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Ralph Alpher
Ralph Asher Alpher (February 3, 1921 – August 12, 2007) was an American cosmologist, who carried out pioneering work in the early 1950s on the Big Bang model, including Big Bang nucleosynthesis and predictions of the cosmic microwave background radiation. Childhood and education Alpher was the son of a Jewish immigrant, Samuel Alpher ( Ilfirovich), from Vitebsk, Russian Empire. His mother, Rose Maleson, died of stomach cancer in 1938, and his father later remarried. Alpher graduated at age 15 from Theodore Roosevelt High School in Washington, D.C., and held the ranks of Major and Commander of his school's Cadet program. He worked in the high school theater as stage manager for two years, supplementing his family's Depression-era income. He also learned Gregg shorthand, and in 1937 began working for the director of the American Geophysical Union as a stenographer. In 1940, he was hired by the Department of Terrestrial Magnetism of the Carnegie Foundation, where he worked ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Big Bang Nucleosynthesis
In physical cosmology, Big Bang nucleosynthesis (also known as primordial nucleosynthesis, and abbreviated as BBN) is a model for the production of light nuclei, deuterium, 3He, 4He, 7Li, between 0.01s and 200s in the lifetime of the universe. The model uses a combination of thermodynamic arguments and results from equations for the expansion of the universe to define a changing temperature and density, then analyzes the rates of nuclear reactions at these temperatures and densities to predict the nuclear abundance ratios. Refined models agree very well with observations with the exception of the abundance of 7Li. The model is one of the key concepts in standard cosmology. Elements heavier than lithium are thought to have been created later in the life of the Universe by stellar nucleosynthesis, through the formation, evolution and death of stars. Characteristics The Big Bang nucleosynthesis (BBN) model assumes a homogeneous plasma, at a temperature corresponding to 1 MeV, co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neutron Capture
Neutron capture is a nuclear reaction in which an atomic nucleus and one or more neutrons collide and merge to form a heavier nucleus. Since neutrons have no electric charge, they can enter a nucleus more easily than positively charged protons, which are repelled Electrostatics, electrostatically. Neutron capture plays a significant role in the cosmic nucleosynthesis of heavy elements. In stars it can proceed in two ways: as a rapid process (r-process) or a slow process (s-process). Nuclei of Mass number, masses greater than 56 Iron peak, cannot be formed by exothermic thermonuclear reactions (i.e., by nuclear fusion) but can be formed by neutron capture. Neutron capture on protons yields a line at 2.223 MeV predicted and commonly observed in solar flares. Neutron capture at small neutron flux At small neutron flux, as in a nuclear reactor, a single neutron is captured by a nucleus. For example, when natural gold (197Au) is irradiated by neutrons (n), the isotope gold-198, 198A ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Applied Physics Laboratory
The Johns Hopkins University Applied Physics Laboratory (or simply Applied Physics Laboratory, or APL) is a not-for-profit university-affiliated research center (UARC) in Howard County, Maryland. It is affiliated with Johns Hopkins University and employs 8,700 people as of 2024. APL is the nation's largest UARC. The lab serves as a technical resource for the Department of Defense, NASA, and other government agencies. APL has developed numerous systems and technologies in the areas of air and missile defense, surface and undersea naval warfare, computer security, and space science and spacecraft construction. While APL provides research and engineering services to the government, it is not a traditional defense contractor, as it is a UARC and a division of Johns Hopkins University. APL is a scientific and engineering research and development division, rather than an academic division, of Johns Hopkins. Hopkins' Whiting School of Engineering offers part-time graduate programs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War II
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] |
Degaussing
Degaussing, or deperming, is the process of decreasing or eliminating a remnant magnetic field. It is named after the gauss, a unit of magnetism, which in turn was named after Carl Friedrich Gauss. Due to magnetic hysteresis, it is generally not possible to reduce a magnetic field completely to zero, so degaussing typically induces a very small "known" field referred to as bias. Degaussing was originally applied to reduce ships' magnetic signatures during World War II. Degaussing is also used to reduce magnetic fields in tape recorders and cathode-ray tube displays, and to destroy data held on magnetic storage. Ships' hulls The term was first used by then-Commander Charles F. Goodeve, Royal Canadian Naval Volunteer Reserve, during World War II while trying to counter the German magnetic naval mines that were wreaking havoc on the British fleet. The mines detected the increase in the magnetic field when the steel in a ship concentrated the Earth's magnetic field over it ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scott Forbush
Scott Ellsworth Forbush (April 10, 1904 – April 4, 1984) was an American astronomer, physicist and geophysicist who is recognized as having laid the observational foundations for many of the central features of solar-interplanetary-terrestrial physics, which at the time was an underdeveloped field of study. In 1937 Forbush discovered the Forbush Effect: an occasional decrease in the intensity of cosmic rays as observed on Earth that is caused by the solar wind and its interaction with the magnetosphere.Article from the Encyclopædia Britannica''"Forbush effect (Astronomy)"'' Visited on August the 10th, 2010. Scott conducted most of his research during his career at the Department of Terrestrial Magnetism (DTM) of the Carnegie Institution of Washington where he was appointed chairman of a section on theoretical geophysics in 1957. Forbush used statistical methods in analyses of magnetic storms, solar activity, rotation of the Earth, and the rotation of the sun, and the correl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carnegie Foundation For The Advancement Of Teaching
The Carnegie Foundation for the Advancement of Teaching (CFAT) is a U.S.-based education policy and research center. It was founded by Andrew Carnegie in 1905 and chartered in 1906 by an act of the United States Congress. Among its most notable accomplishments are the development of the Teachers Insurance and Annuity Association (TIAA), the '' Flexner Report'' on medical education, the Carnegie Unit, the Educational Testing Service, and the Carnegie Classification of Institutions of Higher Education. History The foundation was founded by Andrew Carnegie in 1905 and chartered in 1906 by an act of the United States Congress under the leadership of its first president, Henry Pritchett. The foundation credits Pritchett with broadening their mission to include work in education policy and standards. John W. Gardner became president in 1955 while also serving as president of the Carnegie Corporation of New York. He was followed by Alan Pifer whose most notable accomplishment ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Geophysical Union
The American Geophysical Union (AGU) is a 501(c)(3) nonprofit organization of Earth, Atmospheric science, atmospheric, Oceanography, ocean, Hydrology, hydrologic, Astronomy, space, and Planetary science, planetary scientists and enthusiasts that according to their website includes 130,000 people (not members). AGU's activities are focused on the organization and dissemination of scientific information in the interdisciplinary and international fields within the Earth and space sciences. The geophysical sciences involve four fundamental areas: atmospheric sciences, atmospheric and ocean sciences; solid-Earth sciences; hydrologic sciences; and space sciences. The organization's headquarters is located on Florida Avenue in Washington, D.C. History The AGU was established in December 1919 by the United States National Research Council, National Research Council (NRC) to represent the United States in the International Union of Geodesy and Geophysics (IUGG), and its first chairman w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gregg Shorthand
Gregg shorthand is a system of shorthand developed by John Robert Gregg in 1888. Distinguished by its phonemic basis, the system prioritizes the sounds of speech over traditional English spelling, enabling rapid writing by employing elliptical figures and lines that bisect them. Gregg shorthand's design facilitates smooth, cursive strokes without the angular outlines characteristic of earlier systems like Duployan shorthand, thereby enhancing writing-speed and legibility. Over the years, Gregg shorthand has undergone several revisions, each aimed at simplifying the system and increasing its speed and efficiency. These versions range from the Pre-Anniversary editions to the more recent Centennial version, with each adaptation maintaining the core principles while introducing modifications to suit varying needs and preferences. Its efficiency, once mastered, allows for speeds upwards of 280 words per minute. The system is adaptable to both right- and left-handed writers. Backgroun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Junior Reserve Officers' Training Corps
The Junior Reserve Officers' Training Corps (JROTC) is a federal program sponsored by the United States Armed Forces in high schools and also in some middle schools across the United States and at US military bases across the world. The program was originally created as part of the National Defense Act of 1916 and later expanded under the 1964 ROTC Vitalization Act. Role and purpose According to Title 10, Section 2031 of the United States Code, the purpose of the Junior Reserve Officers' Training Corps is "to instill in students in he United Statessecondary educational institutions the values of citizenship, service to the United States, and personal responsibility and a sense of accomplishment." Additional objectives are established by the service departments of the Department of Defense. Under 542.4 of Title 32 (National Defense) of the Code of Federal Regulations, the Department of the Army has declared those objectives for each cadet to be: *Developing citizenship a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Theodore Roosevelt High School (Washington D
Roosevelt High School may refer to: Eleanor Roosevelt * Eleanor Roosevelt High School (California), Eastvale, California * Eleanor Roosevelt High School (Maryland) * Eleanor Roosevelt High School (New York City) * Eleanor Roosevelt School, Warm Springs, Georgia Franklin Delano Roosevelt * Franklin Delano Roosevelt High School (Hyde Park, New York) * Franklin Delano Roosevelt High School (New York City) * Franklin D. Roosevelt High School (Texas), Dallas, Texas Theodore Roosevelt * Theodore Roosevelt College and Career Academy, Gary, Indiana; formerly known as Theodore Roosevelt High School * Theodore Roosevelt High School (Fresno, California) * Theodore Roosevelt High School (Los Angeles, California) * Theodore Roosevelt High School (Colorado) * President Theodore Roosevelt High School, Honolulu, Hawaii * Theodore Roosevelt High School (Illinois), Chicago, Illinois * Theodore Roosevelt High School (Indiana), Gary, Indiana where Dick Barnett played * Theodore Roosevelt High S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
