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Operation Freshman
Operation Freshman was the codename given to a British airborne operation conducted in November 1942 during World War II. It was the first British airborne operation using Airspeed Horsa gliders, and its target was the Vemork ''Norsk Hydro'' hydrogen electrolysis plant in Telemark, Norway which produced heavy water as a by-product. By 1942, the German nuclear weapons programme had come close to being able to develop a nuclear reactor, but for the reactor to function it would require a great deal of heavy water. The source of the heavy water was the Norsk Hydro plant, which had been occupied since 1940. When the British government learned of the German nuclear developments, it was decided that a raid would be launched to destroy the plant and deny the Germans the heavy water required to develop a nuclear weapon. Several plans were discussed and discarded as impractical; it was decided that a small airborne force composed of sappers from the Royal Engineer units attached ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Second World War
World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the world's countries participated, with many nations mobilising all resources in pursuit of total war. Tanks in World War II, Tanks and Air warfare of World War II, aircraft played major roles, enabling the strategic bombing of cities and delivery of the Atomic bombings of Hiroshima and Nagasaki, first and only nuclear weapons ever used in war. World War II is the List of wars by death toll, deadliest conflict in history, causing World War II casualties, the death of 70 to 85 million people, more than half of whom were civilians. Millions died in genocides, including the Holocaust, and by massacres, starvation, and disease. After the Allied victory, Allied-occupied Germany, Germany, Allied-occupied Austria, Austria, Occupation of Japan, Japan, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Engineers
The Corps of Royal Engineers, usually called the Royal Engineers (RE), and commonly known as the ''Sappers'', is the engineering arm of the British Army. It provides military engineering and other technical support to the British Armed Forces and is headed by the Chief Royal Engineer. The Corps Headquarters and the Royal School of Military Engineering are in Chatham, Kent, Chatham in Kent, England. The corps is divided into several regiments, barracked at various places in the United Kingdom and around the world. History The Royal Engineers trace their origins back to the military engineers brought to England by William the Conqueror, specifically Gundulf of Rochester, Bishop Gundulf of Rochester Cathedral, and claim over 900 years of unbroken service to the crown. Engineers have always served in the armies of the Crown; however, the origins of the modern corps, along with those of the Royal Artillery, lie in the Board of Ordnance established in the 15th century. In Woolwich ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Weapon
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission or atomic bomb) or a combination of fission and fusion reactions (thermonuclear weapon), producing a nuclear explosion. Both bomb types release large quantities of energy from relatively small amounts of matter. Nuclear bombs have had yields between 10 tons (the W54) and 50 megatons for the Tsar Bomba (see TNT equivalent). Yields in the low kilotons can devastate cities. A thermonuclear weapon weighing as little as can release energy equal to more than 1.2 megatons of TNT (5.0 PJ). Apart from the blast, effects of nuclear weapons include firestorms, extreme heat and ionizing radiation, radioactive nuclear fallout, an electromagnetic pulse, and a radar blackout. The first nuclear weapons were developed by the Allied Manhattan Project during World War II. Their production continues to require a large scientific and industrial complex, pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uranium
Uranium is a chemical element; it has chemical symbol, symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium radioactive decay, radioactively decays, usually by emitting an alpha particle. The half-life of this decay varies between 159,200 and 4.5 billion years for different isotopes of uranium, isotopes, making them useful for dating the age of the Earth. The most common isotopes in natural uranium are uranium-238 (which has 146 neutrons and accounts for over 99% of uranium on Earth) and uranium-235 (which has 143 neutrons). Uranium has the highest atomic weight of the primordial nuclide, primordially occurring elements. Its density is about 70% higher than that of lead and slightly lower than that of gold or tungsten. It occurs naturally in low concentrations of a few Parts-per notation#Parts-per expressions, parts per million in soil, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neutron Moderator
In nuclear engineering, a neutron moderator is a medium that reduces the speed of fast neutrons, ideally without capturing any, leaving them as thermal neutrons with only minimal (thermal) kinetic energy. These thermal neutrons are immensely more susceptible than fast neutrons to propagate a nuclear chain reaction of uranium-235 or other fissile isotope by colliding with their atomic nucleus. Water (sometimes called "light water" in this context) is the most commonly used moderator (roughly 75% of the world's reactors). Solid graphite (20% of reactors) and heavy water (5% of reactors) are the main alternatives. Beryllium has also been used in some experimental types, and hydrocarbons have been suggested as another possibility. Moderation Neutrons are normally bound into an atomic nucleus and do not exist free for long in nature. The unbound neutron has a half-life of 10 minutes and 11 seconds. The release of neutrons from the nucleus requires exceeding the binding ener ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Fission
Nuclear fission is a reaction in which the nucleus of an atom splits into two or more smaller nuclei. The fission process often produces gamma photons, and releases a very large amount of energy even by the energetic standards of radioactive decay. Nuclear fission was discovered by chemists Otto Hahn and Fritz Strassmann and physicists Lise Meitner and Otto Robert Frisch. Hahn and Strassmann proved that a fission reaction had taken place on 19 December 1938, and Meitner and her nephew Frisch explained it theoretically in January 1939. Frisch named the process "fission" by analogy with biological fission of living cells. In their second publication on nuclear fission in February 1939, Hahn and Strassmann predicted the existence and liberation of additional neutrons during the fission process, opening up the possibility of a nuclear chain reaction. For heavy nuclides, it is an exothermic reaction which can release large amounts of energy both as electromagnetic radiat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nature (journal)
''Nature'' is a British weekly scientific journal founded and based in London, England. As a multidisciplinary publication, ''Nature'' features Peer review, peer-reviewed research from a variety of academic disciplines, mainly in science and technology. It has core editorial offices across the United States, continental Europe, and Asia under the international scientific publishing company Springer Nature. ''Nature'' was one of the world's most cited scientific journals by the Science Edition of the 2022 ''Journal Citation Reports'' (with an ascribed impact factor of 50.5), making it one of the world's most-read and most prestigious academic journals. , it claimed an online readership of about three million unique readers per month. Founded in the autumn of 1869, ''Nature'' was first circulated by Norman Lockyer and Alexander MacMillan (publisher), Alexander MacMillan as a public forum for scientific innovations. The mid-20th century facilitated an editorial expansion for the j ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scientific Journal
In academic publishing, a scientific journal is a periodical publication designed to further the progress of science by disseminating new research findings to the scientific community. These journals serve as a platform for researchers, scholars, and scientists to share their latest discoveries, insights, and methodologies across a multitude of scientific disciplines. Unlike professional or trade magazines, the articles are mostly written by scientists rather than staff writers employed by the journal. Scientific journals are characterized by their rigorous peer review process, which aims to ensure the validity, reliability, and quality of the published content. In peer review, submitted articles are reviewed by active scientists (peers) to ensure scientific rigor. With origins dating back to the 17th century, the publication of scientific journals has evolved significantly, advancing scientific knowledge, fostering academic discourse, and facilitating collaboration within ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Otto Frisch
Otto Robert Frisch (1 October 1904 – 22 September 1979) was an Austrian-born British physicist who worked on nuclear physics. With Otto Stern and Immanuel Estermann, he first measured the magnetic moment of the proton. With his aunt, Lise Meitner, he advanced the first theoretical explanation of nuclear fission (coining the term) and first experimentally detected the fission by-products. Later, with his collaborator, Rudolf Peierls, he designed the first theoretical mechanism for the detonation of an atomic bomb in 1940. Leading the Los Alamos Critical Assemblies experiments in 1945, he oversaw the world's first prompt criticality in the Dragon device. Early life Otto Robert Frisch was born in Vienna in 1904 to a Jewish family, the son of Justinian Frisch, a painter, and Auguste Meitner Frisch, a concert pianist. He himself was talented at both but also shared his maternal aunt Lise Meitner's love of physics and commenced a period of study at the University of Vienna, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lise Meitner
Elise Lise Meitner ( ; ; 7 November 1878 – 27 October 1968) was an Austrian-Swedish nuclear physicist who was instrumental in the discovery of nuclear fission. After completing her doctoral research in 1906, Meitner became the second woman from the University of Vienna to earn a doctorate in physics. She spent much of her scientific career in Berlin, where she was a physics professor and a department head at the Max Planck Institute for Chemistry, Kaiser Wilhelm Institute for Chemistry. She was the first woman to become a full professor of physics in Germany. She lost her positions in 1935 because of the anti-Jewish Nuremberg Laws of Nazi Germany, and the 1938 Anschluss resulted in the loss of her Austrian citizenship. On 13–14 July 1938, she fled to the Netherlands with the help of Dirk Coster. She lived in Stockholm for many years, ultimately becoming a Swedish citizen in 1949, but relocated to Britain in the 1950s to be with family members. In mid-1938, chemists Otto H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
German Nuclear Energy Project
Nazi Germany undertook several research programs relating to nuclear technology, including nuclear weapons and nuclear reactors, before and during World War II. These were variously called () or (). The first effort started in April 1939, just months after the discovery of nuclear fission in Berlin in December 1938, but ended shortly ahead of the September 1939 German invasion of Poland, for which many German physicists were drafted into the . A second effort under the administrative purview of the 's began on September 1, 1939, the day of the invasion of Poland. The program eventually expanded into three main efforts: (nuclear reactor) development, uranium and heavy water production, and uranium isotope separation. Eventually, the German military determined that nuclear fission would not contribute significantly to the war, and in January 1942 the turned the program over to the Reich Research Council () while continuing to fund the activity. The program was split up among ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Commandos (United Kingdom)
The Commandos, also known as the British Commandos, were formed during the Second World War in June 1940, following a request from Winston Churchill, for special forces that could carry out raids against German-occupied Europe. Initially drawn from within the British Army from soldiers who volunteered for the Special Service Brigade, the Commandos' ranks were eventually filled by members of all branches of the British Armed Forces and a number of foreign volunteers from German-occupied countries. By the end of the war 25,000 men had passed through the Commando course at Achnacarry. This total includes not only the British volunteers, but volunteers from Greece, France, Belgium, Netherlands, Canada, Norway and Poland. The United States Army Rangers and US Marine Corps Raiders, Portuguese Fuzileiros Portuguese Marine Corps were modelled on the Commandos.Moreman, p. 40. Reaching a wartime strength of over 30 units and four assault brigades, the Commandos served in all theatres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
