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Quehanna Trail 1
Quehanna Wild Area () is a protected area within parts of Cameron County, Pennsylvania, Cameron, Clearfield County, Pennsylvania, Clearfield and Elk County, Pennsylvania, Elk counties in the U.S. state of Pennsylvania; with a total area of , it covers parts of Elk State Forest, Elk and Moshannon State Forests. Founded in the 1950s as a nuclear physics, nuclear research center, Quehanna has a legacy of radioactive waste, radioactive and toxic waste contamination, while also being the largest List of Pennsylvania state forest wild areas, state forest wild area in Pennsylvania, with herds of elk. The wild area is bisected by the Quehanna Highway and is home to second growth forest with mixed hardwood forest, hardwoods and evergreens. Quehanna has two state forest natural areas: the M.K. Goddard/Wykoff Run Natural Area, and the Marion Brooks Natural Area. The latter has the largest stand of Betula papyrifera, white birch in Pennsylvania and the eastern United States. The land that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Betula Papyrifera
A birch is a thin-leaved deciduous hardwood tree of the genus ''Betula'' (), in the family Betulaceae, which also includes alders, hazels, and hornbeams. It is closely related to the beech- oak family Fagaceae. The genus ''Betula'' contains 30 to 60 known taxa of which 11 are on the IUCN 2011 Red List of Threatened Species. They are typically short-lived pioneer species and are widespread in the Northern Hemisphere, particularly in northern areas of temperate climates and in boreal climates. Birch wood is used for a wide range of purposes. Description Birch species are generally small to medium-sized trees or shrubs, mostly of northern temperate and boreal climates. The simple leaves are alternate, singly or doubly serrate, feather-veined, petiolate and stipulate. They often appear in pairs, but these pairs are really borne on spur-like, two-leaved, lateral branchlets. The fruit is a small samara, although the wings may be obscure in some species. They differ fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Native Americans In The United States
Native Americans (also called American Indians, First Americans, or Indigenous Americans) are the Indigenous peoples of the Americas, Indigenous peoples of the United States, particularly of the Contiguous United States, lower 48 states and Alaska. They may also include any Americans whose origins lie in any of the indigenous peoples of North or South America. The United States Census Bureau publishes data about "American Indians and Alaska Natives", whom it defines as anyone "having origins in any of the original peoples of North and South America ... and who maintains tribal affiliation or community attachment". The census does not, however, enumerate "Native Americans" as such, noting that the latter term can encompass a broader set of groups, e.g. Native Hawaiians, which it tabulates separately. The European colonization of the Americas from 1492 resulted in a Population history of Indigenous peoples of the Americas, precipitous decline in the size of the Native American ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Strontium-90
Strontium-90 () is a radioactive isotope of strontium produced by nuclear fission, with a half-life of 28.79 years. It undergoes β− decay into yttrium-90, with a decay energy of 0.546 MeV. Strontium-90 has applications in medicine and industry and is an isotope of concern in fallout from nuclear weapons, nuclear weapons testing, and nuclear accidents. Radioactivity Naturally occurring strontium is nonradioactive and nontoxic at levels normally found in the environment, but 90Sr is a radiation hazard. 90Sr undergoes β− decay with a half-life of 28.79 years and a decay energy of 0.546 MeV distributed to an electron, an antineutrino, and the yttrium isotope 90Y, which in turn undergoes β− decay with a half-life of 64 hours and a decay energy of 2.28 MeV distributed to an electron, an antineutrino, and 90Zr (zirconium), which is stable. Note that 90Sr/Y is almost a pure beta particle source; the gamma photon emission from the decay of 90Y is so infrequen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radionuclide
A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess numbers of either neutrons or protons, giving it excess nuclear energy, and making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transferred to one of its electrons to release it as a conversion electron; or used to create and emit a new particle (alpha particle or beta particle) from the nucleus. During those processes, the radionuclide is said to undergo radioactive decay. These emissions are considered ionizing radiation because they are energetic enough to liberate an electron from another atom. The radioactive decay can produce a stable nuclide or will sometimes produce a new unstable radionuclide which may undergo further decay. Radioactive decay is a random process at the level of single atoms: it is impossible to predict when one particular atom will decay. However, for a collection of atoms of a single nu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hot Cell
A hot cell is a name given to a containment chamber that is shielded against nuclear radiation. The word ''hot'' refers to radioactivity. Hot cells are used in both the nuclear-energy and the nuclear-medicines industries. They are required to protect individuals from radioactive isotopes by providing a safe containment box in which they can control and manipulate the equipment required. Nuclear industry Hot cells are used to inspect spent nuclear fuel rods and to work with other items which are high-energy gamma ray emitters. For instance, the processing of medical isotopes, having been irradiated in a nuclear reactor or particle accelerator, would be carried out in a hot cell. Hot cells are of nuclear proliferation concern, as they can be used to carry out the chemical steps used to extract plutonium (whether weapons grade or not) from reactor fuel. The cutting of the used fuel, the dissolving of the fuel in hot nitric acid and the first extraction cycle of a nuclear re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jet Engine
A jet engine is a type of reaction engine, discharging a fast-moving jet (fluid), jet of heated gas (usually air) that generates thrust by jet propulsion. While this broad definition may include Rocket engine, rocket, Pump-jet, water jet, and hybrid propulsion, the term typically refers to an internal combustion airbreathing jet engine, air-breathing jet engine such as a turbojet, turbofan, ramjet, pulse jet engine, pulse jet, or scramjet. In general, jet engines are internal combustion engines. Air-breathing jet engines typically feature a Axial compressor, rotating air compressor powered by a turbine, with the leftover power providing thrust through the propelling nozzle—this process is known as the Brayton cycle, Brayton thermodynamic cycle. Jet aircraft use such engines for long-distance travel. Early jet aircraft used turbojet engines that were relatively inefficient for subsonic flight. Most modern subsonic jet aircraft use more complex High-bypass turbofan, high-bypas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Curtiss-Wright
The Curtiss-Wright Corporation is an American manufacturer and services provider headquartered in Davidson, North Carolina, with factories and operations in and outside the United States. Created in 1929 from the consolidation (business), consolidation of Curtiss Aeroplane and Motor Company, Curtiss, Wright Aeronautical, Wright, and various supplier companies, the company was immediately the country's largest aviation firm and built more than 142,000 aircraft engines for the U.S. military during World War II. It no longer makes aircraft but still makes many related components, particularly actuators, Aircraft flight control system, aircraft controls, valves, and it provides surface-treatment services. It supplies equipment to the Aerospace manufacturer, commercial, Manufacturing, industrial, defense industry, defense, and energy markets. It makes parts for nuclear power, commercial and nuclear navy, naval nuclear power systems, industrial vehicles, and petroleum industry, oil- and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Civilian Conservation Corps
The Civilian Conservation Corps (CCC) was a voluntary government unemployment, work relief program that ran from 1933 to 1942 in the United States for unemployed, unmarried men ages 18–25 and eventually expanded to ages 17–28. The CCC was a major part of President Franklin D. Roosevelt's New Deal that supplied manual labor jobs related to the conservation and development of natural resources in rural lands owned by federal, state, and local governments. The CCC was designed to supply jobs for young men and to relieve families who had difficulty finding jobs during the Great Depression in the United States. There was eventually a smaller counterpart program for unemployed women called the She-She-She Camps, which were championed by Eleanor Roosevelt. Robert Fechner was the first director of this agency, succeeded by James McEntee (labor leader), James McEntee following Fechner's death. The largest enrollment at any one time was 300,000. Through the course of its nine years ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
List Of Pennsylvania State Forests
There are 20 state forests in the Commonwealth of Pennsylvania in the United States. They are managed by the Pennsylvania Bureau of Forestry, a division of the Pennsylvania Department of Conservation and Natural Resources. A reorganization effective July 1, 2005 shifted territory among several state forests in eastern Pennsylvania, resulting in the elimination of Wyoming State Forest and the creation of Loyalsock State Forest. List of Pennsylvania state forests Former State Forests Former Names of State Forests See also * List of Pennsylvania state forest wild areas * List of Pennsylvania state forest natural areas References External linksPA Bureau of Forestry homepage {{DEFAULTSORT:Pennsylvania state forests Pennsylvania state forests, * Lists ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clearcutting
Clearcutting, clearfelling or clearcut logging is a forestry/logging practice in which most or all trees in an area are uniformly cut down. Along with Shelterwood cutting, shelterwood and Seed tree, seed tree harvests, it is used by foresters to create certain types of forest ecosystems and to promote select species that require an abundance of sunlight or grow in large, even-age stand level modelling, stands. Clearcutting is a forestry practice that mimics the stand initiation stage of forest succession after a natural disturbance such as Wildfire, stand replacing fire or Windthrow, wind-throw, and is successful for regeneration of fast growing, Douglas fir, sun tolerant tree species and wildlife species that readily regenerate in post-stand replacing sites. Logging companies and forest-worker unions in some countries support the practice for scientific, safety and economic reasons, while detractors consider it a form of deforestation that habitat destruction, destroys natural h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virgin Forest
An old-growth forest or primary forest is a forest that has developed over a long period of time without Disturbance (ecology), disturbance. Due to this, old-growth forests exhibit unique ecological features. The Food and Agriculture Organization of the United Nations defines primary forests as naturally regenerated forests of native tree species where there are no clearly visible indications of human activity and the ecological processes are not significantly disturbed. One-third (34 percent) of the world's forests are primary forests. Old-growth features include diverse tree-related structures that provide diverse wildlife habitats that increases the biodiversity of the forested ecosystem. Virgin or first-growth forests are old-growth forests that have never been logged. The concept of diverse tree structure includes multi-layered canopies and Canopy (biology), canopy gaps, greatly varying tree heights and diameters, and diverse tree species and classes and sizes of woody debr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logging
Logging is the process of cutting, processing, and moving trees to a location for transport. It may include skidder, skidding, on-site processing, and loading of trees or trunk (botany), logs onto logging truck, trucksSociety of American Foresters, 1998. Dictionary of Forestry. or flatcar#Skeleton car, skeleton cars. In forestry, the term logging is sometimes used narrowly to describe the logistics of moving wood from the stump to somewhere outside the forest, usually a sawmill or a lumber yard. In common usage, however, the term may cover a range of forestry or silviculture activities. Logging is the beginning of a supply chain that provides raw material for many products societies worldwide use for housing, construction, energy, and consumer paper products. Logging systems are a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
