sentence-transformers/squad huggingface dataset:
Passage: Education in Eritrea is officially compulsory between seven and 13 years of age. However, the education infrastructure is inadequate to meet current needs. Statistics vary at the elementary level, suggesting that between 65 and 70% of school-aged children attend primary school; Approximately 61% attend secondary school. Student-teacher ratios are high: 45 to 1 at the elementary level and 54 to 1 at the secondary level. There are an average 63 students per classroom at the elementary level and 97 per classroom at the secondary level. Learning hours at school are often less than six hours per day. Skill shortages are present at all levels of the education system, and funding for and access to education vary significantly by gender and location. Illiteracy estimates for Eritrea range from around 40% to as high as 70%.

Question: What ages are officially compulsary for education in Eritrea?

Question: What percentage of school-aged children are estimated to attend primary school?

Question: What percentage of school-aged children are estimated to attend secondary school?

Question: What is the student-teacher ratio in elementary schools?

Question: What is the student-teacher ratio in secondary schools?
Passage: A typical traditional Eritrean dish consists of injera accompanied by a spicy stew, which frequently includes beef, kid, lamb or fish. Overall, Eritrean cuisine strongly resembles those of neighboring Ethiopia, Eritrean cooking tend to feature more seafood than Ethiopian cuisine on account of their coastal location. Eritrean dishes are also frequently "lighter" in texture than Ethiopian meals. They likewise tend to employ less seasoned butter and spices and more tomatoes, as in the tsebhi dorho delicacy.

Question: What meat does a traditional Eritrean stew consist of?

Question: Which neighbor does Eritrean cuisine strongly resemble?

Question: Why does Eritrean cooking tend to feature more seafood than Ethiopian cuisine?

Question: How does the texture of Eritrean dishes compare to Ethiopian meals?

Question: What ingredients fo Eritreans tend to use less of than Ethiopians?
Passage: Depleted uranium is also used as a shielding material in some containers used to store and transport radioactive materials. While the metal itself is radioactive, its high density makes it more effective than lead in halting radiation from strong sources such as radium. Other uses of depleted uranium include counterweights for aircraft control surfaces, as ballast for missile re-entry vehicles and as a shielding material. Due to its high density, this material is found in inertial guidance systems and in gyroscopic compasses. Depleted uranium is preferred over similarly dense metals due to its ability to be easily machined and cast as well as its relatively low cost. The main risk of exposure to depleted uranium is chemical poisoning by uranium oxide rather than radioactivity (uranium being only a weak alpha emitter).

Question: What kind of uranium is sometimes used to shield radioactive materials in containers?

Question: What is a strong source of radiation that is blocked by depleted uranium?

Question: How is depleted uranium used in missile re-entry vehicles?

Question: What trait causes depleted uranium to be used in gyroscopic compasses?

Question: What type of alpha emitter is uranium?
Passage: The discovery and isolation of radium in uranium ore (pitchblende) by Marie Curie sparked the development of uranium mining to extract the radium, which was used to make glow-in-the-dark paints for clock and aircraft dials. This left a prodigious quantity of uranium as a waste product, since it takes three tonnes of uranium to extract one gram of radium. This waste product was diverted to the glazing industry, making uranium glazes very inexpensive and abundant. Besides the pottery glazes, uranium tile glazes accounted for the bulk of the use, including common bathroom and kitchen tiles which can be produced in green, yellow, mauve, black, blue, red and other colors.

Question: What is another term for uranium ore?

Question: Who isolated radium in uranium ore?

Question: In what types of paints was radium first used?

Question: What devices were painted with radium paint?

Question: Along with red, blue, black, yellow and green, what was a notable color of uranium tile glaze?
Passage: The X-10 Graphite Reactor at Oak Ridge National Laboratory (ORNL) in Oak Ridge, Tennessee, formerly known as the Clinton Pile and X-10 Pile, was the world's second artificial nuclear reactor (after Enrico Fermi's Chicago Pile) and was the first reactor designed and built for continuous operation. Argonne National Laboratory's Experimental Breeder Reactor I, located at the Atomic Energy Commission's National Reactor Testing Station near Arco, Idaho, became the first nuclear reactor to create electricity on 20 December 1951. Initially, four 150-watt light bulbs were lit by the reactor, but improvements eventually enabled it to power the whole facility (later, the town of Arco became the first in the world to have all its electricity come from nuclear power generated by BORAX-III, another reactor designed and operated by Argonne National Laboratory). The world's first commercial scale nuclear power station, Obninsk in the Soviet Union, began generation with its reactor AM-1 on 27 June 1954. Other early nuclear power plants were Calder Hall in England, which began generation on 17 October 1956, and the Shippingport Atomic Power Station in Pennsylvania, which began on 26 May 1958. Nuclear power was used for the first time for propulsion by a submarine, the USS Nautilus, in 1954.

Question: What was the world's first artificial nuclear reactor?

Question: In what state is the X-10 Graphite Reactor located?

Question: Along with the X-10 Pile, what was the X-10 Graphite Reactor previously known as?

Question: In what state is Argonne National Laboratory's Experimental Breeder Reactor I located?

Question: On what date did Breeder Reactor I first make electricity?
Passage: Uranium is a naturally occurring element that can be found in low levels within all rock, soil, and water. Uranium is the 51st element in order of abundance in the Earth's crust. Uranium is also the highest-numbered element to be found naturally in significant quantities on Earth and is almost always found combined with other elements. Along with all elements having atomic weights higher than that of iron, it is only naturally formed in supernovae. The decay of uranium, thorium, and potassium-40 in the Earth's mantle is thought to be the main source of heat that keeps the outer core liquid and drives mantle convection, which in turn drives plate tectonics.

Question: Where does uranium rank among elements in terms of its abundance in the Earth's crust?

Question: Where is uranium naturally formed?

Question: Along with potassium-40 and uranium, the decay of what element is a primary heat source driving plate tectonics?

Question: In what state is the Earth's outer core?
Passage: Uranium-235 was the first isotope that was found to be fissile. Other naturally occurring isotopes are fissionable, but not fissile. On bombardment with slow neutrons, its uranium-235 isotope will most of the time divide into two smaller nuclei, releasing nuclear binding energy and more neutrons. If too many of these neutrons are absorbed by other uranium-235 nuclei, a nuclear chain reaction occurs that results in a burst of heat or (in special circumstances) an explosion. In a nuclear reactor, such a chain reaction is slowed and controlled by a neutron poison, absorbing some of the free neutrons. Such neutron absorbent materials are often part of reactor control rods (see nuclear reactor physics for a description of this process of reactor control).

Question: What isotope of uranium was the first to be found fissile?

Question: When a nuclear chain reaction in uranium-235 doesn't result in a burst of heat, what does it result in?

Question: How many nuclei does uranium-235 usually divide into when bombarded with slow neutrons?

Question: What is used to slow a chain reaction in a nuclear reactor?

Question: What does a neutron poison absorb?
Passage: In nature, uranium(VI) forms highly soluble carbonate complexes at alkaline pH. This leads to an increase in mobility and availability of uranium to groundwater and soil from nuclear wastes which leads to health hazards. However, it is difficult to precipitate uranium as phosphate in the presence of excess carbonate at alkaline pH. A Sphingomonas sp. strain BSAR-1 has been found to express a high activity alkaline phosphatase (PhoK) that has been applied for bioprecipitation of uranium as uranyl phosphate species from alkaline solutions. The precipitation ability was enhanced by overexpressing PhoK protein in E. coli.

Question: What type of complexes does uranium(VI) form in nature?

Question: The presence of what substance at alkaline pH makes it difficult to precipitate uranium as phosphate?

Question: What is BSAR-1 a strain of?
Passage: It is estimated that 5.5 million tonnes of uranium exists in ore reserves that are economically viable at US$59 per lb of uranium, while 35 million tonnes are classed as mineral resources (reasonable prospects for eventual economic extraction). Prices went from about $10/lb in May 2003 to $138/lb in July 2007. This has caused a big increase in spending on exploration, with US$200 million being spent worldwide in 2005, a 54% increase on the previous year. This trend continued through 2006, when expenditure on exploration rocketed to over $774 million, an increase of over 250% compared to 2004. The OECD Nuclear Energy Agency said exploration figures for 2007 would likely match those for 2006.

Question: How much economically viable uranium is there in ore reserves, in millions of tonnes?

Question: How many millions of tonnes are uranium are regarded as mineral resources?

Question: What was the price of uranium per pound as of May 2003?

Question: In 2005, how much money was spent on uranium exploration?

Question: How much money was spent to explore for uranium in 2006?
Passage: A team led by Enrico Fermi in 1934 observed that bombarding uranium with neutrons produces the emission of beta rays (electrons or positrons from the elements produced; see beta particle). The fission products were at first mistaken for new elements of atomic numbers 93 and 94, which the Dean of the Faculty of Rome, Orso Mario Corbino, christened ausonium and hesperium, respectively. The experiments leading to the discovery of uranium's ability to fission (break apart) into lighter elements and release binding energy were conducted by Otto Hahn and Fritz Strassmann in Hahn's laboratory in Berlin. Lise Meitner and her nephew, the physicist Otto Robert Frisch, published the physical explanation in February 1939 and named the process "nuclear fission". Soon after, Fermi hypothesized that the fission of uranium might release enough neutrons to sustain a fission reaction. Confirmation of this hypothesis came in 1939, and later work found that on average about 2.5 neutrons are released by each fission of the rare uranium isotope uranium-235. Further work found that the far more common uranium-238 isotope can be transmuted into plutonium, which, like uranium-235, is also fissile by thermal neutrons. These discoveries led numerous countries to begin working on the development of nuclear weapons and nuclear power.

Question: When was it observed that bombarding uranium with neutrons results in beta ray emission?

Question: Who led the team that discovered that bombarding uranium with neutrons created beta ray emissions?

Question: What was the name given by Corbino to the incorrectly designated atomic number 94?

Question: What was the job title of Orso Mario Corbino?

Question: Who was the aunt of Otto Robert Frisch?
Passage: The interactions of carbonate anions with uranium(VI) cause the Pourbaix diagram to change greatly when the medium is changed from water to a carbonate containing solution. While the vast majority of carbonates are insoluble in water (students are often taught that all carbonates other than those of alkali metals are insoluble in water), uranium carbonates are often soluble in water. This is because a U(VI) cation is able to bind two terminal oxides and three or more carbonates to form anionic complexes.

Question: In what medium does the Pourbaix diagram change when carbonate anions interact with uranium(VI)?

Question: What notable carbonates are often water soluble?

Question: What does a uranium(VI) cation form when it binds to two terminal oxides and three or more carbonates?
Passage: Uranium is more plentiful than antimony, tin, cadmium, mercury, or silver, and it is about as abundant as arsenic or molybdenum. Uranium is found in hundreds of minerals, including uraninite (the most common uranium ore), carnotite, autunite, uranophane, torbernite, and coffinite. Significant concentrations of uranium occur in some substances such as phosphate rock deposits, and minerals such as lignite, and monazite sands in uranium-rich ores (it is recovered commercially from sources with as little as 0.1% uranium).

Question: Along with arsenic, what metal is roughly as abundant as uranium?

Question: Along with silver, mercury, tin and cadmium, what metal is uranium more plentiful than?

Question: What is the most prevalent uranium ore?

Question: What mineral sometimes contains uranium?

Question: What types of rocks sometimes contain uranium?
Passage: Natural uranium consists of three major isotopes: uranium-238 (99.28% natural abundance), uranium-235 (0.71%), and uranium-234 (0.0054%). All three are radioactive, emitting alpha particles, with the exception that all three of these isotopes have small probabilities of undergoing spontaneous fission, rather than alpha emission. There are also five other trace isotopes: uranium-239, which is formed when 238U undergoes spontaneous fission, releasing neutrons that are captured by another 238U atom; uranium-237, which is formed when 238U captures a neutron but emits two more, which then decays to neptunium-237; uranium-233, which is formed in the decay chain of that neptunium-237; and finally, uranium-236 and -240, which appear in the decay chain of primordial plutonium-244. It is also expected that thorium-232 should be able to undergo double beta decay, which would produce uranium-232, but this has not yet been observed experimentally.

Question: What is the least prevalent major isotope of natural uranium?

Question: What is the natural abundance of uranium-235?

Question: What isotope of uranium is formed when 238U experiences spontaneous fission?

Question: When uranium isotope is formed from the decay of neptunium-237?

Question: What isotope is it theorized will form uranium-2343 after double beta decay?
Passage: An additional 4.6 billion tonnes of uranium are estimated to be in sea water (Japanese scientists in the 1980s showed that extraction of uranium from sea water using ion exchangers was technically feasible). There have been experiments to extract uranium from sea water, but the yield has been low due to the carbonate present in the water. In 2012, ORNL researchers announced the successful development of a new absorbent material dubbed HiCap which performs surface retention of solid or gas molecules, atoms or ions and also effectively removes toxic metals from water, according to results verified by researchers at Pacific Northwest National Laboratory.

Question: About how many tonnes of uranium is theorized to be present in the sea?

Question: What did ORNL call their material that performs surface retention on solid molecules?

Question: The presence of what substance in sea water has resulted in low yields when attempting to extract uranium?

Question: Where were ORNL's results verified?

Question: When was HiCap announced?
Passage: Many contemporary uses of uranium exploit its unique nuclear properties. Uranium-235 has the distinction of being the only naturally occurring fissile isotope. Uranium-238 is fissionable by fast neutrons, and is fertile, meaning it can be transmuted to fissile plutonium-239 in a nuclear reactor. Another fissile isotope, uranium-233, can be produced from natural thorium and is also important in nuclear technology. While uranium-238 has a small probability for spontaneous fission or even induced fission with fast neutrons, uranium-235 and to a lesser degree uranium-233 have a much higher fission cross-section for slow neutrons. In sufficient concentration, these isotopes maintain a sustained nuclear chain reaction. This generates the heat in nuclear power reactors, and produces the fissile material for nuclear weapons. Depleted uranium (238U) is used in kinetic energy penetrators and armor plating.

Question: What is the sole fissile isotope that occurs in nature?

Question: What can be turned into plutonium-239 in a nuclear reactor?

Question: What uranium isotope is produced from thorium?

Question: Along with uranium-235, what isotope is noted for having a high fission cross-section for slow neutrons?

Question: What is 238U?
Passage: A person can be exposed to uranium (or its radioactive daughters, such as radon) by inhaling dust in air or by ingesting contaminated water and food. The amount of uranium in air is usually very small; however, people who work in factories that process phosphate fertilizers, live near government facilities that made or tested nuclear weapons, live or work near a modern battlefield where depleted uranium weapons have been used, or live or work near a coal-fired power plant, facilities that mine or process uranium ore, or enrich uranium for reactor fuel, may have increased exposure to uranium. Houses or structures that are over uranium deposits (either natural or man-made slag deposits) may have an increased incidence of exposure to radon gas. The Occupational Safety and Health Administration (OSHA) has set the permissible exposure limit for uranium exposure in the workplace as 0.25 mg/m3 over an 8-hour workday. The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 0.2 mg/m3 over an 8-hour workday and a short-term limit of 0.6 mg/m3. At levels of 10 mg/m3, uranium is immediately dangerous to life and health.

Question: What is OSHA?

Question: What is the OSHA uranium exposure limit for an 8-hour workday?

Question: What does REL stand for?

Question: What is the NIOSH uranium exposure standard over an 8-hour workday?

Question: At what level of exposure does uranium become imminently dangerous to health?
Passage: The most common forms of uranium oxide are triuranium octoxide (U 3O 8) and UO 2. Both oxide forms are solids that have low solubility in water and are relatively stable over a wide range of environmental conditions. Triuranium octoxide is (depending on conditions) the most stable compound of uranium and is the form most commonly found in nature. Uranium dioxide is the form in which uranium is most commonly used as a nuclear reactor fuel. At ambient temperatures, UO 2 will gradually convert to U 3O 8. Because of their stability, uranium oxides are generally considered the preferred chemical form for storage or disposal.

Question: Along with UO2, what is the commonest form of uranium oxide?

Question: What is the stablest uranium compound?

Question: In what form is uranium most often used as fuel for nuclear reactors?
Passage: The use of uranium in its natural oxide form dates back to at least the year 79 CE, when it was used to add a yellow color to ceramic glazes. Yellow glass with 1% uranium oxide was found in a Roman villa on Cape Posillipo in the Bay of Naples, Italy, by R. T. Gunther of the University of Oxford in 1912. Starting in the late Middle Ages, pitchblende was extracted from the Habsburg silver mines in Joachimsthal, Bohemia (now Jáchymov in the Czech Republic), and was used as a coloring agent in the local glassmaking industry. In the early 19th century, the world's only known sources of uranium ore were these mines.

Question: What was the earliest year in recorded history that uranium oxide was used?

Question: In what county was glass with uranium oxide content found?

Question: What color of ceramic glaze was extracted from uranium oxide?

Question: In what year was yellow uranium oxide glass discovered?

Question: What institution did R.T. Gunther belong to?
Passage: On 2 December 1942, as part of the Manhattan Project, another team led by Enrico Fermi was able to initiate the first artificial self-sustained nuclear chain reaction, Chicago Pile-1. Working in a lab below the stands of Stagg Field at the University of Chicago, the team created the conditions needed for such a reaction by piling together 400 short tons (360 metric tons) of graphite, 58 short tons (53 metric tons) of uranium oxide, and six short tons (5.5 metric tons) of uranium metal, a majority of which was supplied by Westinghouse Lamp Plant in a makeshift production process.

Question: What was the first self-sustained nuclear chain reaction created by human beings called?

Question: On what date was the first self-sustained nuclear chain reaction created artificially?

Question: What project was Fermi working for?

Question: On the campus of what educational institution was Chicago Pile-1 created?

Question: How many metric tons of uranium oxide was used in Chicago Pile-1?
Passage: Uranium is used as a colorant in uranium glass producing orange-red to lemon yellow hues. It was also used for tinting and shading in early photography. The 1789 discovery of uranium in the mineral pitchblende is credited to Martin Heinrich Klaproth, who named the new element after the planet Uranus. Eugène-Melchior Péligot was the first person to isolate the metal and its radioactive properties were discovered in 1896 by Henri Becquerel. Research by Otto Hahn, Lise Meitner, Enrico Fermi and others, such as J. Robert Oppenheimer starting in 1934 led to its use as a fuel in the nuclear power industry and in Little Boy, the first nuclear weapon used in war. An ensuing arms race during the Cold War between the United States and the Soviet Union produced tens of thousands of nuclear weapons that used uranium metal and uranium-derived plutonium-239. The security of those weapons and their fissile material following the breakup of the Soviet Union in 1991 is an ongoing concern for public health and safety. See Nuclear proliferation.

Question: Along with lemon yellow, what color is produced in uranium glass?

Question: Who discovered uranium in pitchblende?

Question: Who was responsible for first isolating uranium?

Question: Who discovered that uranium was radioactive?

Question: What was the first nuclear weapon used in a war called?
Passage: In nature, uranium is found as uranium-238 (99.2742%) and uranium-235 (0.7204%). Isotope separation concentrates (enriches) the fissionable uranium-235 for nuclear weapons and most nuclear power plants, except for gas cooled reactors and pressurised heavy water reactors. Most neutrons released by a fissioning atom of uranium-235 must impact other uranium-235 atoms to sustain the nuclear chain reaction. The concentration and amount of uranium-235 needed to achieve this is called a 'critical mass'.

Question: What percentage of uranium in nature is uranium-235?

Question: What is the term for the amount of uranium-235 needed to sustain a nuclear chain reaction?

Question: What is the most prevalent natural isotope of uranium?

Question: What percentage of natural uranium is isotope 238?

Question: Along with gas cooled reactors, what type of reactor doesn't use uranium-235?