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Aviva Brecher
Aviva Brecher (born July 4, 1945) is a Romanian-American applied physicist and transportation scientist who studied magnetic levitation for many years at the John A. Volpe National Transportation Systems Center, a research center of the United States Department of Transportation. Early life and education Brecher was born on July 4, 1945, to a Jewish family in Bucharest, where her father was a gynecologist. Her family moved to Israel when she was 15. While attending high school in Israel, she meet and became involved with her future husband, Kenneth Brecher, a physics student at the Massachusetts Institute of Technology (MIT) who had visited Israel to work with Nathan Rosen. After graduating as valedictorian from high school in Kiryat Haim, she began her university studies in applied physics at the Technion – Israel Institute of Technology, but transferred to MIT to be closer to Brecher, whom she married in Israel before moving to the US and becoming a naturalized US citi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Levitation
Magnetic levitation (maglev) or magnetic suspension is a method by which an object is suspended with no support other than magnetic fields. Magnetic force is used to counteract the effects of the gravitational force and any other forces. The two primary issues involved in magnetic levitation are ''lifting forces'': providing an upward force sufficient to counteract gravity, and ''stability'': ensuring that the system does not spontaneously slide or flip into a configuration where the lift is neutralized. Magnetic levitation is used for maglev trains, contactless melting, magnetic bearings and for product display purposes. Lift Magnetic materials and systems are able to attract or repel each other with a force dependent on the magnetic field and the area of the magnets. For example, the simplest example of lift would be a simple dipole magnet positioned in the magnetic fields of another dipole magnet, oriented with like poles facing each other, so that the force between mag ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Doctoral Advisor
A doctoral advisor (also dissertation director, dissertation advisor; or doctoral supervisor) is a member of a university faculty whose role is to guide graduate students who are candidates for a doctorate, helping them select coursework, as well as shaping, refining and directing the students' choice of sub-discipline in which they will be examined or on which they will write a dissertation. Students generally choose advisors based on their areas of interest within their discipline, their desire to work closely with particular graduate faculty, and the willingness and availability of those faculty to work with them. In some countries, the student's advisor serves as the chair of the dissertation committee or the examination committee. In some cases, though, the person who serves those roles may be different from the faculty member who has most closely advised the student. For instance, in the Dutch academic system, only full professors (''hoogleraren'') and associate professo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul Tsongas
Paul Efthemios Tsongas (; February 14, 1941 – January 18, 1997) was an American politician who represented Massachusetts in the United States Senate from 1979 until 1985 and in the United States House of Representatives from 1975 until 1979. A member of the Democratic Party, he ran for president in 1992. He won eight contests during the presidential primaries, but lost the nomination to Bill Clinton, who later won the general election. Born in Lowell, Massachusetts, Tsongas graduated from Dartmouth College, Yale Law School and the Kennedy School of Government. After working for the Peace Corps and as an aide to Congressman F. Bradford Morse, Tsongas successively won election as a city councilor and county commissioner. In 1974, he was elected to the House of Representatives representing Massachusetts's 5th congressional district, after defeating incumbent Paul W. Cronin. In 1978, he ran for senate, and defeated incumbent Republican Edward Brooke. In Congress, Tsongas esta ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Space Exploration
Space exploration is the use of astronomy and space technology to explore outer space. While the exploration of space is carried out mainly by astronomers with telescopes, its physical exploration though is conducted both by robotic spacecraft, uncrewed robotic space probes and human spaceflight. Space exploration, like its classical form astronomy, is one of the main sources for space science. While the observation of objects in space, known as astronomy, predates reliable recorded history, it was the development of large and relatively efficient rockets during the mid-twentieth century that allowed physical space exploration to become a reality. The world's first large-scale experimental rocket program was Opel-RAK under the leadership of Fritz von Opel and Max Valier during the late 1920s leading to the first crewed rocket cars and rocket planes, which paved the way for the Nazi era V2 program and US and Soviet activities from 1950 onwards. The Opel-RAK program and the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mining
Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic viability of investing in the equipment, labor, and energy required to extract, refine and transport the materials found at the mine to manufacturers who can use the material. Ores recovered by mining include metals, coal, oil shale, gemstones, limestone, chalk, dimension stone, rock salt, potash, gravel, and clay. Mining is required to obtain most materials that cannot be grown through agricultural processes, or feasibly created artificially in a laboratory or factory. Mining in a wider sense includes extraction of any non-renewable resource such as petroleum, natural gas, or even water. Modern mining processes involve prospecting for ore bodies, analysis of the profit potential of a proposed mine, extraction of the desired materials, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Waste
Radioactive waste is a type of hazardous waste that contains radioactive material. Radioactive waste is a result of many activities, including nuclear medicine, nuclear research, nuclear power generation, rare-earth mining, and nuclear weapons reprocessing. The storage and disposal of radioactive waste is regulated by government agencies in order to protect human health and the environment. Radioactive waste is broadly classified into low-level waste (LLW), such as paper, rags, tools, clothing, which contain small amounts of mostly short-lived radioactivity, intermediate-level waste (ILW), which contains higher amounts of radioactivity and requires some shielding, and high-level waste (HLW), which is highly radioactive and hot due to decay heat, so requires cooling and shielding. In nuclear reprocessing plants about 96% of spent nuclear fuel is recycled back into uranium-based and mixed-oxide (MOX) fuels. The residual 4% is minor actinides and fission products the latter of wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arthur D
Arthur is a common male given name of Brythonic origin. Its popularity derives from it being the name of the legendary hero King Arthur. The etymology is disputed. It may derive from the Celtic ''Artos'' meaning “Bear”. Another theory, more widely believed, is that the name is derived from the Roman clan '' Artorius'' who lived in Roman Britain for centuries. A common spelling variant used in many Slavic, Romance, and Germanic languages is Artur. In Spanish and Italian it is Arturo. Etymology The earliest datable attestation of the name Arthur is in the early 9th century Welsh-Latin text ''Historia Brittonum'', where it refers to a circa 5th to 6th-century Briton general who fought against the invading Saxons, and who later gave rise to the famous King Arthur of medieval legend and literature. A possible earlier mention of the same man is to be found in the epic Welsh poem ''Y Gododdin'' by Aneirin, which some scholars assign to the late 6th century, though this is still a ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wellesley College
Wellesley College is a private women's liberal arts college in Wellesley, Massachusetts, United States. Founded in 1870 by Henry and Pauline Durant as a female seminary, it is a member of the original Seven Sisters Colleges, an unofficial grouping of elite current and former women's colleges in the northeastern United States. Wellesley's endowment of $3.226 billion is the largest out of all women's colleges and the 49th largest among all colleges and universities in the United States in 2019. Wellesley is frequently considered to be one of the best liberal arts colleges in the United States. The college is currently ranked #5 on the National Liberal Arts College list produced by ''U.S. News & World Report''. Wellesley is home to 56 departmental and interdepartmental majors spanning the liberal arts, as well as over 150 student clubs and organizations. Wellesley athletes compete in the NCAA Division III New England Women's and Men's Athletic Conference. Its 500-acre (2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moon Rock
Moon rock or lunar rock is rock originating from Earth's Moon. This includes lunar material collected during the course of human exploration of the Moon, and rock that has been ejected naturally from the Moon's surface and landed on Earth as meteorites. Sources Moon rocks on Earth come from four sources: those collected by six United States Apollo program crewed lunar landings from 1969 to 1972; those collected by three Soviet uncrewed Luna probes in the 1970s; those collected by the Chinese Lunar Exploration Program's uncrewed probes; and rocks that were ejected naturally from the lunar surface before falling to Earth as lunar meteorites. Apollo program Six Apollo missions collected 2,200 samples of material weighing , processed into more than 110,000 individually cataloged samples. Luna program Three Luna spacecraft returned with of samples. The Soviet Union abandoned its attempts at a crewed lunar program in the 1970s, but succeeded in landing three robotic Luna s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interstellar Medium
In astronomy, the interstellar medium is the matter and radiation that exist in the space between the star systems in a galaxy. This matter includes gas in ionic, atomic, and molecular form, as well as dust and cosmic rays. It fills interstellar space and blends smoothly into the surrounding intergalactic space. The energy that occupies the same volume, in the form of electromagnetic radiation, is the interstellar radiation field. The interstellar medium is composed of multiple phases distinguished by whether matter is ionic, atomic, or molecular, and the temperature and density of the matter. The interstellar medium is composed, primarily, of hydrogen, followed by helium with trace amounts of carbon, oxygen, and nitrogen. The thermal pressures of these phases are in rough equilibrium with one another. Magnetic fields and turbulent motions also provide pressure in the ISM, and are typically more important, dynamically, than the thermal pressure is. In the interstellar medium, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solar System
The Solar SystemCapitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar System" and "solar system" structures in theinaming guidelines document. The name is commonly rendered in lower case ('solar system'), as, for example, in the ''Oxford English Dictionary'' an''Merriam-Webster's 11th Collegiate Dictionary''. is the gravity, gravitationally bound system of the Sun and the objects that orbit it. It Formation and evolution of the Solar System, formed 4.6 billion years ago from the gravitational collapse of a giant interstellar molecular cloud. The solar mass, vast majority (99.86%) of the system's mass is in the Sun, with most of the Jupiter mass, remaining mass contained in the planet Jupiter. The four inner Solar System, inner system planets—Mercury (planet), Mercury, Venus, Earth and Mars—are terrest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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