a manifesto of the Negro revolution; he planned the drives in Alabama for the registration of Negroes as voters; he directed the peaceful march on Washington, D.C., of 250,000 people to whom he delivered his address, "l Have a Dream", he conferred with President John F. Kennedy and campaigned for President Lyndon B. Johnson; he was arrested upwards of twenty times and assaulted at least four times; he was awarded five honorary degrees; was named Man of the Year by Time magazine in 1963; and became not only the symbolic leader of American blacks but also a world figure.

At the age of thirty-five, Martin Luther King, Jr., was the youngest man to have received the Nobel Peace Prize. When notified of his selection, he announced that he would turn over the prize money of $54,123 to the furtherance of the civil rights movement.

On the evening of April 4, 1968, while standing on the balcony of his motel room in Memphis, Tennessee, where he was to lead a protest march in sympathy with striking garbage workers of that city, he was assassinated.

Barack Obama

President of the United States. Born Barack Hussein Obama on August 4, 1961, in Honolulu, Hawaii. Obama's mother, Ann Dunham, grew up in Wichita, Kansas, where her father worked on oil rigs during the Depression. After the Japanese attack on Pearl Harbor, Dunham's father, Stanley, enlisted in the service and marched across Europe in Patton's army. Dunham's mother, Madelyn, went to work on a bomber assembly line. After the war, the couple studied on the G.I. Bill, bought a house through the Federal Housing Program and, after several moves, landed in Hawaii.
Obama's father, Barack Obama, Sr., was born of Luo ethnicity in Nyanza Province, Kenya. The elder Obama grew up herding goats in Africa, eventually earning a scholarship that allowed him to leave Kenya and pursue his dreams of college in Hawaii. While studying at the University of Hawaii in Manoa, Obama, Sr. met fellow student, Ann Dunham. They married on February 2, 1961. Barack was born six months later.
Obama's parents separated when he was two years old, later divorcing. Obama, Sr. went on to Harvard to pursue Ph.D. studies, and then returned to Kenya in 1965. In 1966, Dunham married Lolo Soetoro, another East–West Center student from Indonesia. A year later, the family moved to Jakarta, Indonesia, where Obama's half-sister Maya Soetoro Ng was born. Several incidents in Indonesia left Dunham afraid for her son's safety and education so, at the age of 10, Barack was sent back to Hawaii to live with his maternal grandparents. His mother and sister later joined them.
While living with his grandparents, Obama enrolled in the esteemed Punahou Academy, excelling in basketball and graduating with academic honors in 1979. As one of only three black students at the school, Obama became conscious of racism and what it meant to be African-American. He later described how he struggled to reconcile social perceptions of his multiracial heritage with his own sense of self. "I began to notice there was nobody like me in the Sears, Roebuck Christmas catalog...and that Santa was a white man," he said. "I went to the bathroom and stood in front of the mirror with all my senses and limbs seemingly intact, looking the way I had always looked, and wondered if something was wrong with me."
Obama also struggled with the absence of his father, who he saw only once more after his parents divorced, in a brief 1971 visit. "[My father] had left paradise, and nothing that my mother or grandparents told me could obviate that single, unassailable fact," he later reflected. "They couldn't describe what it might have been like had he stayed." Obama, Sr. eventually lost his legs in an automobile accident, also losing his job as a result. In 1982, he died in yet another car accident while traveling in Nairobi. Obama, Jr. was 22 years old when he received the news of his father's passing. "At the time of his death, my father remained a myth to me," Obama said, "both more and less than a man."

Bill Gates

William Henry "Bill" Gates III (born October 28, 1955)^[2] is an American business magnate, philanthropist, author and chairman^[3] of Microsoft, the software company he founded with Paul Allen. He is consistently ranked among the world's wealthiest people^[4] and was the wealthiest overall from 1995 to 2009, excluding 2008, when he was ranked third.^[5] During his career at Microsoft, Gates held the positions of CEO and chief software architect, and remains the largest individual shareholder with more than 8 percent of the common stock.^[6] He has also authored or co-authored several books.
Gates is one of the best-known entrepreneurs of the personal computer revolution. Although he is admired by many, a number of industry insiders criticize his business tactics, which they consider anti-competitive, an opinion which has in some cases been upheld by the courts.^[7][8] In the later stages of his career, Gates has pursued a number of philanthropic endeavors, donating large amounts of money to various charitable organizations and scientific research programs through the Bill & Melinda Gates Foundation, established in 2000.
Bill Gates stepped down as chief executive officer of Microsoft in January 2000. He remained as chairman and created the position of chief software architect. In June 2006, Gates announced that he would be transitioning from full-time work at Microsoft to part-time work and full-time work at the Bill & Melinda Gates Foundation. He gradually transferred his duties to Ray Ozzie, chief software architect and Craig Mundie, chief research and strategy officer. Gates' last full-time day at Microsoft was June 27, 2008. He remains at Microsoft as non-executive chairman.

Contents [hide] 1 Early life 2 Microsoft 2.1 BASIC 2.2 IBM partnership 2.3 Windows 2.4 Management style 2.5 Antitrust litigation 2.6 Appearance in ads 3 Post-Microsoft 4 Personal life 4.1 Philanthropy 4.2 Recognition 4.3 Investments 5 Bibliography 6 Filmography 7 References 8 See also 8.1 Books 9 Further reading 10 External links

Early life

Gates was born in Seattle, Washington, to William H. Gates, Sr. and Mary Maxwell Gates, of English, German, and Scottish-Irish descent.^[9][10] His family was upper middle class; his father was a prominent lawyer, his mother served on the board of directors for First Interstate BancSystem and the United Way, and her father, J. W. Maxwell, was a national bank president. Gates has one elder sister, Kristi (Kristianne), and one younger sister, Libby. He was the fourth of his name in his family, but was known as William Gates III or "Trey" because his father had dropped his own "III" suffix.^[11] Early on in his life, Gates' parents had a law career in mind for him.^[12]
At 13 he enrolled in the Lakeside School, an exclusive preparatory school.^[13] When he was in the eighth grade, the Mothers Club at the school used proceeds from Lakeside School's rummage sale to buy an ASR-33 teletype terminal and a block of computer time on a General Electric (GE) computer for the school's students.^[14] Gates took an interest in programming the GE system in BASIC and was excused from math classes to pursue his interest. He wrote his first computer program on this machine: an implementation of tic-tac-toe that allowed users to play games against the computer. Gates was fascinated by the machine and how it would always execute software code perfectly. When he reflected back on that moment, he commented on it and said, "There was just something neat about the machine."^[15] After the Mothers Club donation was exhausted, he and other students sought time on systems including DEC PDP minicomputers. One of these systems was a PDP-10 belonging to Computer Center Corporation (CCC), which banned four Lakeside students—Gates, Paul Allen, Ric Weiland, and Kent Evans—for the summer after it caught them exploiting bugs in the operating system to obtain free computer time.^[16]
At the end of the ban, the four students offered to find bugs in CCC's software in exchange for computer time. Rather than use the system via teletype, Gates went to CCC's offices and studied source code for various programs that ran on the system, including programs in FORTRAN, LISP, and machine language. The arrangement with CCC continued until 1970, when the company went out of business. The following year, Information Sciences, Inc. hired the four Lakeside students to write a payroll program in COBOL, providing them computer time and royalties. After his administrators became aware of his programming abilities, Gates wrote the school's computer program to schedule students in classes. He modified the code so that he was placed in classes with mostly female students. He later stated that "it was hard to tear myself away from a machine at which I could so unambiguously demonstrate success."^[15] At age 17, Gates formed a venture with Allen, called Traf-O-Data, to make traffic counters based on the Intel 8008 processor.^[17] In early 1973, Bill Gates served as a congressional page in the U.S. House of Representatives.^[18]

Bill Gates' mugshot from a traffic violation in 1977

Gates graduated from Lakeside School in 1973. He scored 1590 out of 1600 on the SAT^[19] and enrolled at Harvard College in the autumn of 1973.^[20] While at Harvard, he met Steve Ballmer, who later succeeded Gates as CEO of Microsoft. In his sophomore year, Gates devised an algorithm for pancake sorting as a solution to one of a series of unsolved problems,^[21] presented in a combinatorics class by Harry Lewis, one of his professors. Gates' solution, which was later formalized in a published paper in collaboration with Harvard computer scientist Christos Papadimitriou,^[22] held the record as the fastest version for over thirty years;^[21][23] its successor is faster by only one percent^[21]. Gates did not have a definite study plan while a student at Harvard^[24] and spent a lot of time using the school's computers. He remained in contact with Paul Allen, joining him at Honeywell during the summer of 1974.^[25] The following year saw the release of the MITS Altair 8800 based on the Intel 8080 CPU, and Gates and Allen saw this as the opportunity to start their own computer software company.^[26] He had talked this decision over with his parents, who were supportive of him after seeing how much Gates wanted to start a company.^[24]

Microsoft

Main articles: History of Microsoft and Microsoft

BASIC

MITS Altair 8800 Computer with 8-inch (200 mm) floppy disk system

After reading the January 1975 issue of Popular Electronics that demonstrated the Altair 8800, Gates contacted Micro Instrumentation and Telemetry Systems (MITS), the creators of the new microcomputer, to inform them that he and others were working on a BASIC interpreter for the platform.^[27] In reality, Gates and Allen did not have an Altair and had not written code for it; they merely wanted to gauge MITS's interest. MITS president Ed Roberts agreed to meet them for a demo, and over the course of a few weeks they developed an Altair emulator that ran on a minicomputer, and then the BASIC interpreter. The demonstration, held at MITS's offices in Albuquerque, was a success and resulted in a deal with MITS to distribute the interpreter as Altair BASIC. Paul Allen was hired into MITS,^[28] and Gates took a leave of absence from Harvard to work with Allen at MITS in Albuquerque in November 1975. They named their partnership "Micro-Soft" and had their first office located in Albuquerque.^[28] Within a year, the hyphen was dropped, and on November 26, 1976, the trade name "Microsoft" was registered with the Office of the Secretary of the State of New Mexico.^[28] Gates never returned to Harvard to complete his studies.
Microsoft's BASIC was popular with computer hobbyists, but Gates discovered that a pre-market copy had leaked into the community and was being widely copied and distributed. In February 1976, Gates wrote an Open Letter to Hobbyists in the MITS newsletter saying that MITS could not continue to produce, distribute, and maintain high-quality software without payment.^[29] This letter was unpopular with many computer hobbyists, but Gates persisted in his belief that software developers should be able to demand payment. Microsoft became independent of MITS in late 1976, and it continued to develop programming language software for various systems.^[28] The company moved from Albuquerque to its new home in Bellevue, Washington on January 1, 1979.^[27]
During Microsoft's early years, all employees had broad responsibility for the company's business. Gates oversaw the business details, but continued to write code as well. In the first five years, he personally reviewed every line of code the company shipped, and often rewrote parts of it as he saw fit.^[30]

IBM partnership

In 1980, IBM approached Microsoft to write the BASIC interpreter for its upcoming personal computer, the IBM PC. When IBM's representatives mentioned that they needed an operating system, Gates referred them to Digital Research (DRI), makers of the widely used CP/M operating system.^[31] IBM's discussions with Digital Research went poorly, and they did not reach a licensing agreement. IBM representative Jack Sams mentioned the licensing difficulties during a subsequent meeting with Gates and told him to get an acceptable operating system. A few weeks later Gates proposed using 86-DOS (QDOS), an operating system similar to CP/M that Tim Paterson of Seattle Computer Products (SCP) had made for hardware similar to the PC. Microsoft made a deal with SCP to become the exclusive licensing agent, and later the full owner, of 86-DOS. After adapting the operating system for the PC, Microsoft delivered it to IBM as PC-DOS in exchange for a one-time fee of $50,000. Gates did not offer to transfer the copyright on the operating system, because he believed that other hardware vendors would clone IBM's system.^[32] They did, and the sales of MS-DOS made Microsoft a major player in the industry.^[33]
Gates oversaw Microsoft's company restructuring on June 25, 1981, which re-incorporated the company in Washington state and made Gates President of Microsoft and the Chairman of the Board.^[27]

Windows

Microsoft launched its first retail version of Microsoft Windows on November 20, 1985, and in August, the company struck a deal with IBM to develop a separate operating system called OS/2. Although the two companies successfully developed the first version of the new system, mounting creative differences undermined the partnership. Gates distributed an internal memo on May 16, 1991, announcing that the OS/2 partnership was over and Microsoft would shift its efforts to the Windows NT kernel development.^[34]

Management style

From Microsoft's founding in 1975 until 2006, Gates had primary responsibility for the company's product strategy. He aggressively broadened the company's range of products, and wherever Microsoft achieved a dominant position he vigorously defended it.
As an executive, Gates met regularly with Microsoft's senior managers and program managers. Firsthand accounts of these meetings describe him as verbally combative, berating managers for perceived holes in their business strategies or proposals that placed the company's long-term interests at risk.^[35][36] He often interrupted presentations with such comments as, "That's the stupidest thing I've ever heard!"^[37] and, "Why don't you just give up your options and join the Peace Corps?"^[38] The target of his outburst then had to defend the proposal in detail until, hopefully, Gates was fully convinced.^[37] When subordinates appeared to be procrastinating, he was known to remark sarcastically, "I'll do it over the weekend."^[3][39][40]
Gates's role at Microsoft for most of its history was primarily a management and executive role. However, he was an active software developer in the early years, particularly on the company's programming language products. He has not officially been on a development team since working on the TRS-80 Model 100 line, but wrote code as late as 1989 that shipped in the company's products.^[39] On June 15, 2006, Gates announced that he would transition out of his day-to-day role over the next two years to dedicate more time to philanthropy. He divided his responsibilities between two successors, placing Ray Ozzie in charge of day-to-day management and Craig Mundie in charge of long-term product strategy.^[41]

Antitrust litigation

Further information: United States Microsoft antitrust case and European Union Microsoft competition case

Bill Gates giving his deposition at Microsoft on August 27, 1998

Many decisions that led to antitrust litigation over Microsoft's business practices have had Gates' approval. In the 1998 United States v. Microsoft case, Gates gave deposition testimony that several journalists characterized as evasive. He argued with examiner David Boies over the contextual meaning of words like "compete", "concerned" and "we".^[42] BusinessWeek reported:

Early rounds of his deposition show him offering obfuscatory answers and saying 'I don't recall,' so many times that even the presiding judge had to chuckle. Worse, many of the technology chief's denials and pleas of ignorance were directly refuted by prosecutors with snippets of e-mail Gates both sent and received.^[43]

Gates later said that he had simply resisted attempts by Boies to mischaracterize his words and actions. As to his demeanor during the deposition, he said, "Did I fence with Boies? ... I plead guilty. Whatever that penalty is should be levied against me: rudeness to Boies in the first degree."^[44] Despite Gates's denials, the judge ruled that Microsoft had committed monopolization and tying, and blocking competition, both in violation of the Sherman Antitrust Act.

Large Hadron Collider

The Large Hadron Collider (LHC) is the world's largest and highest-energy particle accelerator. It is expected that it will address some of the most fundamental questions of physics, advancing humanity's understanding of the deepest laws of nature.
The LHC lies in a tunnel 27 kilometres (17 mi) in circumference, as much as 175 metres (574 ft) beneath the Franco-Swiss border near Geneva, Switzerland. This synchrotron is designed to collide opposing particle beams of either protons at an energy of 7 teraelectronvolts (1.12 microjoules) per particle, or lead nuclei at an energy of 574 TeV (92.0 µJ) per nucleus.^[1][2] The term hadron refers to particles composed of quarks.
The Large Hadron Collider was built by the European Organization for Nuclear Research (CERN) with the intention of testing various predictions of high-energy physics, including the existence of the hypothesized Higgs boson^[3] and of the large family of new particles predicted by supersymmetry.^[4] It is funded by and built in collaboration with over 10,000 scientists and engineers from over 100 countries as well as hundreds of universities and laboratories.^[5]
On 10 September 2008, the proton beams were successfully circulated in the main ring of the LHC for the first time,^[6] but 9 days later operations were halted due to a serious fault.^[7] On 20 November 2009 they were successfully circulated again,^[8] with the first proton–proton collisions being recorded 3 days later at the injection energy of 450 GeV per beam.^[9] After the 2009 winter shutdown, the LHC was restarted and the beam was ramped up to 3.5 TeV per beam,^[10] half its designed energy.^[11] On 30 March 2010, the first planned collisions took place between two 3.5 TeV beams, which set a new world record for the highest-energy man-made particle collisions.^[12]

Contents [hide] 1 Purpose 2 Design 2.1 Detectors 3 Operational timeline 4 Findings 5 Proposed upgrade 6 Cost 7 Computing resources 8 Safety of particle collisions 9 Operational challenges 10 Construction accidents and delays 11 Popular culture 12 See also 13 References 14 External links

[edit] Purpose

A simulated event in the CMS detector, featuring the appearance of the Higgs boson

Physicists hope that the LHC will help answer many of the most fundamental questions in physics: questions concerning the basic laws governing the interactions and forces among the elementary objects, the deep structure of space and time, especially regarding the intersection of quantum mechanics and general relativity, where current theories and knowledge are unclear or break down altogether. These issues include, at least:^[13]

• Is the Higgs mechanism for generating elementary particle masses via electroweak symmetry breaking indeed realised in nature?^[14] It is anticipated that the collider will either demonstrate or rule out the existence of the elusive Higgs boson(s), completing (or refuting) the Standard Model.^[15][16][17]
• Is supersymmetry, an extension of the Standard Model and Poincaré symmetry, realised in nature, implying that all known particles have supersymmetric partners?^[18][19][20]
• Are there extra dimensions,^[21] as predicted by various models inspired by string theory, and can we detect them?^[22]
• What is the nature of the Dark Matter which appears to account for 23% of the energy density of the Universe?

Other questions are:

• Are electromagnetism, the strong nuclear force and the weak nuclear force just different manifestations of a single unified force, as predicted by various Grand Unification Theories?
• Why is gravity so many orders of magnitude weaker than the other three fundamental forces? See also Hierarchy problem.
• Are there additional sources of quark flavour mixing, beyond those already predicted within the Standard Model?
• Why are there apparent violations of the symmetry between matter and antimatter? See also CP violation.
• What was the nature of the quark-gluon plasma in the early universe? This will be investigated by heavy ion collisions in ALICE.

[edit] Design

A Feynman diagram of one way the Higgs boson may be produced at the LHC. Here, two quarks each emit a W or Z boson, which combine to make a neutral Higgs.

Map of the Large Hadron Collider at CERN

The LHC is the world's largest and highest-energy particle accelerator.^[1][23] The collider is contained in a circular tunnel, with a circumference of 27 kilometres (17 mi), at a depth ranging from 50 to 175 metres (160 to 574 ft) underground.
The 3.8-metre (12 ft) wide concrete-lined tunnel, constructed between 1983 and 1988, was formerly used to house the Large Electron–Positron Collider.^[24] It crosses the border between Switzerland and France at four points, with most of it in France. Surface buildings hold ancillary equipment such as compressors, ventilation equipment, control electronics and refrigeration plants.
The collider tunnel contains two adjacent parallel beam pipes that intersect at four points, each containing a proton beam, which travel in opposite directions around the ring. Some 1,232 dipole magnets keep the beams on their circular path, while an additional 392 quadrupole magnets are used to keep the beams focused, in order to maximize the chances of interaction between the particles in the four intersection points, where the two beams will cross. In total, over 1,600 superconducting magnets are installed, with most weighing over 27 tonnes. Approximately 96 tonnes of liquid helium is needed to keep the magnets at their operating temperature of 1.9 K (−271.25 °C), making the LHC the largest cryogenic facility in the world at liquid helium temperature.

Superconducting quadrupole electromagnets are used to direct the beams to four intersection points, where interactions between accelerated protons will take place.

Once or twice a day, as the protons are accelerated from 450 GeV to 7 TeV, the field of the superconducting dipole magnets will be increased from 0.54 to 8.3 teslas (T). The protons will each have an energy of 7 TeV, giving a total collision energy of 14 TeV. At this energy the protons have a Lorentz factor of about 7,500 and move at about 0.999999991 c, or about 3 metres per second slower than the speed of light (c).^[25] It will take less than 90 microseconds (μs) for a proton to travel once around the main ring – a speed of about 11,000 revolutions per second. Rather than continuous beams, the protons will be bunched together, into 2,808 bunches, so that interactions between the two beams will take place at discrete intervals never shorter than 25 nanoseconds (ns) apart. However it will be operated with fewer bunches when it is first commissioned, giving it a bunch crossing interval of 75 ns.^[26] The design luminosity of the LHC is 10³⁴ cm⁻²s⁻¹, providing a bunch collision rate of 40 MHz.^[27]
Prior to being injected into the main accelerator, the particles are prepared by a series of systems that successively increase their energy. The first system is the linear particle accelerator LINAC 2 generating 50-MeV protons, which feeds the Proton Synchrotron Booster (PSB). There the protons are accelerated to 1.4 GeV and injected into the Proton Synchrotron (PS), where they are accelerated to 26 GeV. Finally the Super Proton Synchrotron (SPS) is used to further increase their energy to 450 GeV before they are at last injected (over a period of 20 minutes) into the main ring. Here the proton bunches are accumulated, accelerated (over a period of 20 minutes) to their peak 7-TeV energy, and finally circulated for 10 to 24 hours while collisions occur at the four intersection points.^[28]

CMS detector for LHC

The LHC physics program is mainly based on proton–proton collisions. However, shorter running periods, typically one month per year, with heavy-ion collisions are included in the program. While lighter ions are considered as well, the baseline scheme deals with lead ions^[29] (see A Large Ion Collider Experiment). The lead ions will be first accelerated by the linear accelerator LINAC 3, and the Low-Energy Ion Ring (LEIR) will be used as an ion storage and cooler unit. The ions will then be further accelerated by the PS and SPS before being injected into LHC ring, where they will reach an energy of 2.76 TeV per nucleon (or 575 TeV per ion), higher than the energies reached by the Relativistic Heavy Ion Collider. The aim of the heavy-ion program is to investigate quark–gluon plasma, which existed in the early universe.

[edit] Detectors

See also: List of Large Hadron Collider experiments

Six detectors have been constructed at the LHC, located underground in large caverns excavated at the LHC's intersection points. Two of them, the ATLAS experiment and the Compact Muon Solenoid (CMS), are large, general purpose particle detectors.^[23] A Large Ion Collider Experiment (ALICE) and LHCb, have more specific roles and the last two, TOTEM and LHCf, are very much smaller and are for very specialized research. The BBC's summary of the main detectors is:^[30]

Detector	Description
ATLAS	one of two general purpose detectors. ATLAS will be used to look for signs of new physics, including the origins of mass and extra dimensions.
CMS	the other general purpose detector will, like ATLAS, hunt for the Higgs boson and look for clues to the nature of dark matter.
ALICE	is studying a "fluid" form of matter called quark–gluon plasma that existed shortly after the Big Bang.
LHCb	equal amounts of matter and antimatter were created in the Big Bang. LHCb will try to investigate what happened to the "missing" antimatter.

[edit] Operational timeline

The first beam was circulated through the collider on the morning of 10 September 2008.^[30] CERN successfully fired the protons around the tunnel in stages, three kilometres at a time. The particles were fired in a clockwise direction into the accelerator and successfully steered around it at 10:28 local time.^[31] The LHC successfully completed its first major test: after a series of trial runs, two white dots flashed on a computer screen showing the protons travelled the full length of the collider. It took less than one hour to guide the stream of particles around its inaugural circuit.^[32] CERN next successfully sent a beam of protons in a counterclockwise direction, taking slightly longer at one and a half hours due to a problem with the cryogenics, with the full circuit being completed at 14:59. In the original timeline of the LHC commissioning, the first "modest" high-energy collisions at a center-of-mass energy of 900 GeV were expected to take place before the end of September 2008, and the LHC was expected to be operating at 10 TeV by the time of the official inauguration on 21 October 2008.^[33] However, due to the delay caused by the above-mentioned incident, the collider was not operational until November 2009.^[34] Despite the delay, LHC was officially inaugurated on 21 October 2008, in the presence of political leaders, science ministers from CERN's 20 Member States, CERN officials, and members of the worldwide scientific community.^[35]
On 19 September 2008, a quench occurred in about 100 bending magnets in sectors 3 and 4, causing a loss of approximately six tonnes of liquid helium, which was vented into the tunnel, and a temperature rise of about 100 kelvin in some of the affected magnets. Vacuum conditions in the beam pipe were also lost.^[36] Shortly after the incident CERN reported that the most likely cause of the problem was a faulty electrical connection between two magnets, and that – due to the time needed to warm up the affected sectors and then cool them back down to operating temperature – it would take at least two months to fix it.^[37] Subsequently, CERN released a preliminary analysis of the incident on 16 October 2008,^[38] and a more detailed one on 5 December 2008.^[39] Both analyses confirmed that the incident was indeed initiated by a faulty electrical connection. A total of 53 magnets were damaged in the incident and were repaired or replaced during the winter shutdown.^[40]
Most of 2009 was spent on repairs and reviews from the damage caused by the quench incident. On November 20, the first low-energy beams circulated in the tunnel for the first time since the incident. The early part of 2010 saw the continue ramp-up of beam in energies and early physic experiments. On 30 March 2010, LHC set a record for high-energy collisions, by colliding proton beams at a combined energy level of 7 TeV. The attempt was the third that day, after two unsuccessful attempts in which the protons had to be "dumped" from the collider and new beams had to be injected.^[41] CERN has declared a schedule to operate the LHC through the rest of 2010 and most of 2011 before the next scheduled shutdown.^[42] The first proton run ended on 4 November 2010. A run with lead ions started on 8 November 2010, and it will continue until early December 2010.^[43] This allows the ALICE experiment to study matter under extreme conditions similar to those shortly after the Big Bang.^[44]

Timeline

Date	Event
10 Sep 2008	CERN successfully fired the first protons around the entire tunnel circuit in stages.
19 Sep 2008	Magnetic quench occurred in about 100 bending magnets in sectors 3 and 4, causing a loss of approximately 6 tonnes of liquid helium.
30 Sep 2008	First "modest" high-energy collisions planned but postponed due to accident.
16 Oct 2008	CERN released a preliminary analysis of the incident.
21 Oct 2008	Official inauguration.
5 Dec 2008	CERN released detailed analysis.
20 Nov 2009	Low-energy beams circulated in the tunnel for the first time since the incident.[45]
23 Nov 2009	First particle collisions in all four detectors at 450 GeV.[9]
30 Nov 2009	LHC becomes the world's highest-energy particle accelerator achieving 1.18 TeV per beam, beating the Tevatron's previous record of 0.98 TeV per beam held for eight years.[46]
28 Feb 2010	The LHC continues operations ramping energies to run at 3.5 TeV for 18 months to two years, after which it will be shut down to prepare for the 14 TeV collisions (7 TeV per beam).[47]
30 Mar 2010	The two beams collided at 7 TeV (3.5 TeV per beam) in the LHC at 13:06 CEST, marking the start of the LHC research program.
8 Nov 2010	Start of the first run with lead ions.

[edit] Findings

CERN scientists estimate that, if the Standard Model is correct, a single Higgs boson may be produced every few hours. At this rate, it may take about two to three years to collect enough data to discover the Higgs boson unambiguously. Similarly, it may take one year or more before sufficient results concerning supersymmetric particles have been gathered to draw meaningful conclusions.^[1] On the other hand, some extensions of the Standard Model predict additional particles, such as the heavy W' and Z' gauge bosons, whose existence might already be probed after a few months of data taking.^[48]
The first physics results from the LHC, involving 284 collisions which took place in the ALICE detector, were reported on 15 December 2009.^[49] The results of the first proton–proton collisions at energies higher than Fermilab's Tevatron proton–antiproton collisions were published by the CMS collaboration in early February 2010, yielding greater-than-predicted charged-hadron production.^[50] The CMS paper reports that the increase in the production rate of charged hadrons (mostly kaons and pions) when the center-of-mass energy goes from 0.9 TeV to 2.36 TeV exceeds by roughly 10% the predictions of the theoretical models used in the analysis.^[51]

[edit] Proposed upgrade

Main article: Super Large Hadron Collider

After some years of running, any particle physics experiment typically begins to suffer from diminishing returns: each additional year of operation discovers less than the year before. The way around the diminishing returns is to upgrade the experiment, either in energy or in luminosity. A luminosity upgrade of the LHC, called the Super LHC, has been proposed,^[52] to be made after ten years of LHC operation.
The optimal path for the LHC luminosity upgrade includes an increase in the beam current (i.e., the number of protons in the beams) and the modification of the two high-luminosity interaction regions, ATLAS and CMS. To achieve these increases, the energy of the beams at the point that they are injected into the (Super) LHC should also be increased to 1 TeV. This will require an upgrade of the full pre-injector system, the needed changes in the Super Proton Synchrotron being the most expensive.

[edit] Cost

With a budget of 9 billion US dollars (approx. €7.5bn or £6.19bn as of Jun 2010), the LHC is one of the most expensive scientific instruments^[53] ever built.^[54] The total cost of the project is expected to be of the order of 4.6bn Swiss francs (approx. $4.4bn, €3.1bn, or £2.8bn as of Jan 2010) for the accelerator and SFr 1.16bn (approx. $1.1bn, €0.8bn, or £0.7bn as of Jan 2010) for the CERN contribution to the experiments.^[55]
The construction of LHC was approved in 1995 with a budget of SFr 2.6bn, with another SFr 210M towards the experiments. However, cost overruns, estimated in a major review in 2001 at around SFr 480M for the accelerator, and SFr 50M for the experiments, along with a reduction in CERN's budget, pushed the completion date from 2005 to April 2007.^[56] The superconducting magnets were responsible for SFr 180M of the cost increase. There were also further costs and delays due to engineering difficulties encountered while building the underground cavern for the Compact Muon Solenoid,^[57] and also due to faulty parts provided by Fermilab.^[58] Due to lower electricity costs during the summer, it is expected that the LHC will normally not operate over the winter months,^[59] although an exception was made to make up for the 2008 start-up delays over the 2009/10 winter.

[edit] Computing resources

Data produced by LHC as well as LHC-related simulation will produce a total data output of 15 petabytes per year (max throughput while running not stated).^[60]
The LHC Computing Grid^[61] is being constructed to handle the massive amounts of data produced. It incorporates both private fiber optic cable links and existing high-speed portions of the public Internet, enabling data transfer from CERN to academic institutions around the world.
The Open Science Grid is used as the primary infrastructure in the United States, and also as part of an interoperable federation with the LHC Computing Grid.
The distributed computing project http://en.wikipedia.org/wiki/LHC@home was started to support the construction and calibration of the LHC. The project uses the BOINC platform, enabling anybody with an internet connection to use their computer idle time to simulate how particles will travel in the tunnel. With this information, the scientists will be able to determine how the magnets should be calibrated to gain the most stable "orbit" of the beams in the ring.

[edit] Safety of particle collisions

Main article: Safety of particle collisions at the Large Hadron Collider

The experiments at the Large Hadron Collider sparked fears among the public that the particle collisions might produce doomsday phenomena, involving the production of stable microscopic black holes or the creation of hypothetical particles called strangelets.^[62] Two CERN-commissioned safety reviews examined these concerns and concluded that the experiments at the LHC present no danger and that there is no reason for concern,^[63][64][65] a conclusion expressly endorsed by the American Physical Society.^[66]

[edit] Operational challenges

The size of the LHC constitutes an exceptional engineering challenge with unique operational issues on account of the amount of energy stored in the magnets and the beams.^[28][67] While operating, the total energy stored in the magnets is 10 GJ (equivalent to 2.4 tons of TNT) and the total energy carried by the two beams reaches 724 MJ (173 kilograms of TNT).^[68]
Loss of only one ten-millionth part (10⁻⁷) of the beam is sufficient to quench a superconducting magnet, while the beam dump must absorb 362 MJ (87 kilograms of TNT) for each of the two beams. These energies are carried by very little matter: under nominal operating conditions (2,808 bunches per beam, 1.15×10¹¹ protons per bunch), the beam pipes contain 1.0×10⁻⁹ gram of hydrogen, which, in standard conditions for temperature and pressure, would fill the volume of one grain of fine sand.

[edit] Construction accidents and delays

Wikinews has related news: CERN says repairs to LHC particle accelerator to cost €16.6 million

• On 25 October 2005, José Pereira Lages, a technician, was killed in the LHC when a switchgear that was being transported fell on him.^[69]
• On 27 March 2007 a cryogenic magnet support broke during a pressure test involving one of the LHC's inner triplet (focusing quadrupole) magnet assemblies, provided by Fermilab and KEK. No one was injured. Fermilab director Pier Oddone stated "In this case we are dumbfounded that we missed some very simple balance of forces". This fault had been present in the original design, and remained during four engineering reviews over the following years.^[70] Analysis revealed that its design, made as thin as possible for better insulation, was not strong enough to withstand the forces generated during pressure testing. Details are available in a statement from Fermilab, with which CERN is in agreement.^[71][72] Repairing the broken magnet and reinforcing the eight identical assemblies used by LHC delayed the startup date, then planned for November 2007.
• Problems occurred on 19 September 2008 during powering tests of the main dipole circuit, when an electrical fault in the bus between magnets caused a rupture and a leak of six tonnes of liquid helium. The operation was delayed for several months.^[73] It is currently believed that a faulty electrical connection between two magnets caused an arc, which compromised the liquid-helium containment. Once the cooling layer was broken, the helium flooded the surrounding vacuum layer with sufficient force to break 10-ton magnets from their mountings. The explosion also contaminated the proton tubes with soot.^[39][74] This accident was more recently thoroughly discussed in a 22 February 2010 Superconductor Science and Technology article by CERN physicist Lucio Rossi.^[75]
• Two vacuum leaks were identified in July 2009, and the start of operations was further postponed to mid-November 2009.^[76]