Fallturm Bremen

Fallturm Bremen is a drop tower at the Center for Applied Space Travel Technology and Microgravitation at the University of Bremen in Bremen. It has a 123-meter-high drop tube (actual drop distance is 110 m), in which for 4.74 seconds (with release of the drop cap) and/or for over 9 seconds (with the use of a catapult, installed 2004) weightlessness can be produced. The entire tower, which is formed out of a reinforced concrete shank is 146 meters high. The 123-meter drop tube is actually its own tower inside the concrete shell, only connected to the rest of the tower via the foundation, in order to prevent the transmission of vibrations caused by wind, which could otherwise result in the drop capsule hitting the walls.

External links

- http://www.structurae.de/de/structures/data/str11081.php
- http://www.reproteam-bremen.de/fallturm/
- http://rats.muenster.org/faecher/physik/exkursionen/fallturm/fallturm_bremen.htm
- http://www.zarm.uni-bremen.de/ Category:Bremen Category:Technology

University of Bremen

The University of Bremen (Universität Bremen) is a university of about 22,000 students and 1,500 scientists in Bremen, Germany. It was founded in 1970. Bremen has been awarded City of Science 2005 by the Foundation for German Science (Stifterverband für die Deutsche Wissenschaft). It has a collaboration with International University Bremen in Bremen.

Academics

The university has most notably reputation in industrial engineering, computer science, microbiology and astronautics. There are 12 departments (Fachbereiche):
- 01: physics / electrical engineering
- 02: biology / chemistry
- 03: mathematics / computer science
- 04: industrial engineering
- 05: earth science
- 06: law
- 07: economic science
- 08: social sciences
- 09: cultural sciences
- 10: philology / literature
- 11: anthropology / health
- 12: educational science

External links

- http://www.uni-bremen.de
- http://www.io.uni-bremen.de/englishhome/studying_bremen.php3 - International office - Studying in Bremen Bremen

Catapult

Catapults are siege engines using an arm to hurl a projectile a great distance. Any machine that hurls an object can be considered a catapult, but the term is generally understood to mean medieval siege weapons. The name is derived from the Greek κατα (against) and παλλειγ(to hurl (a missile)). Originally, "catapult" referred to a dart-thrower, while "ballista" referred to a stone-thrower, but over the years, the two terms have swapped meaning. Catapults were usually assembled at the site of a siege, and an army carried few or no pieces of it with them because wood was easily available on site.

Types

Catapults can be classified according to the physical concept used to store and release the energy required to propel the projectile. The first catapult distinct from hand-held launchers (bows, crossbows, slings etc.) was the greek gastrophetes, a crossbow so large it was braced against the abdomen rather than being held in the hand, hence the nickname belly-bow. The next step from this was a larger form a crossbow mounted on a stand, including early versions of the oxybeles (Greek for bolt shooter) and the ballista (the Roman version of the oxybeles). The arbalette à tour is a medieval version of the stand-mounted crossbow. These catapults are tensional, in that the energy is stored as tension and compression of the bow. Although similar to a crossbow, a sling on the end of the rope meant these weapons could be used for firing all sorts of projectiles, from rocks to pots of Greek Fire. Subsequently, torsional catapults were developed: those with two torsion powered arms, the later versions of the ballista and oxybeles, and those with one torsion powered arm, the onager, known in medieval times as the mangonel. The bottom end of the throwing arm of the onager and the inner ends of both ballista arms are inserted into rope or fibers that are twisted, providing a torsional store of energy. Torsional ballistas were operationally equivalent to their tensional cousins, except the torsional energy store gave greater power. Onagers have an arm with a bucket, cup, or most often a sling to hold the projectile at one end. Finally, the last type of catapult is a trebuchet, which uses gravity or traction rather than tension or torsion to propel the throwing arm. A falling counterweight or the effort of the operator(s) pulls down the bottom end of the arm and the projectile is thrown from a sling attached to a rope hanging from the top end of the arm, essentially like a sling attached to a giant see-saw. The counterweight is much heavier than the projectile.

History

In Europe, the first catapults appeared in later Greek times (400 BC-300 BC), early adopters being Dionysius of Syracuse and Onomarchus of Phocis. Alexander the Great introduced the idea of using them to provide cover on the battlefield in addition to using them during sieges. Catapults were more fully developed in Roman and Medieval times, with the trebuchet being introduced a relatively short time before the advent of gunpowder, which made the catapult obsolete. Cannons replaced catapults as the standard siege weapon in Europe in the 14th century. During medieval times, catapults and related siege machines were the first weapons used for biological warfare. The carcasses of diseased animals and those who had perished from the Black Death or other diseases were loaded up and then thrown over the castle's walls to infect those barricaded inside. There have even been recorded instances of beehives catapulted over castle walls. During the trench warfare of the First World War, smaller catapults were used to throw hand grenades across no man's land into enemy trenches.

External links

- [http://www.redstoneprojects.com/trebuchetstore/build_a_catapult.html Catapult Plans and Design]
- [http://www.medieval-castle-siege-weapons.com/medieval-catapults.html Medieval Catapult Articles]
- [http://www.medieval-castles.org/uses/medieval_catapults.htm Information about a Medieval Catapult]

References

Catapult. The Compact Edition of the Oxford English Dictionary (1971) Category:Siege engines Category:Ancient Roman military technology

2004

2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. It was designated the:
- International Year of Rice (by the United Nations)
- International Year to Commemorate the Struggle against Slavery and its Abolition (by UNESCO)
- 2004 World Health Day topic was Road Safety (by World Health Organization)
- Year of the Monkey (by the Chinese calendar) See the world in 2004 for a description of the state of the world in this year. See also Wikipedia's almanac of events for this year.
Events

January

- January 1 - Pervez Musharraf gets a vote of confidence from an electoral college consisting of Parliament and the provincial assemblies, confirming him as President of Pakistan until 2007.
- January 3 - Flash Airlines Flight 604 crashes into the Red Sea off the coast of Egypt, killing all 148 aboard.
- January 4 - Mikhail Saakashvili wins the presidential elections in Georgia.
- January 4 -NASA's MER-A (Spirit) lands on Mars.
- January 8 - Queen Elizabeth II christens the RMS Queen Mary 2 cruise liner, currently the largest ocean liner in the world.
- January 13 - An Uzbekistan Airways plane crashes in Uzbekistan's capital of Tashkent, killing 37.
- January 22 - The European Union bans the import of poultry from Thailand, as bird flu spreads throughout Southeast Asia.
- January 24 - NASA's MER-B (Opportunity) lands on Mars.
- January 27 - The British government narrowly wins a House of Commons vote on the proposed introduction of tuition top-up fees in British universities.
- January 28 - The findings of the Hutton Inquiry are published in London. The British Government is found not to have falsified information in the "sexed up dossier". The report criticises the BBC's role in the death of David Kelly, a weapons expert on Iraq.
- January 28 - At a hearing of the National Commission on Terrorist Attacks Upon the United States, it is revealed that the September 11, 2001, terrorists used Mace (a brand of tear gas) or pepper spray in overpowering the flight crew of American Airlines Flight 11.
February

- February 1 - A hajj stampede in Mina, Saudi Arabia, kills 251 pilgrims.
- February 3 - The CIA admits that there was no imminent threat from weapons of mass destruction before the 2003 invasion of Iraq.
- February 6 - A suicide bomber kills 41 people on a metro car in Moscow.
- February 7 - Several leaders of Abnaa el-Balad arrested in Israel.
- February 10 - At least 50 people killed in a car bomb attack on a police recruitment centre south of Baghdad.
- February 10 - The French National Assembly votes to pass a law banning religious items and clothing from schools.
- February 12 - Same sex marriage in the United States: The City and County of San Francisco begins issuing marriage licenses to same-sex couples as an act of civil disobedience.
- February 13 - Scientists in South Korea announce the cloning of 30 human embryos.
- February 14 - Riots break out between New South Wales Police and Aboriginal residents of Redfern, a suburb of Sydney, Australia.
- February 18 - A train carrying a convoy of petrol, fertiliser, and sulfur derails and explodes in Iran, killing 320 people.
- February 20 - Conservatives win a majority in the Iranian parliament election.
- February 24 - 6.5 Richter scale earthquake in Northern Morocco hits in the Rif mountains near the city of Al Hoceima - over 400 dead. Ait Kamara is destroyed. 517 dead.
- February 25- Ash Wednesday. Also, the religious docudrama, The Passion of the Christ was released.
- February 26 - The United States lifts a ban on travel to Libya, ending travel restrictions to the nation that had lasted for 23 years.
- February 26 - Macedonian President Boris Trajkovski is killed in a plane crash near Mostar, Bosnia and Herzegovina.
- February 29 - 2004 Haiti rebellion: Jean-Bertrand Aristide resigns as president of Haiti. The chief justice of the Haitian Supreme Court, Boniface Alexandre, is sworn in as interim president.
- February 29 - The film The Lord of the Rings: The Return of the King directed by Peter Jackson wins 11 Academy Awards in every category it was nominated.
March

- March 2 - John Kerry effectively clinches the 2004 U.S. Democratic Party presidential nomination by winning nine out of 10 "Super Tuesday" primaries and caucuses.
- March 2 - NASA announces that the Mars rover MER-B (Opportunity), has confirmed that the area of Mars they landed in was once drenched in water.
- March 10 - Five British men released from detention at Camp Delta, Guantanamo Bay land at RAF Brize Norton. Four are immediately arrested for questioning.
- March 11 - Simultaneous explosions on rush hour trains in Madrid kill 190 people.
- March 12 - Following the terrorist attacks in Madrid on March 11, millions of protesters take to the streets of Spanish cities against terrorism.
- March 14 - Two suicide bombers kill eleven Israeli civilians in Ashdod, Israel.
- March 14 - The Spanish parliamentary elections of 2004 take place. The incumbent government led by José María Aznar is defeated by the Socialist José Luis Rodríguez Zapatero.
- March 14 - Presidential elections in Russia are held. Vladimir Putin easily wins a second term.
- March 15 - A trio of astronomers announce they have discovered a large trans-Neptunian object, the largest object found in the solar system since Pluto was discovered in 1930. Initially designated 2003 VB₁₂, it was named 90377 Sedna in late September.
- March 15 - The new Spanish government announces that it will withdraw Spain's 1,300 troops in Iraq.
- March 17 - Organized violence breaks out over two days in Kosovo. Nineteen people are killed, 139 Serbian homes are burned, schools and businesses are vandalized, and over 30 orthodox monasteries and churches are burned and destroyed.
- March 19 - The UN launches a corruption investigation due to the scandal over its Iraqi Oil for Food program.
- March 20 - President Chen Shui-bian wins the Taiwanese presidential election by 0.2% of the vote. The day before, he and Vice President Annette Lu were 'shot'. Lien Chan refuses to concede and demands a recount. A controversial 'peace referendum' opposed by the People's Republic of China is invalidated.
- March 21 - The 2004 Malaysian general election takes place. The incumbent Barisan Nasional party wins 198 out of 219 seats in the Malaysian Parliament.
- March 21 - Tony Saca is elected President of El Salvador (inauguration June 1).
- March 22 - Palestinians protest in the streets after an Israeli helicopter gunship fires a missile at the entourage of Ahmed Yassin in Gaza City, killing Yassin and 7 others.
- March 25 - British Prime Minister Tony Blair visits Libyan leader Colonel Muammar al-Qaddafi, in return for the dismantling of Libya's WMD programme in December 2003 - the first time a major western leader has visited the nation in several decades.
- March 28 - In France, the government of Prime Minister Jean-Pierre Raffarin suffers a stunning and unprecedented defeat in regional elections. The first ever South Atlantic Hurricane makes landfall in South Brazil on the state of Santa Catarina, the Hurricane is dubbed Hurricane Catarina.
- March 29 - The Republic of Ireland bans smoking in all enclosed work places including: restaurants, pubs and bars.
- March 29 - Largest expansion of NATO to date, allowing Bulgaria, Estonia, Latvia, Lithuania, Romania, Slovakia and Slovenia into the organization.
- March 31 - Four American private military contractors working for Blackwater USA, are killed and their bodies mutilated after being ambushed in Fallujah, Iraq.
April

- April 1 - Faroese Prime Minister's Office announces that from then on the Prime Minister and the Prime Minister's Office would use a new version of the Faroese Coat of Arms. The colours were inspired from the Merkið (flag) and yellow/gold was added. The new Coat of Arms depicts a Ram on a blue shield ready to defend. It can be used by the Government Ministries and by Faroese embassies, but some still use older versions of the Coat of Arms. Coat of Arms
- April 3 - A bomb explosion in a Madrid flat kills a Spanish policeman and five terrorists suspected of responsibility for the Madrid train bombings on March 11.
- April 4 - Serious fighting breaks out in Najaf, Sadr City, and Basra in Iraq as Shia insurgents supporting Muqtada al-Sadr rise against coalition forces.
- April 5 - Queen Elizabeth II begins a state visit to France to celebrate the 100th anniversary of the Entente Cordiale.
- April 8 - Darfur conflict: The Humanitarian Ceasefire Agreement is signed by the Sudanese government and two rebel groups.
- April 8 - Three Japanese citizens are taken hostage in Iraq.
- April 8 - Former Japanese famous economist, professor at Waseda University graduate school Kazuhide Uekusa was arrested on the escalator of JR Shinagawa Station because of trying to peep under high school girl's skirt with his hand mirror.
- April 16 - India defeats Pakistan in their first cricket tour in 14 years.
- April 17 - Israeli helicopters fire missiles at a convoy of vehicles in the Gaza Strip, killing the Gaza leader of Hamas, Abdel Aziz al-Rantissi.
- April 20 - In Iraq, 12 mortars were fired on Abu Ghraib Prison by insurgents. Twenty two detainees were killed and 92 wounded. [http://www.usatoday.com/news/world/iraq/2004-04-20-iraq_x.htm]
- April 21 - Mordechai Vanunu, who revealed an Israeli nuclear weapons programme in the 1980s, is released from prison in Israel after an 18 year term for treason.
- April 22 - Two trains carrying explosives and fuel collide in the North Korean town of Ryongchon, killing 161 people, injuring 1,300 and destroying thousands of homes.
- April 22 - The last coal mine in France closes, ending nearly 300 years of coal mining.
- April 25 - Referenda on a United Nations plan, which proposes to re-unite the island of Cyprus, take place in both the Greek and Turkish parts. Although the Turks vote in favour, the Greeks reject the proposal.
- April 28 - Abuse of prisoners at the Abu Ghraib prison in Iraq is revealed on the television show 60 Minutes II.
May

- May 1 - the largest expansion to date of the European Union takes place, extending the Union by 10 member-states: Poland, Lithuania, Latvia, Estonia, the Czech Republic, Slovakia, Slovenia, Hungary, Malta and Cyprus.
- May 6 - The final episode of Friends airs on NBC, drawing an estimated 52 million viewers in North America.
- May 8 - Would-be "Saudi Princess" "Antoinette Millard" surfaces in New York City and claims that muggers had stolen jewels worth of $262.000 from her (she later proves to be an impostor).
- May 9 - Chechen president Akhmad Kadyrov is killed by landmine placed under a VIP stage during a World War II memorial parade in Grozny.
- May 9 - Team of Canada won the World Ice Hockey Championship in Prague.
- May 10 - The 2004 Philippine presidential and legislative elections take place. Incumbent president Gloria Macapagal-Arroyo wins the presidency.
- May 11 - An explosion destroys a plastics factory in Glasgow, UK, killing nine people and injuring over a hundred.
- May 12 - An American civilian contractor in Iraq, Nick Berg, is shown being decapitated by a group allegedly linked to al-Qaida on a web-distributed video.
- May 13 - In India, the Congress Party wins a surprise victory in the elections to the Lok Sabha.
- May 14 - Frederik, Crown Prince of Denmark, marries Australian Mary Donaldson in Copenhagen.
- May 17 - Ezzedine Salim, holder of the rotating leadership of the Iraqi Governing Council, is killed in a bomb blast in Baghdad.
- May 17 - Massachusetts legalizes same-sex marriage in compliance with a ruling from the state's Supreme Judicial Court (Goodridge v. Department of Public Health).
- May 19 - Tony Blair is hit with a purple flour bomb in the chamber of the House of Commons during a session of Prime Minister's Questions.
- May 19 - Jeremy Sivits pleads guilty in a court-martial in connection with alleged abuse of Iraqi prisoners at Abu Ghraib prison in Baghdad.
- May 23 - A section of the ceiling in Terminal 2E at Paris's Charles de Gaulle International Airport collapses, claiming at least six lives.
- May 23 - Japanese prime minister Junichiro Koizumi visits North Korea to secure the release of the families of the nine abducted Japanese citizens returned earlier.
- May 26 - Terry Nichols is convicted by an Oklahoma state court on murder charges stemming from the 1995 Oklahoma City bombing.
- May 29 - Dedication of the National World War II Memorial takes place in Washington, DC.
- May 30 - Thousands of people in Hong Kong take to the streets to commemorate the 15th anniversary of the Tiananmen Square massacre.
June

- June 1 - Twelve-year-old Satomi Mitarai, a Japanese schoolgirl attending Okubo Elementary School in Sasebo, Japan is murdered. Her killer, an 11-year-old classmate identified by Japanese authorities as "Girl A", becomes the basis for the Nevada-tan Internet meme.
- June 4 - Marvin Heemeyer destroys many local buildings with a home-made tank in Grancby, Colorado
- June 5 - Former President of the United States, Ronald Reagan, dies at age 93.
- June 6 - The 60th anniversary of D-Day is remembered by world leaders.
- June 7 - Tampa Bay Lightning defeat Calgary Flames in 2004 Stanley Cup Finals.
- June 8 - The first transit of Venus since 1882 occurs; the next one will occur in 2012.
- June 8 - The G8 Summit takes place over the next 2 days on Sea Island, in Georgia, USA.
- June 8 - The pickled heart of Louis XVII of France is buried in the royal crypt at Saint-Denis.
- June 11 - Terry Nichols is spared the death penalty by an Oklahoma state court on murder charges stemming from the 1995 Oklahoma City bombing. The decision came on the third anniversary of the execution of his co-defendant, Timothy James McVeigh, in Terre Haute, Indiana.
- June 11 - After the first presidential state funeral since 1973, President Ronald Wilson Reagan is laid to rest at Simi Valley, California, at the site of the Reagan Presidential Library.
- June 12 - A 1.3 kg chondrite type meteorite struck a house in Ellerslie, New Zealand causing serious damage but no injuries.Ellerslie, New Zealand
- June 15 - The Detroit Pistons upset the heavily favored Los Angeles Lakers to win the 2004 NBA Finals, four games to one.
- June 16 - The National Commission on Terrorist Attacks Upon the United States (or "9/11 Commission") issues an initial report of its findings.
- June 21 - SpaceShipOne becomes the first privately-funded spaceplane to achieve spaceflight.
- June 28 - Union Pacific and Burlington Northern Santa Fe trains collided in a rural area outside of San Antonio, Texas. Forty cars were derailed, including one chlorine car, and three people died, another 50 people were hospitalized because of exposure to the gas.
- June 28 - The U.S.-led coalition occupying Iraq transfers sovereignty to an interim Iraqi government.
- June 28 - Canadian election: The Liberal Party, led by Paul Martin, is reduced to a minority government, after holding a majority since November 1993.
- June 30 - The preliminary hearings begin in Iraq in the trial of former president Saddam Hussein, for war crimes and crimes against humanity.
July

- July 1 - The Cassini-Huygens spacecraft arrives at Saturn.
- July 4 - Groundbreaking of Freedom Tower at Ground Zero in New York City.
- July 4 - The Euro 2004 final between Portugal and Greece takes place in Lisbon, Portugal. Greece wins the match 1:0.
- July 22 - The Old Bridge of Mostar in Bosnia-Herzegovina is reconstructed and reopened after being destroyed by Bosnian Croat forces on November 9, 1993.
- July 25 - Over 100,000 opponents to Israel's unilateral disengagement plan of 2004 participate in a human chain from Gush Katif, to the Western Wall, Jerusalem (90 kilometers).
- July 25 - Lance Armstrong of Austin, Texas wins an unprecedented 6th consecutive Tour de France cycling title.
August

- August 1 - Supermarket fire in Asunción, Paraguay, kills about 400 people and leaves over 100 missing.
- August 3 - Statue of Liberty reopens after security improvements.
- August 6 - A United Nations report that blames the government of Sudan for crimes against humanity in Darfur is released.
- August 12 - Singapore's prime minister Goh Chok Tong hands over his position to Lee Hsien Loong.
- August 13 - The 2004 Summer Olympics begin in Athens. They end on August 29.
- August 13 - Hurricane Charley kills 27 people in Florida after killing four in Cuba and one in Jamaica. Charley made landfall near Cayo Costa, FL as a Category 4 hurricane. Charley was the most intense hurricane to strike the United States since Hurricane Andrew in 1992.
- August 16 - Severe flooding in the village of Boscastle in Cornwall.
- August 18 - In Dublin, Ireland the Dublin Port Tunnel excavation works were completed and the final tunnel boring machine breakthrough ceremony took place.
- August 21 - A series of blasts rocks a rally of an opposition party in Dhaka, Bangladesh, killing at least 13 people.
- August 22 - Armed robbers steal Edvard Munch's The Scream, Madonna and other paintings from the Munch Museum in Oslo, Norway.
- August 24 - Two airliners in Russia, carrying a total of 89 passengers, crash within minutes of each other after flying out of Domodedovo International Airport, leaving no survivors. Authorities suspect suicide attacks by rebels from Chechnya to be the cause of the crashes.
- August 29 - Around 200,000 protesters demonstrate in New York City against President George W. Bush and his government, ahead of the 2004 Republican National Convention.
- August 31 - Two suicide attacks on buses in Beer Sheva, Israel, kill at least 16 people and injure at least 60. Hamas claims responsibility for the attacks.
- August 31 - A woman commits a suicide attack near a subway station in northern Moscow, Russia, killing at least 10 people and injuring at least 50. Authorities hold Chechen rebels responsible.
September

- September 1 - Chechen rebels take between 1,000 and 1,500 people hostage, mostly children, in a school in Beslan, Northern Ossetia. The hostage-takers demand the release of Chechen rebels imprisoned in neighbouring Ingushetia and the independence of Chechnya from Russia.
- September 2 - The United Nations Security Council adopts Resolution 1559 calling for the removal of all foreign troops from Lebanon. This measure is largely aimed at Syrian troops.
- September 3 - Russian forces end the siege at a school in Beslan, Northern Ossetia. At least 335 people (among which at least 32 of the approximately 40 hostage-takers) have been killed and at least 700 people have been injured.
- September 3 - Hurricane Frances makes landfall in Florida. After killing two people in the Bahamas, Hurricane Frances killed ten people in Florida, two in Georgia and one in South Carolina.
- September 7 - The Scottish Parliament meets in the new Scottish Parliament Building for the first time.
- September 7 - Hurricane Ivan passes directly over Grenada, killing 37 people. It passes over other Caribbean islands over the next two days, killing 5 people in Venezuela, 4 in the Dominican Republic, 1 in Tobago and 20 in Jamaica.
- September 8 - In the "Rathergate" affair, the first Internet posts appear pointing out that documents claimed by CBS News to be typewritten memos from the early 1970s appear instead to have been produced using modern word processing systems.
- September 9 - A bomb blast outside the Australian embassy in Jakarta, Indonesia, kills eleven people and injures up to 100 people.
- September 13 - The Assault Weapons Ban expires.
- September 15 - Davíð Oddsson prime minister of Iceland steps down after serving as prime minister since April 30 1991. Oddson becomes foreign minister as his foreign minister Halldór Ásgrímsson becomes prime minister.
- September 15 - Security at the Palace of Westminster is compromised when the House of Commons is stormed by a small group of protestors during a debate about fox hunting.
- September 15 - "Girl A" is sentenced to be institutionalized due to the murder of classmate Satomi Mitarai.
- September 16 - Hurricane Ivan strikes Gulf Shores, Alabama, as a Category 3 storm, killing 25 in Alabama and Florida.
- September 17 - 2004 Summer Paralympics commences in Athens, Greece.
- September 17 - Mexico and Japan finish the two year long negotiations and sign a Free Trade Agreement in Mexico City.
- September 23 - Mount St. Helens becomes active again.
- September 23 - Tropical Storm Ivan, having come around and reformed in the Gulf of Mexico, makes its final landfall near Cameron, Louisiana, to little effect. In total, the storm killed 92 people.
- September 25 - Hurricane Jeanne makes landfall near Hutchinson Island, FL. In all, Jeanne killed over 3,000, most in Haiti.
- September 29 - First Ansari X-Prize flight of SpaceShipOne.
October

- October 4 - Two car bombs kill at least 16 people and injure dozens more in Baghdad.
- October 5 - A fire breaks out on the Canadian submarine HMCS Chicoutimi leaving it stranded without power in the North Atlantic ocean, off the north coast of Ireland. One crewmember is killed.
- October 8 - Kenneth Bigley, the British hostage held by Abu Musab al-Zarqawi, an Iraqi insurgent, is killed after a failed escape attempt.
- October 8 - Suicide bombers detonate two bombs at the Red Sea resort of Taba, Egypt, killing 34 people, mainly Israeli tourists and Egyptian workers.
- October 9 - Queen Elizabeth II opens the new Scottish Parliament Building in a ceremony in Edinburgh
- October 9 - Incumbent Prime Minister of Australia John Howard leads the Liberal-National coalition to victory over the Labor Party led by Mark Latham in federal elections.
- October 9 - Direct elections for president held for the first time in Afghanistan. Interim president Hamid Karzai is eventually declared the winner.
- October 10 - Abdullahi Yusuf is chosen as the new transitional president of Somalia.
- October 14 - Prince Norodom Sihamoni is chosen as the new king of Cambodia.
- October 16 - The New York Yankees defeat the Boston Red Sox, 19-8 in Game 3 of Major League Baseball's American League Championship Series. The game, which pushed the Yankees to a 3 games to none series lead, sets a record for longest nine inning baseball game.
- October 17 - A referendum in Belarus approves the lifting of constitutional term limits for the presidency.
- October 18 - Three men attack Greek journalist Philippos Syrigos in Athens and seriously wound him
- October 19 - General Khin Nyunt is replaced by Lieutenant-General Soe Win as Prime Minister of Myanmar.
- October 20 - The Boston Red Sox defeat the New York Yankees in Game 7 of the American League Championship Series, completing an unprecedented comeback from three games to none down.
- October 20 - Corporate Airlines Flight 5966 crashes in Missouri, killing 13 people, and injuring 2.
- October 20 - Susilo Bambang Yudhoyono becomes the first directly-elected President of Indonesia.
- October 21 - The Ministry of Defence approves the deployment of the Black Watch regiment of the British Army to Baghdad, Iraq after a request for assistance by the U.S. government.
- October 24 - The bodies of 49 Iraqi soldiers discovered after being ambushed by insurgents.
- October 24 - Brazil successfully launches its first rocket into space.
- October 25 - Reverand Dr Martin Luther King, Jr and Coretta Scott King receive Congressional Gold Medal.
- October 26 - October 26The Cassini probe passes within 1,200km of Titan
- October 27 - Details of the discovery of a new, recent, species of fossil hominid, Homo floresiensis, from the island of Flores, Indonesia are published.
- October 27 - The Boston Red Sox sweep the St. Louis Cardinals to win the World Series championship for the first time since 1918.
- October 29 - A videotape of Osama Bin Laden speaking airs on Arabic TV, in which he threatens terrorist attacks on the United States, and taunts the president, George W. Bush, over the September 11 Terrorist attacks.
- October 29 - European heads of state signed in Rome the Treaty and Final Act establishing the first European Constitution.
- October 30 - A 163 metre high radio mast in Peterborough, UK collapsed at a fire
- October 31 - Leftist candidate Tabaré Vázquez is elected President of Uruguay.
November

- November 1 - a 16 year old Palestinian, a muslim, blew himself up in an outdoor market in Tel Aviv, killing three Israelis.
- November 2 - U.S. presidential election: President George W. Bush defeats Senator John Kerry. Republicans make gains in the In construction, concrete is a composite building material made from the combination of aggregate and cement binder. The most common form of concrete is Portland cement concrete, which consists of mineral aggregate (generally gravel and sand), Portland cement and water. It is commonly believed that concrete dries after mixing and placement. Actually, concrete does not solidify because water evaporates, but rather cement hydrates, gluing the other components together and eventually creating a stone-like material. When used in the generic sense, this is the material referred to by the term concrete. Concrete is used to make pavements, building structures, foundations, motorways/roads, overpasses, parking structures, bases for gates/fences/poles, and cement in brick or block walls. An old name for concrete is liquid stone.
History
The Assyrians and Babylonians used clay as cement in their concretes. The Egyptians used lime and gypsum cement. In the Roman Empire, cements made from pozzolanic ash/pozzolana and an aggregate made from pumice were used to make a concrete very similar to modern portland cement concrete. In 1756, British engineer John Smeaton pioneered the use of portland cement in concrete, using pebbles and powdered brick as aggregate. In the modern day, the use of recycled/reused materials as concrete ingredients is gaining popularity due to increasingly stringent environmental legislation. The most conspicuous of these is pulverized fuel ash, recycled from the ash by-products of coal power plants. This has a significant impact in reducing the amount of quarrying and the ever-attenuating landfill space.
Characteristics
During hydration and hardening, concrete needs to develop certain physical and chemical properties, among others, mechanical strength, low permeability to ingress of moisture, and chemical and volume stability. Concrete has relatively high compressive strength, but significantly lower tensile strength (about 10% of the compressive strength). As a result, concrete always fails from tensile stresses - even when loaded in compression. The practical implication of these facts is that concrete elements that are subjected to tensile stresses must be reinforced. Concrete is most often constructed with the addition of steel bar or fiber reinforcement. The reinforcement can be by bars (rebars), mesh, or fibres to produce reinforced concrete. Concrete can also be prestressed (reducing tensile stress) using steel cables, allowing for beams or slabs with a longer span than is practical with reinforced concrete. The ultimate strength of concrete is related to water/cement ratio, the proportion and type of cement to fillers, and the size, shape, and strength of the aggregate used. Concrete with lower water/cement ratio (down to 0.35) makes a stronger concrete than a higher ratio. Concrete made with smooth pebbles is weaker than that made with rough-surfaced broken rock pieces for example. Certain shapes are very strong in compression, such as arches and vaults, and are therefore preferred for concrete construction. Concrete is placed in a wet or plastic state, and therefore can be manipulated and molded as needed. Hydration and hardening of concrete may lead to tensile stresses at a time when it has not yet gained significant strength, resulting in shrinkage cracks. However, when concrete mix is placed in accordance with the best recommended practice, cracking may be minimal. vault
Additives
Additives are organic or non-organic materials in form of solids or fluids that are added to the concrete to give it certain characteristics. In normal use the additives make up less than 5% of the cement weight. The most used types of additives are:
- Accelerators: Speed up the hydration (strengthening) of the concete.
- Retarders: Slow the hydration of concrete.
- Air-entrainers: Add and distribute air to the concrete.
- Plasticizers: Increase the workability of concrete.
Workability
Workability is the ability of a fresh (plastic) concrete mix to fill the form/mould properly with the desired work (vibration) and without reducing the concrete's quality. Workability depends on water content, additives, aggregate (shape and size distribution) and age (level of hydration). Raising the water content or adding plasticizer will increase the workability. Too much water will lead to bleeding (loss of water) and/or segregation (concrete starts to get heterogeneous) and the resulting concrete will have reduced quality. Workability is normally tested by slump measurement. High flow concrete, like self compacting concrete, are normaly tested by one of several flow measuring methods. Concrete slump is a simplistic measure of fresh (plastic) concrete's workability. Slump is normally determined by the ASTM C 143 or EN 12350-2 slump test standards, using the Abrams cone, into which concrete is placed for testing. When the cone is carefully lifted off the enclosed material, it will slump a certain amount due to its water content. A relatively dry sample will slump very little, and be given a slump of one or two inches (25 or 50 mm), while a relatively wet concrete sample may slump as much as six or seven inches (150 to 175 mm). To increase the slump, the rule of thumb is:
- US units :Add 1 US gallon of water per cubic yard of concrete in the mixer truck to increase slump by 1 inch. Adding 27 US gallons to 9 cubic yards of batched concrete will therefore increase the slump by about 3 inches.
- Metric units (converted from US rule of thumb) :Add 2 litres of water per cubic metre of concrete in the mixer truck to increase slump by 1 cm. Adding 54 litres to 9 cubic metres of batched concrete will therefore increase the slump by about 3 cm. Slump can also be increased by adding a plasticizer, without changing the water/cement ratio.
Self compacting concretes
During the 1980s a number of countries including Japan, Sweden and France developed a range of concretes that were self-compacting. These 'SCC's are characterised by their extreme fluidity (using plasticizers), behaving more like water than the traditional viscous concrete. SCCs are characterized by
- extreme fluidity measured by flow or slump, typically measured between 700-750 mm.
- no need for vibrators to compact the concrete, which can be noisy
- no or little need for expensive concrete pumping equipment
- no bleed water (excess water draining out of the concrete) SCC can offer benefits of up to 50% in labour costs, due to it being poured up to 80% faster and having reduced wear and tear on formwork. As of 2005, self compacting concretes account for 10-15% of concrete sales in some European countries.
Shotcrete / sprayed concrete
Main article: Shotcrete
Shotcrete uses compressed air to shoot (cast) concrete to a frame or structure. Shotcrete is mostly used for rock support, especially in tunnelling. Today there are two application methods for shotcrete: the dry-mix and the wet-mix procedure. In Dry-mix the dry mixture of cement and aggregates is filled into the machine and conveyed with compressed air through the hoses. The water needed for the hydration is added at the nozzle. In Wet-mix the mixes are prepared with all necessary water for hydration. The mixes are pumped through the hoses. At the nozzle compressed air is added for spraying. For both methods additives such as plasticizers and accelerators may be used. Shotcrete is normally reinforced by fibers.
See also

- Building construction
- Concrete mixer
- Concrete recycling
- Concrete resurfacing
- Reinforced concrete
- Slab-on-grade foundations
- Shotcrete
- Formwork
External link

- [http://inventors.about.com/library/inventors/blconcrete.htm History of Concrete] Category:Concrete Category:Civil engineering Category:Materials Category:Construction Category:Pavements Category:Heterogeneous mixtures ms:Konkrit ja:コンクリート simple:Concrete

Vibration

:For other uses, see oscillator (disambiguation) Oscillation is the periodic variation, typically in time, of some measure as seen, for example, in a swinging pendulum. The term vibration is sometimes used more narrowly to mean a mechanical oscillation but sometimes is used to be synonymous with oscillation. Oscillations occur not only in physical systems but also in biological systems and in human society. Oscillations are the origin of the sensation of musical tone.
Simple systems
The simplest oscillating system is a mass, subject to the force of gravity, attached to a linear spring. The system is in an equilibrium state when the weight of the mass is balanced by the tension of the spring. If the system is displaced from the equilibrium, there is a net restoring force on the mass, tending to bring it back to equilibrium. However, in moving the mass back to the equilibrium position, it has acquired inertia which keeps it moving beyond that position, establishing a new restoring force, now in the opposite sense. The specific dynamics of this spring-mass system are described mathematically by the simple harmonic oscillator and the regular periodic motion is known as simple harmonic motion. In the spring-mass system, oscillations occur because, when at the static equilibrium displacement, the mass has kinetic energy which is converted into energy stored in the spring at the extremes of its path. The spring-mass system illustrates some important and universal principles of oscillation:
- Existence of an equilibrium;
- Presence of some restoring force (or restoring principle in non-mechanical systems);
- Some form of "inertia" that maintains motion; and
- Exchange in "energy" between that associated with "inertia" and that of the restoring force. The harmonic oscillator offers a model of many more complicated types of oscillation and can be extended by the use of Fourier analysis.
Damped, driven and self-excited oscillations
In real-world systems, the second law of thermodynamics dictates that there is some continual and inevitable conversion of energy into the thermal energy of the environment. Thus, damped oscillations tend to decay with time unless there is some net source of energy in the system. The simplest description of this decay process can be illustrated by the harmonic oscillator.
Self-exciting systems
Some systems are able to extract energy from their environment. This typically occurs where systems are embedded in some fluid flow. For example, the phenomenon of flutter in aerodynamics occurs when an, arbitrarily small, displacement of an aircraft wing, from its equilibrium, results in an increase in the angle of attack of the wing on the air flow and a consequential increase in lift coefficient leading to a greater displacement before, at sufficiently large displacements, the stiffness of the wing dominates to provide the restoring force that enables an oscillation. The phenomenon of hunting is a self-exciting oscillation in non-linear electrical circuits.
Coupled oscillations
The harmonic oscillator, and the more complicated systems for which it stands as a simple model, has a single degree of freedom. More complicated systems have more degrees of freedom, for example two masses and two springs. In such cases, energy is converted between the respective inertias of each degree of freedom and the several restoring forces in the system. This leads to a coupling of the oscillations of the individual degrees of freedom. For example, two pendulum clocks mounted on a common wall will tend to synchronise. The apparent motions of the individual oscillations typically appears very complicated but a more economic, computationally simpler and conceptually deeper description is given by resolving the motion into normal modes.
Continuous systems - waves
As the number of degrees of freedom becomes indefinitely large, a system approaches continuity, for example, a string or the surface of a body of water. Such systems have an infinite number of normal modes and their oscillations occur in the form of waves that have the characteristic that they can propagate.
Neural systems
Neural oscillations occur in individual cells and cell ensembles. Depending on the frequency, brain area and behavior associated with neuronal oscillations, a diversity of functions have been suggested.
Examples
See also: list of wave topics
Mechanical

- Pendulum
- Double pendulum
- Foucault pendulum
- String instruments
- Vibrating string
- Helmholtz resonator
- Tacoma Narrows Bridge - Galloping Gertie, an example of a self-exciting system
- Tuning fork
Electrical

- Armstrong oscillator
- Astable multivibrator
- Blocking Oscillator
- Clapp oscillator
- Colpitts oscillator
- Crystal oscillator
- Electronic oscillator
- Hartley oscillator
- Relaxation oscillator
- RLC circuit
- Vackar oscillator
- Royer oscillator
Electro-mechanical

- Microphone
- Loudspeaker
Biological

- Prey-predator systems
Human

- Pilot-induced oscillation
- Voice production
- Brain waves
- "Good vibrations"
Economic and social

- Business cycle
- Publicly funded medicine
Climate and geophysics

- Chandler wobble
- El Niño-Southern Oscillation
- Quasi-biennial oscillation
- Tides in the Earth's oceans
See also

- Dynamical system
- Feedback
- Instability
- Oscillation (mathematics)
- Periodic function
- Signal generator
- Strange attractor
- Tuned mass damper
- Vibrator Category:Dynamical systems ko:진동 ja:振動

Category:Bremen

Category:States of Germany Category:Cities in Germany ko:분류:브레멘 주

Category:Technology

Category:Top 8 ko:분류:기술 ja:Category:技術

大學生研經宣教會

大學生研經宣教會(University Bible Fellowshop, UBF)是一個基督教教會，其信徒多為大學生，起源於1960年代的南韓。該教會的目標是於2041年前，派10萬位宣教士到233個國家宣道，其主要目標為中國、北韓和回教國家。但據不少在香港的大學生並網上資源指出，大學生研經宣教會對其會友有精神虐待的行為存在。

外部連結

- [http://www.ubf.or.kr UBF韓國總部]
- [http://www.ubf-net.de/index.en.htm Infopages Unversity Bible Fellowhship]
- [http://rsqubf.fortunecity.net/ RSQUBF] category:基督教教會與教派

online casinos Sklep Nurkowy darmowe statystyki Nurkowanie Nieruchomo�ci ��d�

:: RELATED NEWS ::

Nicolas Antoine Sanson
Sanson, Nicolas Antoine Sanson, Nicolas Antoine Sanson, Nicolas Antoine Nicolas Antoine Sanson, né le 7 décembre 1756, mort en 1824) fut un gé

Massacre de Srebrenica
en Republika Srpska]] Le massacre de Srebrenica est un épisode tragique et controversé de la guerre de Bosnie qui s'est déroulé entre le 13 et le 16 juillet 1995 près de la ville de Srebrenica. Il se rapporte au

Pratique
Une pratique est une façon de procéder dans la réalisation d'une action ou qualifie une action particulière.
- Elle peut se pratiquer seul ou en groupe.
- Elle peut être innée, issue de tradition, d'une religion, d'un métier.
- Une pratique religieuse est dénommée

Pratique religieuse
Catégorie:Anthropologie Catégorie:Religion Un rite ou rituel est une répétition d'occasion et de forme, chargée de signification (action « symbolique »). Il n'est pas d'essence spontanée : au contraire, le rituel est réglé, fixé, codifié, et le respect de la règle garantit l'efficacité du rituel.

Opinions diverses

Les opinions sur les rites sont diverses. :
- Une mouvance dominante du

Giovanni Domenico Cassini
Jean-Dominique Cassini dit Cassini I (8 juin 1625, Perinaldo, République génoise - 14 septembre 1712, Paris) est un astronome et Catégorie:Anthropologie Catégorie:Religion Un rite ou rituel est une répétition d'occasion et de forme, chargée de signification (action « symbolique »). Il n'est pas d'essence spontanée : au contraire, le rituel est réglé, fixé, codifié, et le respect de la règle garantit l'efficacité du rituel.

Opinions diverses

Les opinions sur les rites sont diverses. :
- Une mouvance dominante du

Arjumand Bânu Begam
ja:ムムターズ・マハル Arjumand Bânu Begam, surnommée Mumtâz-i Mahal - parfois simplifié en Mumtâz Mahal - en ourdou, la merveille du palais, est l'une des épouses de l'empereur moghol Shâh Jahân. Arjumand naît en avril 1593 à ja:ムムターズ・マハル Arjumand Bânu Begam, surnommée Mumtâz-i Mahal - parfois simplifié en Mumtâz Mahal - en ourdou, la merveille du palais, est l'une des épouses de l'empereur moghol Shâh Jahân. Arjumand naît en avril 1593 à ja:ムムターズ・マハル Arjumand Bânu Begam, surnommée Mumtâz-i Mahal - parfois simplifié en Mumtâz Mahal - en ourdou, la merveille du palais, est l'une des épouses de l'empereur moghol Shâh Jahân. Arjumand naît en avril 1593 à série télévisée étasunienne en 13 épisodes de 42 minutes, créée par Joe Michael Straczynski et diffusée du 9 juin au 1 septembre 1999 sur le réseau