Context and question: The first issue was ammunition. Before the war it was recognised that ammunition needed to explode in the air. Both high explosive (HE) and shrapnel were used, mostly the former. Airburst fuses were either igniferious (based on a burning fuse) or mechanical (clockwork). Igniferious fuses were not well suited for anti-aircraft use. The fuse length was determined by time of flight, but the burning rate of the gunpowder was affected by altitude. The British pom-poms had only contact-fused ammunition. Zeppelins, being hydrogen filled balloons, were targets for incendiary shells and the British introduced these with airburst fuses, both shrapnel type-forward projection of incendiary 'pot' and base ejection of an incendiary stream. The British also fitted tracers to their shells for use at night. Smoke shells were also available for some AA guns, these bursts were used as targets during training.
What was used as targets in training practices?
Answer: Smoke shells
Context and question: Yugoslavia had a liberal travel policy permitting foreigners to freely travel through the country and its citizens to travel worldwide, whereas it was limited by most Communist countries. A number[quantify] of Yugoslav citizens worked throughout Western Europe. Tito met many world leaders during his rule, such as Soviet rulers Joseph Stalin, Nikita Khrushchev and Leonid Brezhnev; Egypt's Gamal Abdel Nasser, Indian politicians Jawaharlal Nehru and Indira Gandhi; British Prime Ministers Winston Churchill, James Callaghan and Margaret Thatcher; U.S. Presidents Dwight D. Eisenhower, John F. Kennedy, Richard Nixon, Gerald Ford and Jimmy Carter; other political leaders, dignitaries and heads of state that Tito met at least once in his lifetime included Che Guevara, Fidel Castro, Yasser Arafat, Willy Brandt, Helmut Schmidt, Georges Pompidou, Queen Elizabeth II, Hua Guofeng, Kim Il Sung, Sukarno, Sheikh Mujibur Rahman, Suharto, Idi Amin, Haile Selassie, Kenneth Kaunda, Gaddafi, Erich Honecker, Nicolae Ceausescu, Janos Kadar and Urho Kekkonen. He also met numerous celebrities.
Nehru was a leader of what country?
Answer: Indian
Context and question: Many mechanical aids to calculation and measurement were constructed for astronomical and navigation use. The planisphere was a star chart invented by Abu Rayhan al-Biruni in the early 11th century. The astrolabe was invented in the Hellenistic world in either the 1st or 2nd centuries BC and is often attributed to Hipparchus. A combination of the planisphere and dioptra, the astrolabe was effectively an analog computer capable of working out several different kinds of problems in spherical astronomy. An astrolabe incorporating a mechanical calendar computer and gear-wheels was invented by Abi Bakr of Isfahan, Persia in 1235. Abu Rayhan al-Biruni invented the first mechanical geared lunisolar calendar astrolabe, an early fixed-wired knowledge processing machine with a gear train and gear-wheels, circa 1000 AD.
The first astrolabe with gear-wheels was invented when?
Answer:
1235