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John D. Hoffman
John Drake Hoffman (November 26, 1922 – February 21, 2004) was an American chemist and author who was awarded the Soldier's Medal, the United States Army's highest award for an act of valor in a non-combat situation, and the only one awarded to a member of the Manhattan District. After the war he worked for the National Bureau of Standards, becoming the director of its national measurements laboratory. He was a professor and director of the engineering materials program at the University of Maryland from 1982 to 1985, director of the Michigan Molecular Institute, and a professor of materials science and engineering at Johns Hopkins University. Early life John Drake Hoffman was born in Washington, D.C., on November 26, 1922. He grew up in Bethesda, Maryland, and attended Bethesda-Chevy Chase High School. He entered Franklin & Marshall College in Pennsylvania, graduating with a B.S. in chemistry in 1942. Manhattan Project Hoffman served in the U.S. Army during World War II. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Washington, D
Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered on Washington, D.C. * George Washington (1732–1799), the first president of the United States Washington may also refer to: Places England * Washington, Tyne and Wear, a town in the City of Sunderland metropolitan borough ** Washington Old Hall, ancestral home of the family of George Washington * Washington, West Sussex, a village and civil parish Greenland * Cape Washington, Greenland * Washington Land Philippines *New Washington, Aklan, a municipality *Washington, a barangay in Catarman, Northern Samar *Washington, a barangay in Escalante, Negros Occidental *Washington, a barangay in San Jacinto, Masbate *Washington, a barangay in Surigao City United States * Washington, Wisconsin (other) * Fort Washington (other) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bethesda, Maryland
Bethesda () is an unincorporated, census-designated place in southern Montgomery County, Maryland. It is located just northwest of Washington, D.C. It takes its name from a local church, the Bethesda Meeting House (1820, rebuilt 1849), which in turn took its name from Jerusalem's Pool of Bethesda. The National Institutes of Health's main campus and the Walter Reed National Military Medical Center are in Bethesda, in addition to a number of corporate and government headquarters. As an unincorporated community, Bethesda has no official boundaries. According to the 2020 U.S. census, the community had a total population of 68,056. History Bethesda is located in a region that was populated by the Piscataway and Nacotchtank tribes at the time of European colonization. Fur trader Henry Fleet became the first European to visit the area, reaching it by sailing up the Potomac River. He stayed with the Piscataway tribe from 1623 to 1627, either as a guest or prisoner (historical accounts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
S-50 (Manhattan Project)
The S-50 Project was the Manhattan Project's effort to produce enriched uranium by liquid thermal diffusion during World War II. It was one of three technologies for uranium enrichment pursued by the Manhattan Project. The liquid thermal diffusion process was not one of the enrichment technologies initially selected for use in the Manhattan Project, and was developed independently by Philip H. Abelson and other scientists at the United States Naval Research Laboratory. This was primarily due to doubts about the process's technical feasibility, but inter-service rivalry between the United States Army and United States Navy also played a part. Pilot plants were built at the Anacostia Naval Air Station and the Philadelphia Navy Yard, and a production facility at the Clinton Engineer Works in Oak Ridge, Tennessee. This was the only production-scale liquid thermal diffusion plant ever built. It could not enrich uranium sufficiently for use in an atomic bomb, but it could provid ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philadelphia Navy Yard
The Philadelphia Naval Shipyard was an important naval shipyard of the United States for almost two centuries. Philadelphia's original navy yard, begun in 1776 on Front Street and Federal Street in what is now the Pennsport section of the city, was the first naval shipyard of the United States. It was replaced by a new, much larger yard developed around facilities begun in 1871 on League Island, at the confluence of the Delaware and Schuylkill rivers. The Navy Yard expansion stimulated the development over time of residential and businesses in South Philadelphia, where many shipyard workers lived. During World War II, some 40,000 workers operated on shifts around the clock to produce and repair ships at the yard for the war effort. The United States Navy ended most of its activities there in the 1990s, closing its base after recommendations by the Base Realignment and Closure commission. In 2000, the Philadelphia Industrial Development Corporation, on behalf of the city of Ph ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uranium Enrichment
Enriched uranium is a type of uranium in which the percent composition of uranium-235 (written 235U) has been increased through the process of isotope separation. Naturally occurring uranium is composed of three major isotopes: uranium-238 (238U with 99.2739–99.2752% natural abundance), uranium-235 (235U, 0.7198–0.7202%), and uranium-234 (234U, 0.0050–0.0059%). 235U is the only nuclide existing in nature (in any appreciable amount) that is fissile with thermal neutrons. Enriched uranium is a critical component for both civil nuclear power generation and military nuclear weapons. The International Atomic Energy Agency attempts to monitor and control enriched uranium supplies and processes in its efforts to ensure nuclear power generation safety and curb nuclear weapons proliferation. There are about 2,000 tonnes of highly enriched uranium in the world, produced mostly for nuclear power, nuclear weapons, naval propulsion, and smaller quantities for research reactors. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermophoresis
Thermophoresis (also thermomigration, thermodiffusion, the Soret effect, or the Ludwig–Soret effect) is a phenomenon observed in mixtures of mobile particles where the different particle types exhibit different responses to the force of a temperature gradient. This phenomenon tends to move light molecules to hot regions and heavy molecules to cold regions. The term ''thermophoresis'' most often applies to aerosol mixtures whose mean free path \lambda is comparable to its characteristic length scale L, but may also commonly refer to the phenomenon in all phases of matter. The term ''Soret effect'' normally applies to liquid mixtures, which behave according to different, less well-understood mechanisms than gaseous mixtures. Thermophoresis may not apply to thermomigration in solids, especially multi-phase alloys. Thermophoretic force The phenomenon is observed at the scale of one millimeter or less. An example that may be observed by the naked eye with good lighting is when the hot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enlisted Men
An enlisted rank (also known as an enlisted grade or enlisted rate) is, in some armed services, any rank below that of a commissioned officer. The term can be inclusive of non-commissioned officers or warrant officers, except in United States military usage where warrant officers/chief warrant officers are a separate officer category ranking above enlisted grades and below commissioned officer grades. In most cases, enlisted service personnel perform jobs specific to their own occupational specialty, as opposed to the more generalized command responsibilities of commissioned officers. The term "enlistment" refers solely to a military commitment (whether officer or enlisted) whereas the terms "taken on strength" and "struck off strength" refer to a service member being carried on a given unit's roll. Canadian Forces In the Canadian Forces, the term non-commissioned member (NCM) is used. North Atlantic Treaty Organization For the ranks used by the North Atlantic Treaty Organizati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oak Ridge, Tennessee
Oak Ridge is a city in Anderson and Roane counties in the eastern part of the U.S. state of Tennessee, about west of downtown Knoxville. Oak Ridge's population was 31,402 at the 2020 census. It is part of the Knoxville Metropolitan Area. Oak Ridge's nicknames include ''the Atomic City'', ''the Secret City'', ''the Ridge'', ''the Town the Atomic Bomb Built'', and ''the City Behind the Fence''. In 1942, the United States federal government purchased nearly of farmland in the Clinch River Valley for the development of a planned city supporting 75,000 residents. It was constructed with assistance from architectural and engineering firm Skidmore, Owings & Merrill, from 1942 to 1943. Oak Ridge was established in 1942 as a production site for the Manhattan Project—the massive American, British, and Canadian operation that developed the atomic bomb. Being the site of Oak Ridge National Laboratory and Y-12 National Security Complex, scientific and technological development still pla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clinton Engineer Works
The Clinton Engineer Works (CEW) was the production installation of the Manhattan Project that during World War II produced the enriched uranium used in the 1945 bombing of Hiroshima, as well as the first examples of reactor-produced plutonium. It consisted of production facilities arranged at three major sites, various utilities including a power plant, and the town of Oak Ridge. It was in East Tennessee, about west of Knoxville, and was named after the town of Clinton, to the north. The production facilities were mainly in Roane County, and the northern part of the site was in Anderson County. The Manhattan District Engineer, Kenneth Nichols, moved the Manhattan District headquarters from Manhattan to Oak Ridge in August 1943. During the war, Clinton's advanced research was managed for the government by the University of Chicago. Construction workers were housed in a community known as Happy Valley. Built by the Army Corps of Engineers in 1943, this temporary commun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Special Engineer Detachment
The Special Engineer Detachment (SED) was a US Army program that identified enlisted personnel with technical skills, such as machining, or who had some science education beyond high school. Those identified were organized into the Special Engineer Detachment, or SED. SED personnel began arriving at Los Alamos in October 1943. By August 1945, 1800 SED personnel worked at Los Alamos. These troops worked in all areas and activities of the Laboratory, including the Trinity Test, and were involved in overseas operations on Tinian Tinian ( or ; old Japanese name: 天仁安島, ''Tenian-shima'') is one of the three principal islands of the Commonwealth of the Northern Mariana Islands. Together with uninhabited neighboring Aguiguan, it forms Tinian Municipality, one of th .... References Sources * Further reading * * *{{citation, publisher=Library of Congress, work=Veterans History Project, title=Herbert M. Lehr Collection (Special Engineering Detachment 1943–1946), date=2019-11- ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing military alliances: the Allies and the Axis powers. World War II was a total war that directly involved more than 100 million personnel from more than 30 countries. The major participants in the war threw their entire economic, industrial, and scientific capabilities behind the war effort, blurring the distinction between civilian and military resources. Aircraft played a major role in the conflict, enabling the strategic bombing of population centres and deploying the only two nuclear weapons ever used in war. World War II was by far the deadliest conflict in human history; it resulted in 70 to 85 million fatalities, mostly among civilians. Tens of millions died due to genocides (including the Holocaust), starvation, ma ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemistry
Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during a Chemical reaction, reaction with other Chemical substance, substances. Chemistry also addresses the nature of chemical bonds in chemical compounds. In the scope of its subject, chemistry occupies an intermediate position between physics and biology. It is sometimes called the central science because it provides a foundation for understanding both Basic research, basic and Applied science, applied scientific disciplines at a fundamental level. For example, chemistry explains aspects of plant growth (botany), the formation of igneous rocks (geology), how atmospheric ozone is formed and how environmental pollutants are degraded (ecology), the properties ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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